Method and apparatus for compensating for color variation in a video system

A method of tracking a prop having one or more color regions, each of said color regions being subject to deviation from a nominal value, comprising the steps of:

• observing a color ratio of one of said color regions of said prop;
• for each of said color regions, updating an expected color ratio based on said observed color ratio;
• employing said expected color ratio for detecting said color region of said prop;
• and
• detecting a loss of tracking of said prop.

A method of tracking a prop having one or more color regions, comprising the steps of:

• detecting a color ratio for a selected color region of said prop;
• computing for said color region a mix ratio, said mix ratio representing a proportional deviation from a nominal color value of said color region;
• computing for each of said color regions of said prop a desired color, said desired color being the sum of said nominal color and the product of said mix ratio and a difference between said nominal color and a maximum whiteness of said color region;
• and
• employing said desired color of each of said color regions in tracking said color regions.

A color compensation system, comprising:

• a prop having a plurality of color regions, each of said color regions being subject to whiting out at an equal rate;
• a detector for detecting a color ratio of a measured color region, said measured color region being one of said color regions;
• a processor for:
• (i) computing for said color region a deviation from a nominal value of said color region;
• and
• (ii) computing for each of said color regions of said prop an expected color ratio, said ratio representing said nominal color of said color region, adjusted by said deviation from said nominal value of said measured color region.

A method of white balance compensation for a succession of frames of video data, comprising the steps of:

• for each frame, estimating a white color balance ratio;
• for each frame, also estimating color ratios for background white pixels;
• employing said estimates of said color ratios to compute a new estimate of said white color balance ratio for each subsequent frame of video data;
• and
• also employing said estimates of said color ratios to compensate for variations in a light source affecting subsequent frames of video data.