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tesseract/textord/strokewidth.cpp

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///////////////////////////////////////////////////////////////////////
// File: strokewidth.cpp
// Description: Subclass of BBGrid to find uniformity of strokewidth.
// Author: Ray Smith
// Created: Mon Mar 31 16:17:01 PST 2008
//
// (C) Copyright 2008, Google Inc.
// Licensed under the Apache License, Version 2.0 (the "License");
// you may not use this file except in compliance with the License.
// You may obtain a copy of the License at
// http://www.apache.org/licenses/LICENSE-2.0
// Unless required by applicable law or agreed to in writing, software
// distributed under the License is distributed on an "AS IS" BASIS,
// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
// See the License for the specific language governing permissions and
// limitations under the License.
//
///////////////////////////////////////////////////////////////////////
#ifdef _MSC_VER
#pragma warning(disable:4244) // Conversion warnings
#endif
#ifdef HAVE_CONFIG_H
#include "config_auto.h"
#endif
#include "strokewidth.h"
#include <math.h>
#include "blobbox.h"
#include "colpartition.h"
#include "colpartitiongrid.h"
#include "imagefind.h"
#include "linlsq.h"
#include "statistc.h"
#include "tabfind.h"
#include "textlineprojection.h"
#include "tordmain.h" // For SetBlobStrokeWidth.
namespace tesseract {
INT_VAR(textord_tabfind_show_strokewidths, 0, "Show stroke widths");
BOOL_VAR(textord_tabfind_only_strokewidths, false, "Only run stroke widths");
/** Allowed proportional change in stroke width to be the same font. */
const double kStrokeWidthFractionTolerance = 0.125;
/**
* Allowed constant change in stroke width to be the same font.
* Really 1.5 pixels.
*/
const double kStrokeWidthTolerance = 1.5;
// Same but for CJK we are a bit more generous.
const double kStrokeWidthFractionCJK = 0.25;
const double kStrokeWidthCJK = 2.0;
// Radius in grid cells of search for broken CJK. Doesn't need to be very
// large as the grid size should be about the size of a character anyway.
const int kCJKRadius = 2;
// Max distance fraction of size to join close but broken CJK characters.
const double kCJKBrokenDistanceFraction = 0.25;
// Max number of components in a broken CJK character.
const int kCJKMaxComponents = 8;
// Max aspect ratio of CJK broken characters when put back together.
const double kCJKAspectRatio = 1.25;
// Max increase in aspect ratio of CJK broken characters when merged.
const double kCJKAspectRatioIncrease = 1.0625;
// Max multiple of the grid size that will be used in computing median CJKsize.
const int kMaxCJKSizeRatio = 5;
// Min fraction of blobs broken CJK to iterate and run it again.
const double kBrokenCJKIterationFraction = 0.125;
// Multiple of gridsize as x-padding for a search box for diacritic base
// characters.
const double kDiacriticXPadRatio = 7.0;
// Multiple of gridsize as y-padding for a search box for diacritic base
// characters.
const double kDiacriticYPadRatio = 1.75;
// Min multiple of diacritic height that a neighbour must be to be a
// convincing base character.
const double kMinDiacriticSizeRatio = 1.0625;
// Max multiple of a textline's median height as a threshold for the sum of
// a diacritic's farthest x and y distances (gap + size).
const double kMaxDiacriticDistanceRatio = 1.25;
// Max x-gap between a diacritic and its base char as a fraction of the height
// of the base char (allowing other blobs to fill the gap.)
const double kMaxDiacriticGapToBaseCharHeight = 1.0;
// Radius of a search for diacritics in grid units.
const int kSearchRadius = 2;
// Ratio between longest side of a line and longest side of a character.
// (neighbor_min > blob_min * kLineTrapShortest &&
// neighbor_max < blob_max / kLineTrapLongest)
// => neighbor is a grapheme and blob is a line.
const int kLineTrapLongest = 4;
// Ratio between shortest side of a line and shortest side of a character.
const int kLineTrapShortest = 2;
// Max aspect ratio of the total box before CountNeighbourGaps
// decides immediately based on the aspect ratio.
const int kMostlyOneDirRatio = 3;
// Aspect ratio for a blob to be considered as line residue.
const double kLineResidueAspectRatio = 8.0;
// Padding ratio for line residue search box.
const int kLineResiduePadRatio = 3;
// Min multiple of neighbour size for a line residue to be genuine.
const double kLineResidueSizeRatio = 1.75;
// Aspect ratio filter for OSD.
const float kSizeRatioToReject = 2.0;
// Max number of normal blobs a large blob may overlap before it is rejected
// and determined to be image
const int kMaxLargeOverlaps = 3;
// Expansion factor for search box for good neighbours.
const double kNeighbourSearchFactor = 2.5;
// Factor of increase of overlap when adding diacritics to make an image noisy.
const double kNoiseOverlapGrowthFactor = 4.0;
// Fraction of the image size to add overlap when adding diacritics for an
// image to qualify as noisy.
const double kNoiseOverlapAreaFactor = 1.0 / 512;
// Ratio of perimeter^2/area for a blob to be considered noise vs i dot.
const double kShapePerimeterRatio = 3.0;
StrokeWidth::StrokeWidth(int gridsize,
const ICOORD& bleft, const ICOORD& tright)
: BlobGrid(gridsize, bleft, tright), nontext_map_(NULL), projection_(NULL),
denorm_(NULL), grid_box_(bleft, tright), rerotation_(1.0f, 0.0f) {
leaders_win_ = NULL;
widths_win_ = NULL;
initial_widths_win_ = NULL;
chains_win_ = NULL;
diacritics_win_ = NULL;
textlines_win_ = NULL;
smoothed_win_ = NULL;
}
StrokeWidth::~StrokeWidth() {
if (widths_win_ != NULL) {
#ifndef GRAPHICS_DISABLED
delete widths_win_->AwaitEvent(SVET_DESTROY);
#endif // GRAPHICS_DISABLED
if (textord_tabfind_only_strokewidths)
exit(0);
delete widths_win_;
}
delete leaders_win_;
delete initial_widths_win_;
delete chains_win_;
delete textlines_win_;
delete smoothed_win_;
delete diacritics_win_;
}
// Sets the neighbours member of the medium-sized blobs in the block.
// Searches on 4 sides of each blob for similar-sized, similar-strokewidth
// blobs and sets pointers to the good neighbours.
void StrokeWidth::SetNeighboursOnMediumBlobs(TO_BLOCK* block) {
// Run a preliminary strokewidth neighbour detection on the medium blobs.
InsertBlobList(&block->blobs);
BLOBNBOX_IT blob_it(&block->blobs);
for (blob_it.mark_cycle_pt(); !blob_it.cycled_list(); blob_it.forward()) {
SetNeighbours(false, false, blob_it.data());
}
Clear();
}
// Sets the neighbour/textline writing direction members of the medium
// and large blobs with optional repair of broken CJK characters first.
// Repair of broken CJK is needed here because broken CJK characters
// can fool the textline direction detection algorithm.
void StrokeWidth::FindTextlineDirectionAndFixBrokenCJK(PageSegMode pageseg_mode,
bool cjk_merge,
TO_BLOCK* input_block) {
// Setup the grid with the remaining (non-noise) blobs.
InsertBlobs(input_block);
// Repair broken CJK characters if needed.
while (cjk_merge && FixBrokenCJK(input_block));
// Grade blobs by inspection of neighbours.
FindTextlineFlowDirection(pageseg_mode, false);
// Clear the grid ready for rotation or leader finding.
Clear();
}
// Helper to collect and count horizontal and vertical blobs from a list.
static void CollectHorizVertBlobs(BLOBNBOX_LIST* input_blobs,
int* num_vertical_blobs,
int* num_horizontal_blobs,
BLOBNBOX_CLIST* vertical_blobs,
BLOBNBOX_CLIST* horizontal_blobs,
BLOBNBOX_CLIST* nondescript_blobs) {
BLOBNBOX_C_IT v_it(vertical_blobs);
BLOBNBOX_C_IT h_it(horizontal_blobs);
BLOBNBOX_C_IT n_it(nondescript_blobs);
BLOBNBOX_IT blob_it(input_blobs);
for (blob_it.mark_cycle_pt(); !blob_it.cycled_list(); blob_it.forward()) {
BLOBNBOX* blob = blob_it.data();
const TBOX& box = blob->bounding_box();
float y_x = static_cast<float>(box.height()) / box.width();
float x_y = 1.0f / y_x;
// Select a >= 1.0 ratio
float ratio = x_y > y_x ? x_y : y_x;
// If the aspect ratio is small and we want them for osd, save the blob.
bool ok_blob = ratio <= kSizeRatioToReject;
if (blob->UniquelyVertical()) {
++*num_vertical_blobs;
if (ok_blob) v_it.add_after_then_move(blob);
} else if (blob->UniquelyHorizontal()) {
++*num_horizontal_blobs;
if (ok_blob) h_it.add_after_then_move(blob);
} else if (ok_blob) {
n_it.add_after_then_move(blob);
}
}
}
// Types all the blobs as vertical or horizontal text or unknown and
// returns true if the majority are vertical.
// If the blobs are rotated, it is necessary to call CorrectForRotation
// after rotating everything, otherwise the work done here will be enough.
// If osd_blobs is not null, a list of blobs from the dominant textline
// direction are returned for use in orientation and script detection.
bool StrokeWidth::TestVerticalTextDirection(double find_vertical_text_ratio,
TO_BLOCK* block,
BLOBNBOX_CLIST* osd_blobs) {
int vertical_boxes = 0;
int horizontal_boxes = 0;
// Count vertical normal and large blobs.
BLOBNBOX_CLIST vertical_blobs;
BLOBNBOX_CLIST horizontal_blobs;
BLOBNBOX_CLIST nondescript_blobs;
CollectHorizVertBlobs(&block->blobs, &vertical_boxes, &horizontal_boxes,
&vertical_blobs, &horizontal_blobs, &nondescript_blobs);
CollectHorizVertBlobs(&block->large_blobs, &vertical_boxes, &horizontal_boxes,
&vertical_blobs, &horizontal_blobs, &nondescript_blobs);
if (textord_debug_tabfind)
tprintf("TextDir hbox=%d vs vbox=%d, %dH, %dV, %dN osd blobs\n",
horizontal_boxes, vertical_boxes,
horizontal_blobs.length(), vertical_blobs.length(),
nondescript_blobs.length());
if (osd_blobs != NULL && vertical_boxes == 0 && horizontal_boxes == 0) {
// Only nondescript blobs available, so return those.
BLOBNBOX_C_IT osd_it(osd_blobs);
osd_it.add_list_after(&nondescript_blobs);
return false;
}
int min_vert_boxes = static_cast<int>((vertical_boxes + horizontal_boxes) *
find_vertical_text_ratio);
if (vertical_boxes >= min_vert_boxes) {
if (osd_blobs != NULL) {
BLOBNBOX_C_IT osd_it(osd_blobs);
osd_it.add_list_after(&vertical_blobs);
}
return true;
} else {
if (osd_blobs != NULL) {
BLOBNBOX_C_IT osd_it(osd_blobs);
osd_it.add_list_after(&horizontal_blobs);
}
return false;
}
}
// Corrects the data structures for the given rotation.
void StrokeWidth::CorrectForRotation(const FCOORD& rotation,
ColPartitionGrid* part_grid) {
Init(part_grid->gridsize(), part_grid->bleft(), part_grid->tright());
grid_box_ = TBOX(bleft(), tright());
rerotation_.set_x(rotation.x());
rerotation_.set_y(-rotation.y());
}
// Finds leader partitions and inserts them into the given part_grid.
void StrokeWidth::FindLeaderPartitions(TO_BLOCK* block,
ColPartitionGrid* part_grid) {
Clear();
// Find and isolate leaders in the noise list.
ColPartition_LIST leader_parts;
FindLeadersAndMarkNoise(block, &leader_parts);
// Setup the strokewidth grid with the block's remaining (non-noise) blobs.
InsertBlobList(&block->blobs);
// Mark blobs that have leader neighbours.
for (ColPartition_IT it(&leader_parts); !it.empty(); it.forward()) {
ColPartition* part = it.extract();
part->ClaimBoxes();
MarkLeaderNeighbours(part, LR_LEFT);
MarkLeaderNeighbours(part, LR_RIGHT);
part_grid->InsertBBox(true, true, part);
}
}
// Finds and marks noise those blobs that look like bits of vertical lines
// that would otherwise screw up layout analysis.
void StrokeWidth::RemoveLineResidue(ColPartition_LIST* big_part_list) {
BlobGridSearch gsearch(this);
BLOBNBOX* bbox;
// For every vertical line-like bbox in the grid, search its neighbours
// to find the tallest, and if the original box is taller by sufficient
// margin, then call it line residue and delete it.
gsearch.StartFullSearch();
while ((bbox = gsearch.NextFullSearch()) != NULL) {
TBOX box = bbox->bounding_box();
if (box.height() < box.width() * kLineResidueAspectRatio)
continue;
// Set up a rectangle search around the blob to find the size of its
// neighbours.
int padding = box.height() * kLineResiduePadRatio;
TBOX search_box = box;
search_box.pad(padding, padding);
bool debug = AlignedBlob::WithinTestRegion(2, box.left(),
box.bottom());
// Find the largest object in the search box not equal to bbox.
BlobGridSearch rsearch(this);
int max_size = 0;
BLOBNBOX* n;
rsearch.StartRectSearch(search_box);
while ((n = rsearch.NextRectSearch()) != NULL) {
if (n == bbox) continue;
TBOX nbox = n->bounding_box();
if (nbox.height() > max_size) {
max_size = nbox.height();
}
}
if (debug) {
tprintf("Max neighbour size=%d for candidate line box at:", max_size);
box.print();
}
if (max_size * kLineResidueSizeRatio < box.height()) {
#ifndef GRAPHICS_DISABLED
if (leaders_win_ != NULL) {
// We are debugging, so display deleted in pink blobs in the same
// window that we use to display leader detection.
leaders_win_->Pen(ScrollView::PINK);
leaders_win_->Rectangle(box.left(), box.bottom(),
box.right(), box.top());
}
#endif // GRAPHICS_DISABLED
ColPartition::MakeBigPartition(bbox, big_part_list);
}
}
}
// Types all the blobs as vertical text or horizontal text or unknown and
// puts them into initial ColPartitions in the supplied part_grid.
// rerotation determines how to get back to the image coordinates from the
// blob coordinates (since they may have been rotated for vertical text).
// block is the single block for the whole page or rectangle to be OCRed.
// nontext_pix (full-size), is a binary mask used to prevent merges across
// photo/text boundaries. It is not kept beyond this function.
// denorm provides a mapping back to the image from the current blob
// coordinate space.
// projection provides a measure of textline density over the image and
// provides functions to assist with diacritic detection. It should be a
// pointer to a new TextlineProjection, and will be setup here.
// part_grid is the output grid of textline partitions.
// Large blobs that cause overlap are put in separate partitions and added
// to the big_parts list.
void StrokeWidth::GradeBlobsIntoPartitions(
PageSegMode pageseg_mode, const FCOORD& rerotation, TO_BLOCK* block,
Pix* nontext_pix, const DENORM* denorm, bool cjk_script,
TextlineProjection* projection, BLOBNBOX_LIST* diacritic_blobs,
ColPartitionGrid* part_grid, ColPartition_LIST* big_parts) {
nontext_map_ = nontext_pix;
projection_ = projection;
denorm_ = denorm;
// Clear and re Insert to take advantage of the tab stops in the blobs.
Clear();
// Setup the strokewidth grid with the remaining non-noise, non-leader blobs.
InsertBlobs(block);
// Run FixBrokenCJK() again if the page is CJK.
if (cjk_script) {
FixBrokenCJK(block);
}
FindTextlineFlowDirection(pageseg_mode, false);
projection_->ConstructProjection(block, rerotation, nontext_map_);
if (textord_tabfind_show_strokewidths) {
ScrollView* line_blobs_win = MakeWindow(0, 0, "Initial textline Blobs");
projection_->PlotGradedBlobs(&block->blobs, line_blobs_win);
projection_->PlotGradedBlobs(&block->small_blobs, line_blobs_win);
}
projection_->MoveNonTextlineBlobs(&block->blobs, &block->noise_blobs);
projection_->MoveNonTextlineBlobs(&block->small_blobs, &block->noise_blobs);
// Clear and re Insert to take advantage of the removed diacritics.
Clear();
InsertBlobs(block);
FCOORD skew;
FindTextlineFlowDirection(pageseg_mode, true);
PartitionFindResult r =
FindInitialPartitions(pageseg_mode, rerotation, true, block,
diacritic_blobs, part_grid, big_parts, &skew);
if (r == PFR_NOISE) {
tprintf("Detected %d diacritics\n", diacritic_blobs->length());
// Noise was found, and removed.
Clear();
InsertBlobs(block);
FindTextlineFlowDirection(pageseg_mode, true);
r = FindInitialPartitions(pageseg_mode, rerotation, false, block,
diacritic_blobs, part_grid, big_parts, &skew);
}
nontext_map_ = NULL;
projection_ = NULL;
denorm_ = NULL;
}
static void PrintBoxWidths(BLOBNBOX* neighbour) {
TBOX nbox = neighbour->bounding_box();
tprintf("Box (%d,%d)->(%d,%d): h-width=%.1f, v-width=%.1f p-width=%1.f\n",
nbox.left(), nbox.bottom(), nbox.right(), nbox.top(),
neighbour->horz_stroke_width(), neighbour->vert_stroke_width(),
2.0 * neighbour->cblob()->area()/neighbour->cblob()->perimeter());
}
/** Handles a click event in a display window. */
void StrokeWidth::HandleClick(int x, int y) {
BBGrid<BLOBNBOX, BLOBNBOX_CLIST, BLOBNBOX_C_IT>::HandleClick(x, y);
// Run a radial search for blobs that overlap.
BlobGridSearch radsearch(this);
radsearch.StartRadSearch(x, y, 1);
BLOBNBOX* neighbour;
FCOORD click(static_cast<float>(x), static_cast<float>(y));
while ((neighbour = radsearch.NextRadSearch()) != NULL) {
TBOX nbox = neighbour->bounding_box();
if (nbox.contains(click) && neighbour->cblob() != NULL) {
PrintBoxWidths(neighbour);
if (neighbour->neighbour(BND_LEFT) != NULL)
PrintBoxWidths(neighbour->neighbour(BND_LEFT));
if (neighbour->neighbour(BND_RIGHT) != NULL)
PrintBoxWidths(neighbour->neighbour(BND_RIGHT));
if (neighbour->neighbour(BND_ABOVE) != NULL)
PrintBoxWidths(neighbour->neighbour(BND_ABOVE));
if (neighbour->neighbour(BND_BELOW) != NULL)
PrintBoxWidths(neighbour->neighbour(BND_BELOW));
int gaps[BND_COUNT];
neighbour->NeighbourGaps(gaps);
tprintf("Left gap=%d, right=%d, above=%d, below=%d, horz=%d, vert=%d\n"
"Good= %d %d %d %d\n",
gaps[BND_LEFT], gaps[BND_RIGHT],
gaps[BND_ABOVE], gaps[BND_BELOW],
neighbour->horz_possible(),
neighbour->vert_possible(),
neighbour->good_stroke_neighbour(BND_LEFT),
neighbour->good_stroke_neighbour(BND_RIGHT),
neighbour->good_stroke_neighbour(BND_ABOVE),
neighbour->good_stroke_neighbour(BND_BELOW));
break;
}
}
}
// Detects and marks leader dots/dashes.
// Leaders are horizontal chains of small or noise blobs that look
// monospace according to ColPartition::MarkAsLeaderIfMonospaced().
// Detected leaders become the only occupants of the block->small_blobs list.
// Non-leader small blobs get moved to the blobs list.
// Non-leader noise blobs remain singletons in the noise list.
// All small and noise blobs in high density regions are marked BTFT_NONTEXT.
// block is the single block for the whole page or rectangle to be OCRed.
// leader_parts is the output.
void StrokeWidth::FindLeadersAndMarkNoise(TO_BLOCK* block,
ColPartition_LIST* leader_parts) {
InsertBlobList(&block->small_blobs);
InsertBlobList(&block->noise_blobs);
BlobGridSearch gsearch(this);
BLOBNBOX* bbox;
// For every bbox in the grid, set its neighbours.
gsearch.StartFullSearch();
while ((bbox = gsearch.NextFullSearch()) != NULL) {
SetNeighbours(true, false, bbox);
}
ColPartition_IT part_it(leader_parts);
gsearch.StartFullSearch();
while ((bbox = gsearch.NextFullSearch()) != NULL) {
if (bbox->flow() == BTFT_NONE) {
if (bbox->neighbour(BND_RIGHT) == NULL &&
bbox->neighbour(BND_LEFT) == NULL)
continue;
// Put all the linked blobs into a ColPartition.
ColPartition* part = new ColPartition(BRT_UNKNOWN, ICOORD(0, 1));
BLOBNBOX* blob;
for (blob = bbox; blob != NULL && blob->flow() == BTFT_NONE;
blob = blob->neighbour(BND_RIGHT))
part->AddBox(blob);
for (blob = bbox->neighbour(BND_LEFT); blob != NULL &&
blob->flow() == BTFT_NONE;
blob = blob->neighbour(BND_LEFT))
part->AddBox(blob);
if (part->MarkAsLeaderIfMonospaced())
part_it.add_after_then_move(part);
else
delete part;
}
}
if (textord_tabfind_show_strokewidths) {
leaders_win_ = DisplayGoodBlobs("LeaderNeighbours", 0, 0);
}
// Move any non-leaders from the small to the blobs list, as they are
// most likely dashes or broken characters.
BLOBNBOX_IT blob_it(&block->blobs);
BLOBNBOX_IT small_it(&block->small_blobs);
for (small_it.mark_cycle_pt(); !small_it.cycled_list(); small_it.forward()) {
BLOBNBOX* blob = small_it.data();
if (blob->flow() != BTFT_LEADER) {
if (blob->flow() == BTFT_NEIGHBOURS)
blob->set_flow(BTFT_NONE);
blob->ClearNeighbours();
blob_it.add_to_end(small_it.extract());
}
}
// Move leaders from the noise list to the small list, leaving the small
// list exclusively leaders, so they don't get processed further,
// and the remaining small blobs all in the noise list.
BLOBNBOX_IT noise_it(&block->noise_blobs);
for (noise_it.mark_cycle_pt(); !noise_it.cycled_list(); noise_it.forward()) {
BLOBNBOX* blob = noise_it.data();
if (blob->flow() == BTFT_LEADER || blob->joined_to_prev()) {
small_it.add_to_end(noise_it.extract());
} else if (blob->flow() == BTFT_NEIGHBOURS) {
blob->set_flow(BTFT_NONE);
blob->ClearNeighbours();
}
}
// Clear the grid as we don't want the small stuff hanging around in it.
Clear();
}
/** Inserts the block blobs (normal and large) into this grid.
* Blobs remain owned by the block. */
void StrokeWidth::InsertBlobs(TO_BLOCK* block) {
InsertBlobList(&block->blobs);
InsertBlobList(&block->large_blobs);
}
// Checks the left or right side of the given leader partition and sets the
// (opposite) leader_on_right or leader_on_left flags for blobs
// that are next to the given side of the given leader partition.
void StrokeWidth::MarkLeaderNeighbours(const ColPartition* part,
LeftOrRight side) {
const TBOX& part_box = part->bounding_box();
BlobGridSearch blobsearch(this);
// Search to the side of the leader for the nearest neighbour.
BLOBNBOX* best_blob = NULL;
int best_gap = 0;
blobsearch.StartSideSearch(side == LR_LEFT ? part_box.left()
: part_box.right(),
part_box.bottom(), part_box.top());
BLOBNBOX* blob;
while ((blob = blobsearch.NextSideSearch(side == LR_LEFT)) != NULL) {
const TBOX& blob_box = blob->bounding_box();
if (!blob_box.y_overlap(part_box))
continue;
int x_gap = blob_box.x_gap(part_box);
if (x_gap > 2 * gridsize()) {
break;
} else if (best_blob == NULL || x_gap < best_gap) {
best_blob = blob;
best_gap = x_gap;
}
}
if (best_blob != NULL) {
if (side == LR_LEFT)
best_blob->set_leader_on_right(true);
else
best_blob->set_leader_on_left(true);
#ifndef GRAPHICS_DISABLED
if (leaders_win_ != NULL) {
leaders_win_->Pen(side == LR_LEFT ? ScrollView::RED : ScrollView::GREEN);
const TBOX& blob_box = best_blob->bounding_box();
leaders_win_->Rectangle(blob_box.left(), blob_box.bottom(),
blob_box.right(), blob_box.top());
}
#endif // GRAPHICS_DISABLED
}
}
// Helper to compute the UQ of the square-ish CJK charcters.
static int UpperQuartileCJKSize(int gridsize, BLOBNBOX_LIST* blobs) {
STATS sizes(0, gridsize * kMaxCJKSizeRatio);
BLOBNBOX_IT it(blobs);
for (it.mark_cycle_pt(); !it.cycled_list(); it.forward()) {
BLOBNBOX* blob = it.data();
int width = blob->bounding_box().width();
int height = blob->bounding_box().height();
if (width <= height * kCJKAspectRatio && height < width * kCJKAspectRatio)
sizes.add(height, 1);
}
return static_cast<int>(sizes.ile(0.75f) + 0.5);
}
// Fix broken CJK characters, using the fake joined blobs mechanism.
// Blobs are really merged, ie the master takes all the outlines and the
// others are deleted.
// Returns true if sufficient blobs are merged that it may be worth running
// again, due to a better estimate of character size.
bool StrokeWidth::FixBrokenCJK(TO_BLOCK* block) {
BLOBNBOX_LIST* blobs = &block->blobs;
int median_height = UpperQuartileCJKSize(gridsize(), blobs);
int max_dist = static_cast<int>(median_height * kCJKBrokenDistanceFraction);
int max_size = static_cast<int>(median_height * kCJKAspectRatio);
int num_fixed = 0;
BLOBNBOX_IT blob_it(blobs);
for (blob_it.mark_cycle_pt(); !blob_it.cycled_list(); blob_it.forward()) {
BLOBNBOX* blob = blob_it.data();
if (blob->cblob() == NULL || blob->cblob()->out_list()->empty())
continue;
TBOX bbox = blob->bounding_box();
bool debug = AlignedBlob::WithinTestRegion(3, bbox.left(),
bbox.bottom());
if (debug) {
tprintf("Checking for Broken CJK (max size=%d):", max_size);
bbox.print();
}
// Generate a list of blobs that overlap or are near enough to merge.
BLOBNBOX_CLIST overlapped_blobs;
AccumulateOverlaps(blob, debug, max_size, max_dist,
&bbox, &overlapped_blobs);
if (!overlapped_blobs.empty()) {
// There are overlapping blobs, so qualify them as being satisfactory
// before removing them from the grid and replacing them with the union.
// The final box must be roughly square.
if (bbox.width() > bbox.height() * kCJKAspectRatio ||
bbox.height() > bbox.width() * kCJKAspectRatio) {
if (debug) {
tprintf("Bad final aspectratio:");
bbox.print();
}
continue;
}
// There can't be too many blobs to merge.
if (overlapped_blobs.length() >= kCJKMaxComponents) {
if (debug)
tprintf("Too many neighbours: %d\n", overlapped_blobs.length());
continue;
}
// The strokewidths must match amongst the join candidates.
BLOBNBOX_C_IT n_it(&overlapped_blobs);
for (n_it.mark_cycle_pt(); !n_it.cycled_list(); n_it.forward()) {
BLOBNBOX* neighbour = NULL;
neighbour = n_it.data();
if (!blob->MatchingStrokeWidth(*neighbour, kStrokeWidthFractionCJK,
kStrokeWidthCJK))
break;
}
if (!n_it.cycled_list()) {
if (debug) {
tprintf("Bad stroke widths:");
PrintBoxWidths(blob);
}
continue; // Not good enough.
}
// Merge all the candidates into blob.
// We must remove blob from the grid and reinsert it after merging
// to maintain the integrity of the grid.
RemoveBBox(blob);
// Everything else will be calculated later.
for (n_it.mark_cycle_pt(); !n_it.cycled_list(); n_it.forward()) {
BLOBNBOX* neighbour = n_it.data();
RemoveBBox(neighbour);
// Mark empty blob for deletion.
neighbour->set_region_type(BRT_NOISE);
blob->really_merge(neighbour);
if (rerotation_.x() != 1.0f || rerotation_.y() != 0.0f) {
blob->rotate_box(rerotation_);
}
}
InsertBBox(true, true, blob);
++num_fixed;
if (debug) {
tprintf("Done! Final box:");
bbox.print();
}
}
}
// Count remaining blobs.
int num_remaining = 0;
for (blob_it.mark_cycle_pt(); !blob_it.cycled_list(); blob_it.forward()) {
BLOBNBOX* blob = blob_it.data();
if (blob->cblob() != NULL && !blob->cblob()->out_list()->empty()) {
++num_remaining;
}
}
// Permanently delete all the marked blobs after first removing all
// references in the neighbour members.
block->DeleteUnownedNoise();
return num_fixed > num_remaining * kBrokenCJKIterationFraction;
}
// Helper function to determine whether it is reasonable to merge the
// bbox and the nbox for repairing broken CJK.
// The distance apart must not exceed max_dist, the combined size must
// not exceed max_size, and the aspect ratio must either improve or at
// least not get worse by much.
static bool AcceptableCJKMerge(const TBOX& bbox, const TBOX& nbox,
bool debug, int max_size, int max_dist,
int* x_gap, int* y_gap) {
*x_gap = bbox.x_gap(nbox);
*y_gap = bbox.y_gap(nbox);
TBOX merged(nbox);
merged += bbox;
if (debug) {
tprintf("gaps = %d, %d, merged_box:", *x_gap, *y_gap);
merged.print();
}
if (*x_gap <= max_dist && *y_gap <= max_dist &&
merged.width() <= max_size && merged.height() <= max_size) {
// Close enough to call overlapping. Check aspect ratios.
double old_ratio = static_cast<double>(bbox.width()) / bbox.height();
if (old_ratio < 1.0) old_ratio = 1.0 / old_ratio;
double new_ratio = static_cast<double>(merged.width()) / merged.height();
if (new_ratio < 1.0) new_ratio = 1.0 / new_ratio;
if (new_ratio <= old_ratio * kCJKAspectRatioIncrease)
return true;
}
return false;
}
// Collect blobs that overlap or are within max_dist of the input bbox.
// Return them in the list of blobs and expand the bbox to be the union
// of all the boxes. not_this is excluded from the search, as are blobs
// that cause the merged box to exceed max_size in either dimension.
void StrokeWidth::AccumulateOverlaps(const BLOBNBOX* not_this, bool debug,
int max_size, int max_dist,
TBOX* bbox, BLOBNBOX_CLIST* blobs) {
// While searching, nearests holds the nearest failed blob in each
// direction. When we have a nearest in each of the 4 directions, then
// the search is over, and at this point the final bbox must not overlap
// any of the nearests.
BLOBNBOX* nearests[BND_COUNT];
for (int i = 0; i < BND_COUNT; ++i) {
nearests[i] = NULL;
}
int x = (bbox->left() + bbox->right()) / 2;
int y = (bbox->bottom() + bbox->top()) / 2;
// Run a radial search for blobs that overlap or are sufficiently close.
BlobGridSearch radsearch(this);
radsearch.StartRadSearch(x, y, kCJKRadius);
BLOBNBOX* neighbour;
while ((neighbour = radsearch.NextRadSearch()) != NULL) {
if (neighbour == not_this) continue;
TBOX nbox = neighbour->bounding_box();
int x_gap, y_gap;
if (AcceptableCJKMerge(*bbox, nbox, debug, max_size, max_dist,
&x_gap, &y_gap)) {
// Close enough to call overlapping. Merge boxes.
*bbox += nbox;
blobs->add_sorted(SortByBoxLeft<BLOBNBOX>, true, neighbour);
if (debug) {
tprintf("Added:");
nbox.print();
}
// Since we merged, search the nearests, as some might now me mergeable.
for (int dir = 0; dir < BND_COUNT; ++dir) {
if (nearests[dir] == NULL) continue;
nbox = nearests[dir]->bounding_box();
if (AcceptableCJKMerge(*bbox, nbox, debug, max_size,
max_dist, &x_gap, &y_gap)) {
// Close enough to call overlapping. Merge boxes.
*bbox += nbox;
blobs->add_sorted(SortByBoxLeft<BLOBNBOX>, true, nearests[dir]);
if (debug) {
tprintf("Added:");
nbox.print();
}
nearests[dir] = NULL;
dir = -1; // Restart the search.
}
}
} else if (x_gap < 0 && x_gap <= y_gap) {
// A vertical neighbour. Record the nearest.
BlobNeighbourDir dir = nbox.top() > bbox->top() ? BND_ABOVE : BND_BELOW;
if (nearests[dir] == NULL ||
y_gap < bbox->y_gap(nearests[dir]->bounding_box())) {
nearests[dir] = neighbour;
}
} else if (y_gap < 0 && y_gap <= x_gap) {
// A horizontal neighbour. Record the nearest.
BlobNeighbourDir dir = nbox.left() > bbox->left() ? BND_RIGHT : BND_LEFT;
if (nearests[dir] == NULL ||
x_gap < bbox->x_gap(nearests[dir]->bounding_box())) {
nearests[dir] = neighbour;
}
}
// If all nearests are non-null, then we have finished.
if (nearests[BND_LEFT] && nearests[BND_RIGHT] &&
nearests[BND_ABOVE] && nearests[BND_BELOW])
break;
}
// Final overlap with a nearest is not allowed.
for (int dir = 0; dir < BND_COUNT; ++dir) {
if (nearests[dir] == NULL) continue;
const TBOX& nbox = nearests[dir]->bounding_box();
if (debug) {
tprintf("Testing for overlap with:");
nbox.print();
}
if (bbox->overlap(nbox)) {
blobs->shallow_clear();
if (debug)
tprintf("Final box overlaps nearest\n");
return;
}
}
}
// For each blob in this grid, Finds the textline direction to be horizontal
// or vertical according to distance to neighbours and 1st and 2nd order
// neighbours. Non-text tends to end up without a definite direction.
// Result is setting of the neighbours and vert_possible/horz_possible
// flags in the BLOBNBOXes currently in this grid.
// This function is called more than once if page orientation is uncertain,
// so display_if_debugging is true on the final call to display the results.
void StrokeWidth::FindTextlineFlowDirection(PageSegMode pageseg_mode,
bool display_if_debugging) {
BlobGridSearch gsearch(this);
BLOBNBOX* bbox;
// For every bbox in the grid, set its neighbours.
gsearch.StartFullSearch();
while ((bbox = gsearch.NextFullSearch()) != NULL) {
SetNeighbours(false, display_if_debugging, bbox);
}
// Where vertical or horizontal wins by a big margin, clarify it.
gsearch.StartFullSearch();
while ((bbox = gsearch.NextFullSearch()) != NULL) {
SimplifyObviousNeighbours(bbox);
}
// Now try to make the blobs only vertical or horizontal using neighbours.
gsearch.StartFullSearch();
while ((bbox = gsearch.NextFullSearch()) != NULL) {
if (FindingVerticalOnly(pageseg_mode)) {
bbox->set_vert_possible(true);
bbox->set_horz_possible(false);
} else if (FindingHorizontalOnly(pageseg_mode)) {
bbox->set_vert_possible(false);
bbox->set_horz_possible(true);
} else {
SetNeighbourFlows(bbox);
}
}
if ((textord_tabfind_show_strokewidths && display_if_debugging) ||
textord_tabfind_show_strokewidths > 1) {
initial_widths_win_ = DisplayGoodBlobs("InitialStrokewidths", 400, 0);
}
// Improve flow direction with neighbours.
gsearch.StartFullSearch();
while ((bbox = gsearch.NextFullSearch()) != NULL) {
SmoothNeighbourTypes(pageseg_mode, false, bbox);
}
// Now allow reset of firm values to fix renegades.
gsearch.StartFullSearch();
while ((bbox = gsearch.NextFullSearch()) != NULL) {
SmoothNeighbourTypes(pageseg_mode, true, bbox);
}
// Repeat.
gsearch.StartFullSearch();
while ((bbox = gsearch.NextFullSearch()) != NULL) {
SmoothNeighbourTypes(pageseg_mode, true, bbox);
}
if ((textord_tabfind_show_strokewidths && display_if_debugging) ||
textord_tabfind_show_strokewidths > 1) {
widths_win_ = DisplayGoodBlobs("ImprovedStrokewidths", 800, 0);
}
}
// Sets the neighbours and good_stroke_neighbours members of the blob by
// searching close on all 4 sides.
// When finding leader dots/dashes, there is a slightly different rule for
// what makes a good neighbour.
void StrokeWidth::SetNeighbours(bool leaders, bool activate_line_trap,
BLOBNBOX* blob) {
int line_trap_count = 0;
for (int dir = 0; dir < BND_COUNT; ++dir) {
BlobNeighbourDir bnd = static_cast<BlobNeighbourDir>(dir);
line_trap_count += FindGoodNeighbour(bnd, leaders, blob);
}
if (line_trap_count > 0 && activate_line_trap) {
// It looks like a line so isolate it by clearing its neighbours.
blob->ClearNeighbours();
const TBOX& box = blob->bounding_box();
blob->set_region_type(box.width() > box.height() ? BRT_HLINE : BRT_VLINE);
}
}
// Sets the good_stroke_neighbours member of the blob if it has a
// GoodNeighbour on the given side.
// Also sets the neighbour in the blob, whether or not a good one is found.
// Returns the number of blobs in the nearby search area that would lead us to
// believe that this blob is a line separator.
// Leaders get extra special lenient treatment.
int StrokeWidth::FindGoodNeighbour(BlobNeighbourDir dir, bool leaders,
BLOBNBOX* blob) {
// Search for neighbours that overlap vertically.
TBOX blob_box = blob->bounding_box();
bool debug = AlignedBlob::WithinTestRegion(2, blob_box.left(),
blob_box.bottom());
if (debug) {
tprintf("FGN in dir %d for blob:", dir);
blob_box.print();
}
int top = blob_box.top();
int bottom = blob_box.bottom();
int left = blob_box.left();
int right = blob_box.right();
int width = right - left;
int height = top - bottom;
// A trap to detect lines tests for the min dimension of neighbours
// being larger than a multiple of the min dimension of the line
// and the larger dimension being smaller than a fraction of the max
// dimension of the line.
int line_trap_max = MAX(width, height) / kLineTrapLongest;
int line_trap_min = MIN(width, height) * kLineTrapShortest;
int line_trap_count = 0;
int min_good_overlap = (dir == BND_LEFT || dir == BND_RIGHT)
? height / 2 : width / 2;
int min_decent_overlap = (dir == BND_LEFT || dir == BND_RIGHT)
? height / 3 : width / 3;
if (leaders)
min_good_overlap = min_decent_overlap = 1;
int search_pad = static_cast<int>(
sqrt(static_cast<double>(width * height)) * kNeighbourSearchFactor);
if (gridsize() > search_pad)
search_pad = gridsize();
TBOX search_box = blob_box;
// Pad the search in the appropriate direction.
switch (dir) {
case BND_LEFT:
search_box.set_left(search_box.left() - search_pad);
break;
case BND_RIGHT:
search_box.set_right(search_box.right() + search_pad);
break;
case BND_BELOW:
search_box.set_bottom(search_box.bottom() - search_pad);
break;
case BND_ABOVE:
search_box.set_top(search_box.top() + search_pad);
break;
case BND_COUNT:
return 0;
}
BlobGridSearch rectsearch(this);
rectsearch.StartRectSearch(search_box);
BLOBNBOX* best_neighbour = NULL;
double best_goodness = 0.0;
bool best_is_good = false;
BLOBNBOX* neighbour;
while ((neighbour = rectsearch.NextRectSearch()) != NULL) {
TBOX nbox = neighbour->bounding_box();
if (neighbour == blob)
continue;
int mid_x = (nbox.left() + nbox.right()) / 2;
if (mid_x < blob->left_rule() || mid_x > blob->right_rule())
continue; // In a different column.
if (debug) {
tprintf("Neighbour at:");
nbox.print();
}
// Last-minute line detector. There is a small upper limit to the line
// width accepted by the morphological line detector.
int n_width = nbox.width();
int n_height = nbox.height();
if (MIN(n_width, n_height) > line_trap_min &&
MAX(n_width, n_height) < line_trap_max)
++line_trap_count;
// Heavily joined text, such as Arabic may have very different sizes when
// looking at the maxes, but the heights may be almost identical, so check
// for a difference in height if looking sideways or width vertically.
if (TabFind::VeryDifferentSizes(MAX(n_width, n_height),
MAX(width, height)) &&
(((dir == BND_LEFT || dir ==BND_RIGHT) &&
TabFind::DifferentSizes(n_height, height)) ||
((dir == BND_BELOW || dir ==BND_ABOVE) &&
TabFind::DifferentSizes(n_width, width)))) {
if (debug) tprintf("Bad size\n");
continue; // Could be a different font size or non-text.
}
// Amount of vertical overlap between the blobs.
int overlap;
// If the overlap is along the short side of the neighbour, and it
// is fully overlapped, then perp_overlap holds the length of the long
// side of the neighbour. A measure to include hyphens and dashes as
// legitimate neighbours.
int perp_overlap;
int gap;
if (dir == BND_LEFT || dir == BND_RIGHT) {
overlap = MIN(nbox.top(), top) - MAX(nbox.bottom(), bottom);
if (overlap == nbox.height() && nbox.width() > nbox.height())
perp_overlap = nbox.width();
else
perp_overlap = overlap;
gap = dir == BND_LEFT ? left - nbox.left() : nbox.right() - right;
if (gap <= 0) {
if (debug) tprintf("On wrong side\n");
continue; // On the wrong side.
}
gap -= n_width;
} else {
overlap = MIN(nbox.right(), right) - MAX(nbox.left(), left);
if (overlap == nbox.width() && nbox.height() > nbox.width())
perp_overlap = nbox.height();
else
perp_overlap = overlap;
gap = dir == BND_BELOW ? bottom - nbox.bottom() : nbox.top() - top;
if (gap <= 0) {
if (debug) tprintf("On wrong side\n");
continue; // On the wrong side.
}
gap -= n_height;
}
if (-gap > overlap) {
if (debug) tprintf("Overlaps wrong way\n");
continue; // Overlaps the wrong way.
}
if (perp_overlap < min_decent_overlap) {
if (debug) tprintf("Doesn't overlap enough\n");
continue; // Doesn't overlap enough.
}
bool bad_sizes = TabFind::DifferentSizes(height, n_height) &&
TabFind::DifferentSizes(width, n_width);
bool is_good = overlap >= min_good_overlap && !bad_sizes &&
blob->MatchingStrokeWidth(*neighbour,
kStrokeWidthFractionTolerance,
kStrokeWidthTolerance);
// Best is a fuzzy combination of gap, overlap and is good.
// Basically if you make one thing twice as good without making
// anything else twice as bad, then it is better.
if (gap < 1) gap = 1;
double goodness = (1.0 + is_good) * overlap / gap;
if (debug) {
tprintf("goodness = %g vs best of %g, good=%d, overlap=%d, gap=%d\n",
goodness, best_goodness, is_good, overlap, gap);
}
if (goodness > best_goodness) {
best_neighbour = neighbour;
best_goodness = goodness;
best_is_good = is_good;
}
}
blob->set_neighbour(dir, best_neighbour, best_is_good);
return line_trap_count;
}
// Helper to get a list of 1st-order neighbours.
static void ListNeighbours(const BLOBNBOX* blob,
BLOBNBOX_CLIST* neighbours) {
for (int dir = 0; dir < BND_COUNT; ++dir) {
BlobNeighbourDir bnd = static_cast<BlobNeighbourDir>(dir);
BLOBNBOX* neighbour = blob->neighbour(bnd);
if (neighbour != NULL) {
neighbours->add_sorted(SortByBoxLeft<BLOBNBOX>, true, neighbour);
}
}
}
// Helper to get a list of 1st and 2nd order neighbours.
static void List2ndNeighbours(const BLOBNBOX* blob,
BLOBNBOX_CLIST* neighbours) {
ListNeighbours(blob, neighbours);
for (int dir = 0; dir < BND_COUNT; ++dir) {
BlobNeighbourDir bnd = static_cast<BlobNeighbourDir>(dir);
BLOBNBOX* neighbour = blob->neighbour(bnd);
if (neighbour != NULL) {
ListNeighbours(neighbour, neighbours);
}
}
}
// Helper to get a list of 1st, 2nd and 3rd order neighbours.
static void List3rdNeighbours(const BLOBNBOX* blob,
BLOBNBOX_CLIST* neighbours) {
List2ndNeighbours(blob, neighbours);
for (int dir = 0; dir < BND_COUNT; ++dir) {
BlobNeighbourDir bnd = static_cast<BlobNeighbourDir>(dir);
BLOBNBOX* neighbour = blob->neighbour(bnd);
if (neighbour != NULL) {
List2ndNeighbours(neighbour, neighbours);
}
}
}
// Helper to count the evidence for verticalness or horizontalness
// in a list of neighbours.
static void CountNeighbourGaps(bool debug, BLOBNBOX_CLIST* neighbours,
int* pure_h_count, int* pure_v_count) {
if (neighbours->length() <= kMostlyOneDirRatio)
return;
BLOBNBOX_C_IT it(neighbours);
for (it.mark_cycle_pt(); !it.cycled_list(); it.forward()) {
BLOBNBOX* blob = it.data();
int h_min, h_max, v_min, v_max;
blob->MinMaxGapsClipped(&h_min, &h_max, &v_min, &v_max);
if (debug)
tprintf("Hgaps [%d,%d], vgaps [%d,%d]:", h_min, h_max, v_min, v_max);
if (h_max < v_min ||
blob->leader_on_left() || blob->leader_on_right()) {
// Horizontal gaps are clear winners. Count a pure horizontal.
++*pure_h_count;
if (debug) tprintf("Horz at:");
} else if (v_max < h_min) {
// Vertical gaps are clear winners. Clear a pure vertical.
++*pure_v_count;
if (debug) tprintf("Vert at:");
} else {
if (debug) tprintf("Neither at:");
}
if (debug)
blob->bounding_box().print();
}
}
// Makes the blob to be only horizontal or vertical where evidence
// is clear based on gaps of 2nd order neighbours, or definite individual
// blobs.
void StrokeWidth::SetNeighbourFlows(BLOBNBOX* blob) {
if (blob->DefiniteIndividualFlow())
return;
bool debug = AlignedBlob::WithinTestRegion(2, blob->bounding_box().left(),
blob->bounding_box().bottom());
if (debug) {
tprintf("SetNeighbourFlows (current flow=%d, type=%d) on:",
blob->flow(), blob->region_type());
blob->bounding_box().print();
}
BLOBNBOX_CLIST neighbours;
List3rdNeighbours(blob, &neighbours);
// The number of pure horizontal and vertical neighbours.
int pure_h_count = 0;
int pure_v_count = 0;
CountNeighbourGaps(debug, &neighbours, &pure_h_count, &pure_v_count);
if (debug) {
HandleClick(blob->bounding_box().left() + 1,
blob->bounding_box().bottom() + 1);
tprintf("SetFlows: h_count=%d, v_count=%d\n",
pure_h_count, pure_v_count);
}
if (!neighbours.empty()) {
blob->set_vert_possible(true);
blob->set_horz_possible(true);
if (pure_h_count > 2 * pure_v_count) {
// Horizontal gaps are clear winners. Clear vertical neighbours.
blob->set_vert_possible(false);
} else if (pure_v_count > 2 * pure_h_count) {
// Vertical gaps are clear winners. Clear horizontal neighbours.
blob->set_horz_possible(false);
}
} else {
// Lonely blob. Can't tell its flow direction.
blob->set_vert_possible(false);
blob->set_horz_possible(false);
}
}
// Helper to count the number of horizontal and vertical blobs in a list.
static void CountNeighbourTypes(BLOBNBOX_CLIST* neighbours,
int* pure_h_count, int* pure_v_count) {
BLOBNBOX_C_IT it(neighbours);
for (it.mark_cycle_pt(); !it.cycled_list(); it.forward()) {
BLOBNBOX* blob = it.data();
if (blob->UniquelyHorizontal())
++*pure_h_count;
if (blob->UniquelyVertical())
++*pure_v_count;
}
}
// Nullify the neighbours in the wrong directions where the direction
// is clear-cut based on a distance margin. Good for isolating vertical
// text from neighbouring horizontal text.
void StrokeWidth::SimplifyObviousNeighbours(BLOBNBOX* blob) {
// Case 1: We have text that is likely several characters, blurry and joined
// together.
if ((blob->bounding_box().width() > 3 * blob->area_stroke_width() &&
blob->bounding_box().height() > 3 * blob->area_stroke_width())) {
// The blob is complex (not stick-like).
if (blob->bounding_box().width() > 4 * blob->bounding_box().height()) {
// Horizontal conjoined text.
blob->set_neighbour(BND_ABOVE, NULL, false);
blob->set_neighbour(BND_BELOW, NULL, false);
return;
}
if (blob->bounding_box().height() > 4 * blob->bounding_box().width()) {
// Vertical conjoined text.
blob->set_neighbour(BND_LEFT, NULL, false);
blob->set_neighbour(BND_RIGHT, NULL, false);
return;
}
}
// Case 2: This blob is likely a single character.
int margin = gridsize() / 2;
int h_min, h_max, v_min, v_max;
blob->MinMaxGapsClipped(&h_min, &h_max, &v_min, &v_max);
if ((h_max + margin < v_min && h_max < margin / 2) ||
blob->leader_on_left() || blob->leader_on_right()) {
// Horizontal gaps are clear winners. Clear vertical neighbours.
blob->set_neighbour(BND_ABOVE, NULL, false);
blob->set_neighbour(BND_BELOW, NULL, false);
} else if (v_max + margin < h_min && v_max < margin / 2) {
// Vertical gaps are clear winners. Clear horizontal neighbours.
blob->set_neighbour(BND_LEFT, NULL, false);
blob->set_neighbour(BND_RIGHT, NULL, false);
}
}
// Smoothes the vertical/horizontal type of the blob based on the
// 2nd-order neighbours. If reset_all is true, then all blobs are
// changed. Otherwise, only ambiguous blobs are processed.
void StrokeWidth::SmoothNeighbourTypes(PageSegMode pageseg_mode, bool reset_all,
BLOBNBOX* blob) {
if ((blob->vert_possible() && blob->horz_possible()) || reset_all) {
// There are both horizontal and vertical so try to fix it.
BLOBNBOX_CLIST neighbours;
List2ndNeighbours(blob, &neighbours);
// The number of pure horizontal and vertical neighbours.
int pure_h_count = 0;
int pure_v_count = 0;
CountNeighbourTypes(&neighbours, &pure_h_count, &pure_v_count);
if (AlignedBlob::WithinTestRegion(2, blob->bounding_box().left(),
blob->bounding_box().bottom())) {
HandleClick(blob->bounding_box().left() + 1,
blob->bounding_box().bottom() + 1);
tprintf("pure_h=%d, pure_v=%d\n",
pure_h_count, pure_v_count);
}
if (pure_h_count > pure_v_count && !FindingVerticalOnly(pageseg_mode)) {
// Horizontal gaps are clear winners. Clear vertical neighbours.
blob->set_vert_possible(false);
blob->set_horz_possible(true);
} else if (pure_v_count > pure_h_count &&
!FindingHorizontalOnly(pageseg_mode)) {
// Vertical gaps are clear winners. Clear horizontal neighbours.
blob->set_horz_possible(false);
blob->set_vert_possible(true);
}
} else if (AlignedBlob::WithinTestRegion(2, blob->bounding_box().left(),
blob->bounding_box().bottom())) {
HandleClick(blob->bounding_box().left() + 1,
blob->bounding_box().bottom() + 1);
tprintf("Clean on pass 3!\n");
}
}
// Partition creation. Accumulates vertical and horizontal text chains,
// puts the remaining blobs in as unknowns, and then merges/splits to
// minimize overlap and smoothes the types with neighbours and the color
// image if provided. rerotation is used to rotate the coordinate space
// back to the nontext_map_ image.
// If find_problems is true, detects possible noise pollution by the amount
// of partition overlap that is created by the diacritics. If excessive, the
// noise is separated out into diacritic blobs, and PFR_NOISE is returned.
// [TODO(rays): if the partition overlap is caused by heavy skew, deskews
// the components, saves the skew_angle and returns PFR_SKEW.] If the return
// is not PFR_OK, the job is incomplete, and FindInitialPartitions must be
// called again after cleaning up the partly done work.
PartitionFindResult StrokeWidth::FindInitialPartitions(
PageSegMode pageseg_mode, const FCOORD& rerotation, bool find_problems,
TO_BLOCK* block, BLOBNBOX_LIST* diacritic_blobs,
ColPartitionGrid* part_grid, ColPartition_LIST* big_parts,
FCOORD* skew_angle) {
if (!FindingHorizontalOnly(pageseg_mode)) FindVerticalTextChains(part_grid);
if (!FindingVerticalOnly(pageseg_mode)) FindHorizontalTextChains(part_grid);
if (textord_tabfind_show_strokewidths) {
chains_win_ = MakeWindow(0, 400, "Initial text chains");
part_grid->DisplayBoxes(chains_win_);
projection_->DisplayProjection();
}
if (find_problems) {
// TODO(rays) Do something to find skew, set skew_angle and return if there
// is some.
}
part_grid->SplitOverlappingPartitions(big_parts);
EasyMerges(part_grid);
RemoveLargeUnusedBlobs(block, part_grid, big_parts);
TBOX grid_box(bleft(), tright());
while (part_grid->GridSmoothNeighbours(BTFT_CHAIN, nontext_map_, grid_box,
rerotation));
while (part_grid->GridSmoothNeighbours(BTFT_NEIGHBOURS, nontext_map_,
grid_box, rerotation));
int pre_overlap = part_grid->ComputeTotalOverlap(NULL);
TestDiacritics(part_grid, block);
MergeDiacritics(block, part_grid);
if (find_problems && diacritic_blobs != NULL &&
DetectAndRemoveNoise(pre_overlap, grid_box, block, part_grid,
diacritic_blobs)) {
return PFR_NOISE;
}
if (textord_tabfind_show_strokewidths) {
textlines_win_ = MakeWindow(400, 400, "GoodTextline blobs");
part_grid->DisplayBoxes(textlines_win_);
diacritics_win_ = DisplayDiacritics("Diacritics", 0, 0, block);
}
PartitionRemainingBlobs(pageseg_mode, part_grid);
part_grid->SplitOverlappingPartitions(big_parts);
EasyMerges(part_grid);
while (part_grid->GridSmoothNeighbours(BTFT_CHAIN, nontext_map_, grid_box,
rerotation));
while (part_grid->GridSmoothNeighbours(BTFT_NEIGHBOURS, nontext_map_,
grid_box, rerotation));
// Now eliminate strong stuff in a sea of the opposite.
while (part_grid->GridSmoothNeighbours(BTFT_STRONG_CHAIN, nontext_map_,
grid_box, rerotation));
if (textord_tabfind_show_strokewidths) {
smoothed_win_ = MakeWindow(800, 400, "Smoothed blobs");
part_grid->DisplayBoxes(smoothed_win_);
}
return PFR_OK;
}
// Detects noise by a significant increase in partition overlap from
// pre_overlap to now, and removes noise from the union of all the overlapping
// partitions, placing the blobs in diacritic_blobs. Returns true if any noise
// was found and removed.
bool StrokeWidth::DetectAndRemoveNoise(int pre_overlap, const TBOX& grid_box,
TO_BLOCK* block,
ColPartitionGrid* part_grid,
BLOBNBOX_LIST* diacritic_blobs) {
ColPartitionGrid* noise_grid = NULL;
int post_overlap = part_grid->ComputeTotalOverlap(&noise_grid);
if (pre_overlap == 0) pre_overlap = 1;
BLOBNBOX_IT diacritic_it(diacritic_blobs);
if (noise_grid != NULL) {
if (post_overlap > pre_overlap * kNoiseOverlapGrowthFactor &&
post_overlap > grid_box.area() * kNoiseOverlapAreaFactor) {
// This is noisy enough to fix.
if (textord_tabfind_show_strokewidths) {
ScrollView* noise_win = MakeWindow(1000, 500, "Noise Areas");
noise_grid->DisplayBoxes(noise_win);
}
part_grid->DeleteNonLeaderParts();
BLOBNBOX_IT blob_it(&block->noise_blobs);
ColPartitionGridSearch rsearch(noise_grid);
for (blob_it.mark_cycle_pt(); !blob_it.cycled_list(); blob_it.forward()) {
BLOBNBOX* blob = blob_it.data();
blob->ClearNeighbours();
if (!blob->IsDiacritic() || blob->owner() != NULL)
continue; // Not a noise candidate.
TBOX blob_box(blob->bounding_box());
TBOX search_box(blob->bounding_box());
search_box.pad(gridsize(), gridsize());
rsearch.StartRectSearch(search_box);
ColPartition* part = rsearch.NextRectSearch();
if (part != NULL) {
// Consider blob as possible noise.
blob->set_owns_cblob(true);
blob->compute_bounding_box();
diacritic_it.add_after_then_move(blob_it.extract());
}
}
noise_grid->DeleteParts();
delete noise_grid;
return true;
}
noise_grid->DeleteParts();
delete noise_grid;
}
return false;
}
// Helper verifies that blob's neighbour in direction dir is good to add to a
// vertical text chain by returning the neighbour if it is not null, not owned,
// and not uniquely horizontal, as well as its neighbour in the opposite
// direction is blob.
static BLOBNBOX* MutualUnusedVNeighbour(const BLOBNBOX* blob,
BlobNeighbourDir dir) {
BLOBNBOX* next_blob = blob->neighbour(dir);
if (next_blob == NULL || next_blob->owner() != NULL ||
next_blob->UniquelyHorizontal())
return NULL;
if (next_blob->neighbour(DirOtherWay(dir)) == blob)
return next_blob;
return NULL;
}
// Finds vertical chains of text-like blobs and puts them in ColPartitions.
void StrokeWidth::FindVerticalTextChains(ColPartitionGrid* part_grid) {
// A PageSegMode that forces vertical textlines with the current rotation.
PageSegMode pageseg_mode =
rerotation_.y() == 0.0f ? PSM_SINGLE_BLOCK_VERT_TEXT : PSM_SINGLE_COLUMN;
BlobGridSearch gsearch(this);
BLOBNBOX* bbox;
gsearch.StartFullSearch();
while ((bbox = gsearch.NextFullSearch()) != NULL) {
// Only process boxes that have no horizontal hope and have not yet
// been included in a chain.
BLOBNBOX* blob;
if (bbox->owner() == NULL && bbox->UniquelyVertical() &&
(blob = MutualUnusedVNeighbour(bbox, BND_ABOVE)) != NULL) {
// Put all the linked blobs into a ColPartition.
ColPartition* part = new ColPartition(BRT_VERT_TEXT, ICOORD(0, 1));
part->AddBox(bbox);
while (blob != NULL) {
part->AddBox(blob);
blob = MutualUnusedVNeighbour(blob, BND_ABOVE);
}
blob = MutualUnusedVNeighbour(bbox, BND_BELOW);
while (blob != NULL) {
part->AddBox(blob);
blob = MutualUnusedVNeighbour(blob, BND_BELOW);
}
CompletePartition(pageseg_mode, part, part_grid);
}
}
}
// Helper verifies that blob's neighbour in direction dir is good to add to a
// horizontal text chain by returning the neighbour if it is not null, not
// owned, and not uniquely vertical, as well as its neighbour in the opposite
// direction is blob.
static BLOBNBOX* MutualUnusedHNeighbour(const BLOBNBOX* blob,
BlobNeighbourDir dir) {
BLOBNBOX* next_blob = blob->neighbour(dir);
if (next_blob == NULL || next_blob->owner() != NULL ||
next_blob->UniquelyVertical())
return NULL;
if (next_blob->neighbour(DirOtherWay(dir)) == blob)
return next_blob;
return NULL;
}
// Finds horizontal chains of text-like blobs and puts them in ColPartitions.
void StrokeWidth::FindHorizontalTextChains(ColPartitionGrid* part_grid) {
// A PageSegMode that forces horizontal textlines with the current rotation.
PageSegMode pageseg_mode =
rerotation_.y() == 0.0f ? PSM_SINGLE_COLUMN : PSM_SINGLE_BLOCK_VERT_TEXT;
BlobGridSearch gsearch(this);
BLOBNBOX* bbox;
gsearch.StartFullSearch();
while ((bbox = gsearch.NextFullSearch()) != NULL) {
BLOBNBOX* blob;
if (bbox->owner() == NULL && bbox->UniquelyHorizontal() &&
(blob = MutualUnusedHNeighbour(bbox, BND_RIGHT)) != NULL) {
// Put all the linked blobs into a ColPartition.
ColPartition* part = new ColPartition(BRT_TEXT, ICOORD(0, 1));
part->AddBox(bbox);
while (blob != NULL) {
part->AddBox(blob);
blob = MutualUnusedHNeighbour(blob, BND_RIGHT);
}
blob = MutualUnusedHNeighbour(bbox, BND_LEFT);
while (blob != NULL) {
part->AddBox(blob);
blob = MutualUnusedVNeighbour(blob, BND_LEFT);
}
CompletePartition(pageseg_mode, part, part_grid);
}
}
}
// Finds diacritics and saves their base character in the blob.
// The objective is to move all diacritics to the noise_blobs list, so
// they don't mess up early textline finding/merging, or force splits
// on textlines that overlap a bit. Blobs that become diacritics must be
// either part of no ColPartition (NULL owner) or in a small partition in
// which ALL the blobs are diacritics, in which case the partition is
// exploded (deleted) back to its blobs.
void StrokeWidth::TestDiacritics(ColPartitionGrid* part_grid, TO_BLOCK* block) {
BlobGrid small_grid(gridsize(), bleft(), tright());
small_grid.InsertBlobList(&block->noise_blobs);
small_grid.InsertBlobList(&block->blobs);
int medium_diacritics = 0;
int small_diacritics = 0;
BLOBNBOX_IT small_it(&block->noise_blobs);
for (small_it.mark_cycle_pt(); !small_it.cycled_list(); small_it.forward()) {
BLOBNBOX* blob = small_it.data();
if (blob->owner() == NULL && !blob->IsDiacritic() &&
DiacriticBlob(&small_grid, blob)) {
++small_diacritics;
}
}
BLOBNBOX_IT blob_it(&block->blobs);
for (blob_it.mark_cycle_pt(); !blob_it.cycled_list(); blob_it.forward()) {
BLOBNBOX* blob = blob_it.data();
if (blob->IsDiacritic()) {
small_it.add_to_end(blob_it.extract());
continue; // Already a diacritic.
}
ColPartition* part = blob->owner();
if (part == NULL && DiacriticBlob(&small_grid, blob)) {
++medium_diacritics;
RemoveBBox(blob);
small_it.add_to_end(blob_it.extract());
} else if (part != NULL && !part->block_owned() &&
part->boxes_count() < 3) {
// We allow blobs in small partitions to become diacritics if ALL the
// blobs in the partition qualify as we can then cleanly delete the
// partition, turn all the blobs in it to diacritics and they can be
// merged into the base character partition more easily than merging
// the partitions.
BLOBNBOX_C_IT box_it(part->boxes());
for (box_it.mark_cycle_pt(); !box_it.cycled_list() &&
DiacriticBlob(&small_grid, box_it.data());
box_it.forward());
if (box_it.cycled_list()) {
// They are all good.
while (!box_it.empty()) {
// Liberate the blob from its partition so it can be treated
// as a diacritic and merged explicitly with the base part.
// The blob is really owned by the block. The partition "owner"
// is NULLed to allow the blob to get merged with its base character
// partition.
BLOBNBOX* box = box_it.extract();
box->set_owner(NULL);
box_it.forward();
++medium_diacritics;
// We remove the blob from the grid so it isn't found by subsequent
// searches where we might not want to include diacritics.
RemoveBBox(box);
}
// We only move the one blob to the small list here, but the others
// all get moved by the test at the top of the loop.
small_it.add_to_end(blob_it.extract());
part_grid->RemoveBBox(part);
delete part;
}
} else if (AlignedBlob::WithinTestRegion(2, blob->bounding_box().left(),
blob->bounding_box().bottom())) {
tprintf("Blob not available to be a diacritic at:");
blob->bounding_box().print();
}
}
if (textord_tabfind_show_strokewidths) {
tprintf("Found %d small diacritics, %d medium\n",
small_diacritics, medium_diacritics);
}
}
// Searches this grid for an appropriately close and sized neighbour of the
// given [small] blob. If such a blob is found, the diacritic base is saved
// in the blob and true is returned.
// The small_grid is a secondary grid that contains the small/noise objects
// that are not in this grid, but may be useful for determining a connection
// between blob and its potential base character. (See DiacriticXGapFilled.)
bool StrokeWidth::DiacriticBlob(BlobGrid* small_grid, BLOBNBOX* blob) {
if (BLOBNBOX::UnMergeableType(blob->region_type()) ||
blob->region_type() == BRT_VERT_TEXT)
return false;
TBOX small_box(blob->bounding_box());
bool debug = AlignedBlob::WithinTestRegion(2, small_box.left(),
small_box.bottom());
if (debug) {
tprintf("Testing blob for diacriticness at:");
small_box.print();
}
int x = (small_box.left() + small_box.right()) / 2;
int y = (small_box.bottom() + small_box.top()) / 2;
int grid_x, grid_y;
GridCoords(x, y, &grid_x, &grid_y);
int height = small_box.height();
// Setup a rectangle search to find its nearest base-character neighbour.
// We keep 2 different best candidates:
// best_x_overlap is a category of base characters that have an overlap in x
// (like a acute) in which we look for the least y-gap, computed using the
// projection to favor base characters in the same textline.
// best_y_overlap is a category of base characters that have no x overlap,
// (nominally a y-overlap is preferrecd but not essential) in which we
// look for the least weighted sum of x-gap and y-gap, with x-gap getting
// a lower weight to catch quotes at the end of a textline.
// NOTE that x-gap and y-gap are measured from the nearest side of the base
// character to the FARTHEST side of the diacritic to allow small diacritics
// to be a reasonable distance away, but not big diacritics.
BLOBNBOX* best_x_overlap = NULL;
BLOBNBOX* best_y_overlap = NULL;
int best_total_dist = 0;
int best_y_gap = 0;
TBOX best_xbox;
// TODO(rays) the search box could be setup using the projection as a guide.
TBOX search_box(small_box);
int x_pad = IntCastRounded(gridsize() * kDiacriticXPadRatio);
int y_pad = IntCastRounded(gridsize() * kDiacriticYPadRatio);
search_box.pad(x_pad, y_pad);
BlobGridSearch rsearch(this);
rsearch.SetUniqueMode(true);
int min_height = height * kMinDiacriticSizeRatio;
rsearch.StartRectSearch(search_box);
BLOBNBOX* neighbour;
while ((neighbour = rsearch.NextRectSearch()) != NULL) {
if (BLOBNBOX::UnMergeableType(neighbour->region_type()) ||
neighbour == blob || neighbour->owner() == blob->owner())
continue;
TBOX nbox = neighbour->bounding_box();
if (neighbour->owner() == NULL || neighbour->owner()->IsVerticalType() ||
(neighbour->flow() != BTFT_CHAIN &&
neighbour->flow() != BTFT_STRONG_CHAIN)) {
if (debug) {
tprintf("Neighbour not strong enough:");
nbox.print();
}
continue; // Diacritics must be attached to strong text.
}
if (nbox.height() < min_height) {
if (debug) {
tprintf("Neighbour not big enough:");
nbox.print();
}
continue; // Too small to be the base character.
}
int x_gap = small_box.x_gap(nbox);
int y_gap = small_box.y_gap(nbox);
int total_distance = projection_->DistanceOfBoxFromBox(small_box, nbox,
true, denorm_,
debug);
if (debug) tprintf("xgap=%d, y=%d, total dist=%d\n",
x_gap, y_gap, total_distance);
if (total_distance >
neighbour->owner()->median_size() * kMaxDiacriticDistanceRatio) {
if (debug) {
tprintf("Neighbour with median size %d too far away:",
neighbour->owner()->median_size());
neighbour->bounding_box().print();
}
continue; // Diacritics must not be too distant.
}
if (x_gap <= 0) {
if (debug) {
tprintf("Computing reduced box for :");
nbox.print();
}
int left = small_box.left() - small_box.width();
int right = small_box.right() + small_box.width();
nbox = neighbour->BoundsWithinLimits(left, right);
y_gap = small_box.y_gap(nbox);
if (best_x_overlap == NULL || y_gap < best_y_gap) {
best_x_overlap = neighbour;
best_xbox = nbox;
best_y_gap = y_gap;
if (debug) {
tprintf("New best:");
nbox.print();
}
} else if (debug) {
tprintf("Shrunken box doesn't win:");
nbox.print();
}
} else if (blob->ConfirmNoTabViolation(*neighbour)) {
if (best_y_overlap == NULL || total_distance < best_total_dist) {
if (debug) {
tprintf("New best y overlap:");
nbox.print();
}
best_y_overlap = neighbour;
best_total_dist = total_distance;
} else if (debug) {
tprintf("New y overlap box doesn't win:");
nbox.print();
}
} else if (debug) {
tprintf("Neighbour wrong side of a tab:");
nbox.print();
}
}
if (best_x_overlap != NULL &&
(best_y_overlap == NULL ||
best_xbox.major_y_overlap(best_y_overlap->bounding_box()))) {
blob->set_diacritic_box(best_xbox);
blob->set_base_char_blob(best_x_overlap);
if (debug) {
tprintf("DiacriticBlob OK! (x-overlap:");
small_box.print();
best_xbox.print();
}
return true;
}
if (best_y_overlap != NULL &&
DiacriticXGapFilled(small_grid, small_box,
best_y_overlap->bounding_box()) &&
NoNoiseInBetween(small_box, best_y_overlap->bounding_box())) {
blob->set_diacritic_box(best_y_overlap->bounding_box());
blob->set_base_char_blob(best_y_overlap);
if (debug) {
tprintf("DiacriticBlob OK! (y-overlap:");
small_box.print();
best_y_overlap->bounding_box().print();
}
return true;
}
if (debug) {
tprintf("DiacriticBlob fails:");
small_box.print();
tprintf("Best x+y gap = %d, y = %d\n", best_total_dist, best_y_gap);
if (best_y_overlap != NULL) {
tprintf("XGapFilled=%d, NoiseBetween=%d\n",
DiacriticXGapFilled(small_grid, small_box,
best_y_overlap->bounding_box()),
NoNoiseInBetween(small_box, best_y_overlap->bounding_box()));
}
}
return false;
}
// Returns true if there is no gap between the base char and the diacritic
// bigger than a fraction of the height of the base char:
// Eg: line end.....'
// The quote is a long way from the end of the line, yet it needs to be a
// diacritic. To determine that the quote is not part of an image, or
// a different text block, we check for other marks in the gap between
// the base char and the diacritic.
// '<--Diacritic
// |---------|
// | |<-toobig-gap->
// | Base |<ok gap>
// |---------| x<-----Dot occupying gap
// The grid is const really.
bool StrokeWidth::DiacriticXGapFilled(BlobGrid* grid,
const TBOX& diacritic_box,
const TBOX& base_box) {
// Since most gaps are small, use an iterative algorithm to search the gap.
int max_gap = IntCastRounded(base_box.height() *
kMaxDiacriticGapToBaseCharHeight);
TBOX occupied_box(base_box);
int diacritic_gap;
while ((diacritic_gap = diacritic_box.x_gap(occupied_box)) > max_gap) {
TBOX search_box(occupied_box);
if (diacritic_box.left() > search_box.right()) {
// We are looking right.
search_box.set_left(search_box.right());
search_box.set_right(search_box.left() + max_gap);
} else {
// We are looking left.
search_box.set_right(search_box.left());
search_box.set_left(search_box.left() - max_gap);
}
BlobGridSearch rsearch(grid);
rsearch.StartRectSearch(search_box);
BLOBNBOX* neighbour;
while ((neighbour = rsearch.NextRectSearch()) != NULL) {
const TBOX& nbox = neighbour->bounding_box();
if (nbox.x_gap(diacritic_box) < diacritic_gap) {
if (nbox.left() < occupied_box.left())
occupied_box.set_left(nbox.left());
if (nbox.right() > occupied_box.right())
occupied_box.set_right(nbox.right());
break;
}
}
if (neighbour == NULL)
return false; // Found a big gap.
}
return true; // The gap was filled.
}
// Merges diacritics with the ColPartition of the base character blob.
void StrokeWidth::MergeDiacritics(TO_BLOCK* block,
ColPartitionGrid* part_grid) {
BLOBNBOX_IT small_it(&block->noise_blobs);
for (small_it.mark_cycle_pt(); !small_it.cycled_list(); small_it.forward()) {
BLOBNBOX* blob = small_it.data();
if (blob->base_char_blob() != NULL) {
ColPartition* part = blob->base_char_blob()->owner();
// The base character must be owned by a partition and that partition
// must not be on the big_parts list (not block owned).
if (part != NULL && !part->block_owned() && blob->owner() == NULL &&
blob->IsDiacritic()) {
// The partition has to be removed from the grid and reinserted
// because its bounding box may change.
part_grid->RemoveBBox(part);
part->AddBox(blob);
blob->set_region_type(part->blob_type());
blob->set_flow(part->flow());
blob->set_owner(part);
part_grid->InsertBBox(true, true, part);
}
// Set all base chars to NULL before any blobs get deleted.
blob->set_base_char_blob(NULL);
}
}
}
// Any blobs on the large_blobs list of block that are still unowned by a
// ColPartition, are probably drop-cap or vertically touching so the blobs
// are removed to the big_parts list and treated separately.
void StrokeWidth::RemoveLargeUnusedBlobs(TO_BLOCK* block,
ColPartitionGrid* part_grid,
ColPartition_LIST* big_parts) {
BLOBNBOX_IT large_it(&block->large_blobs);
for (large_it.mark_cycle_pt(); !large_it.cycled_list(); large_it.forward()) {
BLOBNBOX* blob = large_it.data();
ColPartition* big_part = blob->owner();
if (big_part == NULL) {
// Large blobs should have gone into partitions by now if they are
// genuine characters, so move any unowned ones out to the big parts
// list. This will include drop caps and vertically touching characters.
ColPartition::MakeBigPartition(blob, big_parts);
}
}
}
// All remaining unused blobs are put in individual ColPartitions.
void StrokeWidth::PartitionRemainingBlobs(PageSegMode pageseg_mode,
ColPartitionGrid* part_grid) {
BlobGridSearch gsearch(this);
BLOBNBOX* bbox;
int prev_grid_x = -1;
int prev_grid_y = -1;
BLOBNBOX_CLIST cell_list;
BLOBNBOX_C_IT cell_it(&cell_list);
bool cell_all_noise = true;
gsearch.StartFullSearch();
while ((bbox = gsearch.NextFullSearch()) != NULL) {
int grid_x = gsearch.GridX();
int grid_y = gsearch.GridY();
if (grid_x != prev_grid_x || grid_y != prev_grid_y) {
// New cell. Process old cell.
MakePartitionsFromCellList(pageseg_mode, cell_all_noise, part_grid,
&cell_list);
cell_it.set_to_list(&cell_list);
prev_grid_x = grid_x;
prev_grid_y = grid_y;
cell_all_noise = true;
}
if (bbox->owner() == NULL) {
cell_it.add_to_end(bbox);
if (bbox->flow() != BTFT_NONTEXT)
cell_all_noise = false;
} else {
cell_all_noise = false;
}
}
MakePartitionsFromCellList(pageseg_mode, cell_all_noise, part_grid,
&cell_list);
}
// If combine, put all blobs in the cell_list into a single partition, otherwise
// put each one into its own partition.
void StrokeWidth::MakePartitionsFromCellList(PageSegMode pageseg_mode,
bool combine,
ColPartitionGrid* part_grid,
BLOBNBOX_CLIST* cell_list) {
if (cell_list->empty())
return;
BLOBNBOX_C_IT cell_it(cell_list);
if (combine) {
BLOBNBOX* bbox = cell_it.extract();
ColPartition* part = new ColPartition(bbox->region_type(), ICOORD(0, 1));
part->AddBox(bbox);
part->set_flow(bbox->flow());
for (cell_it.forward(); !cell_it.empty(); cell_it.forward()) {
part->AddBox(cell_it.extract());
}
CompletePartition(pageseg_mode, part, part_grid);
} else {
for (; !cell_it.empty(); cell_it.forward()) {
BLOBNBOX* bbox = cell_it.extract();
ColPartition* part = new ColPartition(bbox->region_type(), ICOORD(0, 1));
part->set_flow(bbox->flow());
part->AddBox(bbox);
CompletePartition(pageseg_mode, part, part_grid);
}
}
}
// Helper function to finish setting up a ColPartition and insert into
// part_grid.
void StrokeWidth::CompletePartition(PageSegMode pageseg_mode,
ColPartition* part,
ColPartitionGrid* part_grid) {
part->ComputeLimits();
TBOX box = part->bounding_box();
bool debug = AlignedBlob::WithinTestRegion(2, box.left(),
box.bottom());
int value = projection_->EvaluateColPartition(*part, denorm_, debug);
// Override value if pageseg_mode disagrees.
if (value > 0 && FindingVerticalOnly(pageseg_mode)) {
value = part->boxes_count() == 1 ? 0 : -2;
} else if (value < 0 && FindingHorizontalOnly(pageseg_mode)) {
value = part->boxes_count() == 1 ? 0 : 2;
}
part->SetRegionAndFlowTypesFromProjectionValue(value);
part->ClaimBoxes();
part_grid->InsertBBox(true, true, part);
}
// Merge partitions where the merge appears harmless.
// As this
void StrokeWidth::EasyMerges(ColPartitionGrid* part_grid) {
part_grid->Merges(
NewPermanentTessCallback(this, &StrokeWidth::OrientationSearchBox),
NewPermanentTessCallback(this, &StrokeWidth::ConfirmEasyMerge));
}
// Compute a search box based on the orientation of the partition.
// Returns true if a suitable box can be calculated.
// Callback for EasyMerges.
bool StrokeWidth::OrientationSearchBox(ColPartition* part, TBOX* box) {
if (part->IsVerticalType()) {
box->set_top(box->top() + box->width());
box->set_bottom(box->bottom() - box->width());
} else {
box->set_left(box->left() - box->height());
box->set_right(box->right() + box->height());
}
return true;
}
// Merge confirmation callback for EasyMerges.
bool StrokeWidth::ConfirmEasyMerge(const ColPartition* p1,
const ColPartition* p2) {
ASSERT_HOST(p1 != NULL && p2 != NULL);
ASSERT_HOST(!p1->IsEmpty() && !p2->IsEmpty());
if ((p1->flow() == BTFT_NONTEXT && p2->flow() >= BTFT_CHAIN) ||
(p1->flow() >= BTFT_CHAIN && p2->flow() == BTFT_NONTEXT))
return false; // Don't merge confirmed image with text.
if ((p1->IsVerticalType() || p2->IsVerticalType()) &&
p1->HCoreOverlap(*p2) <= 0 &&
((!p1->IsSingleton() &&
!p2->IsSingleton()) ||
!p1->bounding_box().major_overlap(p2->bounding_box())))
return false; // Overlap must be in the text line.
if ((p1->IsHorizontalType() || p2->IsHorizontalType()) &&
p1->VCoreOverlap(*p2) <= 0 &&
((!p1->IsSingleton() &&
!p2->IsSingleton()) ||
(!p1->bounding_box().major_overlap(p2->bounding_box()) &&
!p1->OKDiacriticMerge(*p2, false) &&
!p2->OKDiacriticMerge(*p1, false))))
return false; // Overlap must be in the text line.
if (!p1->ConfirmNoTabViolation(*p2))
return false;
if (p1->flow() <= BTFT_NONTEXT && p2->flow() <= BTFT_NONTEXT)
return true;
return NoNoiseInBetween(p1->bounding_box(), p2->bounding_box());
}
// Returns true if there is no significant noise in between the boxes.
bool StrokeWidth::NoNoiseInBetween(const TBOX& box1, const TBOX& box2) const {
return ImageFind::BlankImageInBetween(box1, box2, grid_box_, rerotation_,
nontext_map_);
}
/** Displays the blobs colored according to the number of good neighbours
* and the vertical/horizontal flow.
*/
ScrollView* StrokeWidth::DisplayGoodBlobs(const char* window_name,
int x, int y) {
ScrollView* window = NULL;
#ifndef GRAPHICS_DISABLED
window = MakeWindow(x, y, window_name);
// For every blob in the grid, display it.
window->Brush(ScrollView::NONE);
// For every bbox in the grid, display it.
BlobGridSearch gsearch(this);
gsearch.StartFullSearch();
BLOBNBOX* bbox;
while ((bbox = gsearch.NextFullSearch()) != NULL) {
TBOX box = bbox->bounding_box();
int left_x = box.left();
int right_x = box.right();
int top_y = box.top();
int bottom_y = box.bottom();
int goodness = bbox->GoodTextBlob();
BlobRegionType blob_type = bbox->region_type();
if (bbox->UniquelyVertical())
blob_type = BRT_VERT_TEXT;
if (bbox->UniquelyHorizontal())
blob_type = BRT_TEXT;
BlobTextFlowType flow = bbox->flow();
if (flow == BTFT_NONE) {
if (goodness == 0)
flow = BTFT_NEIGHBOURS;
else if (goodness == 1)
flow = BTFT_CHAIN;
else
flow = BTFT_STRONG_CHAIN;
}
window->Pen(BLOBNBOX::TextlineColor(blob_type, flow));
window->Rectangle(left_x, bottom_y, right_x, top_y);
}
window->Update();
#endif
return window;
}
static void DrawDiacriticJoiner(const BLOBNBOX* blob, ScrollView* window) {
#ifndef GRAPHICS_DISABLED
const TBOX& blob_box(blob->bounding_box());
int top = MAX(blob_box.top(), blob->base_char_top());
int bottom = MIN(blob_box.bottom(), blob->base_char_bottom());
int x = (blob_box.left() + blob_box.right()) / 2;
window->Line(x, top, x, bottom);
#endif // GRAPHICS_DISABLED
}
// Displays blobs colored according to whether or not they are diacritics.
ScrollView* StrokeWidth::DisplayDiacritics(const char* window_name,
int x, int y, TO_BLOCK* block) {
ScrollView* window = NULL;
#ifndef GRAPHICS_DISABLED
window = MakeWindow(x, y, window_name);
// For every blob in the grid, display it.
window->Brush(ScrollView::NONE);
BLOBNBOX_IT it(&block->blobs);
for (it.mark_cycle_pt(); !it.cycled_list(); it.forward()) {
BLOBNBOX* blob = it.data();
if (blob->IsDiacritic()) {
window->Pen(ScrollView::GREEN);
DrawDiacriticJoiner(blob, window);
} else {
window->Pen(blob->BoxColor());
}
const TBOX& box = blob->bounding_box();
window->Rectangle(box.left(), box. bottom(), box.right(), box.top());
}
it.set_to_list(&block->noise_blobs);
for (it.mark_cycle_pt(); !it.cycled_list(); it.forward()) {
BLOBNBOX* blob = it.data();
if (blob->IsDiacritic()) {
window->Pen(ScrollView::GREEN);
DrawDiacriticJoiner(blob, window);
} else {
window->Pen(ScrollView::WHITE);
}
const TBOX& box = blob->bounding_box();
window->Rectangle(box.left(), box. bottom(), box.right(), box.top());
}
window->Update();
#endif
return window;
}
} // namespace tesseract.
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