Uneven Illumination/Contrast Correction

I am having troubles correcting a microscope image with uneven illumination. I need to count cells in an image, of which are touching. The area I am showing is the section that is darker in the image.

I have tried the following code, and also functions such as: bw2 = imbinarize(I,'adaptive','ForegroundPolarity','dark'); to correct for it. Unfortunately either non-cells stay in the final image or some of the cells that are in a darker area of the image disappear entirely.

(Invertgray is just the original grayscale image, inverted.)

I have included various different results I have gotten:

background = imopen(invertgray, strel('disk', 10));
I2 = invertgray - 1.2*background;
adjust = imadjust(I2);
BW = imbinarize(adjust);

Answer 1

[Divya Gaddipati]

Hi,

You could try to perform image enhancement prior to converting it to a binary image.

For non-uniform illumination correction, you could refer to the following page: https://www.mathworks.com/help/images/correcting-nonuniform-illumination.html

Alternatively, you could also explore File Exchange for any submissions on other methods for illumination correction.

For example, https://www.mathworks.com/matlabcentral/fileexchange?q=contrast+correction