Since different bands (or wavelengths) have a different contrast, computers can be used to produce a color image from a black and white remote sensing data set. Remember, satellites record the reflected and emitted brightness in the different parts of the spectrum, as is demonstrated in the figure above.
Similar to the screen on a color television set, computer screens can display three different images using blue light, green light and red light. The combination of these three wavelengths of light will generate the color image that our eyes can see. This is accomplished by displaying black and white satellite images corresponding to various bands in either blue, green, or red light to achieve the relative contrast between the bands. Finally, when these three colors are combined, a color imagecalled a "false color image"is produced (it's called "false color" because colors are assigned that we can see and easily interpret with our eyes).
In order to understand what the colors mean in the satellite image, we must know which band (or wavelength) is used for each of the blue, green and red parts of the computer display. Without detailed knowledge of how each band has been changed for contrast and brightness, we cannot be sure why the colors are what they are.
Related Data Sets: