what is the difference b/w image size 256*256 and image size 256*256*3?

I m doing project with medical images... i have read a .tiff image and calculated size ..it is showing 256*256*3..what is it??

Answer 1

[Walter Roberson]

The image that has *3 is an RGB image. The image that does not have *3 is a grayscale image (or a pseudocolor image)

[radhika]

but medical images doesnot have rgb color know.. thn how cme it is possible to say as rgb

[Matt Kindig]

It is an RGB file, just one where the red, green, and blue channels are all set to the same value. By definition, this will create a grayscale image. To confirm, both of the following statements should be true:

isequal( RGB(:,:,1), RGB(:,:,2))
isequal( RGB(:,:,2), RGB(:,:,3))

[Walter Roberson]

Medical images can have RGB, depending on how the image is created.

[Image Analyst]

Sometimes if you save images without specifying the correct options you could get an image stored as color even though it's grayscale. I often see jpg or bmp images that people uploaded as having 3 color channels even though it's a grayscale image in appearance. It saved it as color with all 3 channels being the same gray level image.