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https://github.com/tesseract-ocr/tesseract.git
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108 lines
4.1 KiB
C++
108 lines
4.1 KiB
C++
/**********************************************************************
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* File: lstmboxrenderer.cpp
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* Description: Renderer for creating box file for LSTM training.
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* based on the tsv renderer.
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*
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* (C) Copyright 2019, Google Inc.
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** Licensed under the Apache License, Version 2.0 (the "License");
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** you may not use this file except in compliance with the License.
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** You may obtain a copy of the License at
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** http://www.apache.org/licenses/LICENSE-2.0
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** Unless required by applicable law or agreed to in writing, software
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** distributed under the License is distributed on an "AS IS" BASIS,
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** WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
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** See the License for the specific language governing permissions and
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** limitations under the License.
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*
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**********************************************************************/
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#include "baseapi.h" // for TessBaseAPI
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#include "renderer.h"
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#include "tesseractclass.h" // for Tesseract
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namespace tesseract {
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/**
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* Create a UTF8 box file for LSTM training from the internal data structures.
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* page_number is a 0-base page index that will appear in the box file.
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* Returned string must be freed with the delete [] operator.
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*/
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static void AddBoxToLSTM(int right, int bottom, int top, int image_height,
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int page_num, STRING* text) {
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text->add_str_int(" ", image_height - bottom);
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text->add_str_int(" ", right + 5);
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text->add_str_int(" ", image_height - top);
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text->add_str_int(" ", page_num);
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}
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char* TessBaseAPI::GetLSTMBoxText(int page_number=0) {
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if (tesseract_ == nullptr || (page_res_ == nullptr && Recognize(nullptr) < 0))
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return nullptr;
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STRING lstm_box_str("");
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bool first_word = true;
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int left = 0, top = 0, right = 0, bottom = 0;
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LTRResultIterator* res_it = GetLTRIterator();
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while (!res_it->Empty(RIL_BLOCK)) {
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if (res_it->Empty(RIL_SYMBOL)) {
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res_it->Next(RIL_SYMBOL);
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continue;
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}
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if (!first_word) {
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if (!(res_it->IsAtBeginningOf(RIL_TEXTLINE))) {
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if (res_it->IsAtBeginningOf(RIL_WORD)) {
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lstm_box_str.add_str_int(" ", left);
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AddBoxToLSTM(right, bottom, top, image_height_, page_number,
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&lstm_box_str);
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lstm_box_str += "\n"; // end of row for word
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} // word
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} else {
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if (res_it->IsAtBeginningOf(RIL_TEXTLINE)) {
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lstm_box_str.add_str_int("\t ", left);
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AddBoxToLSTM(right, bottom, top, image_height_, page_number,
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&lstm_box_str);
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lstm_box_str += "\n"; // end of row for line
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} // line
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}
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} // not first word
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first_word = false;
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// Use bounding box for whole line for everything
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res_it->BoundingBox(RIL_TEXTLINE, &left, &top, &right, &bottom);
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do {
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lstm_box_str +=
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std::unique_ptr<const char[]>(res_it->GetUTF8Text(RIL_SYMBOL)).get();
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res_it->Next(RIL_SYMBOL);
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} while (!res_it->Empty(RIL_BLOCK) && !res_it->IsAtBeginningOf(RIL_SYMBOL));
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lstm_box_str.add_str_int(" ", left);
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AddBoxToLSTM(right, bottom, top, image_height_, page_number, &lstm_box_str);
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lstm_box_str += "\n"; // end of row for symbol
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}
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if (!first_word) { // if first_word is true => empty page
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lstm_box_str.add_str_int("\t ", left);
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AddBoxToLSTM(right, bottom, top, image_height_, page_number, &lstm_box_str);
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lstm_box_str += "\n"; // end of PAGE
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}
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char* ret = new char[lstm_box_str.length() + 1];
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strcpy(ret, lstm_box_str.string());
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delete res_it;
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return ret;
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}
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/**********************************************************************
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* LSTMBox Renderer interface implementation
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**********************************************************************/
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TessLSTMBoxRenderer::TessLSTMBoxRenderer(const char* outputbase)
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: TessResultRenderer(outputbase, "box") {}
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bool TessLSTMBoxRenderer::AddImageHandler(TessBaseAPI* api) {
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const std::unique_ptr<const char[]> lstmbox(api->GetLSTMBoxText(imagenum()));
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if (lstmbox == nullptr) return false;
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AppendString(lstmbox.get());
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return true;
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}
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} // namespace tesseract.
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