OpenCV cvFindContours - 如何分离轮廓的组件

Question

我一直在使用 OpenCV，并且通过大量的试验和错误设法学会了如何检测照片中的圆圈（硬币）。一切都很好，除了我将硬币直接放在彼此旁边（如下所示，忽略第二张图片倒置的事实）。

似乎是因为硬币靠得很近，cvFindContours 认为它​​们是同一个物体。我的问题是如何将这些轮廓分成单独的对象，或者获取已经分离的轮廓列表。

我用于 cvFindContours 的参数是：

cvFindContours( img, storage, &contour, sizeof(CvContour), CV_RETR_LIST, CV_CHAIN_APPROX_SIMPLE, cvPoint(0, 0) );

任何帮助或建议将不胜感激。

Answer 1

这不是很好，但它显示了如何到达那里：

IplImage* src = cvLoadImage(argv[1], CV_LOAD_IMAGE_UNCHANGED);
IplImage* gray = cvCreateImage(cvGetSize(src), IPL_DEPTH_8U, 1); 
cvCvtColor(src, gray, CV_BGR2GRAY);
cvSmooth(gray, gray, CV_GAUSSIAN, 7, 7); 

IplImage* cc_img = cvCreateImage(cvGetSize(gray), gray->depth, 3); 
cvSetZero(cc_img);
CvScalar(ext_color);

cvCanny(gray, gray, 10, 30, 3); 

CvMemStorage* storage = cvCreateMemStorage(0);
CvSeq* circles = cvHoughCircles(gray, storage, CV_HOUGH_GRADIENT, 1, src->height/6, 100, 50);
cvCvtColor(gray, src, CV_GRAY2BGR);
for (size_t i = 0; i < circles->total; i++)
{   
     // round the floats to an int
     float* p = (float*)cvGetSeqElem(circles, i); 
     cv::Point center(cvRound(p[0]), cvRound(p[1]));
     int radius = cvRound(p[2]);

     // draw the circle center
     //cvCircle(cc_img, center, 3, CV_RGB(0,255,0), -1, 8, 0 );

     // draw the circle outline
     cvCircle(cc_img, center, radius+1, CV_RGB(0,0,255), 2, 8, 0 );

     //printf("x: %d y: %d r: %d\n", center.x, center.y, radius);
}   

CvMemStorage *mem;
mem = cvCreateMemStorage(0);
CvSeq *contours = 0;
cvCvtColor(cc_img, gray, CV_BGR2GRAY);
// Use either this:
int n = cvFindContours(gray, mem, &contours, sizeof(CvContour), CV_RETR_CCOMP, CV_CHAIN_APPROX_NONE, cvPoint(0,0));
// Or this:
//int n = cvFindContours(gray, mem, &contours, sizeof(CvContour), CV_RETR_LIST, CV_CHAIN_APPROX_SIMPLE, cvPoint(0,0));

for (; contours != 0; contours = contours->h_next)
{
    ext_color = CV_RGB( rand()&255, rand()&255, rand()&255 ); //randomly coloring different contours
    cvDrawContours(cc_img, contours, ext_color, CV_RGB(0,0,0), -1, CV_FILLED, 8, cvPoint(0,0));
}

cvSaveImage("out.png", cc_img);

Answer 2

您可以尝试对图像进行阈值处理 (cvThreshold)，然后腐蚀 (cvErode) 生成的二进制图像以分离硬币。然后找到侵蚀图像的轮廓。