Basic motion detection, not sure why error below is being thrown, how to fix?
OpenCV Error: Assertion failed (npoints >= 0 && (depth == CV_32F || depth == CV_32S)) in contourArea, file /home/jshmo/opencv-3.1.0/modules/imgproc/src/shapedescr.cpp, line 314
terminate called after throwing an instance of ‘cv::Exception’
what(): /home/jshmo/opencv-3.1.0/modules/imgproc/src/shapedescr.cpp:314: error: (-215) npoints >= 0 && (depth == CV_32F || depth == CV_32S) in function contourArea
int main (int argc, char * const argv[])
{
const string EXT = “.jpg”; // extension of any images
if (argc<3) {
fprintf(stderr, “Usage: motion INPUT_FILE_NAME OUTPUT_FILE_NAME [ObjectSizeSensitivity]\n”);
exit(1);
}
double detected_area;
int min_area = atoi(argv[3]);
Mat kernel_dilate = getStructuringElement(MORPH_RECT, Size(3,3));
VideoCapture camera(argv[1]);
Size size2 = Size(1920, 1080);
int codec = CV_FOURCC(‘M’, ‘P’, ‘E’, ‘G’);
VideoWriter out(argv[2], codec, 6.0, size2, true);
Mat result, new_frame, avg, avgconv, frameDelta, thresh;
vector> contours;
vector hierarchy;
camera.read(new_frame);
avg = Mat::zeros(new_frame.size(), CV_32FC1);
//
while ( 1 ){
//Take a new image
camera.read(new_frame);
if(!new_frame.empty()) {
result = new_frame;
cvtColor(new_frame, new_frame, CV_RGB2GRAY);
GaussianBlur(new_frame, new_frame, Size(21, 21), 0);
accumulateWeighted(new_frame, avg, 0.5);
convertScaleAbs(avg,avgconv);
absdiff(new_frame,avgconv,frameDelta);
threshold(frameDelta, thresh, 35, 255, THRESH_BINARY);
dilate(thresh, thresh, kernel_dilate, Point(-1, -1), 2, BORDER_CONSTANT);
findContours(thresh, contours, hierarchy, RETR_EXTERNAL,CHAIN_APPROX_SIMPLE, Point(0, 0));
for(size_t i = 0; i < contours.size(); i++)
detected_area = contourArea(i);
if (detected_area > min_area) {
out << result;
}
}
else
{
camera.open(argv[1]);
}
}
return 0;
}
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