posted on Nov, 12 2014 @ 03:13 PM
originally posted by: Spruce
It would be nice if we could get some color photos. I'm really getting sick of black and white. This is the 21st century. Color has been in since the
All digital color images are basically just "approximated color" anyway -- Including the cameras on spacecraft, and even the color images from you
consumer digital camera or your mobile phone. You may be surprised to find out that digital cameras are essentially "color blind"...
...That is to say that the light sensor (CCD, CMOS, or whatever) that picks up the light from the camera can only sense shades of gray
-- not color. The way your digital camera works is essentially by putting each image seen through three filters (most consumer cameras actually use a
single three-color filter called a "bayer filer") to get a grayscale image that is translated in your camera into a color image -- based on what
imaging science knows about how different colors look in grayscale through various filters of different wavelengths. This is all done inside of your
camera, and takes less than one second. You never know that the camera is doing this.
So the light sensor can only "see" grayscale, but the computer approximates the color for you -- thus it is not really a true color image, but a
computer approximation of what it thinks is a true color image based on the graysacle information.
Many spacecraft also employ this same technique. For example, the twin rovers on Mars (Spirit and Opportunity) had cameras essentially did the same
thing, but instead of combining the information from the three filters inside the camera, it keeps the three grayscale images separate (three
grayscale images as seen through the various filters) and transmits them back to Earth so imaging scientists here can combine them and assign the
colors. This is done because more imformation can be found by analyzing the three separate grayscale images. If they would be combined prior to
transmitting to Earth, information would be lost.
The Curiosity Rover on mars does it slightly differently. It has the ability to view the grayscales through different wavetentgh filters (thus being
able to discern greater information at those wavelengths), but it also has a bayer filter for creating instantaneous near-true-color images.
I think I read that Rosetta/Philae has filters in wavelengths of red and green, but I wouldn't be surprised if the cameras could NOT produce the
near-true-color like a consumer digital camera.
edit on 11/12/2014 by Soylent Green Is People because: (no reason given)