mirror of
https://github.com/tesseract-ocr/tesseract.git
synced 2024-11-25 11:39:06 +08:00
dbf6197471
git-svn-id: https://tesseract-ocr.googlecode.com/svn/trunk@1147 d0cd1f9f-072b-0410-8dd7-cf729c803f20
548 lines
20 KiB
C++
548 lines
20 KiB
C++
/**********************************************************************
|
|
* File: stepblob.cpp (Formerly cblob.c)
|
|
* Description: Code for C_BLOB class.
|
|
* Author: Ray Smith
|
|
* Created: Tue Oct 08 10:41:13 BST 1991
|
|
*
|
|
* (C) Copyright 1991, Hewlett-Packard Ltd.
|
|
** 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.
|
|
*
|
|
**********************************************************************/
|
|
|
|
#include "stepblob.h"
|
|
#include "allheaders.h"
|
|
|
|
// Include automatically generated configuration file if running autoconf.
|
|
#ifdef HAVE_CONFIG_H
|
|
#include "config_auto.h"
|
|
#endif
|
|
|
|
// Max perimeter to width ratio for a baseline position above box bottom.
|
|
const double kMaxPerimeterWidthRatio = 8.0;
|
|
|
|
ELISTIZE (C_BLOB)
|
|
/**********************************************************************
|
|
* position_outline
|
|
*
|
|
* Position the outline in the given list at the relevant place
|
|
* according to its nesting.
|
|
**********************************************************************/
|
|
static void position_outline( //put in place
|
|
C_OUTLINE *outline, //thing to place
|
|
C_OUTLINE_LIST *destlist //desstination list
|
|
) {
|
|
C_OUTLINE *dest_outline; //outline from dest list
|
|
C_OUTLINE_IT it = destlist; //iterator
|
|
//iterator on children
|
|
C_OUTLINE_IT child_it = outline->child ();
|
|
|
|
if (!it.empty ()) {
|
|
do {
|
|
dest_outline = it.data (); //get destination
|
|
//encloses dest
|
|
if (*dest_outline < *outline) {
|
|
//take off list
|
|
dest_outline = it.extract ();
|
|
//put this in place
|
|
it.add_after_then_move (outline);
|
|
//make it a child
|
|
child_it.add_to_end (dest_outline);
|
|
while (!it.at_last ()) {
|
|
it.forward (); //do rest of list
|
|
//check for other children
|
|
dest_outline = it.data ();
|
|
if (*dest_outline < *outline) {
|
|
//take off list
|
|
dest_outline = it.extract ();
|
|
child_it.add_to_end (dest_outline);
|
|
//make it a child
|
|
if (it.empty ())
|
|
break;
|
|
}
|
|
}
|
|
return; //finished
|
|
}
|
|
//enclosed by dest
|
|
else if (*outline < *dest_outline) {
|
|
position_outline (outline, dest_outline->child ());
|
|
//place in child list
|
|
return; //finished
|
|
}
|
|
it.forward ();
|
|
}
|
|
while (!it.at_first ());
|
|
}
|
|
it.add_to_end (outline); //at outer level
|
|
}
|
|
|
|
|
|
/**********************************************************************
|
|
* plot_outline_list
|
|
*
|
|
* Draw a list of outlines in the given colour and their children
|
|
* in the child colour.
|
|
**********************************************************************/
|
|
|
|
#ifndef GRAPHICS_DISABLED
|
|
static void plot_outline_list( //draw outlines
|
|
C_OUTLINE_LIST *list, //outline to draw
|
|
ScrollView* window, //window to draw in
|
|
ScrollView::Color colour, //colour to use
|
|
ScrollView::Color child_colour //colour of children
|
|
) {
|
|
C_OUTLINE *outline; //current outline
|
|
C_OUTLINE_IT it = list; //iterator
|
|
|
|
for (it.mark_cycle_pt (); !it.cycled_list (); it.forward ()) {
|
|
outline = it.data ();
|
|
//draw it
|
|
outline->plot (window, colour);
|
|
if (!outline->child ()->empty ())
|
|
plot_outline_list (outline->child (), window,
|
|
child_colour, child_colour);
|
|
}
|
|
}
|
|
// Draws the outlines in the given colour, and child_colour, normalized
|
|
// using the given denorm, making use of sub-pixel accurate information
|
|
// if available.
|
|
static void plot_normed_outline_list(const DENORM& denorm,
|
|
C_OUTLINE_LIST *list,
|
|
ScrollView::Color colour,
|
|
ScrollView::Color child_colour,
|
|
ScrollView* window) {
|
|
C_OUTLINE_IT it(list);
|
|
for (it.mark_cycle_pt(); !it.cycled_list(); it.forward()) {
|
|
C_OUTLINE* outline = it.data();
|
|
outline->plot_normed(denorm, colour, window);
|
|
if (!outline->child()->empty())
|
|
plot_normed_outline_list(denorm, outline->child(), child_colour,
|
|
child_colour, window);
|
|
}
|
|
}
|
|
#endif
|
|
|
|
|
|
/**********************************************************************
|
|
* reverse_outline_list
|
|
*
|
|
* Reverse a list of outlines and their children.
|
|
**********************************************************************/
|
|
|
|
static void reverse_outline_list(C_OUTLINE_LIST *list) {
|
|
C_OUTLINE_IT it = list; // iterator
|
|
|
|
for (it.mark_cycle_pt(); !it.cycled_list(); it.forward()) {
|
|
C_OUTLINE* outline = it.data();
|
|
outline->reverse(); // reverse it
|
|
outline->set_flag(COUT_INVERSE, TRUE);
|
|
if (!outline->child()->empty())
|
|
reverse_outline_list(outline->child());
|
|
}
|
|
}
|
|
|
|
|
|
/**********************************************************************
|
|
* C_BLOB::C_BLOB
|
|
*
|
|
* Constructor to build a C_BLOB from a list of C_OUTLINEs.
|
|
* The C_OUTLINEs are not copied so the source list is emptied.
|
|
* The C_OUTLINEs are nested correctly in the blob.
|
|
**********************************************************************/
|
|
|
|
C_BLOB::C_BLOB(C_OUTLINE_LIST *outline_list) {
|
|
for (C_OUTLINE_IT ol_it(outline_list); !ol_it.empty(); ol_it.forward()) {
|
|
C_OUTLINE* outline = ol_it.extract();
|
|
// Position this outline in appropriate position in the hierarchy.
|
|
position_outline(outline, &outlines);
|
|
}
|
|
CheckInverseFlagAndDirection();
|
|
}
|
|
|
|
// Simpler constructor to build a blob from a single outline that has
|
|
// already been fully initialized.
|
|
C_BLOB::C_BLOB(C_OUTLINE* outline) {
|
|
C_OUTLINE_IT it(&outlines);
|
|
it.add_to_end(outline);
|
|
}
|
|
|
|
// Builds a set of one or more blobs from a list of outlines.
|
|
// Input: one outline on outline_list contains all the others, but the
|
|
// nesting and order are undefined.
|
|
// If good_blob is true, the blob is added to good_blobs_it, unless
|
|
// an illegal (generation-skipping) parent-child relationship is found.
|
|
// If so, the parent blob goes to bad_blobs_it, and the immediate children
|
|
// are promoted to the top level, recursively being sent to good_blobs_it.
|
|
// If good_blob is false, all created blobs will go to the bad_blobs_it.
|
|
// Output: outline_list is empty. One or more blobs are added to
|
|
// good_blobs_it and/or bad_blobs_it.
|
|
void C_BLOB::ConstructBlobsFromOutlines(bool good_blob,
|
|
C_OUTLINE_LIST* outline_list,
|
|
C_BLOB_IT* good_blobs_it,
|
|
C_BLOB_IT* bad_blobs_it) {
|
|
// List of top-level outlines with correctly nested children.
|
|
C_OUTLINE_LIST nested_outlines;
|
|
for (C_OUTLINE_IT ol_it(outline_list); !ol_it.empty(); ol_it.forward()) {
|
|
C_OUTLINE* outline = ol_it.extract();
|
|
// Position this outline in appropriate position in the hierarchy.
|
|
position_outline(outline, &nested_outlines);
|
|
}
|
|
// Check for legal nesting and reassign as required.
|
|
for (C_OUTLINE_IT ol_it(&nested_outlines); !ol_it.empty(); ol_it.forward()) {
|
|
C_OUTLINE* outline = ol_it.extract();
|
|
bool blob_is_good = good_blob;
|
|
if (!outline->IsLegallyNested()) {
|
|
// The blob is illegally nested.
|
|
// Mark it bad, and add all its children to the top-level list.
|
|
blob_is_good = false;
|
|
ol_it.add_list_after(outline->child());
|
|
}
|
|
C_BLOB* blob = new C_BLOB(outline);
|
|
// Set inverse flag and reverse if needed.
|
|
blob->CheckInverseFlagAndDirection();
|
|
// Put on appropriate list.
|
|
if (!blob_is_good && bad_blobs_it != NULL)
|
|
bad_blobs_it->add_after_then_move(blob);
|
|
else
|
|
good_blobs_it->add_after_then_move(blob);
|
|
}
|
|
}
|
|
|
|
// Sets the COUT_INVERSE flag appropriately on the outlines and their
|
|
// children recursively, reversing the outlines if needed so that
|
|
// everything has an anticlockwise top-level.
|
|
void C_BLOB::CheckInverseFlagAndDirection() {
|
|
C_OUTLINE_IT ol_it(&outlines);
|
|
for (ol_it.mark_cycle_pt(); !ol_it.cycled_list(); ol_it.forward()) {
|
|
C_OUTLINE* outline = ol_it.data();
|
|
if (outline->turn_direction() < 0) {
|
|
outline->reverse();
|
|
reverse_outline_list(outline->child());
|
|
outline->set_flag(COUT_INVERSE, TRUE);
|
|
} else {
|
|
outline->set_flag(COUT_INVERSE, FALSE);
|
|
}
|
|
}
|
|
}
|
|
|
|
|
|
// Build and return a fake blob containing a single fake outline with no
|
|
// steps.
|
|
C_BLOB* C_BLOB::FakeBlob(const TBOX& box) {
|
|
C_OUTLINE_LIST outlines;
|
|
C_OUTLINE::FakeOutline(box, &outlines);
|
|
return new C_BLOB(&outlines);
|
|
}
|
|
|
|
/**********************************************************************
|
|
* C_BLOB::bounding_box
|
|
*
|
|
* Return the bounding box of the blob.
|
|
**********************************************************************/
|
|
|
|
TBOX C_BLOB::bounding_box() const { // bounding box
|
|
C_OUTLINE *outline; // current outline
|
|
// This is a read-only iteration of the outlines.
|
|
C_OUTLINE_IT it = const_cast<C_OUTLINE_LIST*>(&outlines);
|
|
TBOX box; // bounding box
|
|
|
|
for (it.mark_cycle_pt (); !it.cycled_list (); it.forward ()) {
|
|
outline = it.data ();
|
|
box += outline->bounding_box ();
|
|
}
|
|
return box;
|
|
}
|
|
|
|
|
|
/**********************************************************************
|
|
* C_BLOB::area
|
|
*
|
|
* Return the area of the blob.
|
|
**********************************************************************/
|
|
|
|
inT32 C_BLOB::area() { //area
|
|
C_OUTLINE *outline; //current outline
|
|
C_OUTLINE_IT it = &outlines; //outlines of blob
|
|
inT32 total; //total area
|
|
|
|
total = 0;
|
|
for (it.mark_cycle_pt (); !it.cycled_list (); it.forward ()) {
|
|
outline = it.data ();
|
|
total += outline->area ();
|
|
}
|
|
return total;
|
|
}
|
|
|
|
/**********************************************************************
|
|
* C_BLOB::perimeter
|
|
*
|
|
* Return the perimeter of the top and 2nd level outlines.
|
|
**********************************************************************/
|
|
|
|
inT32 C_BLOB::perimeter() {
|
|
C_OUTLINE *outline; // current outline
|
|
C_OUTLINE_IT it = &outlines; // outlines of blob
|
|
inT32 total; // total perimeter
|
|
|
|
total = 0;
|
|
for (it.mark_cycle_pt(); !it.cycled_list(); it.forward()) {
|
|
outline = it.data();
|
|
total += outline->perimeter();
|
|
}
|
|
return total;
|
|
}
|
|
|
|
|
|
/**********************************************************************
|
|
* C_BLOB::outer_area
|
|
*
|
|
* Return the area of the blob.
|
|
**********************************************************************/
|
|
|
|
inT32 C_BLOB::outer_area() { //area
|
|
C_OUTLINE *outline; //current outline
|
|
C_OUTLINE_IT it = &outlines; //outlines of blob
|
|
inT32 total; //total area
|
|
|
|
total = 0;
|
|
for (it.mark_cycle_pt (); !it.cycled_list (); it.forward ()) {
|
|
outline = it.data ();
|
|
total += outline->outer_area ();
|
|
}
|
|
return total;
|
|
}
|
|
|
|
|
|
/**********************************************************************
|
|
* C_BLOB::count_transitions
|
|
*
|
|
* Return the total x and y maxes and mins in the blob.
|
|
* Chlid outlines are not counted.
|
|
**********************************************************************/
|
|
|
|
inT32 C_BLOB::count_transitions( //area
|
|
inT32 threshold //on size
|
|
) {
|
|
C_OUTLINE *outline; //current outline
|
|
C_OUTLINE_IT it = &outlines; //outlines of blob
|
|
inT32 total; //total area
|
|
|
|
total = 0;
|
|
for (it.mark_cycle_pt (); !it.cycled_list (); it.forward ()) {
|
|
outline = it.data ();
|
|
total += outline->count_transitions (threshold);
|
|
}
|
|
return total;
|
|
}
|
|
|
|
|
|
/**********************************************************************
|
|
* C_BLOB::move
|
|
*
|
|
* Move C_BLOB by vector
|
|
**********************************************************************/
|
|
|
|
void C_BLOB::move( // reposition blob
|
|
const ICOORD vec // by vector
|
|
) {
|
|
C_OUTLINE_IT it(&outlines); // iterator
|
|
|
|
for (it.mark_cycle_pt (); !it.cycled_list (); it.forward ())
|
|
it.data ()->move (vec); // move each outline
|
|
}
|
|
|
|
// Static helper for C_BLOB::rotate to allow recursion of child outlines.
|
|
void RotateOutlineList(const FCOORD& rotation, C_OUTLINE_LIST* outlines) {
|
|
C_OUTLINE_LIST new_outlines;
|
|
C_OUTLINE_IT src_it(outlines);
|
|
C_OUTLINE_IT dest_it(&new_outlines);
|
|
while (!src_it.empty()) {
|
|
C_OUTLINE* old_outline = src_it.extract();
|
|
src_it.forward();
|
|
C_OUTLINE* new_outline = new C_OUTLINE(old_outline, rotation);
|
|
if (!old_outline->child()->empty()) {
|
|
RotateOutlineList(rotation, old_outline->child());
|
|
C_OUTLINE_IT child_it(new_outline->child());
|
|
child_it.add_list_after(old_outline->child());
|
|
}
|
|
delete old_outline;
|
|
dest_it.add_to_end(new_outline);
|
|
}
|
|
src_it.add_list_after(&new_outlines);
|
|
}
|
|
|
|
/**********************************************************************
|
|
* C_BLOB::rotate
|
|
*
|
|
* Rotate C_BLOB by rotation.
|
|
* Warning! has to rebuild all the C_OUTLINEs.
|
|
**********************************************************************/
|
|
void C_BLOB::rotate(const FCOORD& rotation) {
|
|
RotateOutlineList(rotation, &outlines);
|
|
}
|
|
|
|
// Helper calls ComputeEdgeOffsets or ComputeBinaryOffsets recursively on the
|
|
// outline list and its children.
|
|
static void ComputeEdgeOffsetsOutlineList(int threshold, Pix* pix,
|
|
C_OUTLINE_LIST *list) {
|
|
C_OUTLINE_IT it(list);
|
|
for (it.mark_cycle_pt(); !it.cycled_list(); it.forward()) {
|
|
C_OUTLINE* outline = it.data();
|
|
if (pix != NULL && pixGetDepth(pix) == 8)
|
|
outline->ComputeEdgeOffsets(threshold, pix);
|
|
else
|
|
outline->ComputeBinaryOffsets();
|
|
if (!outline->child()->empty())
|
|
ComputeEdgeOffsetsOutlineList(threshold, pix, outline->child());
|
|
}
|
|
}
|
|
|
|
// Adds sub-pixel resolution EdgeOffsets for the outlines using greyscale
|
|
// if the supplied pix is 8-bit or the binary edges if NULL.
|
|
void C_BLOB::ComputeEdgeOffsets(int threshold, Pix* pix) {
|
|
ComputeEdgeOffsetsOutlineList(threshold, pix, &outlines);
|
|
}
|
|
|
|
// Estimates and returns the baseline position based on the shape of the
|
|
// outlines.
|
|
// We first find the minimum y-coord (y_mins) at each x-coord within the blob.
|
|
// If there is a run of some y or y+1 in y_mins that is longer than the total
|
|
// number of positions at bottom or bottom+1, subject to the additional
|
|
// condition that at least one side of the y/y+1 run is higher than y+1, so it
|
|
// is not a local minimum, then y, not the bottom, makes a good candidate
|
|
// baseline position for this blob. Eg
|
|
// | ---|
|
|
// | |
|
|
// |- -----------| <= Good candidate baseline position.
|
|
// |- -|
|
|
// | -|
|
|
// |---| <= Bottom of blob
|
|
inT16 C_BLOB::EstimateBaselinePosition() {
|
|
TBOX box = bounding_box();
|
|
int left = box.left();
|
|
int width = box.width();
|
|
int bottom = box.bottom();
|
|
if (outlines.empty() || perimeter() > width * kMaxPerimeterWidthRatio)
|
|
return bottom; // This is only for non-CJK blobs.
|
|
// Get the minimum y coordinate at each x-coordinate.
|
|
GenericVector<int> y_mins;
|
|
y_mins.init_to_size(width + 1, box.top());
|
|
C_OUTLINE_IT it(&outlines);
|
|
for (it.mark_cycle_pt(); !it.cycled_list(); it.forward()) {
|
|
C_OUTLINE* outline = it.data();
|
|
ICOORD pos = outline->start_pos();
|
|
for (int s = 0; s < outline->pathlength(); ++s) {
|
|
if (pos.y() < y_mins[pos.x() - left])
|
|
y_mins[pos.x() - left] = pos.y();
|
|
pos += outline->step(s);
|
|
}
|
|
}
|
|
// Find the total extent of the bottom or bottom + 1.
|
|
int bottom_extent = 0;
|
|
for (int x = 0; x <= width; ++x) {
|
|
if (y_mins[x] == bottom || y_mins[x] == bottom + 1)
|
|
++bottom_extent;
|
|
}
|
|
// Find the lowest run longer than the bottom extent that is not the bottom.
|
|
int best_min = box.top();
|
|
int prev_run = 0;
|
|
int prev_y = box.top();
|
|
int prev_prev_y = box.top();
|
|
for (int x = 0; x < width; x += prev_run) {
|
|
// Find the length of the current run.
|
|
int y_at_x = y_mins[x];
|
|
int run = 1;
|
|
while (x + run <= width && y_mins[x + run] == y_at_x) ++run;
|
|
if (y_at_x > bottom + 1) {
|
|
// Possible contender.
|
|
int total_run = run;
|
|
// Find extent of current value or +1 to the right of x.
|
|
while (x + total_run <= width &&
|
|
(y_mins[x + total_run] == y_at_x ||
|
|
y_mins[x + total_run] == y_at_x + 1)) ++total_run;
|
|
// At least one end has to be higher so it is not a local max.
|
|
if (prev_prev_y > y_at_x + 1 || x + total_run > width ||
|
|
y_mins[x + total_run] > y_at_x + 1) {
|
|
// If the prev_run is at y + 1, then we can add that too. There cannot
|
|
// be a suitable run at y before that or we would have found it already.
|
|
if (prev_run > 0 && prev_y == y_at_x + 1) total_run += prev_run;
|
|
if (total_run > bottom_extent && y_at_x < best_min) {
|
|
best_min = y_at_x;
|
|
}
|
|
}
|
|
}
|
|
prev_run = run;
|
|
prev_prev_y = prev_y;
|
|
prev_y = y_at_x;
|
|
}
|
|
return best_min == box.top() ? bottom : best_min;
|
|
}
|
|
|
|
static void render_outline_list(C_OUTLINE_LIST *list,
|
|
int left, int top, Pix* pix) {
|
|
C_OUTLINE_IT it(list);
|
|
for (it.mark_cycle_pt(); !it.cycled_list(); it.forward()) {
|
|
C_OUTLINE* outline = it.data();
|
|
outline->render(left, top, pix);
|
|
if (!outline->child()->empty())
|
|
render_outline_list(outline->child(), left, top, pix);
|
|
}
|
|
}
|
|
|
|
static void render_outline_list_outline(C_OUTLINE_LIST *list,
|
|
int left, int top, Pix* pix) {
|
|
C_OUTLINE_IT it(list);
|
|
for (it.mark_cycle_pt(); !it.cycled_list(); it.forward()) {
|
|
C_OUTLINE* outline = it.data();
|
|
outline->render_outline(left, top, pix);
|
|
}
|
|
}
|
|
|
|
// Returns a Pix rendering of the blob. pixDestroy after use.
|
|
Pix* C_BLOB::render() {
|
|
TBOX box = bounding_box();
|
|
Pix* pix = pixCreate(box.width(), box.height(), 1);
|
|
render_outline_list(&outlines, box.left(), box.top(), pix);
|
|
return pix;
|
|
}
|
|
|
|
// Returns a Pix rendering of the outline of the blob. (no fill).
|
|
// pixDestroy after use.
|
|
Pix* C_BLOB::render_outline() {
|
|
TBOX box = bounding_box();
|
|
Pix* pix = pixCreate(box.width(), box.height(), 1);
|
|
render_outline_list_outline(&outlines, box.left(), box.top(), pix);
|
|
return pix;
|
|
}
|
|
|
|
/**********************************************************************
|
|
* C_BLOB::plot
|
|
*
|
|
* Draw the C_BLOB in the given colour.
|
|
**********************************************************************/
|
|
|
|
#ifndef GRAPHICS_DISABLED
|
|
void C_BLOB::plot(ScrollView* window, // window to draw in
|
|
ScrollView::Color blob_colour, // main colour
|
|
ScrollView::Color child_colour) { // for holes
|
|
plot_outline_list(&outlines, window, blob_colour, child_colour);
|
|
}
|
|
// Draws the blob in the given colour, and child_colour, normalized
|
|
// using the given denorm, making use of sub-pixel accurate information
|
|
// if available.
|
|
void C_BLOB::plot_normed(const DENORM& denorm,
|
|
ScrollView::Color blob_colour,
|
|
ScrollView::Color child_colour,
|
|
ScrollView* window) {
|
|
plot_normed_outline_list(denorm, &outlines, blob_colour, child_colour,
|
|
window);
|
|
}
|
|
#endif
|