Help in image processing - how to count the number of black shapes on white image

I have a fractography image. It consists of many black spots.. Black spots are of different shapes. I want to count the number of black spots...

Please find the attachment.

Please anyone suggest the code/command for this.. Any help is much appreciated..

[David K.]

First you need to make this greyscale image fully black white. This can be done with a simple threshold with

threshold = 0.5; % fiddle with this
BW = im2bw(yourImage, threshold);
BW = ~BW; % the following code needs white spots black background

Then you can use regionprops to identify every spot

stats = regionprops('table',bw,'Centroid','MajorAxisLength','MinorAxisLength')

test if everything was found with

imshow(yourImage)
centers = stats.Centroid;
diameters = mean([stats.MajorAxisLength stats.MinorAxisLength],2);
radii = diameters/2;
hold on
viscircles(centers,radii);
hold off

Most likely, due to the complexity of your image you will need to look into adaptive thresholding as well as some image processing to clean it up such as imfill. Hope this gets you on your way.

[UMANG NAGPAL]

@David K

The above written has been done but How should I count the number of pores now?

I have got a plot , with circles covering the black regions/pores , but how should I count them?

Answer 1

[KALYAN ACHARJYA]

gray_image=imread('3.bmp');
% Improve the Thresholding to get more accurate answer
% Here I have used Global image threshold using Otsu's method
[T sm]=graythresh(gray_image); 
bw_image=im2bw(gray_image,T);
[L hole_counts]=bwlabel(~bw_image);
fprintf('The Black holes counts: %d',hole_counts-1);
% 1 Minus for lower balck strips

[ruban ramalingam]

Thank you sir.. I want to measure the sizes of various holes and I want to plot the histogram of various pore sizes..

[KALYAN ACHARJYA]

See regionprops