But, this is a technical thread, is it not? I'm eager to hear about more efficient alternatives to the labor intensive Photoshop method, especially if we're talking freeware. I understand that command line applications are not for everyone, but I've used such things in the past, even as mainframe batch jobs. It's not my preferred method in this day and age, but I wouldn't be afraid to try it if it saved me time.
I was intrigued by JohnVV's recommendation of an application that has a spreadsheet interface for image processing. I love spreadsheets, and I downloaded vips and nip2 tonight. I haven't been able to try them yet.
Getting back to the image at hand, the R5 without dropouts came down today. Using the Photoshop method, here is what I came up with.Click to view attachment
I wasn't expecting most of the larger rock fragments to have a hematite signature. The spherical ones and most of the others appear yellow in this IR false color image. I've studied hundreds of Opportunity images created according to this specific algorithm as we've roved across Meridiani Planum. In spite of the fact that they were made from uncalibrated, raw jpegs, the hematite concretions always appear in shades of yellow or occasionally orange. Ignore the purple, as that is how shadows appear in these images.
So, I have to wonder what this might mean regarding the geology and geomorphology of Cape York. Do abundant hematite fragments and spherules mean that the cape was once covered by the younger sulfate sediments with their embedded hematite concetions? Or, might these pieces of hematite have been tossed onto Cape York by meteorite impact processes?