A common problem in image capture for various active illumination methods is ambient light. Say you want to probe a scene using your own light source. You might be using patterned illumination to do 3d reconstruction or using a light pulse to measure distance. You blast the scene without your light source and use an image sensor to capture the interaction of your light source with the scene. There are many techniques that use active illumination and capture. But ambient light which covers a broad spectrum of wavelength will contaminate the captured light and ruin your methods. You have to actively mitigate the ambient or global contamination, which was one of the things I tackled at TetraVue. This can be achieved through various means:
