I am implementing stereovision depth mapping as given in example in opencv text book of O’reilly book.
While implementing this code my cameras are both horizontal and both are not same. After executing the code I’m getting very weird results. I want to verify whether these weird results are only because of disorientation of cameras or is there any problem within the code, please help me out.
#include "cv.h"
#include "cxmisc.h"
#include "highgui.h"
//#include "cvaux.h"
#include <vector>
#include <string>
#include <algorithm>
#include <stdio.h>
#include <ctype.h>
#define WIDTH 426
#define HEIGHT 320
using namespace std;
int main()
{
//---------Initial--------
int nx=7, ny=7, frame = 0, n_boards =20, N;
int count1 = 0,count2 = 0, result1=0, result2=0;
int showUndistorted = 1, successes1 = 0,successes2 = 0 ;
const int maxScale = 1;
const float squareSize = 2.f; //Set this to your actual square size
CvSize imageSize = {WIDTH,HEIGHT};
CvCapture *capture1= NULL, *capture2= NULL;
CvSize board_sz = cvSize( nx,ny );
int i, j, n = nx*ny, N1 = 0, N2 = 0;
vector<CvPoint2D32f> points[2];
vector<int> npoints;
vector<CvPoint3D32f> objectPoints;
vector<CvPoint2D32f> temp1(n);
vector<CvPoint2D32f> temp2(n);
double M1[3][3], M2[3][3], D1[5], D2[5];
double R[3][3], T[3], E[3][3], F[3][3];
double Q[4][4];
CvMat _Q = cvMat(4,4, CV_64F, Q);
CvMat _M1 = cvMat(3, 3, CV_64F, M1 );
CvMat _M2 = cvMat(3, 3, CV_64F, M2 );
CvMat _D1 = cvMat(1, 5, CV_64F, D1 );
CvMat _D2 = cvMat(1, 5, CV_64F, D2 );
CvMat _R = cvMat(3, 3, CV_64F, R );
CvMat _T = cvMat(3, 1, CV_64F, T );
CvMat _E = cvMat(3, 3, CV_64F, E );
CvMat _F = cvMat(3, 3, CV_64F, F );
//---------Starting WebCam----------
capture1= cvCaptureFromCAM(0);
assert(capture1!=NULL); cvWaitKey(0);
capture2= cvCaptureFromCAM(1);
assert(capture2!=NULL);
//assure capture size is correct...
int res=cvSetCaptureProperty(capture1,CV_CAP_PROP_FRAME_WIDTH,WIDTH);
printf("%d",res);
res=cvSetCaptureProperty(capture1,CV_CAP_PROP_FRAME_HEIGHT,HEIGHT);
printf("%d",res);
res=cvSetCaptureProperty(capture2,CV_CAP_PROP_FRAME_WIDTH,WIDTH);
printf("%d",res);
res=cvSetCaptureProperty(capture2,CV_CAP_PROP_FRAME_HEIGHT,HEIGHT);
printf("%d",res); fflush(stdout);
IplImage *frame1 = cvQueryFrame( capture1 );
IplImage* gray_fr1 = cvCreateImage( cvGetSize(frame1), 8, 1 );
IplImage *frame2 = cvQueryFrame( capture2 );
IplImage* gray_fr2 = cvCreateImage( cvGetSize(frame1), 8, 1 );
//imageSize = cvGetSize(frame1);
//Show Window
cvNamedWindow( "camera2", 1 );
cvNamedWindow( "camera1", 1 );
cvNamedWindow("corners camera1",1);
cvNamedWindow("corners camera2",1);
while((successes1<n_boards)||(successes2<n_boards))
{
//--------Find chessboard corner--------------------------------------------------
if((frame++ % 20) == 0)
{
//----------------CAM1-------------------------------------------------------------------------------------------------------
result1 = cvFindChessboardCorners( frame1, board_sz,&temp1[0], &count1,CV_CALIB_CB_ADAPTIVE_THRESH|CV_CALIB_CB_FILTER_QUADS);
cvCvtColor( frame1, gray_fr1, CV_BGR2GRAY );
//----------------CAM2--------------------------------------------------------------------------------------------------------
result2 = cvFindChessboardCorners( frame2, board_sz,&temp2[0], &count2,CV_CALIB_CB_ADAPTIVE_THRESH|CV_CALIB_CB_FILTER_QUADS);
cvCvtColor( frame2, gray_fr2, CV_BGR2GRAY );
if(count1==n&&count2==n&&result1&&result2)
{
cvFindCornerSubPix( gray_fr1, &temp1[0], count1,cvSize(11, 11), cvSize(-1,-1),cvTermCriteria(CV_TERMCRIT_ITER+CV_TERMCRIT_EPS,30, 0.01) );
cvDrawChessboardCorners( frame1, board_sz, &temp1[0], count1, result1 );
cvShowImage( "corners camera1", frame1 );
N1 = points[0].size();
points[0].resize(N1 + n, cvPoint2D32f(0,0));
copy( temp1.begin(), temp1.end(), points[0].begin() + N1 );
++successes1;
cvFindCornerSubPix( gray_fr2, &temp2[0], count2,cvSize(11, 11), cvSize(-1,-1),cvTermCriteria(CV_TERMCRIT_ITER+CV_TERMCRIT_EPS,30, 0.01) );
cvDrawChessboardCorners( frame2, board_sz, &temp2[0], count2, result2 );
cvShowImage( "corners camera2", frame2 );
N2 = points[1].size();
points[1].resize(N2 + n, cvPoint2D32f(0,0));
copy( temp2.begin(), temp2.end(), points[1].begin() + N2 );
++successes2;
putchar('$');
}
else
{ cvShowImage( "corners camera2", gray_fr2 );
cvShowImage( "corners camera1", gray_fr1 );
}
frame1 = cvQueryFrame( capture1 );
cvShowImage("camera1", frame1);
frame2 = cvQueryFrame( capture2 );
cvShowImage("camera2", frame2);
if(cvWaitKey(15)==27) break;
}
}
cvReleaseCapture( &capture1 );
cvReleaseCapture( &capture2 );
cvDestroyWindow("camera1");
cvDestroyWindow("camera2");
cvDestroyWindow("corners camera1");
cvDestroyWindow("corners camera2");
printf("\n");
//--------------Calibaration-------------------
N = n_boards*n;
objectPoints.resize(N);
for( i = 0; i < ny; i++ )
for(j = 0; j < nx; j++ ) objectPoints[i*nx + j] = cvPoint3D32f(i*squareSize, j*squareSize, 0);
for( i = 1; i < n_boards; i++ ) copy( objectPoints.begin(), objectPoints.begin() + n, objectPoints.begin() + i*n );
npoints.resize(n_boards,n);
CvMat _objectPoints = cvMat(1, N, CV_32FC3, &objectPoints[0] );
CvMat _imagePoints1 = cvMat(1, N, CV_32FC2, &points[0][0] );
CvMat _imagePoints2 = cvMat(1, N, CV_32FC2, &points[1][0] );
CvMat _npoints = cvMat(1, npoints.size(), CV_32S, &npoints[0] );
cvSetIdentity(&_M1);
cvSetIdentity(&_M2);
cvZero(&_D1);
cvZero(&_D2);
printf("Running stereo calibration ...");
fflush(stdout);
cvStereoCalibrate( &_objectPoints, &_imagePoints1, &_imagePoints2, &_npoints,&_M1, &_D1, &_M2, &_D2,imageSize, &_R, &_T, &_E, &_F,
cvTermCriteria(CV_TERMCRIT_ITER+CV_TERMCRIT_EPS, 100, 1e-5),
CV_CALIB_FIX_ASPECT_RATIO+CV_CALIB_ZERO_TANGENT_DIST + CV_CALIB_SAME_FOCAL_LENGTH );
printf("done\n");
//-------------Undistort------------------------------------------
cvUndistortPoints( &_imagePoints1, &_imagePoints1,&_M1, &_D1, 0, &_M1 );
cvUndistortPoints( &_imagePoints2, &_imagePoints2,&_M2, &_D2, 0, &_M2 );
//--------Using bouguet algorithm-------------------
CvMat* mx1 = cvCreateMat( imageSize.height,imageSize.width, CV_32F );
CvMat* my1 = cvCreateMat( imageSize.height,imageSize.width, CV_32F );
CvMat* mx2 = cvCreateMat( imageSize.height,imageSize.width, CV_32F );
CvMat* my2 = cvCreateMat( imageSize.height,imageSize.width, CV_32F );
CvMat* frame1r = cvCreateMat( imageSize.height,imageSize.width, CV_8U );
CvMat* frame2r = cvCreateMat( imageSize.height,imageSize.width, CV_8U );
CvMat* disp = cvCreateMat( imageSize.height, imageSize.width, CV_16S );
CvMat* vdisp = cvCreateMat( imageSize.height,imageSize.width, CV_8U );
CvMat* Image3D = cvCreateMat(imageSize.height, imageSize.width, CV_32FC3);
CvMat* pair;
double R1[3][3], R2[3][3], P1[3][4], P2[3][4];
CvMat _R1 = cvMat(3, 3, CV_64F, R1);
CvMat _R2 = cvMat(3, 3, CV_64F, R2);
//Calib with Bouguet algrithm
CvMat _P1 = cvMat(3, 4, CV_64F, P1);
CvMat _P2 = cvMat(3, 4, CV_64F, P2);
cvStereoRectify( &_M1, &_M2, &_D1, &_D2, imageSize,&_R, &_T,&_R1, &_R2, &_P1, &_P2, &_Q,0/*CV_CALIB_ZERO_DISPARITY*/ );
//Find matrix for cvRemap()
cvInitUndistortRectifyMap(&_M1,&_D1,&_R1,&_P1,mx1,my1);
cvInitUndistortRectifyMap(&_M2,&_D2,&_R2,&_P2,mx2,my2);
pair = cvCreateMat( imageSize.height, imageSize.width*2,CV_8UC3 );
//Paramater for stereo corrrespondences
CvStereoBMState *BMState = cvCreateStereoBMState();
assert(BMState != 0);
BMState->preFilterSize=31;
BMState->preFilterCap=31;
BMState->SADWindowSize=35;
BMState->minDisparity= 0;
BMState->numberOfDisparities=48;
BMState->textureThreshold=20; //reduce noise
BMState->uniquenessRatio=15; // uniquenessRatio > (match_val–min_match)/min_match.
/* CvStereoBMState *state = cvCreateStereoBMState(CV_STEREO_BM_BASIC);
BMState->speckleRange = 50;
BMState->textureThreshold = 400;*/
//Bat camera va hien thi
//cvNamedWindow( "camera2", 1 );
//cvNamedWindow( "camera1", 1 );
cvNamedWindow( "rectified",1 );
cvNamedWindow( "disparity",1);
cvNamedWindow("depthmap",1);
capture1= cvCaptureFromCAM(0);
assert(capture1!=NULL); cvWaitKey(10);
capture2= cvCaptureFromCAM(1);
assert(capture2!=NULL);
res=cvSetCaptureProperty(capture1,CV_CAP_PROP_FRAME_WIDTH,WIDTH);
printf("%d",res);
res=cvSetCaptureProperty(capture1,CV_CAP_PROP_FRAME_HEIGHT,HEIGHT);
printf("%d",res);
res=cvSetCaptureProperty(capture2,CV_CAP_PROP_FRAME_WIDTH,WIDTH);
printf("%d",res);
res=cvSetCaptureProperty(capture2,CV_CAP_PROP_FRAME_HEIGHT,HEIGHT);
printf("%d",res); fflush(stdout);
frame1 = cvQueryFrame( capture1 );
frame2 = cvQueryFrame( capture2 );
while(1)
{
CvMat part;
cvCvtColor( frame1, gray_fr1, CV_BGR2GRAY );
cvCvtColor( frame2, gray_fr2, CV_BGR2GRAY );
cvRemap( gray_fr1, frame1r, mx1, my1 );
cvRemap( gray_fr2, frame2r, mx2, my2 );
cvFindStereoCorrespondenceBM( frame1r, frame2r, disp, BMState);
/* cvShowImage("camera1", frame1);
cvShowImage("camera2", frame2); */
// cvConvertScale( disp, disp, 16, 0 );
cvNormalize( disp, vdisp, 0, 256, CV_MINMAX );
cvShowImage( "disparity", vdisp );
cvReprojectImageTo3D(disp, Image3D, &_Q);
cvShowImage("depthmap",Image3D);
//Hien thi anh da rectify
cvGetCols( pair, &part, 0, imageSize.width );
cvCvtColor( frame1r, &part, CV_GRAY2BGR );
cvGetCols( pair, &part, imageSize.width, imageSize.width*2 );
cvCvtColor( frame2r, &part, CV_GRAY2BGR ); //CV_GRAY2BGR
for( j = 0; j < imageSize.height; j += 16 )
cvLine( pair, cvPoint(0,j), cvPoint(imageSize.width*2,j), CV_RGB(0,255,0));
cvShowImage( "rectified", pair );
frame1 = cvQueryFrame( capture1 );
frame2 = cvQueryFrame( capture2 );
if( cvWaitKey(15) == 27 ) break;
}
while( 1 ) { if((cvWaitKey(10)&0x7f) == 27 ) break; }
cvReleaseStereoBMState(&BMState);
cvReleaseMat( &mx1 );
cvReleaseMat( &my1 );
cvReleaseMat( &mx2 );
cvReleaseMat( &my2 );
cvReleaseCapture( &capture1 );
cvReleaseCapture( &capture2 );
cvReleaseMat( &frame1r );
cvReleaseMat( &frame2r );
cvReleaseMat( &disp );
cvReleaseMat(&Image3D);
}
and Photos of disparity maps are given in this link
one is webcam another is usb cam
Having different cameras is going to make your life more difficult. First off, I doubt the cameras have the same focal length, so the parameter
CV_CALIB_SAME_FOCAL_LENGTHbeing set is going to cause you to get wrong calibrations for the pair (remove this as a fixed parameter as it will almost certainly be different).Also, on a related parameter note, you are giving the calibration algorithm a lot of flexibility with the radial distortion parameters k1 – k6 because none of those are fixed. Start by trying to use the minimum number of parameters to get a good fit. For example, fix all but k1 and k2 (i.e., use
CV_CALIB_FIX_K3 + CV_CALIB_FIX_K4 + CV_CALIB_FIX_K5 + CV_CALIB_FIX_K6). If that doesn’t work, allow k3 to be variable etc…EDIT :
Another tip, consider calibrating each camera separately, and then pass
CV_CALIB_FIX_INTRINSICalong with the two camera intrinsic matrices to narrow the search space, which will hopefully allow the algorithm to converge to the global instead of local calibration minimum.Hope that helps!