140 lines
4.4 KiB
C++
140 lines
4.4 KiB
C++
// SPDX-License-Identifier: Apache-2.0
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// File: osdetect.h
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// Description: Orientation and script detection.
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// Author: Samuel Charron
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// Ranjith Unnikrishnan
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//
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// (C) Copyright 2008, 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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#ifndef TESSERACT_CCMAIN_OSDETECT_H_
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#define TESSERACT_CCMAIN_OSDETECT_H_
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#include "export.h" // for TESS_API
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#include <vector> // for std::vector
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namespace tesseract {
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class BLOBNBOX;
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class BLOBNBOX_CLIST;
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class BLOB_CHOICE_LIST;
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class TO_BLOCK_LIST;
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class UNICHARSET;
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class Tesseract;
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// Max number of scripts in ICU + "NULL" + Japanese and Korean + Fraktur
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const int kMaxNumberOfScripts = 116 + 1 + 2 + 1;
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struct OSBestResult {
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OSBestResult()
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: orientation_id(0), script_id(0), sconfidence(0.0), oconfidence(0.0) {}
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int orientation_id;
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int script_id;
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float sconfidence;
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float oconfidence;
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};
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struct OSResults {
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OSResults() : unicharset(nullptr) {
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for (int i = 0; i < 4; ++i) {
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for (int j = 0; j < kMaxNumberOfScripts; ++j) {
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scripts_na[i][j] = 0;
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}
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orientations[i] = 0;
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}
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}
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void update_best_orientation();
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// Set the estimate of the orientation to the given id.
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void set_best_orientation(int orientation_id);
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// Update/Compute the best estimate of the script assuming the given
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// orientation id.
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void update_best_script(int orientation_id);
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// Return the index of the script with the highest score for this orientation.
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TESS_API int get_best_script(int orientation_id) const;
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// Accumulate scores with given OSResults instance and update the best script.
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void accumulate(const OSResults &osr);
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// Print statistics.
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void print_scores(void) const;
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void print_scores(int orientation_id) const;
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// Array holding scores for each orientation id [0,3].
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// Orientation ids [0..3] map to [0, 270, 180, 90] degree orientations of the
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// page respectively, where the values refer to the amount of clockwise
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// rotation to be applied to the page for the text to be upright and readable.
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float orientations[4];
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// Script confidence scores for each of 4 possible orientations.
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float scripts_na[4][kMaxNumberOfScripts];
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UNICHARSET *unicharset;
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OSBestResult best_result;
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};
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class OrientationDetector {
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public:
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OrientationDetector(const std::vector<int> *allowed_scripts,
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OSResults *results);
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bool detect_blob(BLOB_CHOICE_LIST *scores);
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int get_orientation();
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private:
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OSResults *osr_;
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const std::vector<int> *allowed_scripts_;
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};
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class ScriptDetector {
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public:
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ScriptDetector(const std::vector<int> *allowed_scripts, OSResults *osr,
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tesseract::Tesseract *tess);
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void detect_blob(BLOB_CHOICE_LIST *scores);
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bool must_stop(int orientation) const;
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private:
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OSResults *osr_;
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static const char *korean_script_;
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static const char *japanese_script_;
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static const char *fraktur_script_;
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int korean_id_;
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int japanese_id_;
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int katakana_id_;
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int hiragana_id_;
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int han_id_;
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int hangul_id_;
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int latin_id_;
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int fraktur_id_;
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tesseract::Tesseract *tess_;
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const std::vector<int> *allowed_scripts_;
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};
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int orientation_and_script_detection(const char *filename, OSResults *,
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tesseract::Tesseract *);
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int os_detect(TO_BLOCK_LIST *port_blocks, OSResults *osr,
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tesseract::Tesseract *tess);
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int os_detect_blobs(const std::vector<int> *allowed_scripts,
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BLOBNBOX_CLIST *blob_list, OSResults *osr,
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tesseract::Tesseract *tess);
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bool os_detect_blob(BLOBNBOX *bbox, OrientationDetector *o, ScriptDetector *s,
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OSResults *, tesseract::Tesseract *tess);
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// Helper method to convert an orientation index to its value in degrees.
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// The value represents the amount of clockwise rotation in degrees that must be
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// applied for the text to be upright (readable).
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TESS_API int OrientationIdToValue(const int &id);
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} // namespace tesseract
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#endif // TESSERACT_CCMAIN_OSDETECT_H_
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