Comparing Mastcam and Laboratory Spectra
This set of images illustrates how the science filters of the Mast Camera (Mastcam) on NASA's Mars rover Curiosity can be used to investigate aspects of the composition and mineralogy of materials on Mars. On the left is a set of laboratory spectra of some iron oxide minerals (red and orange curves) and some relatively unoxidized minerals from typical basaltic volcanic rocks: pyroxenes (green and blue curves). On the right is the result of plotting the calibrated level of reflectance (the percentage of incident sunlight that is reflected off the surface) of several distinct regions from the Sol 183 (Feb. 9, 2013) Mastcam image of drill holes at rock target "John Klein" as a function of wavelength (color).
The wavelengths correspond to the Mastcam science filters plus the red, green and blue wavelengths of the Mastcam Bayer filters, for a total of 12 unique wavelengths between the two Mastcam cameras. The six filters at the lower wavelengths are within the range of typical human color vision, while the six filters at the higher wavelengths represent infrared colors that our eyes are not sensitive to, but which the Mastcams can detect.
See also http://photojournal.jpl.nasa.gov/catalog/PIA16805 for additional details.
Image credit: NASA/JPL-Caltech/MSSS/ASU