Edge enhancement

In so many ways video technology replicates what the eye does naturally. Consider the illusion called ‘Mach Bands‘. I’ve lifted the following graphic from the Wikipedia entry to which I’ve linked:

What you can see is a light grey block to the left, a dark grey block to the right, and a ramp up in darkness between them, starting at the left from somewhat lighter than the light grey block, and ending up somewhat darker than the dark grey black.

What this picture actually shows is a smooth transition from the light grey to the dark grey. At no point in the picture is it actually lighter than the light block, nor is any single pixel darker than the dark block.

The look that you see is simply edge enhancement performed in our own video processing mechanisms. If you don’t believe me, do a ‘Save Target As…’ on the picture to get it intact onto your computer, then ‘Preview’ it. Zoom in on the boundary and what the light and dark areas simply disappear as you get closer in.

This entry was posted in Imperfect perception, Video. Bookmark the permalink.

Leave a Reply

Your email address will not be published. Required fields are marked *