separating object and bacground with imsubtract

how to separating object and background with imsubstract??

[David Young]

Why do you want to use imsubtract?

[Megah Putri]

hhmm... maybe you know the other way?

Answer 1

[Image Analyst]

How about

subtractedImage = single(originalImage) - single(backgroundImage);

[Megah Putri]

image analyst, I've used it before, but can not change the background..whats wrong?

[Image Analyst]

Because backgroundImage is on the RIGHT side of the equation, not the left side. So the background image does not change. If you're saying that the subtractedImage does not change then you'll have to provide sample images (originalImage and backgroundImage) and code that proves that subtractedImage does not change. It should change - the only way it wouldn't change is if backgroundImage were all zeros. Just a guess . . . you DID remember to cast your integer images into single or double like I showed you, right? Otherwise you'll get clipping of the negative numbers to zero.

Answer 2

[Alex Taylor]

I just wanted to add, as whenever this issue comes up, that Image Analyst's solution of using the MATLAB minus operator instead of imsubtract is the recommended way to perform basic math operations on images in MATLAB.

The IPT versions of these math operations (imadd, imsubtract, immultiply, imdivide) predate the support for non-double math operations in core MATLAB. We leave them in the product primarily for compatibility purposes.