How to find what percentage of image an object covers

From the given image, how can i find the percentage of cells covers the image or in other words what percentage of cell covers that image or what is the percentage of foreground image?

Answer 1

[waqas]

im = im2bw(imread('image.jpeg'));
 imshow(bw)
whitearea = bwarea(bw);
blackarea = bwarea(~bw);

conversion to black and white is not perfect in the above code but this should give you the idea. You can use thresholding before converting to black and white image. This will take care of the pixels that are removed from the cells.