Issue with image background substraction

Hi,

I am trying to perform background substraction. Here I have both the main and background images. I tried imsubstract unfortunately that doesn't performing well.

[Matt J]

Your post doesn't show what you did, so it is difficult to speculate what went wrong.

Answer 1

[DGM]

First off, don't save images by taking screenshots of figures. Use imwrite().

Second, if you're going to use the IPT arithmetic tools, you need to know what they do. They are still dependent on class and scale, just like using normal arithmetic operators. Subtracting a light gray background region from a dark gray foreground feature in uint8 will still cause all the foreground information to be destroyed, since negative values can't be represented. Either convert to floating-point and use the absolute difference, or if the images are both the same class and scale, you can use imabsdiff().

inpict = imread('main image.jpg');
bg = imread('background.jpg');

outpict = imabsdiff(inpict,bg); % absolute difference

imshow(outpict,'border','tight')

There are other ways to solve the same problem.

outpict = im2double(inpict)./im2double(bg); % division

imshow(outpict,'border','tight')

In either case, you can use imcomplement() to invert the result if you want to change the polarity.

[Turbulence Analysis]

Thanks very much, DGM!. It's perfect