MSL Images & Cameras, technical discussions of images, image processing and cameras |
MSL Images & Cameras, technical discussions of images, image processing and cameras |
Aug 16 2012, 11:05 PM
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Senior Member Group: Members Posts: 2228 Joined: 1-December 04 From: Marble Falls, Texas, USA Member No.: 116 |
I'm still trying to figure out a number of things about the new images we are trying to work with. Assuming others are likewise trying to learn, I thought I would open this thread to create a place for such discussions.
I'd like to start out with a comment about raw image contrast. There have been several postings in the main threads about whether or not the MSL raw images have been stretched like those from the MER missions. I am certainly no expert on this, but it looks to me as if the MSL images have not been stretched at all. I haven't tried to analyze all of the image types, but the hazcams and navcams have pixel brightness histograms that are very different from their MER counterparts. This attached image compares MER and MSL navcams along with their luminosity histograms. The MSL images clearly are not using the entire, available range of brightness values, whereas the MER raws do. For this reason, the MSL raw images can usually be nicely enhanced by simply stretching the distribution of brightness across the full 256 value range. -------------------- ...Tom
I'm not a Space Fan, I'm a Space Exploration Enthusiast. |
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Oct 18 2012, 10:42 AM
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Member Group: Members Posts: 154 Joined: 19-September 12 Member No.: 6658 |
I'm still somewhat puzzled with the brightness of the images. There is a nice image down from sol 71 with the rover and surface both in one image. As you can see below I compared this to an image from sol 61 (green filter). In the middle is a brightness corrected version to match the average surface brightness of the sol 61 image (and most other images).
As you can see the rover would be too bright now - so in reverse ... This would be mcaplingers color correction set to about 50% and somewhat reduced brightness (not linear as the highlights are still in and not that much as in the upper comparison). |
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