--- /dev/null
+/*M///////////////////////////////////////////////////////////////////////////////////////
+//
+// IMPORTANT: READ BEFORE DOWNLOADING, COPYING, INSTALLING OR USING.
+//
+// By downloading, copying, installing or using the software you agree to this license.
+// If you do not agree to this license, do not download, install,
+// copy or use the software.
+//
+//
+// Intel License Agreement
+// For Open Source Computer Vision Library
+//
+// Copyright (C) 2000, Intel Corporation, all rights reserved.
+// Third party copyrights are property of their respective owners.
+//
+// Redistribution and use in source and binary forms, with or without modification,
+// are permitted provided that the following conditions are met:
+//
+// * Redistribution's of source code must retain the above copyright notice,
+// this list of conditions and the following disclaimer.
+//
+// * Redistribution's in binary form must reproduce the above copyright notice,
+// this list of conditions and the following disclaimer in the documentation
+// and/or other materials provided with the distribution.
+//
+// * The name of Intel Corporation may not be used to endorse or promote products
+// derived from this software without specific prior written permission.
+//
+// This software is provided by the copyright holders and contributors "as is" and
+// any express or implied warranties, including, but not limited to, the implied
+// warranties of merchantability and fitness for a particular purpose are disclaimed.
+// In no event shall the Intel Corporation or contributors be liable for any direct,
+// indirect, incidental, special, exemplary, or consequential damages
+// (including, but not limited to, procurement of substitute goods or services;
+// loss of use, data, or profits; or business interruption) however caused
+// and on any theory of liability, whether in contract, strict liability,
+// or tort (including negligence or otherwise) arising in any way out of
+// the use of this software, even if advised of the possibility of such damage.
+//
+//M*/
+
+#include "_cvaux.h"
+
+/****************************************************************************************\
+ The code below is some modification of Stan Birchfield's algorithm described in:
+
+ Depth Discontinuities by Pixel-to-Pixel Stereo
+ Stan Birchfield and Carlo Tomasi
+ International Journal of Computer Vision,
+ 35(3): 269-293, December 1999.
+
+ This implementation uses different cost function that results in
+ O(pixPerRow*maxDisparity) complexity of dynamic programming stage versus
+ O(pixPerRow*log(pixPerRow)*maxDisparity) in the above paper.
+\****************************************************************************************/
+
+/****************************************************************************************\
+* Find stereo correspondence by dynamic programming algorithm *
+\****************************************************************************************/
+#define ICV_DP_STEP_LEFT 0
+#define ICV_DP_STEP_UP 1
+#define ICV_DP_STEP_DIAG 2
+
+#define ICV_BIRCH_DIFF_LUM 5
+
+#define ICV_MAX_DP_SUM_VAL (INT_MAX/4)
+
+typedef struct _CvDPCell
+{
+ uchar step; //local-optimal step
+ int sum; //current sum
+}_CvDPCell;
+
+typedef struct _CvRightImData
+{
+ uchar min_val, max_val;
+} _CvRightImData;
+
+#define CV_IMAX3(a,b,c) ((temp3 = (a) >= (b) ? (a) : (b)),(temp3 >= (c) ? temp3 : (c)))
+#define CV_IMIN3(a,b,c) ((temp3 = (a) <= (b) ? (a) : (b)),(temp3 <= (c) ? temp3 : (c)))
+
+void icvFindStereoCorrespondenceByBirchfieldDP( uchar* src1, uchar* src2,
+ uchar* disparities,
+ CvSize size, int widthStep,
+ int maxDisparity,
+ float _param1, float _param2,
+ float _param3, float _param4,
+ float _param5 )
+{
+ int x, y, i, j, temp3;
+ int d, s;
+ int dispH = maxDisparity + 3;
+ uchar *dispdata;
+ int imgW = size.width;
+ int imgH = size.height;
+ uchar val, prevval, prev, curr;
+ int min_val;
+ uchar* dest = disparities;
+ int param1 = cvRound(_param1);
+ int param2 = cvRound(_param2);
+ int param3 = cvRound(_param3);
+ int param4 = cvRound(_param4);
+ int param5 = cvRound(_param5);
+
+ #define CELL(d,x) cells[(d)+(x)*dispH]
+
+ uchar* dsi = (uchar*)cvAlloc(sizeof(uchar)*imgW*dispH);
+ uchar* edges = (uchar*)cvAlloc(sizeof(uchar)*imgW*imgH);
+ _CvDPCell* cells = (_CvDPCell*)cvAlloc(sizeof(_CvDPCell)*imgW*MAX(dispH,(imgH+1)/2));
+ _CvRightImData* rData = (_CvRightImData*)cvAlloc(sizeof(_CvRightImData)*imgW);
+ int* reliabilities = (int*)cells;
+
+ for( y = 0; y < imgH; y++ )
+ {
+ uchar* srcdata1 = src1 + widthStep * y;
+ uchar* srcdata2 = src2 + widthStep * y;
+
+ //init rData
+ prevval = prev = srcdata2[0];
+ for( j = 1; j < imgW; j++ )
+ {
+ curr = srcdata2[j];
+ val = (uchar)((curr + prev)>>1);
+ rData[j-1].max_val = (uchar)CV_IMAX3( val, prevval, prev );
+ rData[j-1].min_val = (uchar)CV_IMIN3( val, prevval, prev );
+ prevval = val;
+ prev = curr;
+ }
+ rData[j-1] = rData[j-2];//last elem
+
+ // fill dissimularity space image
+ for( i = 1; i <= maxDisparity + 1; i++ )
+ {
+ dsi += imgW;
+ rData--;
+ for( j = i - 1; j < imgW - 1; j++ )
+ {
+ int t;
+ if( (t = srcdata1[j] - rData[j+1].max_val) >= 0 )
+ {
+ dsi[j] = (uchar)t;
+ }
+ else if( (t = rData[j+1].min_val - srcdata1[j]) >= 0 )
+ {
+ dsi[j] = (uchar)t;
+ }
+ else
+ {
+ dsi[j] = 0;
+ }
+ }
+ }
+ dsi -= (maxDisparity+1)*imgW;
+ rData += maxDisparity+1;
+
+ //intensity gradients image construction
+ //left row
+ edges[y*imgW] = edges[y*imgW+1] = edges[y*imgW+2] = 2;
+ edges[y*imgW+imgW-1] = edges[y*imgW+imgW-2] = edges[y*imgW+imgW-3] = 1;
+ for( j = 3; j < imgW-4; j++ )
+ {
+ edges[y*imgW+j] = 0;
+
+ if( ( CV_IMAX3( srcdata1[j-3], srcdata1[j-2], srcdata1[j-1] ) -
+ CV_IMIN3( srcdata1[j-3], srcdata1[j-2], srcdata1[j-1] ) ) >= ICV_BIRCH_DIFF_LUM )
+ {
+ edges[y*imgW+j] |= 1;
+ }
+ if( ( CV_IMAX3( srcdata2[j+3], srcdata2[j+2], srcdata2[j+1] ) -
+ CV_IMIN3( srcdata2[j+3], srcdata2[j+2], srcdata2[j+1] ) ) >= ICV_BIRCH_DIFF_LUM )
+ {
+ edges[y*imgW+j] |= 2;
+ }
+ }
+
+ //find correspondence using dynamical programming
+ //init DP table
+ for( x = 0; x < imgW; x++ )
+ {
+ CELL(0,x).sum = CELL(dispH-1,x).sum = ICV_MAX_DP_SUM_VAL;
+ CELL(0,x).step = CELL(dispH-1,x).step = ICV_DP_STEP_LEFT;
+ }
+ for( d = 2; d < dispH; d++ )
+ {
+ CELL(d,d-2).sum = ICV_MAX_DP_SUM_VAL;
+ CELL(d,d-2).step = ICV_DP_STEP_UP;
+ }
+ CELL(1,0).sum = 0;
+ CELL(1,0).step = ICV_DP_STEP_LEFT;
+
+ for( x = 1; x < imgW; x++ )
+ {
+ int d = MIN( x + 1, maxDisparity + 1);
+ uchar* _edges = edges + y*imgW + x;
+ int e0 = _edges[0] & 1;
+ _CvDPCell* _cell = cells + x*dispH;
+
+ do
+ {
+ int s = dsi[d*imgW+x];
+ int sum[3];
+
+ //check left step
+ sum[0] = _cell[d-dispH].sum - param2;
+
+ //check up step
+ if( _cell[d+1].step != ICV_DP_STEP_DIAG && e0 )
+ {
+ sum[1] = _cell[d+1].sum + param1;
+
+ if( _cell[d-1-dispH].step != ICV_DP_STEP_UP && (_edges[1-d] & 2) )
+ {
+ int t;
+
+ sum[2] = _cell[d-1-dispH].sum + param1;
+
+ t = sum[1] < sum[0];
+
+ //choose local-optimal pass
+ if( sum[t] <= sum[2] )
+ {
+ _cell[d].step = (uchar)t;
+ _cell[d].sum = sum[t] + s;
+ }
+ else
+ {
+ _cell[d].step = ICV_DP_STEP_DIAG;
+ _cell[d].sum = sum[2] + s;
+ }
+ }
+ else
+ {
+ if( sum[0] <= sum[1] )
+ {
+ _cell[d].step = ICV_DP_STEP_LEFT;
+ _cell[d].sum = sum[0] + s;
+ }
+ else
+ {
+ _cell[d].step = ICV_DP_STEP_UP;
+ _cell[d].sum = sum[1] + s;
+ }
+ }
+ }
+ else if( _cell[d-1-dispH].step != ICV_DP_STEP_UP && (_edges[1-d] & 2) )
+ {
+ sum[2] = _cell[d-1-dispH].sum + param1;
+ if( sum[0] <= sum[2] )
+ {
+ _cell[d].step = ICV_DP_STEP_LEFT;
+ _cell[d].sum = sum[0] + s;
+ }
+ else
+ {
+ _cell[d].step = ICV_DP_STEP_DIAG;
+ _cell[d].sum = sum[2] + s;
+ }
+ }
+ else
+ {
+ _cell[d].step = ICV_DP_STEP_LEFT;
+ _cell[d].sum = sum[0] + s;
+ }
+ }
+ while( --d );
+ }// for x
+
+ //extract optimal way and fill disparity image
+ dispdata = dest + widthStep * y;
+
+ //find min_val
+ min_val = ICV_MAX_DP_SUM_VAL;
+ for( i = 1; i <= maxDisparity + 1; i++ )
+ {
+ if( min_val > CELL(i,imgW-1).sum )
+ {
+ d = i;
+ min_val = CELL(i,imgW-1).sum;
+ }
+ }
+
+ //track optimal pass
+ for( x = imgW - 1; x > 0; x-- )
+ {
+ dispdata[x] = (uchar)(d - 1);
+ while( CELL(d,x).step == ICV_DP_STEP_UP ) d++;
+ if ( CELL(d,x).step == ICV_DP_STEP_DIAG )
+ {
+ s = x;
+ while( CELL(d,x).step == ICV_DP_STEP_DIAG )
+ {
+ d--;
+ x--;
+ }
+ for( i = x; i < s; i++ )
+ {
+ dispdata[i] = (uchar)(d-1);
+ }
+ }
+ }//for x
+ }// for y
+
+ //Postprocessing the Disparity Map
+
+ //remove obvious errors in the disparity map
+ for( x = 0; x < imgW; x++ )
+ {
+ for( y = 1; y < imgH - 1; y++ )
+ {
+ if( dest[(y-1)*widthStep+x] == dest[(y+1)*widthStep+x] )
+ {
+ dest[y*widthStep+x] = dest[(y-1)*widthStep+x];
+ }
+ }
+ }
+
+ //compute intensity Y-gradients
+ for( x = 0; x < imgW; x++ )
+ {
+ for( y = 1; y < imgH - 1; y++ )
+ {
+ if( ( CV_IMAX3( src1[(y-1)*widthStep+x], src1[y*widthStep+x],
+ src1[(y+1)*widthStep+x] ) -
+ CV_IMIN3( src1[(y-1)*widthStep+x], src1[y*widthStep+x],
+ src1[(y+1)*widthStep+x] ) ) >= ICV_BIRCH_DIFF_LUM )
+ {
+ edges[y*imgW+x] |= 4;
+ edges[(y+1)*imgW+x] |= 4;
+ edges[(y-1)*imgW+x] |= 4;
+ y++;
+ }
+ }
+ }
+
+ //remove along any particular row, every gradient
+ //for which two adjacent columns do not agree.
+ for( y = 0; y < imgH; y++ )
+ {
+ prev = edges[y*imgW];
+ for( x = 1; x < imgW - 1; x++ )
+ {
+ curr = edges[y*imgW+x];
+ if( (curr & 4) &&
+ ( !( prev & 4 ) ||
+ !( edges[y*imgW+x+1] & 4 ) ) )
+ {
+ edges[y*imgW+x] -= 4;
+ }
+ prev = curr;
+ }
+ }
+
+ // define reliability
+ for( x = 0; x < imgW; x++ )
+ {
+ for( y = 1; y < imgH; y++ )
+ {
+ i = y - 1;
+ for( ; y < imgH && dest[y*widthStep+x] == dest[(y-1)*widthStep+x]; y++ )
+ ;
+ s = y - i;
+ for( ; i < y; i++ )
+ {
+ reliabilities[i*imgW+x] = s;
+ }
+ }
+ }
+
+ //Y - propagate reliable regions
+ for( x = 0; x < imgW; x++ )
+ {
+ for( y = 0; y < imgH; y++ )
+ {
+ d = dest[y*widthStep+x];
+ if( reliabilities[y*imgW+x] >= param4 && !(edges[y*imgW+x] & 4) &&
+ d > 0 )//highly || moderately
+ {
+ disparities[y*widthStep+x] = (uchar)d;
+ //up propagation
+ for( i = y - 1; i >= 0; i-- )
+ {
+ if( ( edges[i*imgW+x] & 4 ) ||
+ ( dest[i*widthStep+x] < d &&
+ reliabilities[i*imgW+x] >= param3 ) ||
+ ( reliabilities[y*imgW+x] < param5 &&
+ dest[i*widthStep+x] - 1 == d ) ) break;
+
+ disparities[i*widthStep+x] = (uchar)d;
+ }
+
+ //down propagation
+ for( i = y + 1; i < imgH; i++ )
+ {
+ if( ( edges[i*imgW+x] & 4 ) ||
+ ( dest[i*widthStep+x] < d &&
+ reliabilities[i*imgW+x] >= param3 ) ||
+ ( reliabilities[y*imgW+x] < param5 &&
+ dest[i*widthStep+x] - 1 == d ) ) break;
+
+ disparities[i*widthStep+x] = (uchar)d;
+ }
+ y = i - 1;
+ }
+ else
+ {
+ disparities[y*widthStep+x] = (uchar)d;
+ }
+ }
+ }
+
+ // define reliability along X
+ for( y = 0; y < imgH; y++ )
+ {
+ for( x = 1; x < imgW; x++ )
+ {
+ i = x - 1;
+ for( ; x < imgW && dest[y*widthStep+x] == dest[y*widthStep+x-1]; x++ );
+ s = x - i;
+ for( ; i < x; i++ )
+ {
+ reliabilities[y*imgW+i] = s;
+ }
+ }
+ }
+
+ //X - propagate reliable regions
+ for( y = 0; y < imgH; y++ )
+ {
+ for( x = 0; x < imgW; x++ )
+ {
+ d = dest[y*widthStep+x];
+ if( reliabilities[y*imgW+x] >= param4 && !(edges[y*imgW+x] & 1) &&
+ d > 0 )//highly || moderately
+ {
+ disparities[y*widthStep+x] = (uchar)d;
+ //up propagation
+ for( i = x - 1; i >= 0; i-- )
+ {
+ if( (edges[y*imgW+i] & 1) ||
+ ( dest[y*widthStep+i] < d &&
+ reliabilities[y*imgW+i] >= param3 ) ||
+ ( reliabilities[y*imgW+x] < param5 &&
+ dest[y*widthStep+i] - 1 == d ) ) break;
+
+ disparities[y*widthStep+i] = (uchar)d;
+ }
+
+ //down propagation
+ for( i = x + 1; i < imgW; i++ )
+ {
+ if( (edges[y*imgW+i] & 1) ||
+ ( dest[y*widthStep+i] < d &&
+ reliabilities[y*imgW+i] >= param3 ) ||
+ ( reliabilities[y*imgW+x] < param5 &&
+ dest[y*widthStep+i] - 1 == d ) ) break;
+
+ disparities[y*widthStep+i] = (uchar)d;
+ }
+ x = i - 1;
+ }
+ else
+ {
+ disparities[y*widthStep+x] = (uchar)d;
+ }
+ }
+ }
+
+ //release resources
+ cvFree( &dsi );
+ cvFree( &edges );
+ cvFree( &cells );
+ cvFree( &rData );
+}
+
+
+/*F///////////////////////////////////////////////////////////////////////////
+//
+// Name: cvFindStereoCorrespondence
+// Purpose: find stereo correspondence on stereo-pair
+// Context:
+// Parameters:
+// leftImage - left image of stereo-pair (format 8uC1).
+// rightImage - right image of stereo-pair (format 8uC1).
+// mode -mode of correspondance retrieval (now CV_RETR_DP_BIRCHFIELD only)
+// dispImage - destination disparity image
+// maxDisparity - maximal disparity
+// param1, param2, param3, param4, param5 - parameters of algorithm
+// Returns:
+// Notes:
+// Images must be rectified.
+// All images must have format 8uC1.
+//F*/
+CV_IMPL void
+cvFindStereoCorrespondence(
+ const CvArr* leftImage, const CvArr* rightImage,
+ int mode,
+ CvArr* depthImage,
+ int maxDisparity,
+ double param1, double param2, double param3,
+ double param4, double param5 )
+{
+ CV_FUNCNAME( "cvFindStereoCorrespondence" );
+
+ __BEGIN__;
+
+ CvMat *src1, *src2;
+ CvMat *dst;
+ CvMat src1_stub, src2_stub, dst_stub;
+ int coi;
+
+ CV_CALL( src1 = cvGetMat( leftImage, &src1_stub, &coi ));
+ if( coi ) CV_ERROR( CV_BadCOI, "COI is not supported by the function" );
+ CV_CALL( src2 = cvGetMat( rightImage, &src2_stub, &coi ));
+ if( coi ) CV_ERROR( CV_BadCOI, "COI is not supported by the function" );
+ CV_CALL( dst = cvGetMat( depthImage, &dst_stub, &coi ));
+ if( coi ) CV_ERROR( CV_BadCOI, "COI is not supported by the function" );
+
+ // check args
+ if( CV_MAT_TYPE( src1->type ) != CV_8UC1 ||
+ CV_MAT_TYPE( src2->type ) != CV_8UC1 ||
+ CV_MAT_TYPE( dst->type ) != CV_8UC1) CV_ERROR(CV_StsUnsupportedFormat,
+ "All images must be single-channel and have 8u" );
+
+ if( !CV_ARE_SIZES_EQ( src1, src2 ) || !CV_ARE_SIZES_EQ( src1, dst ) )
+ CV_ERROR( CV_StsUnmatchedSizes, "" );
+
+ if( maxDisparity <= 0 || maxDisparity >= src1->width || maxDisparity > 255 )
+ CV_ERROR(CV_StsOutOfRange,
+ "parameter /maxDisparity/ is out of range");
+
+ if( mode == CV_DISPARITY_BIRCHFIELD )
+ {
+ if( param1 == CV_UNDEF_SC_PARAM ) param1 = CV_IDP_BIRCHFIELD_PARAM1;
+ if( param2 == CV_UNDEF_SC_PARAM ) param2 = CV_IDP_BIRCHFIELD_PARAM2;
+ if( param3 == CV_UNDEF_SC_PARAM ) param3 = CV_IDP_BIRCHFIELD_PARAM3;
+ if( param4 == CV_UNDEF_SC_PARAM ) param4 = CV_IDP_BIRCHFIELD_PARAM4;
+ if( param5 == CV_UNDEF_SC_PARAM ) param5 = CV_IDP_BIRCHFIELD_PARAM5;
+
+ CV_CALL( icvFindStereoCorrespondenceByBirchfieldDP( src1->data.ptr,
+ src2->data.ptr, dst->data.ptr,
+ cvGetMatSize( src1 ), src1->step,
+ maxDisparity, (float)param1, (float)param2, (float)param3,
+ (float)param4, (float)param5 ) );
+ }
+ else
+ {
+ CV_ERROR( CV_StsBadArg, "Unsupported mode of function" );
+ }
+
+ __END__;
+}
+
+/* End of file. */
+