OpenCV unable to capture image from isight webcam
I can not capture image from my webcam using following OpenCV code.
The code can show images from a local AVI file or a video device. It works fine on a "test.avi" file.
When I make use my default webcam(CvCapture* capture =cvCreateCameraCapture(0)), the program can detected the size of the image from webcam,but just unable to display the image .
/I forgot to mention that I can see the iSight is working because the LED indicator is turn on/
Anyone encounter the same problem?
cvNamedWindow( "Example2", CV_WINDOW_AUTOSIZE );
CvCapture* capture =cvCreateFileCapture( "C:test.avi" ) ;// display images from avi file, works well
// CvCapture* capture =cvCreateCameraCapture(0); //display the frame(images) from default webcam not work
assert( capture );
IplImage* image;
while(1) {
image = cvQueryFrame( capture );
if( !image ) break;
cvShowImage( "Example2", image );
char c = cvWaitKey(33);
if( c == 27 ) break;
}
cvReleaseCapture( &capture );
cvDestroyWindow( "Example2" );
I'm working on opencv 2.3 with Macbook pro Mid 2012 and I had that problem with the Isight cam. Somehow I managed to make it work on opencv by simply adjusting the parameters of the Cvcapture and adjusting the frame width and height:
CvCapture* capture = cvCaptureFromCAM(0);
cvSetCaptureProperty( capture, CV_CAP_PROP_FRAME_WIDTH, 500 );
cvSetCaptureProperty( capture, CV_CAP_PROP_FRAME_HEIGHT, 600 );
You can also change these numbers to the frame width and height you want.
Did you try the example from the opencv page?
namely,
#include "cv.h"
#include "highgui.h"
using namespace cv;
int main(int, char**)
{
VideoCapture cap(0); // open the default camera
if(!cap.isOpened()) // check if we succeeded
return -1;
Mat edges;
namedWindow("edges",1);
for(;;)
{
Mat frame;
cap >> frame; // get a new frame from camera
cvtColor(frame, edges, CV_BGR2GRAY);
GaussianBlur(edges, edges, Size(7,7), 1.5, 1.5);
Canny(edges, edges, 0, 30, 3);
imshow("edges", edges);
if(waitKey(30) >= 0) break;
}
// the camera will be deinitialized automatically in VideoCapture destructor
return 0;
}
Works on a macbook pro for me (although on OS X). If it doesn't work, some kind of error message would be helpful.
尝试这个：
int main(int, char**) {
VideoCapture cap(0); // open the default camera
if (!cap.isOpened()) { // check if we succeeded
cout << "===couldn't open camera" << endl;
return -1;
}
Mat edges, frame;
frame = cv::Mat(10, 10, CV_8U);
namedWindow("edges", 1);
for (;;) {
cap >> frame; // get a new frame from camera
cout << "frame size: " << frame.cols << endl;
if (frame.cols > 0 && frame.rows > 0) {
imshow("edges", frame);
}
if (waitKey(30) >= 0)
break;
}
// the camera will be deinitialized automatically in VideoCapture destructor
return 0;
}
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