hi, my goal is to fill with white colour the CLOSED black zones, not that ones that end on the image boundaries but aren't closed by white pixels (i hope i'm clear).
i tried with opening (or closure) functions but the they causes the closure of the opened/connected black rectangular zones, thing that is highly unwanted.
can someone help me?
I had some extra time at work so I whipped up a quick and dirty implementation of my comment above:
Code:
cv::Mat image = cv::imread("image.jpg", 0);
cv::Mat image_thresh;
cv::threshold(image, image_thresh, 125, 255, cv::THRESH_BINARY);
// Loop through the border pixels and if they're black, floodFill from there
cv::Mat mask;
image_thresh.copyTo(mask);
for (int i = 0; i < mask.cols; i++) {
if (mask.at<char>(0, i) == 0) {
cv::floodFill(mask, cv::Point(i, 0), 255, 0, 10, 10);
}
if (mask.at<char>(mask.rows-1, i) == 0) {
cv::floodFill(mask, cv::Point(i, mask.rows-1), 255, 0, 10, 10);
}
}
for (int i = 0; i < mask.rows; i++) {
if (mask.at<char>(i, 0) == 0) {
cv::floodFill(mask, cv::Point(0, i), 255, 0, 10, 10);
}
if (mask.at<char>(i, mask.cols-1) == 0) {
cv::floodFill(mask, cv::Point(mask.cols-1, i), 255, 0, 10, 10);
}
}
// Compare mask with original.
cv::Mat newImage;
image.copyTo(newImage);
for (int row = 0; row < mask.rows; ++row) {
for (int col = 0; col < mask.cols; ++col) {
if (mask.at<char>(row, col) == 0) {
newImage.at<char>(row, col) = 255;
}
}
}
cv::imshow("filled image", mask);
cv::imshow("Final image", newImage);
cv::imwrite("final.jpg", newImage);
cv::waitKey(0);
return 0;
And the result:
HI, there is the other code which is used findContours. I don't know which one is more effictive.
Mat CV_EXPORTS FillHoles( Mat _src)
{
CV_Assert(_src.type()==CV_8UC1);
Mat dst;
vector<vector<cv::Point>> contours;
vector<Vec4i> hierarchy;
findContours(_src,contours,hierarchy,CV_RETR_CCOMP,CV_CHAIN_APPROX_SIMPLE,cv::Point(0,0));
CvScalar color=cvScalar(255);
dst=Mat::zeros(_src.size(),CV_8UC1);
for(int i=0;i<contours.size();i++)
{
drawContours(dst,contours,i,color,-1,8,hierarchy,0,cv::Point());
}
return dst;
}
Asked: 2013-03-21 13:20:09 -0600
Seen: 26,036 times
Last updated: Jul 08 '13
If erosion and dilation aren't what you're looking for, then my approach would be to apply a flood fill to areas connected to the borders to create a mask of just the closed off black boxes. Then apply that mask to the original image to mask out the black boxes.