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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Aug 18 2012, 05:53 AM
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Senior Member Group: Members Posts: 2228 Joined: 1-December 04 From: Marble Falls, Texas, USA Member No.: 116 |
I'm curious about something I am seeing in the mastcam color images (M-34) and hope someone here can explain it. I'm not sure if this is the correct term, but I am seeing what appears to be color banding in most of the color mastcams. It is more apparent in some than others, and if you split the color image into it's red, green, and blue channels it becomes even more apparent.
In the attached example I have put the red channel greyscale alongside the color image. I have contrast stretched both images to make the banding effect more apparent. My best guess is that this may be caused by the raw images having had their bit depth reduced at some point. Or, could this be caused by some kind of image compression? -------------------- ...Tom
I'm not a Space Fan, I'm a Space Exploration Enthusiast. |
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