Reading values of pixels in an image

[BrunoB]

Hello all,

I have a fairly trivial question, applied to a more specific problem.

I am trying to sort through a multitude of satellite images. Some of these images weren't well read by the sensor and have blacked out pixels. The images with too many blacked out pixels will be discarded.

Basically, I want to read all the pixels of a 75x75 matrix and know how many pixels are blacked out.

Thanks for the help,
Bruno

 

[dileeprd]

You have to break down the problem:

What value constitutes a blacked out image
(image ranges could be 0-255 or 0-1 or something else)

instead if your problem is like finding number of entries in a matrix which are greater than a value x, then the answer would be:

sum(A>=x)

where x is the level of black
and A is your image matrix

let me know if it helps