Dodging
Click Images and Links to see Larger Ones.

Dodge and burn are photographic exposure techniques used to lighten and darken images. Dodge lightens and burn darkens.
The large browse image (right) offered at NASA's PDS Planetary Image Atlas website is fairly light, showing lots of geology that is in the shade. However, they are somewhat on the blurry side. At the web site they split this large image into 4 smaller ones that show more shadow in the holes. The PDS raw image also shows much darker shadows - if you stretch the image.
Using the NASA View program didn't produce a lot of difference between these smaller sections and the PDS image.
I used the dodge tool to lighted the dark interior areas of these possible sinkholes.
I am not sure that this is an effective means of enhancement for these particular images.
But they are interesting, nevertheless.



The "Top of the Image"

fha01538 was divided into four parts at the NASA web site.
This is the first part - the top of the image.
I dodged the shadows of these images, trying not to destroy the content.
Dodging is really just a tool used to lighten what is already there to begin with. You can dodge and burn your way right out of an image if you are not careful.
The image to the left compares the original image with the dodged (lightened) one. Click on it to see a larger view. Click the link below to see a larger view of the dodged image alone.

The only thing that my dodging really did was lighten up some of the shadows - but not as much as NASA's browse image. I think that it gives better view of what is in the image, while at the same time keeping the context together. Shadow is produced by light angles, color values, depth and shape of objects. I dodged the midtones, which brought out some detail covered in darker values. If I dodged the shadows, which is the very darkest (black) values, I might possibly bring up some detail if I am careful. But dodging shadows really only lightens up the black, which produces gray. If you compare the browse image with these you might see how the lighter image seems to give a different impression of what is actually there.




Steve Wingate Takes a Look


Click the thumbnails for the larger examples.
This image was processed by Steve Wingate of Anomalous Images and UFO Files.
He used the raw image, destriped it, increased the contrast and brightness, and applied a custom sharpening filter.

Full Image
Steve's complete image is a very large file. But it is faithful to the light and shadow of the original. And the geology of this area is very clear - very interesting.
Full Image - a bit smaller file


I think Steve's image has much sharper detail than mine (or NASA's). And it shows a sharper, clearer view of the surrounding terrain, which seems rather messy in places, as if some sort of subsidence has occured. More detail comes out in the places where the sinkholes seem to be merging as well.

Questions: Have these processes stopped? Is subsidence still going on? Are there active karst processes at work here?



Too much Dodging
Click the thumbnail for the larger example.
This image shows what happens when you dodge the shadows instead of the midtones.
All that happens is that the black turns to grey. It resembles NASA's large browse image. It is a smear job. No detail is revealed. So it cannot be trusted. Better to have the dark shadow, which may represent a deeper, darker, and possibly vacant part of this structure.



Does this image look like a sinkhole?
Does its invert suggest that there may be a hole at the bottom of this funnel-like structure?
I think maybe it does.

From Steve Wingate's Image
A clear view of what appears to be an old drainage channel
leading into the sinkhole

In 3D - from the PDS Images
Click em
Coalescing Doline Structures?
I think maybe they are.





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-- Image Credits --

Steve Wingate of Anomalous Images and UFO Files