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git-svn-id: https://tesseract-ocr.googlecode.com/svn/trunk@536 d0cd1f9f-072b-0410-8dd7-cf729c803f20
124 lines
4.4 KiB
C++
124 lines
4.4 KiB
C++
///////////////////////////////////////////////////////////////////////
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// File: linefind.h
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// Description: Class to find vertical lines in an image and create
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// a corresponding list of empty blobs.
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// Author: Ray Smith
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// Created: Thu Mar 20 09:49:01 PDT 2008
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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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//
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///////////////////////////////////////////////////////////////////////
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#ifndef TESSERACT_TEXTORD_LINEFIND_H__
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#define TESSERACT_TEXTORD_LINEFIND_H__
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struct Pix;
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struct Boxa;
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class C_BLOB_LIST;
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class BLOBNBOX_LIST;
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class ICOORD;
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namespace tesseract {
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class TabVector_LIST;
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/**
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* The LineFinder class is a simple static function wrapper class that mainly
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* exposes the FindVerticalLines function.
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*/
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class LineFinder {
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public:
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/**
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* Finds vertical line objects in the given pix.
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*
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* Uses the given resolution to determine size thresholds instead of any
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* that may be present in the pix.
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*
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* The output vertical_x and vertical_y contain a sum of the output vectors,
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* thereby giving the mean vertical direction.
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*
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* The output vectors are owned by the list and Frozen (cannot refit) by
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* having no boxes, as there is no need to refit or merge separator lines.
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*/
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static void FindVerticalLines(int resolution, Pix* pix,
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int* vertical_x, int* vertical_y,
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TabVector_LIST* vectors);
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/**
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* Finds horizontal line objects in the given pix.
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*
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* Uses the given resolution to determine size thresholds instead of any
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* that may be present in the pix.
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*
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* The output vectors are owned by the list and Frozen (cannot refit) by
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* having no boxes, as there is no need to refit or merge separator lines.
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*/
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static void FindHorizontalLines(int resolution, Pix* pix,
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TabVector_LIST* vectors);
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/**
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* Converts the Boxa array to a list of C_BLOB, getting rid of severely
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* overlapping outlines and those that are children of a bigger one.
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*
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* The output is a list of C_BLOBs that are owned by the list.
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*
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* The C_OUTLINEs in the C_BLOBs contain no outline data - just empty
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* bounding boxes. The Boxa is consumed and destroyed.
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*/
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static void ConvertBoxaToBlobs(int image_width, int image_height,
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Boxa** boxes, C_BLOB_LIST* blobs);
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private:
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/**
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* Finds vertical lines in the given list of BLOBNBOXes. bleft and tright
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* are the bounds of the image on which the input line_bblobs were found.
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*
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* The input line_bblobs list is const really.
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*
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* The output vertical_x and vertical_y are the total of all the vectors.
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* The output list of TabVector makes no reference to the input BLOBNBOXes.
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*/
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static void FindLineVectors(const ICOORD& bleft, const ICOORD& tright,
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BLOBNBOX_LIST* line_bblobs,
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int* vertical_x, int* vertical_y,
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TabVector_LIST* vectors);
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/**
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* Get a set of bounding boxes of possible vertical lines in the image.
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*
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* The input resolution overrides any resolution set in src_pix.
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*
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* The output line_pix contains just all the detected lines.
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*/
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static Boxa* GetVLineBoxes(int resolution, Pix* src_pix, Pix** line_pix);
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/**
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* Get a set of bounding boxes of possible horizontal lines in the image.
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*
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* The input resolution overrides any resolution set in src_pix.
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*
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* The output line_pix contains just all the detected lines.
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*
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* The output boxes undergo the transformation (x,y)->(height-y,x) so the
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* lines can be found with a vertical line finder afterwards.
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*
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* This transformation allows a simple x/y flip to reverse it in tesseract
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* coordinates and it is faster to flip the lines than rotate the image.
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*/
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static Boxa* GetHLineBoxes(int resolution, Pix* src_pix, Pix** line_pix);
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};
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} // namespace tesseract.
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#endif // TESSERACT_TEXTORD_LINEFIND_H__
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