Chroma key is the post-production technique to combine two videos by making a range of color hues transparent in foreground video to reveal the background video. In modern movie-making, you may have seen an actor/actress performing in front of a huge blue or green screen. In post-production, the blue/green background is removed and substituted by other image. The GEM library has similar function and of course the quality depends upon the camera and lighting condition. The following patch is quite straightforward:
The object is pix_chroma_key. It accepts two inputs. They can be digital image, digital video, or webcam live stream, of the same frame size. In addition to the two images, the object requires a number of control data. The value message determines the color value or that we want it to be transparent. The range message defines the range of tolerance for the color value. The
direction message determines which image, left or right, will be transparent. The number...