Problems in automatically set reference color

Question

I was trying to segment blue cells from the image,

I found that using color distance method is highly effective, however, I can only manually set the reference color in RGB. Since I want to do batch processing, I need to automatically select reference color, is there any good solutions?

Answer 1

I would like to present two very basic image processing approaches for this problem. Maybe one of them is useful for you.

Load input image:

cells = imread('cells.png');

Approach #1

Select the blue channel of the input image:

cellsBlue = cells(:, :, 3);
imshow(cellsBlue)

Do some thresholding. A very simple version could be:

cellsSegm = cellsBlue < 100;
imshow(cellsSegm)

Afterwards you will need to apply some morphological filters to improve the masks.

Approach #2

Convert input image to HSV color space:

cellsHSV = rgb2hsv(cells);
imshow(cellsHSV)

Select the "saturation" channel of the HSV image:

cellsSat = cellsHSV(:, :, 2);
imshow(cellsSat)

Do some thresholding. A very simple version could be (attention, HSV values are double values between 0 and 1):

cellsSegm = cellsSat > 0.5;
imshow(cellsSegm)

Afterwards you will need to apply some morphological filters to improve the masks.