Add renderer to create WordStr box files from images

Author: Shreeshrii

CMakeLists.txt

@@ -254,6 +254,7 @@ set(tesseract_src ${tesseract_src}
     src/api/hocrrenderer.cpp
     src/api/lstmboxrenderer.cpp
     src/api/pdfrenderer.cpp
+    src/api/wordstrboxrenderer.cpp
 )
 
 if (WIN32)

src/api/Makefile.am

@@ -37,6 +37,7 @@ libtesseract_api_la_SOURCES += altorenderer.cpp
 libtesseract_api_la_SOURCES += hocrrenderer.cpp
 libtesseract_api_la_SOURCES += lstmboxrenderer.cpp
 libtesseract_api_la_SOURCES += pdfrenderer.cpp
+libtesseract_api_la_SOURCES += wordstrboxrenderer.cpp
 libtesseract_api_la_SOURCES += renderer.cpp
 
 lib_LTLIBRARIES += libtesseract.la

src/api/baseapi.h

@@ -630,7 +630,15 @@ class TESS_API TessBaseAPI {
    * Returned string must be freed with the delete [] operator.
    */
   char* GetBoxText(int page_number);
-
+  
+  /**
+   * The recognized text is returned as a char* which is coded in the same
+   * format as a WordStr box file used in training.
+   * page_number is a 0-based page index that will appear in the box file.
+   * Returned string must be freed with the delete [] operator.
+   */
+  char* GetWordStrBoxText(int page_number);
+  
   /**
    * The recognized text is returned as a char* which is coded
    * as UNLV format Latin-1 with specific reject and suspect codes.

src/api/renderer.h

@@ -269,6 +269,17 @@ class TESS_API TessBoxTextRenderer : public TessResultRenderer {
   virtual bool AddImageHandler(TessBaseAPI* api);
 };
 
+/**
+ * Renders tesseract output into a plain UTF-8 text string in WordStr format
+ */
+class TESS_API TessWordStrBoxRenderer : public TessResultRenderer {
+ public:
+  explicit TessWordStrBoxRenderer(const char* outputbase);
+
+ protected:
+  virtual bool AddImageHandler(TessBaseAPI* api);
+};
+
 #ifndef DISABLED_LEGACY_ENGINE
 
 /**

src/api/tesseractmain.cpp

@@ -524,6 +524,20 @@ static void PreloadRenderers(
       }
     }
 
+    api->GetBoolVariable("tessedit_create_wordstrbox", &b);
+    if (b) {
+      tesseract::TessWordStrBoxRenderer* renderer =
+        new tesseract::TessWordStrBoxRenderer(outputbase);
+      if (renderer->happy()) {
+        renderers->push_back(renderer);
+      } else {
+        delete renderer;
+        tprintf("Error, could not create WordStr BOX output file: %s\n",
+                strerror(errno));
+        error = true;
+      }
+    }
+	
     api->GetBoolVariable("tessedit_create_txt", &b);
     if (b || (!error && renderers->empty())) {
       tesseract::TessTextRenderer* renderer =

src/api/wordstrboxrenderer.cpp

@@ -0,0 +1,101 @@
+/**********************************************************************
+ * File:        wordstrboxrenderer.cpp
+ * Description: Renderer for creating box file with WordStr strings.
+ *              based on the tsv renderer.
+ *
+ * (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 "baseapi.h"  // for TessBaseAPI
+#include "renderer.h"
+#include "tesseractclass.h"  // for Tesseract
+
+namespace tesseract {
+
+/**
+ * Create a UTF8 box file with WordStr strings from the internal data structures.
+ * page_number is a 0-base page index that will appear in the box file.
+ * Returned string must be freed with the delete [] operator.
+ */
+
+char* TessBaseAPI::GetWordStrBoxText(int page_number) {
+  if (tesseract_ == nullptr || (page_res_ == nullptr && Recognize(nullptr) < 0))
+    return nullptr;
+
+  STRING wordstr_box_str("");
+  int left, top, right, bottom;
+  int page_num = page_number;
+  bool first_line = true;
+
+  LTRResultIterator* res_it = GetLTRIterator();
+  while (!res_it->Empty(RIL_BLOCK)) {
+    if (res_it->Empty(RIL_WORD)) {
+      res_it->Next(RIL_WORD);
+      continue;
+    }
+
+  if (res_it->IsAtBeginningOf(RIL_TEXTLINE)) {
+    if (!first_line) {
+        wordstr_box_str.add_str_int("\n\t ", right + 1);
+        wordstr_box_str.add_str_int(" ", image_height_ - bottom);
+        wordstr_box_str.add_str_int(" ", right + 5);
+        wordstr_box_str.add_str_int(" ", image_height_ - top);
+        wordstr_box_str.add_str_int(" ", page_num);  // row for tab for EOL
+        wordstr_box_str += "\n";
+    } else {
+        first_line = false;
+    }
+    // Use bounding box for whole line for WordStr
+    res_it->BoundingBox(RIL_TEXTLINE, &left, &top, &right, &bottom);
+    wordstr_box_str.add_str_int("WordStr ", left);
+    wordstr_box_str.add_str_int(" ", image_height_ - bottom);
+    wordstr_box_str.add_str_int(" ", right);
+    wordstr_box_str.add_str_int(" ", image_height_ - top);
+    wordstr_box_str.add_str_int(" ", page_num);  // word
+    wordstr_box_str += " #";
+  }
+  do { wordstr_box_str +=
+                 std::unique_ptr<const char[]>(res_it->GetUTF8Text(RIL_WORD)).get();
+        wordstr_box_str += " ";
+        res_it->Next(RIL_WORD);
+     } while (!res_it->Empty(RIL_BLOCK) && !res_it->IsAtBeginningOf(RIL_WORD));
+  }
+  wordstr_box_str.add_str_int("\n\t ", right + 1);
+  wordstr_box_str.add_str_int(" ", image_height_ - bottom);
+  wordstr_box_str.add_str_int(" ", right + 5);
+  wordstr_box_str.add_str_int(" ", image_height_ - top);
+  wordstr_box_str.add_str_int(" ", page_num);  // row for tab for EOL
+  wordstr_box_str += "\n";
+  char* ret = new char[wordstr_box_str.length() + 1];
+  strcpy(ret, wordstr_box_str.string());
+  delete res_it;
+  return ret;
+}
+
+/**********************************************************************
+ * WordStrBox Renderer interface implementation
+ **********************************************************************/
+ TessWordStrBoxRenderer::TessWordStrBoxRenderer(const char *outputbase)
+    : TessResultRenderer(outputbase, "box") {
+}
+
+bool TessWordStrBoxRenderer::AddImageHandler(TessBaseAPI* api) {
+  const std::unique_ptr<const char[]> wordstrbox(api->GetWordStrBoxText(imagenum()));
+  if (wordstrbox == nullptr) return false;
+
+  AppendString(wordstrbox.get());
+
+  return true;
+}
+
+}  // namespace tesseract.

src/ccmain/tesseractclass.cpp

@@ -395,6 +395,8 @@ Tesseract::Tesseract()
                   this->params()),
       BOOL_MEMBER(tessedit_create_tsv, false, "Write .tsv output file",
                   this->params()),
+      BOOL_MEMBER(tessedit_create_wordstrbox, false, "Write WordStr format .box output file",
+                  this->params()),
       BOOL_MEMBER(tessedit_create_pdf, false, "Write .pdf output file",
                   this->params()),
       BOOL_MEMBER(textonly_pdf, false,

src/ccmain/tesseractclass.h

@@ -1042,6 +1042,7 @@ class Tesseract : public Wordrec {
   BOOL_VAR_H(tessedit_create_alto, false, "Write .xml ALTO output file");
   BOOL_VAR_H(tessedit_create_lstmbox, false, "Write .box file for LSTM training");
   BOOL_VAR_H(tessedit_create_tsv, false, "Write .tsv output file");
+  BOOL_VAR_H(tessedit_create_wordstrbox, false, "Write WordStr format .box output file");
   BOOL_VAR_H(tessedit_create_pdf, false, "Write .pdf output file");
   BOOL_VAR_H(textonly_pdf, false,
              "Create PDF with only one invisible text layer");

tessdata/configs/wordstrbox

@@ -0,0 +1 @@
+tessedit_create_wordstrbox 1