Chroma Key Masking (a.k.a. Green-Screening)

We explore the topic of chromakey masking (i.e., green-screening, not that the key color need be green). We have an interactive Processing sketch (available as chromaKey.pde) which will allow for exploration of the topic (although we do not expect you to read the source code).

Our software allows the user to control several aspects of the masking process as follows:

/*
 * We allow the user to separately control:
 * -- The chroma key color. This is done by clicking on a pixel of either reference image
 * -- The function used for computing relative difference between two colors:
 *      pressing 'M' (the default) gets you Manhatten distance in RGB space
 *      pressing 'E' gets you Euclidean distance in RGB space
 *      pressing 'L' gets you Euclidean distance in L*a*b space 
 * -- The threshold value used for masking can be changed with UP/DOWN arrows
 * -- The image source can be chosen from a collection by typing the
 *    digit that corresponds to its index in the collection (with 0 = default)
 *
 * Finally, if you like what you see, 'S' saves the current screen to file.
 */

The software will show four panels:

• The first is the original photo (presumably shot against a solid background color).
• The second is a black and white mask. It represents which pixel locations of the original are viewed as matches to the "background" and which are not.
• The third is an example of the masked original, with "foreground" pixels left alone and "background" pixels removed.
• The fourth is an example of the masked original over a checkboard background, to give an idea of how the masked version can be placed over any background.

Here are a few examples (with the second being much more difficult to achieve, given the clothing color and shadows).