tesseract
5.0.0-alpha-619-ge9db
ccnontextdetect.h
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// File: ccnontextdetect.h
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// Description: Connected-Component-based non-text detection.
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// Copyright 2011 Google Inc. All Rights Reserved.
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// Author: rays@google.com (Ray Smith)
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// Created: Sat Jun 11 09:52:01 PST 2011
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//
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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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#ifndef TESSERACT_TEXTORD_CCPHOTODETECT_H_
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#define TESSERACT_TEXTORD_CCPHOTODETECT_H_
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#include "
blobgrid.h
"
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#include "
scrollview.h
"
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namespace
tesseract
{
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// The CCNonTextDetect class contains grid-based operations on blobs to create
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// a full-resolution image mask analogous yet complementary to
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// pixGenHalftoneMask as it is better at line-drawings, graphs and charts.
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class
CCNonTextDetect
:
public
BlobGrid
{
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public
:
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CCNonTextDetect
(
int
gridsize
,
const
ICOORD
&
bleft
,
const
ICOORD
&
tright
);
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~CCNonTextDetect
()
override
;
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// Creates and returns a Pix with the same resolution as the original
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// in which 1 (black) pixels represent likely non text (photo, line drawing)
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// areas of the page, deleting from the blob_block the blobs that were
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// determined to be non-text.
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// The photo_map (binary image mask) is used to bias the decision towards
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// non-text, rather than supplying a definite decision.
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// The blob_block is the usual result of connected component analysis,
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// holding the detected blobs.
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// The returned Pix should be PixDestroyed after use.
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Pix*
ComputeNonTextMask
(
bool
debug, Pix* photo_map,
TO_BLOCK
* blob_block);
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private
:
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// Computes and returns the noise_density IntGrid, at the same gridsize as
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// this by summing the number of small elements in a 3x3 neighbourhood of
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// each grid cell. good_grid is filled with blobs that are considered most
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// likely good text, and this is filled with small and medium blobs that are
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// more likely non-text.
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// The photo_map is used to bias the decision towards non-text, rather than
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// supplying definite decision.
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IntGrid
* ComputeNoiseDensity(
bool
debug, Pix* photo_map,
BlobGrid
* good_grid);
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// Tests each blob in the list to see if it is certain non-text using 2
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// conditions:
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// 1. blob overlaps a cell with high value in noise_density_ (previously set
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// by ComputeNoiseDensity).
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// OR 2. The blob overlaps more than max_blob_overlaps in *this grid. This
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// condition is disabled with max_blob_overlaps == -1.
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// If it does, the blob is declared non-text, and is used to mark up the
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// nontext_mask. Such blobs are fully deleted, and non-noise blobs have their
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// neighbours reset, as they may now point to deleted data.
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// WARNING: The blobs list blobs may be in the *this grid, but they are
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// not removed. If any deleted blobs might be in *this, then this must be
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// Clear()ed immediately after MarkAndDeleteNonTextBlobs is called.
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// If the win is not nullptr, deleted blobs are drawn on it in red, and kept
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void
MarkAndDeleteNonTextBlobs(BLOBNBOX_LIST* blobs,
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int
max_blob_overlaps,
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ScrollView
* win,
ScrollView::Color
ok_color,
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Pix* nontext_mask);
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// Returns true if the given blob overlaps more than max_overlaps blobs
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// in the current grid.
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bool
BlobOverlapsTooMuch(
BLOBNBOX
* blob,
int
max_overlaps);
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// Max entry in noise_density_ before the cell is declared noisy.
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int
max_noise_count_;
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// Completed noise density map, which we keep around to use for secondary
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// noise detection.
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IntGrid
* noise_density_;
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};
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}
// namespace tesseract.
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#endif // TESSERACT_TEXTORD_CCPHOTODETECT_H_
ScrollView
Definition:
scrollview.h:97
tesseract::IntGrid
Definition:
bbgrid.h:97
ICOORD
integer coordinate
Definition:
points.h:30
tesseract::CCNonTextDetect::CCNonTextDetect
CCNonTextDetect(int gridsize, const ICOORD &bleft, const ICOORD &tright)
Definition:
ccnontextdetect.cpp:61
tesseract::BlobGrid
Definition:
blobgrid.h:33
TO_BLOCK
Definition:
blobbox.h:691
tesseract::CCNonTextDetect::~CCNonTextDetect
~CCNonTextDetect() override
Definition:
ccnontextdetect.cpp:72
BLOBNBOX
Definition:
blobbox.h:142
tesseract::GridBase::tright
const ICOORD & tright() const
Definition:
bbgrid.h:75
blobgrid.h
tesseract
Definition:
baseapi.h:65
tesseract::GridBase::gridsize
int gridsize() const
Definition:
bbgrid.h:63
tesseract::CCNonTextDetect
Definition:
ccnontextdetect.h:31
tesseract::CCNonTextDetect::ComputeNonTextMask
Pix * ComputeNonTextMask(bool debug, Pix *photo_map, TO_BLOCK *blob_block)
Definition:
ccnontextdetect.cpp:85
ScrollView::Color
Color
Definition:
scrollview.h:100
scrollview.h
tesseract::GridBase::bleft
const ICOORD & bleft() const
Definition:
bbgrid.h:72
src
textord
ccnontextdetect.h
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