Maximum, median & minimum components

What are these three designations describing and what is the proper use for these three components?

Minimum, maximum, and median pixel values within the image.

Minimum (for example) finds the lowest values of the set and expands them (similar to dilate) hence it enhances the darkened areas. Maximum does the opposite, it expands the highest values within an image. Median picks whats in the middle.

Practical usage: minimum can be used to enhance what's in the dark. Expanded darkened areas can be used as masks for something else, similar can be done with Maximum. Median can be used to remove unwanted noise and very useful for smoothing out values.

Out of FilterForge, minimum is an effective eye-detector for computer vision.

There's no specific usage for these effects, they can be used in a variety of ways so it's kinda up to you.