영상처리2018. 11. 10. 17:06

동전 이미지로 마스크 만들기 (floodFill)

출처 : https://www.learnopencv.com/filling-holes-in-an-image-using-opencv-python-c




imfill opencv steps
Figure 2.

Steps for implementing imfill in OpenCV

Please refer to Figure 2. while reading the steps below.

  1. Read in the image.
  2. Threshold the input image to obtain a binary image.
  3. Flood fill from pixel (0, 0). Notice the difference between the outputs of step 2 and step 3 is that the background in step 3 is now white.
  4. Invert the flood filled image ( i.e. black becomes white and white becomes black ).
  5. Combine the thresholded image with the inverted flood filled image using bitwise OR operation to obtain the final foreground mask with holes filled in. The image in Step 4 has some black areas inside the boundary. By design the image in Step 2 has those holes filled in. So we combine the two to get the mask.


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#include "opencv2/opencv.hpp"
 
using namespace cv;
 
int main(int argc, char **argv)
{
    // Read image
    Mat im_in = imread("nickel.jpg", IMREAD_GRAYSCALE);
 
   
    // Threshold.
    // Set values equal to or above 220 to 0.
    // Set values below 220 to 255.
    Mat im_th;
    threshold(im_in, im_th, 220, 255, THRESH_BINARY_INV);
     
    // Floodfill from point (0, 0)
    Mat im_floodfill = im_th.clone();
    floodFill(im_floodfill, cv::Point(0,0), Scalar(255));
     
    // Invert floodfilled image
    Mat im_floodfill_inv;
    bitwise_not(im_floodfill, im_floodfill_inv);
     
    // Combine the two images to get the foreground.
    Mat im_out = (im_th | im_floodfill_inv);
 
    // Display images
    imshow("Thresholded Image", im_th);
    imshow("Floodfilled Image", im_floodfill);
    imshow("Inverted Floodfilled Image", im_floodfill_inv);
    imshow("Foreground", im_out);
    waitKey(0);
     
}


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