Chroma Key (HSV)

Chroma Key (HSV)¹⁰ (figure 10.32) replaces a color with another color or transparency using HSV variables. This plugin is replaced by the better Chroma Key (Avid) and is maintained only for reasons of compatibility with old projects. Refer to Chroma Key (Avid) for theory and parameter descriptions, which are quite similar, except the description of spill suppression, which differs considerably.

Figure 10.32: Windows config for Chroma Key (HSV)

        Spill light control section

In this section we try to make halos, reflections and parasitic lights present on the foreground less noticeable.

Spill light control:

This step helps you remove the green or blue halo around the edges of the mask. It does so by removing the saturation of pixels of the foreground that have a similar hue to the key color, turning them into gray instead of green or blue. The hues to be desaturated are set with Spill Threshold, the degree of desaturation is set with Spill Compensation. In order for Spill compensation to work, Spill Threshold must be > 0. If you start with Spill Compensation at 100%, slowly increase the Spill Threshold until the remaining green or blue areas turn gray. Then reduce Spill Compensation until the image looks good.

Footnotes

... (HSV)¹⁰

Credit for Plugin by Jerome Cornet http://jcornet.free.fr/linux/chromakey.html