How to find mean gray level in gray scale image

I'm trying to find gray level of a gray scale image. I came through this in one of the questions you answered

X = imread(image);

imshow(X);

minGL = min(X(:));

maxGL = max(X(:));

meanGL = mean(X(:));

but its giving me same answer for every gray scale image i.e

[Guillaume]

Can you post (not as picture) the exact code you're using. It's hopefully not what you've shown above since you're assigning the min, max and mean to variables minGL, maxGL and meanGL respectively, while you're showing us three times the content of a different variable.

[Iqra Rizvi]

i'm getting result meangraylevel .. because i've saved the matlab file with that name .. i'm not getting min , max n mean as the result

[KSSV]

Clear the workspace using clear all and run the code.

Answer 1

[Thorsten]

If you write a script and call it 'meangraylevel.m', that script changes only the variables that you use in the script, but not a variable that has the same name as the script. You should write a function instead.

Answer 2

[Image Analyst]

I don't know what you're running but you're not running meangraylevel.m. How do I know? Well, you don't have any semicolon after the lines where you compute minGL and maxGL yet those are not being echoed to the command window.

Next, you do have a semicolon after the line where you compute meanGL so that will not be echoed to the command window. So I'm not really sure how that meangraylevel number is getting output to the command window. Like I said, it should be minGL and maxGL and nothing else in the command window.

Next, it's not clear to use if you changed the filename each time you ran this. Are we to assume you did?

[Iqra Rizvi]

After putting the semicolon , I am not getting any answer