QUOTE (djellison @ Dec 21 2006, 09:25 AM)
I would say that effect is too small to be really worth considering - how far apart are the CCD's - a cm, an inch - not much more than that....over a distance of 250km We're talking .000002 to .000011 degrees ( for 1 to 5 centimetre offset...if my very old Trig isn't letting me down)
I think your reasoning might be wrong. Let's say the camera has a 1 degree FOV (yes, I know HiRISE is a fraction of this) projected on a 10 cm diameter image area at focus. If the two detectors were 5 cm apart, would that not imply around 0.5 degree look difference? It is small (gives around 0.6 meters ground parallax for topography at 70 meters height), but it's still vastly larger an angle than what your simple trigonometric method neglecting camera projection gives. I wonder what the real numbers for HiRISE are.
That said, color binning on the other two filters is a real possibility and quite likely to make things harder. Sojourner won't be resolvable with 1x1 binning and its spectral signature can only be further diluted in 2x2 binning. Assuming they even get the color portion of the swath over the rover. It's definitely possible some of the color fringes in other color images are due to binning, but the fringes do look a bit stereo-ish to me.
EDIT: Okay, I did a quick calculation based on the layout of the CCDs as seen in
this document. The greatest stereo separation would be between the blue-green and NIR detectors. Visually, they seem to be separated by about 1 CCD width. Given that the CCD width is 2048 pix and with an IFOV of 1 microrad, that means the stereo look angles should differ by 2 millirad. Applied to Victoria crater depth of 70 meters that gives a parallax shift of 70*0.002 or 0.14 meters. This is well below the HiRISE minimal pixel size of 0.25 m/pix so in this case the color fringing probably was due to binning alone. Severe topography would be noticeably affected, however.