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tesseract/training/text2image.cpp
theraysmith@gmail.com f244ab3fc6 New training tool text2image 
git-svn-id: https://tesseract-ocr.googlecode.com/svn/trunk@965 d0cd1f9f-072b-0410-8dd7-cf729c803f20
2014-01-09 18:04:20 +00:00

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/**********************************************************************
* File: text2image.cpp
* Description: Program to generate OCR training pages. Given a text file it
* outputs an image with a given font and degradation.
*
* Note that since the results depend on the fonts available on
* your system, running the code on a different machine, or
* different OS, or even at a different time on the same machine,
* may produce different fonts even if --font is given explicitly.
* To see names of available fonts, use --list_available_fonts with
* the appropriate --fonts_dir path.
* Specifying --use_only_legacy_fonts will restrict the available
* fonts to those listed in legacy_fonts.h
*
* Authors: Ranjith Unnikrishnan, Ray Smith
* Created: Tue Nov 19 2013
*
* (C) Copyright 2013, 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.
*
**********************************************************************/
#include <stdlib.h>
#include <string.h>
#include <algorithm>
#include <iostream>
#include <map>
#include <string>
#include <utility>
#include <vector>
#include "allheaders.h" // from leptonica
#include "boxchar.h"
#include "commandlineflags.h"
#include "degradeimage.h"
#include "errcode.h"
#include "fileio.h"
#include "normstrngs.h"
#include "stringrenderer.h"
#include "tlog.h"
#include "unicharset.h"
#include "util.h"
#ifdef USE_STD_NAMESPACE
using std::make_pair;
using std::map;
using std::pair;
#endif
// The text input file.
STRING_PARAM_FLAG(text, "", "File name of text input to process");
// The text output file.
STRING_PARAM_FLAG(outputbase, "", "Basename for output image/box file");
// Degrade the rendered image to mimic scanner quality.
BOOL_PARAM_FLAG(degrade_image, true,
"Degrade rendered image with speckle noise, dilation/erosion "
"and rotation");
// Degradation to apply to the image.
INT_PARAM_FLAG(exposure, 0, "Exposure level in photocopier");
// Output image resolution.
INT_PARAM_FLAG(resolution, 300, "Pixels per inch");
// Width of output image (in pixels).
INT_PARAM_FLAG(xsize, 3600, "Width of output image");
// Max height of output image (in pixels).
INT_PARAM_FLAG(ysize, 4800, "Height of output image");
// Margin around text (in pixels).
INT_PARAM_FLAG(margin, 100, "Margin round edges of image");
// Size of text (in points).
INT_PARAM_FLAG(ptsize, 12, "Size of printed text");
// Inter-character space (in ems).
DOUBLE_PARAM_FLAG(char_spacing, 0, "Inter-character space in ems");
// Inter-line space (in pixels).
INT_PARAM_FLAG(leading, 12, "Inter-line space (in pixels)");
// Layout and glyph orientation on rendering.
STRING_PARAM_FLAG(writing_mode, "horizontal",
"Specify one of the following writing"
" modes.\n"
"'horizontal' : Render regular horizontal text. (default)\n"
"'vertical' : Render vertical text. Glyph orientation is"
" selected by Pango.\n"
"'vertical-upright' : Render vertical text. Glyph "
" orientation is set to be upright.");
INT_PARAM_FLAG(box_padding, 0, "Padding around produced bounding boxes");
BOOL_PARAM_FLAG(strip_unrenderable_words, false,
"Remove unrenderable words from source text");
// Font name.
STRING_PARAM_FLAG(font, "Arial", "Font description name to use");
BOOL_PARAM_FLAG(ligatures, false,
"Rebuild and render ligatures");
BOOL_PARAM_FLAG(find_fonts, false,
"Search for all fonts that can render the text");
BOOL_PARAM_FLAG(render_per_font, true,
"If find_fonts==true, render each font to its own image. "
"Image filenames are of the form output_name.font_name.tif");
BOOL_PARAM_FLAG(list_available_fonts, false, "List available fonts and quit.");
BOOL_PARAM_FLAG(render_ngrams, false, "Put each space-separated entity from the"
" input file into one bounding box. The ngrams in the input"
" file will be randomly permuted before rendering (so that"
" there is sufficient variety of characters on each line).");
BOOL_PARAM_FLAG(output_word_boxes, false,
"Output word bounding boxes instead of character boxes. "
"This is used for Cube training, and implied by "
"--render_ngrams.");
STRING_PARAM_FLAG(unicharset_file, "",
"File with characters in the unicharset. If --render_ngrams"
" is true and --unicharset_file is specified, ngrams with"
" characters that are not in unicharset will be omitted");
BOOL_PARAM_FLAG(bidirectional_rotation, false,
"Rotate the generated characters both ways.");
BOOL_PARAM_FLAG(only_extract_font_properties, false,
"Assumes that the input file contains a list of ngrams. Renders"
" each ngram, extracts spacing properties and records them in"
" output_base/[font_name].fontinfo file.");
// Use these flags to output zero-padded, square individual character images
BOOL_PARAM_FLAG(output_individual_glyph_images, false,
"If true also outputs individual character images");
INT_PARAM_FLAG(glyph_resized_size, 0,
"Each glyph is square with this side length in pixels");
INT_PARAM_FLAG(glyph_num_border_pixels_to_pad, 0,
"Final_size=glyph_resized_size+2*glyph_num_border_pixels_to_pad");
namespace tesseract {
struct SpacingProperties {
SpacingProperties() : x_gap_before(0), x_gap_after(0) {}
SpacingProperties(int b, int a) : x_gap_before(b), x_gap_after(a) {}
// These values are obtained from FT_Glyph_Metrics struct
// used by the FreeType font engine.
int x_gap_before; // horizontal x bearing
int x_gap_after; // horizontal advance - x_gap_before - width
map<string, int> kerned_x_gaps;
};
static bool IsWhitespaceBox(const BoxChar* boxchar) {
return (boxchar->box() == NULL ||
SpanUTF8Whitespace(boxchar->ch().c_str()));
}
static string StringReplace(const string& in,
const string& oldsub, const string& newsub) {
string out;
int start_pos = 0;
do {
int pos = in.find(oldsub, start_pos);
if (pos == string::npos) break;
out.append(in.data() + start_pos, pos - start_pos);
out.append(newsub.data(), newsub.length());
start_pos = pos + oldsub.length();
} while (true);
out.append(in.data() + start_pos, in.length() - start_pos);
return out;
}
// Assumes that each word (whitespace-separated entity) in text is a bigram.
// Renders the bigrams and calls FontInfo::GetSpacingProperties() to
// obtain spacing information. Produces the output .fontinfo file with a line
// per unichar of the form:
// unichar space_before space_after kerned1 kerned_space1 kerned2 ...
// Fox example, if unichar "A" has spacing of 0 pixels before and -1 pixels
// after, is kerned with "V" resulting in spacing of "AV" to be -7 and kerned
// with "T", such that "AT" has spacing of -5, the entry/line for unichar "A"
// in .fontinfo file will be:
// A 0 -1 T -5 V -7
void ExtractFontProperties(const string &utf8_text,
StringRenderer *render,
const string &output_base) {
map<string, SpacingProperties> spacing_map;
map<string, SpacingProperties>::iterator spacing_map_it0;
map<string, SpacingProperties>::iterator spacing_map_it1;
int x_bearing, x_advance;
int len = utf8_text.length();
int offset = 0;
const char* text = utf8_text.c_str();
while (offset < len) {
offset += render->RenderToImage(text + offset, strlen(text + offset), NULL);
const vector<BoxChar*> &boxes = render->GetBoxes();
// If the page break split a bigram, correct the offset so we try the bigram
// on the next iteration.
if (boxes.size() > 2 && !IsWhitespaceBox(boxes[boxes.size() - 1]) &&
IsWhitespaceBox(boxes[boxes.size() - 2])) {
if (boxes.size() > 3) {
tprintf("WARNING: Adjusting to bad page break after '%s%s'\n",
boxes[boxes.size() - 4]->ch().c_str(),
boxes[boxes.size() - 3]->ch().c_str());
}
offset -= boxes[boxes.size() - 1]->ch().size();
}
for (int b = 0; b < boxes.size(); b += 2) {
while (b < boxes.size() && IsWhitespaceBox(boxes[b])) ++b;
if (b + 1 >= boxes.size()) break;
const string &ch0 = boxes[b]->ch();
// We encountered a ligature. This happens in at least two scenarios:
// One is when the rendered bigram forms a grapheme cluster (eg. the
// second character in the bigram is a combining vowel), in which case we
// correctly output only one bounding box.
// A second far less frequent case is when caused some fonts like 'DejaVu
// Sans Ultra-Light' force Pango to render a ligatured character even if
// the input consists of the separated characters. NOTE(ranjith): As per
// behdad@ this is not currently controllable at the level of the Pango
// API.
// Safeguard against these cases here by just skipping the bigram.
if (IsWhitespaceBox(boxes[b+1])) {
tprintf("WARNING: Found unexpected ligature: %s\n", ch0.c_str());
continue;
}
int xgap = (boxes[b+1]->box()->x -
(boxes[b]->box()->x + boxes[b]->box()->w));
spacing_map_it0 = spacing_map.find(ch0);
int ok_count = 0;
if (spacing_map_it0 == spacing_map.end() &&
render->font().GetSpacingProperties(ch0, &x_bearing, &x_advance)) {
spacing_map[ch0] = SpacingProperties(
x_bearing, x_advance - x_bearing - boxes[b]->box()->w);
spacing_map_it0 = spacing_map.find(ch0);
++ok_count;
}
const string &ch1 = boxes[b+1]->ch();
tlog(3, "%s%s\n", ch0.c_str(), ch1.c_str());
spacing_map_it1 = spacing_map.find(ch1);
if (spacing_map_it1 == spacing_map.end() &&
render->font().GetSpacingProperties(ch1, &x_bearing, &x_advance)) {
spacing_map[ch1] = SpacingProperties(
x_bearing, x_advance - x_bearing - boxes[b+1]->box()->w);
spacing_map_it1 = spacing_map.find(ch1);
++ok_count;
}
if (ok_count == 2 && xgap != (spacing_map_it0->second.x_gap_after +
spacing_map_it1->second.x_gap_before)) {
spacing_map_it0->second.kerned_x_gaps[ch1] = xgap;
}
}
render->ClearBoxes();
}
string output_string;
const int kBufSize = 1024;
char buf[kBufSize];
snprintf(buf, kBufSize, "%d\n", static_cast<int>(spacing_map.size()));
output_string.append(buf);
map<string, SpacingProperties>::const_iterator spacing_map_it;
for (spacing_map_it = spacing_map.begin();
spacing_map_it != spacing_map.end(); ++spacing_map_it) {
snprintf(buf, kBufSize,
"%s %d %d %d", spacing_map_it->first.c_str(),
spacing_map_it->second.x_gap_before,
spacing_map_it->second.x_gap_after,
static_cast<int>(spacing_map_it->second.kerned_x_gaps.size()));
output_string.append(buf);
map<string, int>::const_iterator kern_it;
for (kern_it = spacing_map_it->second.kerned_x_gaps.begin();
kern_it != spacing_map_it->second.kerned_x_gaps.end(); ++kern_it) {
snprintf(buf, kBufSize,
" %s %d", kern_it->first.c_str(), kern_it->second);
output_string.append(buf);
}
output_string.append("\n");
}
File::WriteStringToFileOrDie(output_string, output_base + ".fontinfo");
}
bool MakeIndividualGlyphs(Pix* pix,
const vector<BoxChar*>& vbox,
const int input_tiff_page) {
// If checks fail, return false without exiting text2image
if (!pix) {
tprintf("ERROR: MakeIndividualGlyphs(): Input Pix* is NULL\n");
return false;
} else if (FLAGS_glyph_resized_size <= 0) {
tprintf("ERROR: --glyph_resized_size must be positive\n");
return false;
} else if (FLAGS_glyph_num_border_pixels_to_pad < 0) {
tprintf("ERROR: --glyph_num_border_pixels_to_pad must be 0 or positive\n");
return false;
}
const int n_boxes = vbox.size();
int n_boxes_saved = 0;
int current_tiff_page = 0;
int y_previous = 0;
static int glyph_count = 0;
for (int i = 0; i < n_boxes; i++) {
// Get one bounding box
Box* b = vbox[i]->mutable_box();
if (!b) continue;
const int x = b->x;
const int y = b->y;
const int w = b->w;
const int h = b->h;
// Check present tiff page (for multipage tiff)
if (y < y_previous-pixGetHeight(pix)/10) {
tprintf("ERROR: Wrap-around encountered, at i=%d\n", i);
current_tiff_page++;
}
if (current_tiff_page < input_tiff_page) continue;
else if (current_tiff_page > input_tiff_page) break;
// Check box validity
if (x < 0 || y < 0 ||
(x+w-1) >= pixGetWidth(pix) ||
(y+h-1) >= pixGetHeight(pix)) {
tprintf("ERROR: MakeIndividualGlyphs(): Index out of range, at i=%d"
" (x=%d, y=%d, w=%d, h=%d\n)", i, x, y, w, h);
continue;
} else if (w < FLAGS_glyph_num_border_pixels_to_pad &&
h < FLAGS_glyph_num_border_pixels_to_pad) {
tprintf("ERROR: Input image too small to be a character, at i=%d\n", i);
continue;
}
// Crop the boxed character
Pix* pix_glyph = pixClipRectangle(pix, b, NULL);
if (!pix_glyph) {
tprintf("ERROR: MakeIndividualGlyphs(): Failed to clip, at i=%d\n", i);
continue;
}
// Resize to square
Pix* pix_glyph_sq = pixScaleToSize(pix_glyph,
FLAGS_glyph_resized_size,
FLAGS_glyph_resized_size);
if (!pix_glyph_sq) {
tprintf("ERROR: MakeIndividualGlyphs(): Failed to resize, at i=%d\n", i);
continue;
}
// Zero-pad
Pix* pix_glyph_sq_pad = pixAddBorder(pix_glyph_sq,
FLAGS_glyph_num_border_pixels_to_pad,
0);
if (!pix_glyph_sq_pad) {
tprintf("ERROR: MakeIndividualGlyphs(): Failed to zero-pad, at i=%d\n", i);
continue;
}
// Write out
Pix* pix_glyph_sq_pad_8 = pixConvertTo8(pix_glyph_sq_pad, false);
char filename[1024];
snprintf(filename, 1024, "%s_%d.jpg", FLAGS_outputbase.c_str(),
glyph_count++);
if (pixWriteJpeg(filename, pix_glyph_sq_pad_8, 100, 0)) {
tprintf("ERROR: MakeIndividualGlyphs(): Failed to write JPEG to %s,"
" at i=%d\n", filename, i);
continue;
}
pixDestroy(&pix_glyph);
pixDestroy(&pix_glyph_sq);
pixDestroy(&pix_glyph_sq_pad);
pixDestroy(&pix_glyph_sq_pad_8);
n_boxes_saved++;
y_previous = y;
}
if (n_boxes_saved == 0) {
return false;
} else {
tprintf("Total number of characters saved = %d\n", n_boxes_saved);
return true;
}
}
} // namespace tesseract
using tesseract::DegradeImage;
using tesseract::ExtractFontProperties;
using tesseract::File;
using tesseract::FontUtils;
using tesseract::SpanUTF8NotWhitespace;
using tesseract::SpanUTF8Whitespace;
using tesseract::StringRenderer;
int main(int argc, char** argv) {
tesseract::ParseCommandLineFlags(argv[0], &argc, &argv, true);
if (FLAGS_list_available_fonts) {
const vector<string>& all_fonts = FontUtils::ListAvailableFonts();
for (int i = 0; i < all_fonts.size(); ++i) {
tprintf("%3d: %s\n", i, all_fonts[i].c_str());
ASSERT_HOST_MSG(FontUtils::IsAvailableFont(all_fonts[i].c_str()),
"Font %s is unrecognized.\n", all_fonts[i].c_str());
}
return EXIT_SUCCESS;
}
// Check validity of input flags.
ASSERT_HOST_MSG(!FLAGS_text.empty(), "Text file missing!\n");
ASSERT_HOST_MSG(!FLAGS_outputbase.empty(), "Output file missing!\n");
ASSERT_HOST_MSG(FLAGS_render_ngrams || FLAGS_unicharset_file.empty(),
"Use --unicharset_file only if --render_ngrams is set.\n");
ASSERT_HOST_MSG(FLAGS_find_fonts ||
FontUtils::IsAvailableFont(FLAGS_font.c_str()),
"Could not find font named %s\n", FLAGS_font.c_str());
if (FLAGS_render_ngrams)
FLAGS_output_word_boxes = true;
char font_desc_name[1024];
snprintf(font_desc_name, 1024, "%s %d", FLAGS_font.c_str(),
static_cast<int>(FLAGS_ptsize));
StringRenderer render(font_desc_name, FLAGS_xsize, FLAGS_ysize);
render.set_add_ligatures(FLAGS_ligatures);
render.set_leading(FLAGS_leading);
render.set_resolution(FLAGS_resolution);
render.set_char_spacing(FLAGS_char_spacing * FLAGS_ptsize);
render.set_h_margin(FLAGS_margin);
render.set_v_margin(FLAGS_margin);
render.set_output_word_boxes(FLAGS_output_word_boxes);
render.set_box_padding(FLAGS_box_padding);
render.set_strip_unrenderable_words(FLAGS_strip_unrenderable_words);
// Set text rendering orientation and their forms.
if (FLAGS_writing_mode == "horizontal") {
// Render regular horizontal text (default).
render.set_vertical_text(false);
render.set_gravity_hint_strong(false);
render.set_render_fullwidth_latin(false);
} else if (FLAGS_writing_mode == "vertical") {
// Render vertical text. Glyph orientation is selected by Pango.
render.set_vertical_text(true);
render.set_gravity_hint_strong(false);
render.set_render_fullwidth_latin(false);
} else if (FLAGS_writing_mode == "vertical-upright") {
// Render vertical text. Glyph orientation is set to be upright.
// Also Basic Latin characters are converted to their fullwidth forms
// on rendering, since fullwidth Latin characters are well designed to fit
// vertical text lines, while .box files store halfwidth Basic Latin
// unichars.
render.set_vertical_text(true);
render.set_gravity_hint_strong(true);
render.set_render_fullwidth_latin(true);
} else {
TLOG_FATAL("Invalid writing mode : %s\n", FLAGS_writing_mode.c_str());
}
string src_utf8;
// This c_str is NOT redundant!
File::ReadFileToStringOrDie(FLAGS_text.c_str(), &src_utf8);
// Remove the unicode mark if present.
if (strncmp(src_utf8.c_str(), "\xef\xbb\xbf", 3) == 0) {
src_utf8.erase(0, 3);
}
tlog(1, "Render string of size %d\n", src_utf8.length());
if (FLAGS_render_ngrams || FLAGS_only_extract_font_properties) {
// Try to preserve behavior of old text2image by expanding inter-word
// spaces by a factor of 4.
const string kSeparator = FLAGS_render_ngrams ? " " : " ";
// Also restrict the number of charactes per line to try and avoid
// line-breaking in the middle of words like "-A", "R$" etc. which are
// otherwise allowed by the standard unicode line-breaking rules.
const int kCharsPerLine = (FLAGS_ptsize > 20) ? 50 : 100;
string rand_utf8;
UNICHARSET unicharset;
if (FLAGS_render_ngrams && !FLAGS_unicharset_file.empty() &&
!unicharset.load_from_file(FLAGS_unicharset_file.c_str())) {
TLOG_FATAL("Failed to load unicharset from file %s\n",
FLAGS_unicharset_file.c_str());
}
// If we are rendering ngrams that will be OCRed later, shuffle them so that
// tesseract does not have difficulties finding correct baseline, word
// spaces, etc.
const char *str8 = src_utf8.c_str();
int len = src_utf8.length();
int step;
vector<pair<int, int> > offsets;
int offset = SpanUTF8Whitespace(str8);
while (offset < len) {
step = SpanUTF8NotWhitespace(str8 + offset);
offsets.push_back(make_pair(offset, step));
offset += step;
offset += SpanUTF8Whitespace(str8 + offset);
}
if (FLAGS_render_ngrams)
std::random_shuffle(offsets.begin(), offsets.end());
for (int i = 0, line = 1; i < offsets.size(); ++i) {
const char *curr_pos = str8 + offsets[i].first;
int ngram_len = offsets[i].second;
// Skip words that contain characters not in found in unicharset.
if (!FLAGS_unicharset_file.empty() &&
!unicharset.encodable_string(curr_pos, NULL)) {
continue;
}
rand_utf8.append(curr_pos, ngram_len);
if (rand_utf8.length() > line * kCharsPerLine) {
rand_utf8.append(" \n");
++line;
if (line & 0x1) rand_utf8.append(kSeparator);
} else {
rand_utf8.append(kSeparator);
}
}
tlog(1, "Rendered ngram string of size %d\n", rand_utf8.length());
src_utf8.swap(rand_utf8);
}
if (FLAGS_only_extract_font_properties) {
tprintf("Extracting font properties only\n");
ExtractFontProperties(src_utf8, &render, FLAGS_outputbase.c_str());
tprintf("Done!\n");
return 0;
}
int im = 0;
vector<float> page_rotation;
const char* to_render_utf8 = src_utf8.c_str();
// We use a two pass mechanism to rotate images in both direction.
// The first pass(0) will rotate the images in random directions and
// the second pass(1) will mirror those rotations.
int num_pass = FLAGS_bidirectional_rotation ? 2 : 1;
for (int pass = 0; pass < num_pass; ++pass) {
int page_num = 0;
string font_used;
for (int offset = 0; offset < strlen(to_render_utf8); ++im, ++page_num) {
tlog(1, "Starting page %d\n", im);
Pix* pix = NULL;
if (FLAGS_find_fonts) {
offset += render.RenderAllFontsToImage(to_render_utf8 + offset,
strlen(to_render_utf8 + offset),
&font_used, &pix);
} else {
offset += render.RenderToImage(to_render_utf8 + offset,
strlen(to_render_utf8 + offset), &pix);
}
if (pix != NULL) {
float rotation = 0;
if (pass == 1) {
// Pass 2, do mirror rotation.
rotation = -1 * page_rotation[page_num];
}
if (FLAGS_degrade_image) {
pix = DegradeImage(pix, FLAGS_exposure, &rotation);
}
render.RotatePageBoxes(rotation);
if (pass == 0) {
// Pass 1, rotate randomly and store the rotation..
page_rotation.push_back(rotation);
}
Pix* gray_pix = pixConvertTo8(pix, false);
pixDestroy(&pix);
Pix* binary = pixThresholdToBinary(gray_pix, 128);
pixDestroy(&gray_pix);
char tiff_name[1024];
if (FLAGS_find_fonts && FLAGS_render_per_font) {
string fontname_for_file = tesseract::StringReplace(
font_used, " ", "_");
snprintf(tiff_name, 1024, "%s.%s.tif", FLAGS_outputbase.c_str(),
fontname_for_file.c_str());
pixWriteTiff(tiff_name, binary, IFF_TIFF_G4, "w");
} else {
snprintf(tiff_name, 1024, "%s.tif", FLAGS_outputbase.c_str());
pixWriteTiff(tiff_name, binary, IFF_TIFF_G4, im == 0 ? "w" : "a");
}
tprintf("Rendered page %d to file %s\n", im, tiff_name);
// Make individual glyphs
if (FLAGS_output_individual_glyph_images) {
if (!MakeIndividualGlyphs(binary, render.GetBoxes(), im)) {
tprintf("ERROR: Individual glyphs not saved\n");
}
}
pixDestroy(&binary);
}
}
}
if (!FLAGS_find_fonts) {
string box_name = FLAGS_outputbase.c_str();
box_name += ".box";
render.WriteAllBoxes(box_name);
}
return 0;
}
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