Combine images

This function combines multiple images pixel-wisely. Available operations include add, subtract (2 images only), mean, median, and, or, xor, max and min.

In the dialog shown here, you can either select multiple files or specify a folder name to combine all images in that folder (including subfolders). You can only include certain types of files in that folder by giving the file extension. For example, to include all jpg files, use "jpg"; to include all jpg as well as bmp files, use "jpg;bmp"; to include all jpg files and exclude all bmp files, use "jpg;-bmp"; to include all but bmp files, use "-bmp". Leaving the extension box blank will include all files (same as "*.*").

The following example shows two images and the combined results.

Note that:

If images have different sizes, the smallest one will be considered and all images are aligned with respect to the bottom-left corner.
A pixel value is truncated to [0,255].
The subtract operation only considers the first two source files and the first one is the minuend.
If there are only two source files, the median operation is the same as the mean operation.

You can specify a transparent color, which will not be involved in any computation.
In the above example, if we set white as the transparent color, the results will change as follows.

Last update: 08/01/2006 (check html)