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tesseract/api/baseapi.cpp

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/**********************************************************************
* File: baseapi.cpp
* Description: Simple API for calling tesseract.
* Author: Ray Smith
* Created: Fri Oct 06 15:35:01 PDT 2006
*
* (C) Copyright 2006, 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 automatically generated configuration file if running autoconf.
#ifdef HAVE_CONFIG_H
#include "config_auto.h"
#endif
#include "allheaders.h"
#ifdef USE_NLS
#include <libintl.h>
#include <locale.h>
#define _(x) gettext(x)
#else
#define _(x) (x)
#endif
#include "baseapi.h"
#include "resultiterator.h"
#include "mutableiterator.h"
#include "thresholder.h"
#include "tesseractclass.h"
#include "pageres.h"
#include "paragraphs.h"
#include "tessvars.h"
#include "control.h"
#include "pgedit.h"
#include "paramsd.h"
#include "output.h"
#include "globals.h"
#include "edgblob.h"
#include "equationdetect.h"
#include "tessbox.h"
#include "imgs.h"
#include "imgtiff.h"
#include "makerow.h"
#include "permute.h"
#include "otsuthr.h"
#include "osdetect.h"
#include "params.h"
#ifdef _WIN32
#include "version.h"
#endif
namespace tesseract {
// Minimum sensible image size to be worth running tesseract.
const int kMinRectSize = 10;
// Character returned when Tesseract couldn't recognize as anything.
const char kTesseractReject = '~';
// Character used by UNLV error counter as a reject.
const char kUNLVReject = '~';
// Character used by UNLV as a suspect marker.
const char kUNLVSuspect = '^';
// Filename used for input image file, from which to derive a name to search
// for a possible UNLV zone file, if none is specified by SetInputName.
const char* kInputFile = "noname.tif";
// Temp file used for storing current parameters before applying retry values.
const char* kOldVarsFile = "failed_vars.txt";
// Max string length of an int.
const int kMaxIntSize = 22;
// Minimum believable resolution. Used as a default if there is no other
// information, as it is safer to under-estimate than over-estimate.
const int kMinCredibleResolution = 70;
// Maximum believable resolution.
const int kMaxCredibleResolution = 2400;
TessBaseAPI::TessBaseAPI()
: tesseract_(NULL),
osd_tesseract_(NULL),
equ_detect_(NULL),
// Thresholder is initialized to NULL here, but will be set before use by:
// A constructor of a derived API, SetThresholder(), or
// created implicitly when used in InternalSetImage.
thresholder_(NULL),
paragraph_models_(NULL),
block_list_(NULL),
page_res_(NULL),
input_file_(NULL),
output_file_(NULL),
datapath_(NULL),
language_(NULL),
last_oem_requested_(OEM_DEFAULT),
recognition_done_(false),
truth_cb_(NULL),
rect_left_(0), rect_top_(0), rect_width_(0), rect_height_(0),
image_width_(0), image_height_(0) {
}
TessBaseAPI::~TessBaseAPI() {
End();
}
/**
* Returns the version identifier as a static string. Do not delete.
*/
const char* TessBaseAPI::Version() {
return VERSION;
}
// Set the name of the input file. Needed only for training and
// loading a UNLV zone file.
void TessBaseAPI::SetInputName(const char* name) {
if (input_file_ == NULL)
input_file_ = new STRING(name);
else
*input_file_ = name;
}
// Set the name of the output files. Needed only for debugging.
void TessBaseAPI::SetOutputName(const char* name) {
if (output_file_ == NULL)
output_file_ = new STRING(name);
else
*output_file_ = name;
}
bool TessBaseAPI::SetVariable(const char* name, const char* value) {
if (tesseract_ == NULL) tesseract_ = new Tesseract;
return ParamUtils::SetParam(name, value, SET_PARAM_CONSTRAINT_NON_INIT_ONLY,
tesseract_->params());
}
bool TessBaseAPI::SetDebugVariable(const char* name, const char* value) {
if (tesseract_ == NULL) tesseract_ = new Tesseract;
return ParamUtils::SetParam(name, value, SET_PARAM_CONSTRAINT_DEBUG_ONLY,
tesseract_->params());
}
bool TessBaseAPI::GetIntVariable(const char *name, int *value) const {
IntParam *p = ParamUtils::FindParam<IntParam>(
name, GlobalParams()->int_params, tesseract_->params()->int_params);
if (p == NULL) return false;
*value = (inT32)(*p);
return true;
}
bool TessBaseAPI::GetBoolVariable(const char *name, bool *value) const {
BoolParam *p = ParamUtils::FindParam<BoolParam>(
name, GlobalParams()->bool_params, tesseract_->params()->bool_params);
if (p == NULL) return false;
*value = (BOOL8)(*p);
return true;
}
const char *TessBaseAPI::GetStringVariable(const char *name) const {
StringParam *p = ParamUtils::FindParam<StringParam>(
name, GlobalParams()->string_params, tesseract_->params()->string_params);
return (p != NULL) ? p->string() : NULL;
}
bool TessBaseAPI::GetDoubleVariable(const char *name, double *value) const {
DoubleParam *p = ParamUtils::FindParam<DoubleParam>(
name, GlobalParams()->double_params, tesseract_->params()->double_params);
if (p == NULL) return false;
*value = (double)(*p);
return true;
}
// Get value of named variable as a string, if it exists.
bool TessBaseAPI::GetVariableAsString(const char *name, STRING *val) {
return ParamUtils::GetParamAsString(name, tesseract_->params(), val);
}
// Print Tesseract parameters to the given file.
void TessBaseAPI::PrintVariables(FILE *fp) const {
ParamUtils::PrintParams(fp, tesseract_->params());
}
// The datapath must be the name of the data directory (no ending /) or
// some other file in which the data directory resides (for instance argv[0].)
// The language is (usually) an ISO 639-3 string or NULL will default to eng.
// If numeric_mode is true, then only digits and Roman numerals will
// be returned.
// Returns 0 on success and -1 on initialization failure.
int TessBaseAPI::Init(const char* datapath, const char* language,
OcrEngineMode oem, char **configs, int configs_size,
const GenericVector<STRING> *vars_vec,
const GenericVector<STRING> *vars_values,
bool set_only_non_debug_params) {
// Default language is "eng".
if (language == NULL) language = "eng";
// If the datapath, OcrEngineMode or the language have changed - start again.
// Note that the language_ field stores the last requested language that was
// initialized successfully, while tesseract_->lang stores the language
// actually used. They differ only if the requested language was NULL, in
// which case tesseract_->lang is set to the Tesseract default ("eng").
if (tesseract_ != NULL &&
(datapath_ == NULL || language_ == NULL ||
*datapath_ != datapath || last_oem_requested_ != oem ||
(*language_ != language && tesseract_->lang != language))) {
delete tesseract_;
tesseract_ = NULL;
}
bool reset_classifier = true;
if (tesseract_ == NULL) {
reset_classifier = false;
tesseract_ = new Tesseract;
if (tesseract_->init_tesseract(
datapath, output_file_ != NULL ? output_file_->string() : NULL,
language, oem, configs, configs_size, vars_vec, vars_values,
set_only_non_debug_params) != 0) {
return -1;
}
}
// Update datapath and language requested for the last valid initialization.
if (datapath_ == NULL)
datapath_ = new STRING(datapath);
else
*datapath_ = datapath;
if (language_ == NULL)
language_ = new STRING(language);
else
*language_ = language;
last_oem_requested_ = oem;
// For same language and datapath, just reset the adaptive classifier.
if (reset_classifier) tesseract_->ResetAdaptiveClassifier();
return 0;
}
// Returns the languages string used in the last valid initialization.
// If the last initialization specified "deu+hin" then that will be
// returned. If hin loaded eng automatically as well, then that will
// not be included in this list. To find the languages actually
// loaded use GetLoadedLanguagesAsVector.
// The returned string should NOT be deleted.
const char* TessBaseAPI::GetInitLanguagesAsString() const {
return (language_ == NULL || language_->string() == NULL) ?
"" : language_->string();
}
// Returns the loaded languages in the vector of STRINGs.
// Includes all languages loaded by the last Init, including those loaded
// as dependencies of other loaded languages.
void TessBaseAPI::GetLoadedLanguagesAsVector(
GenericVector<STRING>* langs) const {
langs->clear();
if (tesseract_ != NULL) {
langs->push_back(tesseract_->lang);
int num_subs = tesseract_->num_sub_langs();
for (int i = 0; i < num_subs; ++i)
langs->push_back(tesseract_->get_sub_lang(i)->lang);
}
}
// Init only the lang model component of Tesseract. The only functions
// that work after this init are SetVariable and IsValidWord.
// WARNING: temporary! This function will be removed from here and placed
// in a separate API at some future time.
int TessBaseAPI::InitLangMod(const char* datapath, const char* language) {
if (tesseract_ == NULL)
tesseract_ = new Tesseract;
return tesseract_->init_tesseract_lm(datapath, NULL, language);
}
// Init only for page layout analysis. Use only for calls to SetImage and
// AnalysePage. Calls that attempt recognition will generate an error.
void TessBaseAPI::InitForAnalysePage() {
if (tesseract_ == NULL) {
tesseract_ = new Tesseract;
tesseract_->InitAdaptiveClassifier(false);
}
}
// Read a "config" file containing a set of parameter name, value pairs.
// Searches the standard places: tessdata/configs, tessdata/tessconfigs
// and also accepts a relative or absolute path name.
void TessBaseAPI::ReadConfigFile(const char* filename) {
tesseract_->read_config_file(filename, SET_PARAM_CONSTRAINT_NON_INIT_ONLY);
}
// Same as above, but only set debug params from the given config file.
void TessBaseAPI::ReadDebugConfigFile(const char* filename) {
tesseract_->read_config_file(filename, SET_PARAM_CONSTRAINT_DEBUG_ONLY);
}
// Set the current page segmentation mode. Defaults to PSM_AUTO.
// The mode is stored as an IntParam so it can also be modified by
// ReadConfigFile or SetVariable("tessedit_pageseg_mode", mode as string).
void TessBaseAPI::SetPageSegMode(PageSegMode mode) {
if (tesseract_ == NULL)
tesseract_ = new Tesseract;
tesseract_->tessedit_pageseg_mode.set_value(mode);
}
// Return the current page segmentation mode.
PageSegMode TessBaseAPI::GetPageSegMode() const {
if (tesseract_ == NULL)
return PSM_SINGLE_BLOCK;
return static_cast<PageSegMode>(
static_cast<int>(tesseract_->tessedit_pageseg_mode));
}
// Recognize a rectangle from an image and return the result as a string.
// May be called many times for a single Init.
// Currently has no error checking.
// Greyscale of 8 and color of 24 or 32 bits per pixel may be given.
// Palette color images will not work properly and must be converted to
// 24 bit.
// Binary images of 1 bit per pixel may also be given but they must be
// byte packed with the MSB of the first byte being the first pixel, and a
// one pixel is WHITE. For binary images set bytes_per_pixel=0.
// The recognized text is returned as a char* which is coded
// as UTF8 and must be freed with the delete [] operator.
char* TessBaseAPI::TesseractRect(const unsigned char* imagedata,
int bytes_per_pixel,
int bytes_per_line,
int left, int top,
int width, int height) {
if (tesseract_ == NULL || width < kMinRectSize || height < kMinRectSize)
return NULL; // Nothing worth doing.
// Since this original api didn't give the exact size of the image,
// we have to invent a reasonable value.
int bits_per_pixel = bytes_per_pixel == 0 ? 1 : bytes_per_pixel * 8;
SetImage(imagedata, bytes_per_line * 8 / bits_per_pixel, height + top,
bytes_per_pixel, bytes_per_line);
SetRectangle(left, top, width, height);
return GetUTF8Text();
}
// Call between pages or documents etc to free up memory and forget
// adaptive data.
void TessBaseAPI::ClearAdaptiveClassifier() {
if (tesseract_ == NULL)
return;
tesseract_->ResetAdaptiveClassifier();
tesseract_->ResetDocumentDictionary();
}
// Provide an image for Tesseract to recognize. Format is as
// TesseractRect above. Does not copy the image buffer, or take
// ownership. The source image may be destroyed after Recognize is called,
// either explicitly or implicitly via one of the Get*Text functions.
// SetImage clears all recognition results, and sets the rectangle to the
// full image, so it may be followed immediately by a GetUTF8Text, and it
// will automatically perform recognition.
void TessBaseAPI::SetImage(const unsigned char* imagedata,
int width, int height,
int bytes_per_pixel, int bytes_per_line) {
if (InternalSetImage())
thresholder_->SetImage(imagedata, width, height,
bytes_per_pixel, bytes_per_line);
}
void TessBaseAPI::SetSourceResolution(int ppi) {
if (thresholder_)
thresholder_->SetSourceYResolution(ppi);
else
tprintf("Please call SetImage before SetSourceResolution.\n");
}
// Provide an image for Tesseract to recognize. As with SetImage above,
// Tesseract doesn't take a copy or ownership or pixDestroy the image, so
// it must persist until after Recognize.
// Pix vs raw, which to use?
// Use Pix where possible. A future version of Tesseract may choose to use Pix
// as its internal representation and discard IMAGE altogether.
// Because of that, an implementation that sources and targets Pix may end up
// with less copies than an implementation that does not.
void TessBaseAPI::SetImage(const Pix* pix) {
if (InternalSetImage())
thresholder_->SetImage(pix);
}
// Restrict recognition to a sub-rectangle of the image. Call after SetImage.
// Each SetRectangle clears the recogntion results so multiple rectangles
// can be recognized with the same image.
void TessBaseAPI::SetRectangle(int left, int top, int width, int height) {
if (thresholder_ == NULL)
return;
thresholder_->SetRectangle(left, top, width, height);
ClearResults();
}
// ONLY available if you have Leptonica installed.
// Get a copy of the internal thresholded image from Tesseract.
Pix* TessBaseAPI::GetThresholdedImage() {
if (tesseract_ == NULL)
return NULL;
if (tesseract_->pix_binary() == NULL)
Threshold(tesseract_->mutable_pix_binary());
return pixClone(tesseract_->pix_binary());
}
// Get the result of page layout analysis as a leptonica-style
// Boxa, Pixa pair, in reading order.
// Can be called before or after Recognize.
Boxa* TessBaseAPI::GetRegions(Pixa** pixa) {
return GetComponentImages(RIL_BLOCK, false, pixa, NULL);
}
// Get the textlines as a leptonica-style Boxa, Pixa pair, in reading order.
// Can be called before or after Recognize.
// If blockids is not NULL, the block-id of each line is also returned as an
// array of one element per line. delete [] after use.
Boxa* TessBaseAPI::GetTextlines(Pixa** pixa, int** blockids) {
return GetComponentImages(RIL_TEXTLINE, true, pixa, blockids);
}
// Get textlines and strips of image regions as a leptonica-style Boxa, Pixa
// pair, in reading order. Enables downstream handling of non-rectangular
// regions.
// Can be called before or after Recognize.
// If blockids is not NULL, the block-id of each line is also returned as an
// array of one element per line. delete [] after use.
Boxa* TessBaseAPI::GetStrips(Pixa** pixa, int** blockids) {
return GetComponentImages(RIL_TEXTLINE, false, pixa, blockids);
}
// Get the words as a leptonica-style
// Boxa, Pixa pair, in reading order.
// Can be called before or after Recognize.
Boxa* TessBaseAPI::GetWords(Pixa** pixa) {
return GetComponentImages(RIL_WORD, true, pixa, NULL);
}
// Gets the individual connected (text) components (created
// after pages segmentation step, but before recognition)
// as a leptonica-style Boxa, Pixa pair, in reading order.
// Can be called before or after Recognize.
Boxa* TessBaseAPI::GetConnectedComponents(Pixa** pixa) {
return GetComponentImages(RIL_SYMBOL, true, pixa, NULL);
}
// Get the given level kind of components (block, textline, word etc.) as a
// leptonica-style Boxa, Pixa pair, in reading order.
// Can be called before or after Recognize.
// If blockids is not NULL, the block-id of each component is also returned
// as an array of one element per component. delete [] after use.
// If text_only is true, then only text components are returned.
Boxa* TessBaseAPI::GetComponentImages(PageIteratorLevel level,
bool text_only,
Pixa** pixa, int** blockids) {
PageIterator* page_it = GetIterator();
if (page_it == NULL)
page_it = AnalyseLayout();
if (page_it == NULL)
return NULL; // Failed.
// Count the components to get a size for the arrays.
int component_count = 0;
int left, top, right, bottom;
do {
if (page_it->BoundingBoxInternal(level, &left, &top, &right, &bottom) &&
(!text_only || PTIsTextType(page_it->BlockType())))
++component_count;
} while (page_it->Next(level));
Boxa* boxa = boxaCreate(component_count);
if (pixa != NULL)
*pixa = pixaCreate(component_count);
if (blockids != NULL)
*blockids = new int[component_count];
int blockid = 0;
int component_index = 0;
page_it->Begin();
do {
if (page_it->BoundingBoxInternal(level, &left, &top, &right, &bottom) &&
(!text_only || PTIsTextType(page_it->BlockType()))) {
Box* lbox = boxCreate(left, top, right - left, bottom - top);
boxaAddBox(boxa, lbox, L_INSERT);
if (pixa != NULL) {
Pix* pix = page_it->GetBinaryImage(level);
pixaAddPix(*pixa, pix, L_INSERT);
pixaAddBox(*pixa, lbox, L_CLONE);
}
if (blockids != NULL) {
(*blockids)[component_index] = blockid;
if (page_it->IsAtFinalElement(RIL_BLOCK, level))
++blockid;
}
++component_index;
}
} while (page_it->Next(level));
delete page_it;
return boxa;
}
int TessBaseAPI::GetThresholdedImageScaleFactor() const {
if (thresholder_ == NULL) {
return 0;
}
return thresholder_->GetScaleFactor();
}
// Dump the internal binary image to a PGM file.
void TessBaseAPI::DumpPGM(const char* filename) {
if (tesseract_ == NULL)
return;
FILE *fp = fopen(filename, "wb");
Pix* pix = tesseract_->pix_binary();
int width = pixGetWidth(pix);
int height = pixGetHeight(pix);
l_uint32* data = pixGetData(pix);
fprintf(fp, "P5 %d %d 255\n", width, height);
for (int y = 0; y < height; ++y, data += pixGetWpl(pix)) {
for (int x = 0; x < width; ++x) {
uinT8 b = GET_DATA_BIT(data, x) ? 0 : 255;
fwrite(&b, 1, 1, fp);
}
}
fclose(fp);
}
// Placeholder for call to Cube and test that the input data is correct.
// reskew is the direction of baselines in the skewed image in
// normalized (cos theta, sin theta) form, so (0.866, 0.5) would represent
// a 30 degree anticlockwise skew.
int CubeAPITest(Boxa* boxa_blocks, Pixa* pixa_blocks,
Boxa* boxa_words, Pixa* pixa_words,
const FCOORD& reskew, Pix* page_pix,
PAGE_RES* page_res) {
int block_count = boxaGetCount(boxa_blocks);
ASSERT_HOST(block_count == pixaGetCount(pixa_blocks));
// Write each block to the current directory as junk_write_display.nnn.png.
for (int i = 0; i < block_count; ++i) {
Pix* pix = pixaGetPix(pixa_blocks, i, L_CLONE);
pixDisplayWrite(pix, 1);
}
int word_count = boxaGetCount(boxa_words);
ASSERT_HOST(word_count == pixaGetCount(pixa_words));
int pr_word = 0;
PAGE_RES_IT page_res_it(page_res);
for (page_res_it.restart_page(); page_res_it.word () != NULL;
page_res_it.forward(), ++pr_word) {
WERD_RES *word = page_res_it.word();
WERD_CHOICE* choice = word->best_choice;
// Write the first 100 words to files names wordims/<wordstring>.tif.
if (pr_word < 100) {
STRING filename("wordims/");
if (choice != NULL) {
filename += choice->unichar_string();
} else {
char numbuf[32];
filename += "unclassified";
snprintf(numbuf, 32, "%03d", pr_word);
filename += numbuf;
}
filename += ".tif";
Pix* pix = pixaGetPix(pixa_words, pr_word, L_CLONE);
pixWrite(filename.string(), pix, IFF_TIFF_G4);
}
}
ASSERT_HOST(pr_word == word_count);
return 0;
}
// Runs page layout analysis in the mode set by SetPageSegMode.
// May optionally be called prior to Recognize to get access to just
// the page layout results. Returns an iterator to the results.
// Returns NULL on error or an empty page.
// The returned iterator must be deleted after use.
// WARNING! This class points to data held within the TessBaseAPI class, and
// therefore can only be used while the TessBaseAPI class still exists and
// has not been subjected to a call of Init, SetImage, Recognize, Clear, End
// DetectOS, or anything else that changes the internal PAGE_RES.
PageIterator* TessBaseAPI::AnalyseLayout() {
if (FindLines() == 0) {
if (block_list_->empty())
return NULL; // The page was empty.
page_res_ = new PAGE_RES(block_list_, NULL);
return new PageIterator(page_res_, tesseract_,
thresholder_->GetScaleFactor(),
thresholder_->GetScaledYResolution(),
rect_left_, rect_top_, rect_width_, rect_height_);
}
return NULL;
}
// Recognize the tesseract global image and return the result as Tesseract
// internal structures.
int TessBaseAPI::Recognize(ETEXT_DESC* monitor) {
if (tesseract_ == NULL)
return -1;
if (FindLines() != 0)
return -1;
if (page_res_ != NULL)
delete page_res_;
tesseract_->SetBlackAndWhitelist();
recognition_done_ = true;
if (tesseract_->tessedit_resegment_from_line_boxes)
page_res_ = tesseract_->ApplyBoxes(*input_file_, true, block_list_);
else if (tesseract_->tessedit_resegment_from_boxes)
page_res_ = tesseract_->ApplyBoxes(*input_file_, false, block_list_);
else
page_res_ = new PAGE_RES(block_list_, &tesseract_->prev_word_best_choice_);
if (tesseract_->tessedit_make_boxes_from_boxes) {
tesseract_->CorrectClassifyWords(page_res_);
return 0;
}
if (truth_cb_ != NULL) {
tesseract_->wordrec_run_blamer.set_value(true);
truth_cb_->Run(tesseract_->getDict().getUnicharset(),
image_height_, page_res_);
}
int result = 0;
if (tesseract_->interactive_display_mode) {
tesseract_->pgeditor_main(rect_width_, rect_height_, page_res_);
// The page_res is invalid after an interactive session, so cleanup
// in a way that lets us continue to the next page without crashing.
delete page_res_;
page_res_ = NULL;
return -1;
} else if (tesseract_->tessedit_train_from_boxes) {
tesseract_->ApplyBoxTraining(*output_file_, page_res_);
} else if (tesseract_->tessedit_ambigs_training) {
FILE *training_output_file = tesseract_->init_recog_training(*input_file_);
// OCR the page segmented into words by tesseract.
tesseract_->recog_training_segmented(
*input_file_, page_res_, monitor, training_output_file);
fclose(training_output_file);
} else {
// Now run the main recognition.
if (tesseract_->recog_all_words(page_res_, monitor, NULL, NULL, 0)) {
int paragraph_debug_level = 0;
GetIntVariable("paragraph_debug_level", &paragraph_debug_level);
DetectParagraphs(paragraph_debug_level);
} else {
result = -1;
}
}
return result;
}
// Tests the chopper by exhaustively running chop_one_blob.
int TessBaseAPI::RecognizeForChopTest(ETEXT_DESC* monitor) {
if (tesseract_ == NULL)
return -1;
if (thresholder_ == NULL || thresholder_->IsEmpty()) {
tprintf("Please call SetImage before attempting recognition.");
return -1;
}
if (page_res_ != NULL)
ClearResults();
if (FindLines() != 0)
return -1;
// Additional conditions under which chopper test cannot be run
if (tesseract_->interactive_display_mode) return -1;
recognition_done_ = true;
page_res_ = new PAGE_RES(block_list_, &(tesseract_->prev_word_best_choice_));
PAGE_RES_IT page_res_it(page_res_);
while (page_res_it.word() != NULL) {
WERD_RES *word_res = page_res_it.word();
GenericVector<TBOX> boxes;
tesseract_->MaximallyChopWord(boxes, page_res_it.block()->block,
page_res_it.row()->row, word_res);
page_res_it.forward();
}
return 0;
}
// Recognizes all the pages in the named file, as a multi-page tiff or
// list of filenames, or single image, and gets the appropriate kind of text
// according to parameters: tessedit_create_boxfile,
// tessedit_make_boxes_from_boxes, tessedit_write_unlv, tessedit_create_hocr.
// Calls ProcessPage on each page in the input file, which may be a
// multi-page tiff, single-page other file format, or a plain text list of
// images to read. If tessedit_page_number is non-negative, processing begins
// at that page of a multi-page tiff file, or filelist.
// The text is returned in text_out. Returns false on error.
// If non-zero timeout_millisec terminates processing after the timeout on
// a single page.
// If non-NULL and non-empty, and some page fails for some reason,
// the page is reprocessed with the retry_config config file. Useful
// for interactively debugging a bad page.
bool TessBaseAPI::ProcessPages(const char* filename,
const char* retry_config, int timeout_millisec,
STRING* text_out) {
int page = tesseract_->tessedit_page_number;
if (page < 0)
page = 0;
FILE* fp = fopen(filename, "rb");
if (fp == NULL) {
tprintf(_("Image file %s cannot be opened!\n"), filename);
return false;
}
// Find the number of pages if a tiff file, or zero otherwise.
int npages = CountTiffPages(fp);
fclose(fp);
if (tesseract_->tessedit_create_hocr) {
*text_out =
"<!DOCTYPE html PUBLIC \"-//W3C//DTD HTML 4.01 Transitional//EN\""
" \"http://www.w3.org/TR/html4/loose.dtd\">\n"
"<html>\n<head>\n<title></title>\n"
"<meta http-equiv=\"Content-Type\" content=\"text/html;"
"charset=utf-8\" />\n<meta name='ocr-system' content='tesseract'/>\n"
"</head>\n<body>\n";
} else {
*text_out = "";
}
bool success = true;
Pix *pix;
if (npages > 0) {
for (; page < npages && (pix = pixReadTiff(filename, page)) != NULL;
++page) {
if (page >= 0)
tprintf(_("Page %d\n"), page);
char page_str[kMaxIntSize];
snprintf(page_str, kMaxIntSize - 1, "%d", page);
SetVariable("applybox_page", page_str);
success &= ProcessPage(pix, page, filename, retry_config,
timeout_millisec, text_out);
pixDestroy(&pix);
if (tesseract_->tessedit_page_number >= 0 || npages == 1) {
break;
}
}
} else {
// The file is not a tiff file, so use the general pixRead function.
pix = pixRead(filename);
if (pix != NULL) {
success &= ProcessPage(pix, 0, filename, retry_config,
timeout_millisec, text_out);
pixDestroy(&pix);
} else {
// The file is not an image file, so try it as a list of filenames.
FILE* fimg = fopen(filename, "rb");
if (fimg == NULL) {
tprintf(_("File %s cannot be opened!\n"), filename);
return false;
}
tprintf(_("Reading %s as a list of filenames...\n"), filename);
char pagename[MAX_PATH];
// Skip to the requested page number.
for (int i = 0; i < page &&
fgets(pagename, sizeof(pagename), fimg) != NULL;
++i);
while (fgets(pagename, sizeof(pagename), fimg) != NULL) {
chomp_string(pagename);
pix = pixRead(pagename);
if (pix == NULL) {
tprintf(_("Image file %s cannot be read!\n"), pagename);
fclose(fimg);
return false;
}
tprintf(_("Page %d : %s\n"), page, pagename);
success &= ProcessPage(pix, page, pagename, retry_config,
timeout_millisec, text_out);
pixDestroy(&pix);
++page;
}
fclose(fimg);
}
}
if (tesseract_->tessedit_create_hocr)
*text_out += "</body>\n</html>\n";
return success;
}
// Recognizes a single page for ProcessPages, appending the text to text_out.
// The pix is the image processed - filename and page_index are metadata
// used by side-effect processes, such as reading a box file or formatting
// as hOCR.
// If non-zero timeout_millisec terminates processing after the timeout.
// If non-NULL and non-empty, and some page fails for some reason,
// the page is reprocessed with the retry_config config file. Useful
// for interactively debugging a bad page.
// The text is returned in text_out. Returns false on error.
bool TessBaseAPI::ProcessPage(Pix* pix, int page_index, const char* filename,
const char* retry_config, int timeout_millisec,
STRING* text_out) {
SetInputName(filename);
SetImage(pix);
bool failed = false;
if (timeout_millisec > 0) {
// Running with a timeout.
ETEXT_DESC monitor;
monitor.cancel = NULL;
monitor.cancel_this = NULL;
monitor.set_deadline_msecs(timeout_millisec);
// Now run the main recognition.
failed = Recognize(&monitor) < 0;
} else if (tesseract_->tessedit_pageseg_mode == PSM_OSD_ONLY ||
tesseract_->tessedit_pageseg_mode == PSM_AUTO_ONLY) {
// Disabled character recognition.
PageIterator* it = AnalyseLayout();
if (it == NULL) {
failed = true;
} else {
delete it;
return true;
}
} else {
// Normal layout and character recognition with no timeout.
failed = Recognize(NULL) < 0;
}
if (tesseract_->tessedit_write_images) {
Pix* page_pix = GetThresholdedImage();
pixWrite("tessinput.tif", page_pix, IFF_TIFF_G4);
}
if (failed && retry_config != NULL && retry_config[0] != '\0') {
// Save current config variables before switching modes.
FILE* fp = fopen(kOldVarsFile, "wb");
PrintVariables(fp);
fclose(fp);
// Switch to alternate mode for retry.
ReadConfigFile(retry_config);
SetImage(pix);
Recognize(NULL);
// Restore saved config variables.
ReadConfigFile(kOldVarsFile);
}
// Get text only if successful.
if (!failed) {
char* text;
if (tesseract_->tessedit_create_boxfile ||
tesseract_->tessedit_make_boxes_from_boxes) {
text = GetBoxText(page_index);
} else if (tesseract_->tessedit_write_unlv) {
text = GetUNLVText();
} else if (tesseract_->tessedit_create_hocr) {
text = GetHOCRText(page_index);
} else {
text = GetUTF8Text();
}
*text_out += text;
delete [] text;
return true;
}
return false;
}
// Get a left-to-right iterator to the results of LayoutAnalysis and/or
// Recognize. The returned iterator must be deleted after use.
LTRResultIterator* TessBaseAPI::GetLTRIterator() {
if (tesseract_ == NULL || page_res_ == NULL)
return NULL;
return new LTRResultIterator(
page_res_, tesseract_,
thresholder_->GetScaleFactor(), thresholder_->GetScaledYResolution(),
rect_left_, rect_top_, rect_width_, rect_height_);
}
// Get a reading-order iterator to the results of LayoutAnalysis and/or
// Recognize. The returned iterator must be deleted after use.
// WARNING! This class points to data held within the TessBaseAPI class, and
// therefore can only be used while the TessBaseAPI class still exists and
// has not been subjected to a call of Init, SetImage, Recognize, Clear, End
// DetectOS, or anything else that changes the internal PAGE_RES.
ResultIterator* TessBaseAPI::GetIterator() {
if (tesseract_ == NULL || page_res_ == NULL)
return NULL;
return ResultIterator::StartOfParagraph(LTRResultIterator(
page_res_, tesseract_,
thresholder_->GetScaleFactor(), thresholder_->GetScaledYResolution(),
rect_left_, rect_top_, rect_width_, rect_height_));
}
// Get a mutable iterator to the results of LayoutAnalysis and/or Recognize.
// The returned iterator must be deleted after use.
// WARNING! This class points to data held within the TessBaseAPI class, and
// therefore can only be used while the TessBaseAPI class still exists and
// has not been subjected to a call of Init, SetImage, Recognize, Clear, End
// DetectOS, or anything else that changes the internal PAGE_RES.
MutableIterator* TessBaseAPI::GetMutableIterator() {
if (tesseract_ == NULL || page_res_ == NULL)
return NULL;
return new MutableIterator(page_res_, tesseract_,
thresholder_->GetScaleFactor(),
thresholder_->GetScaledYResolution(),
rect_left_, rect_top_, rect_width_, rect_height_);
}
// Make a text string from the internal data structures.
char* TessBaseAPI::GetUTF8Text() {
if (tesseract_ == NULL ||
(!recognition_done_ && Recognize(NULL) < 0))
return NULL;
STRING text("");
ResultIterator *it = GetIterator();
do {
if (it->Empty(RIL_PARA)) continue;
char *para_text = it->GetUTF8Text(RIL_PARA);
text += para_text;
delete []para_text;
} while (it->Next(RIL_PARA));
char* result = new char[text.length() + 1];
strncpy(result, text.string(), text.length() + 1);
delete it;
return result;
}
static void AddBoxTohOCR(const PageIterator *it,
PageIteratorLevel level,
STRING* hocr_str) {
int left, top, right, bottom;
it->BoundingBox(level, &left, &top, &right, &bottom);
hocr_str->add_str_int("' title=\"bbox ", left);
hocr_str->add_str_int(" ", top);
hocr_str->add_str_int(" ", right);
hocr_str->add_str_int(" ", bottom);
*hocr_str += "\">";
}
// Make a HTML-formatted string with hOCR markup from the internal
// data structures.
// page_number is 0-based but will appear in the output as 1-based.
// Image name/input_file_ can be set by SetInputName before calling
// GetHOCRText
// STL removed from original patch submission and refactored by rays.
char* TessBaseAPI::GetHOCRText(int page_number) {
if (tesseract_ == NULL ||
(page_res_ == NULL && Recognize(NULL) < 0))
return NULL;
int lcnt = 1, bcnt = 1, pcnt = 1, wcnt = 1;
int page_id = page_number + 1; // hOCR uses 1-based page numbers.
STRING hocr_str("");
if (input_file_ == NULL)
SetInputName(NULL);
hocr_str.add_str_int("<div class='ocr_page' id='page_", page_id);
hocr_str += "' title='image \"";
hocr_str += *input_file_;
hocr_str.add_str_int("\"; bbox ", rect_left_);
hocr_str.add_str_int(" ", rect_top_);
hocr_str.add_str_int(" ", rect_width_);
hocr_str.add_str_int(" ", rect_height_);
hocr_str += "'>\n";
ResultIterator *res_it = GetIterator();
for (; !res_it->Empty(RIL_BLOCK); wcnt++) {
if (res_it->Empty(RIL_WORD)) {
res_it->Next(RIL_WORD);
continue;
}
// Open any new block/paragraph/textline.
if (res_it->IsAtBeginningOf(RIL_BLOCK)) {
hocr_str.add_str_int("<div class='ocr_carea' id='block_", bcnt);
hocr_str.add_str_int("_", bcnt);
AddBoxTohOCR(res_it, RIL_BLOCK, &hocr_str);
}
if (res_it->IsAtBeginningOf(RIL_PARA)) {
if (res_it->ParagraphIsLtr()) {
hocr_str.add_str_int("\n<p class='ocr_par' dir='ltr' id='par_", pcnt);
} else {
hocr_str.add_str_int("\n<p class='ocr_par' dir='rtl' id='par_", pcnt);
}
AddBoxTohOCR(res_it, RIL_PARA, &hocr_str);
}
if (res_it->IsAtBeginningOf(RIL_TEXTLINE)) {
hocr_str.add_str_int("<span class='ocr_line' id='line_", lcnt);
AddBoxTohOCR(res_it, RIL_TEXTLINE, &hocr_str);
}
// Now, process the word...
hocr_str.add_str_int("<span class='ocr_word' id='word_", wcnt);
AddBoxTohOCR(res_it, RIL_WORD, &hocr_str);
const char *font_name;
bool bold, italic, underlined, monospace, serif, smallcaps;
int pointsize, font_id;
font_name = res_it->WordFontAttributes(&bold, &italic, &underlined,
&monospace, &serif, &smallcaps,
&pointsize, &font_id);
bool last_word_in_line = res_it->IsAtFinalElement(RIL_TEXTLINE, RIL_WORD);
bool last_word_in_para = res_it->IsAtFinalElement(RIL_PARA, RIL_WORD);
bool last_word_in_block = res_it->IsAtFinalElement(RIL_BLOCK, RIL_WORD);
if (bold) hocr_str += "<strong>";
if (italic) hocr_str += "<em>";
do {
const char *grapheme = res_it->GetUTF8Text(RIL_SYMBOL);
if (grapheme && grapheme[0] != 0) {
if (grapheme[1] == 0) {
switch (grapheme[0]) {
case '<': hocr_str += "&lt;"; break;
case '>': hocr_str += "&gt;"; break;
case '&': hocr_str += "&amp;"; break;
case '"': hocr_str += "&quot;"; break;
case '\'': hocr_str += "&#39;"; break;
default: hocr_str += grapheme;
}
} else {
hocr_str += grapheme;
}
}
res_it->Next(RIL_SYMBOL);
} while (!res_it->Empty(RIL_BLOCK) && !res_it->IsAtBeginningOf(RIL_WORD));
if (italic) hocr_str += "</em>";
if (bold) hocr_str += "</strong>";
hocr_str += "</span> ";
wcnt++;
// Close any ending block/paragraph/textline.
if (last_word_in_line) {
hocr_str += "</span>\n";
lcnt++;
}
if (last_word_in_para) {
hocr_str += "</p>\n";
pcnt++;
}
if (last_word_in_block) {
hocr_str += "</div>\n";
bcnt++;
}
}
hocr_str += "</div>\n";
char *ret = new char[hocr_str.length() + 1];
strcpy(ret, hocr_str.string());
delete res_it;
return ret;
}
// The 5 numbers output for each box (the usual 4 and a page number.)
const int kNumbersPerBlob = 5;
// The number of bytes taken by each number. Since we use inT16 for ICOORD,
// assume only 5 digits max.
const int kBytesPerNumber = 5;
// Multiplier for max expected textlength assumes (kBytesPerNumber + space)
// * kNumbersPerBlob plus the newline. Add to this the
// original UTF8 characters, and one kMaxBytesPerLine for safety.
const int kBytesPerBlob = kNumbersPerBlob * (kBytesPerNumber + 1) + 1;
const int kBytesPerBoxFileLine = (kBytesPerNumber + 1) * kNumbersPerBlob + 1;
// Max bytes in the decimal representation of inT64.
const int kBytesPer64BitNumber = 20;
// A maximal single box could occupy kNumbersPerBlob numbers at
// kBytesPer64BitNumber digits (if someone sneaks in a 64 bit value) and a
// space plus the newline and the maximum length of a UNICHAR.
// Test against this on each iteration for safety.
const int kMaxBytesPerLine = kNumbersPerBlob * (kBytesPer64BitNumber + 1) + 1 +
UNICHAR_LEN;
// The recognized text is returned as a char* which is coded
// as a UTF8 box file and must be freed with the delete [] operator.
// page_number is a 0-base page index that will appear in the box file.
char* TessBaseAPI::GetBoxText(int page_number) {
if (tesseract_ == NULL ||
(!recognition_done_ && Recognize(NULL) < 0))
return NULL;
int blob_count;
int utf8_length = TextLength(&blob_count);
int total_length = blob_count * kBytesPerBoxFileLine + utf8_length +
kMaxBytesPerLine;
char* result = new char[total_length];
int output_length = 0;
LTRResultIterator* it = GetLTRIterator();
do {
int left, top, right, bottom;
if (it->BoundingBox(RIL_SYMBOL, &left, &top, &right, &bottom)) {
char* text = it->GetUTF8Text(RIL_SYMBOL);
// Tesseract uses space for recognition failure. Fix to a reject
// character, kTesseractReject so we don't create illegal box files.
for (int i = 0; text[i] != '\0'; ++i) {
if (text[i] == ' ')
text[i] = kTesseractReject;
}
snprintf(result + output_length, total_length - output_length,
"%s %d %d %d %d %d\n",
text, left, image_height_ - bottom,
right, image_height_ - top, page_number);
output_length += strlen(result + output_length);
delete [] text;
// Just in case...
if (output_length + kMaxBytesPerLine > total_length)
break;
}
} while (it->Next(RIL_SYMBOL));
delete it;
return result;
}
// Conversion table for non-latin characters.
// Maps characters out of the latin set into the latin set.
// TODO(rays) incorporate this translation into unicharset.
const int kUniChs[] = {
0x20ac, 0x201c, 0x201d, 0x2018, 0x2019, 0x2022, 0x2014, 0
};
// Latin chars corresponding to the unicode chars above.
const int kLatinChs[] = {
0x00a2, 0x0022, 0x0022, 0x0027, 0x0027, 0x00b7, 0x002d, 0
};
// The recognized text is returned as a char* which is coded
// as UNLV format Latin-1 with specific reject and suspect codes
// and must be freed with the delete [] operator.
char* TessBaseAPI::GetUNLVText() {
if (tesseract_ == NULL ||
(!recognition_done_ && Recognize(NULL) < 0))
return NULL;
bool tilde_crunch_written = false;
bool last_char_was_newline = true;
bool last_char_was_tilde = false;
int total_length = TextLength(NULL);
PAGE_RES_IT page_res_it(page_res_);
char* result = new char[total_length];
char* ptr = result;
for (page_res_it.restart_page(); page_res_it.word () != NULL;
page_res_it.forward()) {
WERD_RES *word = page_res_it.word();
// Process the current word.
if (word->unlv_crunch_mode != CR_NONE) {
if (word->unlv_crunch_mode != CR_DELETE &&
(!tilde_crunch_written ||
(word->unlv_crunch_mode == CR_KEEP_SPACE &&
word->word->space() > 0 &&
!word->word->flag(W_FUZZY_NON) &&
!word->word->flag(W_FUZZY_SP)))) {
if (!word->word->flag(W_BOL) &&
word->word->space() > 0 &&
!word->word->flag(W_FUZZY_NON) &&
!word->word->flag(W_FUZZY_SP)) {
/* Write a space to separate from preceeding good text */
*ptr++ = ' ';
last_char_was_tilde = false;
}
if (!last_char_was_tilde) {
// Write a reject char.
last_char_was_tilde = true;
*ptr++ = kUNLVReject;
tilde_crunch_written = true;
last_char_was_newline = false;
}
}
} else {
// NORMAL PROCESSING of non tilde crunched words.
tilde_crunch_written = false;
tesseract_->set_unlv_suspects(word);
const char* wordstr = word->best_choice->unichar_string().string();
const STRING& lengths = word->best_choice->unichar_lengths();
int length = lengths.length();
int i = 0;
int offset = 0;
if (last_char_was_tilde &&
word->word->space() == 0 && wordstr[offset] == ' ') {
// Prevent adjacent tilde across words - we know that adjacent tildes
// within words have been removed.
// Skip the first character.
offset = lengths[i++];
}
if (i < length && wordstr[offset] != 0) {
if (!last_char_was_newline)
*ptr++ = ' ';
else
last_char_was_newline = false;
for (; i < length; offset += lengths[i++]) {
if (wordstr[offset] == ' ' ||
wordstr[offset] == kTesseractReject) {
*ptr++ = kUNLVReject;
last_char_was_tilde = true;
} else {
if (word->reject_map[i].rejected())
*ptr++ = kUNLVSuspect;
UNICHAR ch(wordstr + offset, lengths[i]);
int uni_ch = ch.first_uni();
for (int j = 0; kUniChs[j] != 0; ++j) {
if (kUniChs[j] == uni_ch) {
uni_ch = kLatinChs[j];
break;
}
}
if (uni_ch <= 0xff) {
*ptr++ = static_cast<char>(uni_ch);
last_char_was_tilde = false;
} else {
*ptr++ = kUNLVReject;
last_char_was_tilde = true;
}
}
}
}
}
if (word->word->flag(W_EOL) && !last_char_was_newline) {
/* Add a new line output */
*ptr++ = '\n';
tilde_crunch_written = false;
last_char_was_newline = true;
last_char_was_tilde = false;
}
}
*ptr++ = '\n';
*ptr = '\0';
return result;
}
// Returns the average word confidence for Tesseract page result.
int TessBaseAPI::MeanTextConf() {
int* conf = AllWordConfidences();
if (!conf) return 0;
int sum = 0;
int *pt = conf;
while (*pt >= 0) sum += *pt++;
if (pt != conf) sum /= pt - conf;
delete [] conf;
return sum;
}
// Returns an array of all word confidences, terminated by -1.
int* TessBaseAPI::AllWordConfidences() {
if (tesseract_ == NULL ||
(!recognition_done_ && Recognize(NULL) < 0))
return NULL;
int n_word = 0;
PAGE_RES_IT res_it(page_res_);
for (res_it.restart_page(); res_it.word() != NULL; res_it.forward())
n_word++;
int* conf = new int[n_word+1];
n_word = 0;
for (res_it.restart_page(); res_it.word() != NULL; res_it.forward()) {
WERD_RES *word = res_it.word();
WERD_CHOICE* choice = word->best_choice;
int w_conf = static_cast<int>(100 + 5 * choice->certainty());
// This is the eq for converting Tesseract confidence to 1..100
if (w_conf < 0) w_conf = 0;
if (w_conf > 100) w_conf = 100;
conf[n_word++] = w_conf;
}
conf[n_word] = -1;
return conf;
}
/**
* Applies the given word to the adaptive classifier if possible.
* The word must be SPACE-DELIMITED UTF-8 - l i k e t h i s , so it can
* tell the boundaries of the graphemes.
* Assumes that SetImage/SetRectangle have been used to set the image
* to the given word. The mode arg should be PSM_SINGLE_WORD or
* PSM_CIRCLE_WORD, as that will be used to control layout analysis.
* The currently set PageSegMode is preserved.
* Returns false if adaption was not possible for some reason.
*/
bool TessBaseAPI::AdaptToWordStr(PageSegMode mode, const char* wordstr) {
int debug = 0;
GetIntVariable("applybox_debug", &debug);
bool success = true;
PageSegMode current_psm = GetPageSegMode();
SetPageSegMode(mode);
SetVariable("classify_enable_learning", "0");
char* text = GetUTF8Text();
if (debug) {
tprintf("Trying to adapt \"%s\" to \"%s\"\n", text, wordstr);
}
if (text != NULL) {
PAGE_RES_IT it(page_res_);
WERD_RES* word_res = it.word();
if (word_res != NULL) {
word_res->word->set_text(wordstr);
} else {
success = false;
}
// Check to see if text matches wordstr.
int w = 0;
int t = 0;
for (t = 0; text[t] != '\0'; ++t) {
if (text[t] == '\n' || text[t] == ' ')
continue;
while (wordstr[w] != '\0' && wordstr[w] == ' ')
++w;
if (text[t] != wordstr[w])
break;
++w;
}
if (text[t] != '\0' || wordstr[w] != '\0') {
// No match.
delete page_res_;
GenericVector<TBOX> boxes;
page_res_ = tesseract_->SetupApplyBoxes(boxes, block_list_);
tesseract_->ReSegmentByClassification(page_res_);
tesseract_->TidyUp(page_res_);
PAGE_RES_IT pr_it(page_res_);
if (pr_it.word() == NULL)
success = false;
else
word_res = pr_it.word();
} else {
word_res->BestChoiceToCorrectText();
}
if (success) {
tesseract_->EnableLearning = true;
tesseract_->LearnWord(NULL, NULL, word_res);
}
delete [] text;
} else {
success = false;
}
SetPageSegMode(current_psm);
return success;
}
// Free up recognition results and any stored image data, without actually
// freeing any recognition data that would be time-consuming to reload.
// Afterwards, you must call SetImage or TesseractRect before doing
// any Recognize or Get* operation.
void TessBaseAPI::Clear() {
if (thresholder_ != NULL)
thresholder_->Clear();
ClearResults();
}
// Close down tesseract and free up all memory. End() is equivalent to
// destructing and reconstructing your TessBaseAPI.
// Once End() has been used, none of the other API functions may be used
// other than Init and anything declared above it in the class definition.
void TessBaseAPI::End() {
if (thresholder_ != NULL) {
delete thresholder_;
thresholder_ = NULL;
}
if (page_res_ != NULL) {
delete page_res_;
page_res_ = NULL;
}
if (block_list_ != NULL) {
delete block_list_;
block_list_ = NULL;
}
if (paragraph_models_ != NULL) {
paragraph_models_->delete_data_pointers();
delete paragraph_models_;
paragraph_models_ = NULL;
}
if (tesseract_ != NULL) {
delete tesseract_;
if (osd_tesseract_ == tesseract_)
osd_tesseract_ = NULL;
tesseract_ = NULL;
}
if (osd_tesseract_ != NULL) {
delete osd_tesseract_;
osd_tesseract_ = NULL;
}
if (equ_detect_ != NULL) {
delete equ_detect_;
equ_detect_ = NULL;
}
if (input_file_ != NULL) {
delete input_file_;
input_file_ = NULL;
}
if (output_file_ != NULL) {
delete output_file_;
output_file_ = NULL;
}
if (datapath_ != NULL) {
delete datapath_;
datapath_ = NULL;
}
if (language_ != NULL) {
delete language_;
language_ = NULL;
}
}
// Check whether a word is valid according to Tesseract's language model
// returns 0 if the word is invalid, non-zero if valid
int TessBaseAPI::IsValidWord(const char *word) {
return tesseract_->getDict().valid_word(word);
}
bool TessBaseAPI::GetTextDirection(int* out_offset, float* out_slope) {
if (page_res_ == NULL)
FindLines();
if (block_list_->length() < 1) {
return false;
}
// Get first block
BLOCK_IT block_it(block_list_);
block_it.move_to_first();
ROW_LIST* rows = block_it.data()->row_list();
if (rows->length() < 1) {
return false;
}
// Get first line of block
ROW_IT row_it(rows);
row_it.move_to_first();
ROW* row = row_it.data();
// Calculate offset and slope (NOTE: Kind of ugly)
*out_offset = static_cast<int>(row->base_line(0.0));
*out_slope = row->base_line(1.0) - row->base_line(0.0);
return true;
}
// Sets Dict::letter_is_okay_ function to point to the given function.
void TessBaseAPI::SetDictFunc(DictFunc f) {
if (tesseract_ != NULL) {
tesseract_->getDict().letter_is_okay_ = f;
}
}
// Sets Dict::probability_in_context_ function to point to the given function.
void TessBaseAPI::SetProbabilityInContextFunc(ProbabilityInContextFunc f) {
if (tesseract_ != NULL) {
tesseract_->getDict().probability_in_context_ = f;
// Set it for the sublangs too.
int num_subs = tesseract_->num_sub_langs();
for (int i = 0; i < num_subs; ++i) {
tesseract_->get_sub_lang(i)->getDict().probability_in_context_ = f;
}
}
}
// Sets Wordrec::fill_lattice_ function to point to the given function.
void TessBaseAPI::SetFillLatticeFunc(FillLatticeFunc f) {
if (tesseract_ != NULL) tesseract_->fill_lattice_ = f;
}
// Common code for setting the image.
bool TessBaseAPI::InternalSetImage() {
if (tesseract_ == NULL) {
tprintf("Please call Init before attempting to send an image.");
return false;
}
if (thresholder_ == NULL)
thresholder_ = new ImageThresholder;
ClearResults();
return true;
}
// Run the thresholder to make the thresholded image, returned in pix,
// which must not be NULL. *pix must be initialized to NULL, or point
// to an existing pixDestroyable Pix.
// The usual argument to Threshold is Tesseract::mutable_pix_binary().
void TessBaseAPI::Threshold(Pix** pix) {
ASSERT_HOST(pix != NULL);
if (!thresholder_->IsBinary()) {
tesseract_->set_pix_grey(thresholder_->GetPixRectGrey());
}
if (*pix != NULL)
pixDestroy(pix);
// Zero resolution messes up the algorithms, so make sure it is credible.
int y_res = thresholder_->GetScaledYResolution();
if (y_res < kMinCredibleResolution || y_res > kMaxCredibleResolution) {
// Use the minimum default resolution, as it is safer to under-estimate
// than over-estimate resolution.
thresholder_->SetSourceYResolution(kMinCredibleResolution);
}
thresholder_->ThresholdToPix(pix);
thresholder_->GetImageSizes(&rect_left_, &rect_top_,
&rect_width_, &rect_height_,
&image_width_, &image_height_);
// Set the internal resolution that is used for layout parameters from the
// estimated resolution, rather than the image resolution, which may be
// fabricated, but we will use the image resolution, if there is one, to
// report output point sizes.
int estimated_res = ClipToRange(thresholder_->GetScaledEstimatedResolution(),
kMinCredibleResolution,
kMaxCredibleResolution);
if (estimated_res != thresholder_->GetScaledEstimatedResolution()) {
tprintf("Estimated resolution %d out of range! Corrected to %d\n",
thresholder_->GetScaledEstimatedResolution(), estimated_res);
}
tesseract_->set_source_resolution(estimated_res);
}
// Find lines from the image making the BLOCK_LIST.
int TessBaseAPI::FindLines() {
if (thresholder_ == NULL || thresholder_->IsEmpty()) {
tprintf("Please call SetImage before attempting recognition.");
return -1;
}
if (recognition_done_)
ClearResults();
if (!block_list_->empty()) {
return 0;
}
if (tesseract_ == NULL) {
tesseract_ = new Tesseract;
tesseract_->InitAdaptiveClassifier(false);
}
if (tesseract_->pix_binary() == NULL)
Threshold(tesseract_->mutable_pix_binary());
if (tesseract_->ImageWidth() > MAX_INT16 ||
tesseract_->ImageHeight() > MAX_INT16) {
tprintf("Image too large: (%d, %d)\n",
tesseract_->ImageWidth(), tesseract_->ImageHeight());
return -1;
}
tesseract_->PrepareForPageseg();
if (tesseract_->textord_equation_detect) {
if (equ_detect_ == NULL && datapath_ != NULL) {
equ_detect_ = new EquationDetect(datapath_->string(), NULL);
}
tesseract_->SetEquationDetect(equ_detect_);
}
Tesseract* osd_tess = osd_tesseract_;
OSResults osr;
if (PSM_OSD_ENABLED(tesseract_->tessedit_pageseg_mode) && osd_tess == NULL) {
if (strcmp(language_->string(), "osd") == 0) {
osd_tess = tesseract_;
} else {
osd_tesseract_ = new Tesseract;
if (osd_tesseract_->init_tesseract(
datapath_->string(), NULL, "osd", OEM_TESSERACT_ONLY,
NULL, 0, NULL, NULL, false) == 0) {
osd_tess = osd_tesseract_;
osd_tesseract_->set_source_resolution(
thresholder_->GetSourceYResolution());
} else {
tprintf("Warning: Auto orientation and script detection requested,"
" but osd language failed to load\n");
delete osd_tesseract_;
osd_tesseract_ = NULL;
}
}
}
if (tesseract_->SegmentPage(input_file_, block_list_, osd_tess, &osr) < 0)
return -1;
// If Devanagari is being recognized, we use different images for page seg
// and for OCR.
tesseract_->PrepareForTessOCR(block_list_, osd_tess, &osr);
return 0;
}
// Delete the pageres and clear the block list ready for a new page.
void TessBaseAPI::ClearResults() {
if (tesseract_ != NULL) {
tesseract_->Clear();
}
if (page_res_ != NULL) {
delete page_res_;
page_res_ = NULL;
}
recognition_done_ = false;
if (block_list_ == NULL)
block_list_ = new BLOCK_LIST;
else
block_list_->clear();
if (paragraph_models_ != NULL) {
paragraph_models_->delete_data_pointers();
delete paragraph_models_;
paragraph_models_ = NULL;
}
}
// Return the length of the output text string, as UTF8, assuming
// liberally two spacing marks after each word (as paragraphs end with two
// newlines), and assuming a single character reject marker for each rejected
// character.
// Also return the number of recognized blobs in blob_count.
int TessBaseAPI::TextLength(int* blob_count) {
if (tesseract_ == NULL || page_res_ == NULL)
return 0;
PAGE_RES_IT page_res_it(page_res_);
int total_length = 2;
int total_blobs = 0;
// Iterate over the data structures to extract the recognition result.
for (page_res_it.restart_page(); page_res_it.word () != NULL;
page_res_it.forward()) {
WERD_RES *word = page_res_it.word();
WERD_CHOICE* choice = word->best_choice;
if (choice != NULL) {
total_blobs += choice->length() + 2;
total_length += choice->unichar_string().length() + 2;
for (int i = 0; i < word->reject_map.length(); ++i) {
if (word->reject_map[i].rejected())
++total_length;
}
}
}
if (blob_count != NULL)
*blob_count = total_blobs;
return total_length;
}
// Estimates the Orientation And Script of the image.
// Returns true if the image was processed successfully.
bool TessBaseAPI::DetectOS(OSResults* osr) {
if (tesseract_ == NULL)
return false;
ClearResults();
if (tesseract_->pix_binary() == NULL)
Threshold(tesseract_->mutable_pix_binary());
if (input_file_ == NULL)
input_file_ = new STRING(kInputFile);
return orientation_and_script_detection(*input_file_, osr, tesseract_);
}
void TessBaseAPI::set_min_orientation_margin(double margin) {
tesseract_->min_orientation_margin.set_value(margin);
}
// Return text orientation of each block as determined in an earlier page layout
// analysis operation. Orientation is returned as the number of ccw 90-degree
// rotations (in [0..3]) required to make the text in the block upright
// (readable). Note that this may not necessary be the block orientation
// preferred for recognition (such as the case of vertical CJK text).
//
// Also returns whether the text in the block is believed to have vertical
// writing direction (when in an upright page orientation).
//
// The returned array is of length equal to the number of text blocks, which may
// be less than the total number of blocks. The ordering is intended to be
// consistent with GetTextLines().
void TessBaseAPI::GetBlockTextOrientations(int** block_orientation,
bool** vertical_writing) {
delete[] *block_orientation;
*block_orientation = NULL;
delete[] *vertical_writing;
*vertical_writing = NULL;
BLOCK_IT block_it(block_list_);
block_it.move_to_first();
int num_blocks = 0;
for (block_it.mark_cycle_pt(); !block_it.cycled_list(); block_it.forward()) {
if (!block_it.data()->poly_block()->IsText()) {
continue;
}
++num_blocks;
}
if (!num_blocks) {
tprintf("WARNING: Found no blocks\n");
return;
}
*block_orientation = new int[num_blocks];
*vertical_writing = new bool[num_blocks];
block_it.move_to_first();
int i = 0;
for (block_it.mark_cycle_pt(); !block_it.cycled_list();
block_it.forward()) {
if (!block_it.data()->poly_block()->IsText()) {
continue;
}
FCOORD re_rotation = block_it.data()->re_rotation();
float re_theta = re_rotation.angle();
FCOORD classify_rotation = block_it.data()->classify_rotation();
float classify_theta = classify_rotation.angle();
double rot_theta = - (re_theta - classify_theta) * 2.0 / PI;
if (rot_theta < 0) rot_theta += 4;
int num_rotations = static_cast<int>(rot_theta + 0.5);
(*block_orientation)[i] = num_rotations;
// The classify_rotation is non-zero only if the text has vertical
// writing direction.
(*vertical_writing)[i] = classify_rotation.y() != 0.0f;
++i;
}
}
// ____________________________________________________________________________
// Ocropus add-ons.
// Find lines from the image making the BLOCK_LIST.
BLOCK_LIST* TessBaseAPI::FindLinesCreateBlockList() {
FindLines();
BLOCK_LIST* result = block_list_;
block_list_ = NULL;
return result;
}
// Delete a block list.
// This is to keep BLOCK_LIST pointer opaque
// and let go of including the other headers.
void TessBaseAPI::DeleteBlockList(BLOCK_LIST *block_list) {
delete block_list;
}
ROW *TessBaseAPI::MakeTessOCRRow(float baseline,
float xheight,
float descender,
float ascender) {
inT32 xstarts[] = {-32000};
double quad_coeffs[] = {0, 0, baseline};
return new ROW(1,
xstarts,
quad_coeffs,
xheight,
ascender - (baseline + xheight),
descender - baseline,
0,
0);
}
// Creates a TBLOB* from the whole pix.
TBLOB *TessBaseAPI::MakeTBLOB(Pix *pix) {
int width = pixGetWidth(pix);
int height = pixGetHeight(pix);
BLOCK block("a character", TRUE, 0, 0, 0, 0, width, height);
// Create C_BLOBs from the page
extract_edges(pix, &block);
// Merge all C_BLOBs
C_BLOB_LIST *list = block.blob_list();
C_BLOB_IT c_blob_it(list);
if (c_blob_it.empty())
return NULL;
// Move all the outlines to the first blob.
C_OUTLINE_IT ol_it(c_blob_it.data()->out_list());
for (c_blob_it.forward();
!c_blob_it.at_first();
c_blob_it.forward()) {
C_BLOB *c_blob = c_blob_it.data();
ol_it.add_list_after(c_blob->out_list());
}
// Convert the first blob to the output TBLOB.
return TBLOB::PolygonalCopy(c_blob_it.data());
}
// This method baseline normalizes a TBLOB in-place. The input row is used
// for normalization. The denorm is an optional parameter in which the
// normalization-antidote is returned.
void TessBaseAPI::NormalizeTBLOB(TBLOB *tblob, ROW *row,
bool numeric_mode, DENORM *denorm) {
TWERD word;
word.blobs = tblob;
if (denorm != NULL) {
word.SetupBLNormalize(NULL, row, row->x_height(), numeric_mode, denorm);
word.Normalize(*denorm);
} else {
DENORM normer;
word.SetupBLNormalize(NULL, row, row->x_height(), numeric_mode, &normer);
word.Normalize(normer);
}
word.blobs = NULL;
}
// Return a TBLOB * from the whole pix.
// To be freed later with delete.
TBLOB *make_tesseract_blob(float baseline, float xheight,
float descender, float ascender,
bool numeric_mode, Pix* pix) {
TBLOB *tblob = TessBaseAPI::MakeTBLOB(pix);
// Normalize TBLOB
ROW *row =
TessBaseAPI::MakeTessOCRRow(baseline, xheight, descender, ascender);
TessBaseAPI::NormalizeTBLOB(tblob, row, numeric_mode, NULL);
delete row;
return tblob;
}
// Adapt to recognize the current image as the given character.
// The image must be preloaded into pix_binary_ and be just an image
// of a single character.
void TessBaseAPI::AdaptToCharacter(const char *unichar_repr,
int length,
float baseline,
float xheight,
float descender,
float ascender) {
UNICHAR_ID id = tesseract_->unicharset.unichar_to_id(unichar_repr, length);
TBLOB *blob = make_tesseract_blob(baseline, xheight, descender, ascender,
tesseract_->classify_bln_numeric_mode,
tesseract_->pix_binary());
float threshold;
UNICHAR_ID best_class = 0;
float best_rating = -100;
// Classify to get a raw choice.
BLOB_CHOICE_LIST choices;
DENORM denorm;
tesseract_->AdaptiveClassifier(blob, denorm, &choices, NULL);
BLOB_CHOICE_IT choice_it;
choice_it.set_to_list(&choices);
for (choice_it.mark_cycle_pt(); !choice_it.cycled_list();
choice_it.forward()) {
if (choice_it.data()->rating() > best_rating) {
best_rating = choice_it.data()->rating();
best_class = choice_it.data()->unichar_id();
}
}
threshold = tesseract_->matcher_good_threshold;
if (blob->outlines)
tesseract_->AdaptToChar(blob, denorm, id, kUnknownFontinfoId, threshold);
delete blob;
}
PAGE_RES* TessBaseAPI::RecognitionPass1(BLOCK_LIST* block_list) {
PAGE_RES *page_res = new PAGE_RES(block_list,
&(tesseract_->prev_word_best_choice_));
tesseract_->recog_all_words(page_res, NULL, NULL, NULL, 1);
return page_res;
}
PAGE_RES* TessBaseAPI::RecognitionPass2(BLOCK_LIST* block_list,
PAGE_RES* pass1_result) {
if (!pass1_result)
pass1_result = new PAGE_RES(block_list,
&(tesseract_->prev_word_best_choice_));
tesseract_->recog_all_words(pass1_result, NULL, NULL, NULL, 2);
return pass1_result;
}
void TessBaseAPI::DetectParagraphs(int debug_level) {
if (paragraph_models_ == NULL)
paragraph_models_ = new GenericVector<ParagraphModel*>;
MutableIterator *result_it = GetMutableIterator();
do { // Detect paragraphs for this block
GenericVector<ParagraphModel *> models;
::tesseract::DetectParagraphs(debug_level, result_it, &models);
*paragraph_models_ += models;
} while (result_it->Next(RIL_BLOCK));
delete result_it;
}
struct TESS_CHAR : ELIST_LINK {
char *unicode_repr;
int length; // of unicode_repr
float cost;
TBOX box;
TESS_CHAR(float _cost, const char *repr, int len = -1) : cost(_cost) {
length = (len == -1 ? strlen(repr) : len);
unicode_repr = new char[length + 1];
strncpy(unicode_repr, repr, length);
}
TESS_CHAR() { // Satisfies ELISTIZE.
}
~TESS_CHAR() {
delete [] unicode_repr;
}
};
ELISTIZEH(TESS_CHAR)
ELISTIZE(TESS_CHAR)
static void add_space(TESS_CHAR_IT* it) {
TESS_CHAR *t = new TESS_CHAR(0, " ");
it->add_after_then_move(t);
}
static float rating_to_cost(float rating) {
rating = 100 + rating;
// cuddled that to save from coverage profiler
// (I have never seen ratings worse than -100,
// but the check won't hurt)
if (rating < 0) rating = 0;
return rating;
}
// Extract the OCR results, costs (penalty points for uncertainty),
// and the bounding boxes of the characters.
static void extract_result(TESS_CHAR_IT* out,
PAGE_RES* page_res) {
PAGE_RES_IT page_res_it(page_res);
int word_count = 0;
while (page_res_it.word() != NULL) {
WERD_RES *word = page_res_it.word();
const char *str = word->best_choice->unichar_string().string();
const char *len = word->best_choice->unichar_lengths().string();
TBOX real_rect = word->word->bounding_box();
if (word_count)
add_space(out);
int n = strlen(len);
for (int i = 0; i < n; i++) {
TESS_CHAR *tc = new TESS_CHAR(rating_to_cost(word->best_choice->rating()),
str, *len);
tc->box = real_rect.intersection(word->box_word->BlobBox(i));
out->add_after_then_move(tc);
str += *len;
len++;
}
page_res_it.forward();
word_count++;
}
}
// Extract the OCR results, costs (penalty points for uncertainty),
// and the bounding boxes of the characters.
int TessBaseAPI::TesseractExtractResult(char** text,
int** lengths,
float** costs,
int** x0,
int** y0,
int** x1,
int** y1,
PAGE_RES* page_res) {
TESS_CHAR_LIST tess_chars;
TESS_CHAR_IT tess_chars_it(&tess_chars);
extract_result(&tess_chars_it, page_res);
tess_chars_it.move_to_first();
int n = tess_chars.length();
int text_len = 0;
*lengths = new int[n];
*costs = new float[n];
*x0 = new int[n];
*y0 = new int[n];
*x1 = new int[n];
*y1 = new int[n];
int i = 0;
for (tess_chars_it.mark_cycle_pt();
!tess_chars_it.cycled_list();
tess_chars_it.forward(), i++) {
TESS_CHAR *tc = tess_chars_it.data();
text_len += (*lengths)[i] = tc->length;
(*costs)[i] = tc->cost;
(*x0)[i] = tc->box.left();
(*y0)[i] = tc->box.bottom();
(*x1)[i] = tc->box.right();
(*y1)[i] = tc->box.top();
}
char *p = *text = new char[text_len];
tess_chars_it.move_to_first();
for (tess_chars_it.mark_cycle_pt();
!tess_chars_it.cycled_list();
tess_chars_it.forward()) {
TESS_CHAR *tc = tess_chars_it.data();
strncpy(p, tc->unicode_repr, tc->length);
p += tc->length;
}
return n;
}
// This method returns the features associated with the input blob.
void TessBaseAPI::GetFeaturesForBlob(TBLOB* blob, const DENORM& denorm,
INT_FEATURE_ARRAY int_features,
int* num_features,
int* FeatureOutlineIndex) {
if (tesseract_) {
tesseract_->ResetFeaturesHaveBeenExtracted();
}
uinT8* norm_array = new uinT8[MAX_NUM_CLASSES];
inT32 len;
*num_features = tesseract_->GetCharNormFeatures(
blob, denorm, tesseract_->PreTrainedTemplates,
int_features, norm_array, norm_array, &len, FeatureOutlineIndex);
delete [] norm_array;
}
// This method returns the row to which a box of specified dimensions would
// belong. If no good match is found, it returns NULL.
ROW* TessBaseAPI::FindRowForBox(BLOCK_LIST* blocks,
int left, int top, int right, int bottom) {
TBOX box(left, bottom, right, top);
BLOCK_IT b_it(blocks);
for (b_it.mark_cycle_pt(); !b_it.cycled_list(); b_it.forward()) {
BLOCK* block = b_it.data();
if (!box.major_overlap(block->bounding_box()))
continue;
ROW_IT r_it(block->row_list());
for (r_it.mark_cycle_pt(); !r_it.cycled_list(); r_it.forward()) {
ROW* row = r_it.data();
if (!box.major_overlap(row->bounding_box()))
continue;
WERD_IT w_it(row->word_list());
for (w_it.mark_cycle_pt(); !w_it.cycled_list(); w_it.forward()) {
WERD* word = w_it.data();
if (box.major_overlap(word->bounding_box()))
return row;
}
}
}
return NULL;
}
// Method to run adaptive classifier on a blob.
void TessBaseAPI::RunAdaptiveClassifier(TBLOB* blob, const DENORM& denorm,
int num_max_matches,
int* unichar_ids,
float* ratings,
int* num_matches_returned) {
BLOB_CHOICE_LIST* choices = new BLOB_CHOICE_LIST;
tesseract_->AdaptiveClassifier(blob, denorm, choices, NULL);
BLOB_CHOICE_IT choices_it(choices);
int& index = *num_matches_returned;
index = 0;
for (choices_it.mark_cycle_pt();
!choices_it.cycled_list() && index < num_max_matches;
choices_it.forward()) {
BLOB_CHOICE* choice = choices_it.data();
unichar_ids[index] = choice->unichar_id();
ratings[index] = choice->rating();
++index;
}
*num_matches_returned = index;
delete choices;
}
// This method returns the string form of the specified unichar.
const char* TessBaseAPI::GetUnichar(int unichar_id) {
return tesseract_->unicharset.id_to_unichar(unichar_id);
}
// Return the pointer to the i-th dawg loaded into tesseract_ object.
const Dawg *TessBaseAPI::GetDawg(int i) const {
if (tesseract_ == NULL || i >= NumDawgs()) return NULL;
return tesseract_->getDict().GetDawg(i);
}
// Return the number of dawgs loaded into tesseract_ object.
int TessBaseAPI::NumDawgs() const {
return tesseract_ == NULL ? 0 : tesseract_->getDict().NumDawgs();
}
// Return a pointer to underlying CubeRecoContext object if present.
CubeRecoContext *TessBaseAPI::GetCubeRecoContext() const {
return (tesseract_ == NULL) ? NULL : tesseract_->GetCubeRecoContext();
}
} // namespace tesseract.
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