I have a picture contains blood smear. What I want to do is to detect the edges of those cells.
I first convert this color image into grayscale image and then fill holes in those cells. And I use the edge() function in matlab to detect edges. Since you can observe the inner part of some cell is much lighter, so there are edges detected inside one cell. The result is shown below:
So is there any methods that only the outer edges of those cells can be detected?
My code is shown below:
I = imread('film02_pattern.jpg');
t1=graythresh(I);
k1=im2bw(I,t1);
k1=~k1;
se = strel('disk',1);
k1=imfill(k1,'holes');
imshow(k1);
k1=~k1;
bw = edge(k1,'canny',[],sqrt(2));
figure,imshow(bw);
To deal with the contours that intersect with the edge of the image, you can use use
bwconncomp
to separate the background from the unfillable contours. Then, instead ofedge
, you can get the outer perimeters only viabwperim
, but that is just a variation.Using connected components seems a bit like overkill, but there doesn't seem to be an easier way to distinguish background from the centers of cells that hit the edge of the image, at least not while
imfill
is unable to fill those contours.