reply to post by Soylent Green Is People
I forgot to add to my post above that this is the came "basic" concept used by most digital cameras. The actual light sensor (CCD) in a digital
camera is color-blind. It can only "detect" shades of gray. When you take a picture with your digital camera, the light is sent through different
color filters (different wavelengths) before striking the CCD, giving the CCD information about the image in various shades of gray as seen through
the different filters.
The camera's computer then takes over, and uses those shades of gray to try to determine what the color is actually supposed to be. This all happens
very quickly, and all we ever see is the color picture -- albeit a color picture created by the camera's computer based on multiple gray-scale
That's why the "raw" pictures from the Mars Rovers are in black-and-white. Instead of the rover itself using the various gray-scale images (as
seen through different filters in the Rover's camera) to build a color image inside
the rover itself, the gray-scale images are sent back to
Earth to allow the imaging scientists on Earth to build those color images. The reason for this is that there is valuable information in those
multiple gray-scale pictures that can be lost when they are compiled into a single color image.