MSL Images & Cameras, technical discussions of images, image processing and cameras Options

[CosmicRocker]

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.

[elakdawalla]

An interesting trivium from Mike Malin's review of the Mastcam section in my book. In my text I mention that most Mastcam images are 1344 by 1200 pixels to crop away the sides, and he commented:

This has been changed to 1328 x 1184 between sol 1587 and 1589 (1/22/2017 and 1/24/2017). The reason was for more efficient memory managment in the DEA. 1344x1200 led to much greater fragmentation of the flash memory that is broken down into integer units of 512KByte blocks, so 1344÷15 x 1200÷16 = 6300 pages÷512= 12.3 blocks, whereas 1328÷16 x 1184÷16 = 6142 pages ÷ 512 = 11.996 blocks or just a tad less than 12 blocks...more efficient packing.