Discussion :

[ZAYDOUN]

Je cherche à utiliser l'algorithme de block matching. J'ai cherché dans la doc d'openCv et j'ai trouvé une fonction qui permet de faire ça : cvCalcOpticalFlowBM
voici le code que j'ai écrit:

Code :

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#include <stdio.h>
#include <cv.h>
#include <highgui.h>
 
int main()
{
    IplImage* ImTemp1=NULL;
    IplImage* source1=NULL;
    IplImage* ImTemp2=NULL;
    IplImage* source2=NULL;
    CvCapture *input_video = cvCaptureFromFile("video.avi");
    cvSetCaptureProperty(input_video, CV_CAP_PROP_POS_FRAMES,10);
    ImTemp1=cvCloneImage(cvQueryFrame(input_video));
    cvSetCaptureProperty(input_video, CV_CAP_PROP_POS_FRAMES,11);
    ImTemp2=cvCloneImage(cvQueryFrame(input_video));
    source1 = cvCreateImage(cvGetSize(ImTemp1), IPL_DEPTH_8U, 1);
    source2 = cvCreateImage(cvGetSize(ImTemp2), IPL_DEPTH_8U, 1);
    cvCvtColor(ImTemp1, source1, CV_BGR2GRAY);
    cvCvtColor(ImTemp2, source2, CV_BGR2GRAY);
 
    cvNamedWindow("Pic1", CV_WINDOW_AUTOSIZE);
    cvShowImage("Pic1", source1);
 
    cvNamedWindow("Pic2", CV_WINDOW_AUTOSIZE);
    cvShowImage("Pic2", source2);
 
 
    IplImage* velocityX=NULL;
    IplImage* velocityY=NULL;
    velocityX = cvCreateImage(cvGetSize(source1), IPL_DEPTH_32F, 1);
    velocityY = cvCreateImage(cvGetSize(source1), IPL_DEPTH_32F, 1);
 
    cvCalcOpticalFlowBM(source1, source2, cvSize(4, 4), cvSize(1, 1), cvSize(4, 4), 0, velocityX, velocityY);
 
    cvNamedWindow("Horizontal", CV_WINDOW_AUTOSIZE);
    cvShowImage("Horizontal", velocityX);
 
    cvNamedWindow("Vertical", CV_WINDOW_AUTOSIZE);
    cvShowImage("Vertical", velocityY);
 
    cvDestroyWindow("Pic1");
    cvDestroyWindow("Pic2");
    cvDestroyWindow("Horizontal");
    cvDestroyWindow("Vertical");
 
    cvReleaseImage(&ImTemp1);
    cvReleaseImage(&ImTemp2);
    cvReleaseImage(&source1);
    cvReleaseImage(&source2);
    cvReleaseImage(&velocityY);
    cvReleaseImage(&velocityX);
    cvReleaseCapture(&input_video);
    return 0;
}

Le code compile bien mais à l'exécution il se plante et il affiche une erreur:

Code :

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Sizes of input arguments do not match()
in function cvCalcOpticalFlowBM C:\..\cvoptflowbm.cpp(592)

L'erreur vient des tailles des blocs je pense.
Avez vous une idée sur les paramètres correctes de cette fonction?
Merci

[Vinsss84]

http://www.itl.k.u-tokyo.ac.jp/~naka...ml#ch4_optflow

il te faut des images en paramètres et non des captures

CalcOpticalFlowBM

Calculates optical flow for two images by block matching method

void cvCalcOpticalFlowBM( const CvArr* imgA, const CvArr* imgB, CvSize blockSize,
CvSize shiftSize, CvSize maxRange, int usePrevious,
CvArr* velx, CvArr* vely );

imgA
First image, 8-bit, single-channel.
imgB
Second image, 8-bit, single-channel.
blockSize
Size of basic blocks that are compared.
shiftSize
Block coordinate increments.
maxRange
Size of the scanned neighborhood in pixels around block.
usePrevious
Uses previous (input) velocity field.
velx
Horizontal component of the optical flow of
floor((imgA->width - blockSize.width)/shiftSize.width) × floor((imgA->height - blockSize.height)/shiftSize.height) size, 32-bit floating-point, single-channel.
vely
Vertical component of the optical flow of the same size velx, 32-bit floating-point, single-channel.

The function cvCalcOpticalFlowBM calculates optical flow for overlapped blocks blockSize.width×blockSize.height pixels each, thus the velocity fields are smaller than the original images. For every block in imgA the functions tries to find a similar block in imgB in some neighborhood of the original block or shifted by (velx(x0,y0),vely(x0,y0)) block as has been calculated by previous function call (if usePrevious=1)

[ZAYDOUN]

C'est pas ça le probleme
J'ai essayé avec des images et ça marche toujours pas : la même erreur

[ZAYDOUN]

J'ai trouvé la réponse

Code :

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#include <cv.h>
#include <highgui.h>
#define BS 4
 
void main() {
        IplImage *imgA = NULL, *imgB = NULL;
        IplImage *grayA = NULL, *grayB = NULL;
        IplImage *velx = NULL, *vely = NULL;
        IplImage *result = NULL;
        imgA = cvLoadImage("00.bmp", 1);
        imgB = cvLoadImage("01.bmp", 1);
        grayA = cvCreateImage(cvGetSize(imgA), IPL_DEPTH_8U, 1);
        grayB = cvCreateImage(cvGetSize(imgA), IPL_DEPTH_8U, 1);
 
        cvCvtColor(imgA, grayA, CV_BGR2GRAY);
        cvCvtColor(imgB, grayB, CV_BGR2GRAY);
 
        CvSize size = cvGetSize(imgA);
        size.width /= BS;
        size.height /= BS;
        result = cvCreateImage(size, IPL_DEPTH_8U, 1);
        for (int i=0; i<size.height; i++) {
                for (int j=0; j<size.width; j++) {
                        cvSet(result, CV_RGB(255,255,255), NULL);
                }
        }
        velx = cvCreateImage(size, IPL_DEPTH_32F, 1);
        vely = cvCreateImage(size, IPL_DEPTH_32F, 1);
        cvCalcOpticalFlowBM(grayB, grayA, cvSize(BS, BS), cvSize(1, 1), cvSize(1, 1), 0, velx, vely);
        cvNamedWindow("HorFlowBM", CV_WINDOW_AUTOSIZE);
        cvShowImage("HorFlowBM", velx);
        cvNamedWindow("VerFlowBM", CV_WINDOW_AUTOSIZE);
        cvShowImage("VerFlowBM", vely);
        for (i=0; i<size.height; i+=2) {
                for (int j=0; j<size.width; j+=2) {
                        int dx = (int)cvGetReal2D(velx, i, j);
                        int dy = (int)cvGetReal2D(vely, i, j);
                        cvLine(result, cvPoint(j, i), cvPoint(j+dx, i+dy), CV_RGB(0,0,0), 1, 8, 0);
                }
        }
        cvNamedWindow("OpticalFlow", CV_WINDOW_AUTOSIZE);
        cvShowImage("OpticalFlow", result);
        cvWaitKey(0);
}