determine quantity of pixel in one image

HI ALLS!

i am working an square's grayscale image 252*252, now i just wanna to focus on smaller area in this image and count how many pixels this area have in there.

hope you guys help me! thanks so much!

Answer 1

[Image Analyst]

See my attached demo where you can hand-draw some region (doesn't have to be rectangular) and it will report the area and do some other stuff too, like masking.

Answer 2

[José-Luis]

Well, that would depend on the area, wouldn't it?

 number_of_pixels = width * height;

Answer 3

[cuong nguyen]

sorry to reply lately! Thanks you guys!

Imange Analyst : Does it count the pixels of each grayscale level?

[Image Analyst]

I don't think so, but you can pass the pixels into hist().