HiPOD, HiRISE Picture Of the Day Options

[CosmicRocker]

The Holden Crater Megabreccia image from Release 4 is one of my favorites. I cropped an area containing some of the larger fragments, and added a scale bar and an overlay of Eagle Crater with lander (~22 meters) for another sense of scale.

As I was looking at the larger image, I noticed that my brain would sometimes invert the topography, creating a completely different impression of the geology. Most of you are probably familiar with the effect. The description from the HiRise site tells us that the illumination is coming from the north, so it is clear that these large breccia clasts are softer than the surrounding matrix, and have eroded to become depressions rather than elevated blocks.

I thought it might be fun to hear how others initially "see" the topography in this area, so I made the attachment containing two images. The one on top has the original orientation, and the bottom image has been flipped vertically.

edit: I was led into this exercise because one of the cropped images at the HiRise site is flipped or rotated, thus creating a misleading impression.

[edstrick]

A psychological trick to de-invert "flipped" topography in space images (craters that look like domes, etc) is to orient the image with the real direction of illumination from the top, and to actually position a light source "above" the picture if just orienting it so light is coming from "above" doesn't work.

[CosmicRocker]

Hmm, a psychological trick? Are you suggesting a real light source above my monitor? I never would have considered that. I have looked at that image so many times that it changes every time I blink.

[Bob Shaw]

Hmm, a psychological trick? Are you suggesting a real light source above my monitor? I never would have considered that. I have looked at that image so many times that it changes every time I blink.

That's exactly how to do it. Point your finger at the screen, make a shadow, and POW! those Martian Domed Cities become, er, craters!


Bob Shaw

[edstrick]

"Are you suggesting a real light source above my monitor? "

Exactly. It's a desperation last trick for images that won't de-invert. Usually, just orienting the pic so the pic's illumination is coming from above -- as seen by the viewer -- works, but some pics are "recalcitrant"

[CosmicRocker]

I really tried to make that work, using various light sources at different positions. But I don't see how I would create the shadow of my finger on my bright screen, short of using a blinding light. It sounds like a good idea, though.

In keeping with the theme of illusions, here is something different. When I first saw North Sinus Meridiani Landforms from Release 6, I knew instantly how it needed to be "enhanced." The f@ce and pyr@mids of the Cydonia region are nothing compared to this place. Kick me, if I am bad, but I thought we made allowances for artistic impression here.

The detail that HiRise is able to capture is amazing. I've named this image, "Mars...Land of Change."

[Pando]

I really tried to make that work, using various light sources at different positions. But I don't see how I would create the shadow of my finger on my bright screen, short of using a blinding light.

What helps is the way your finger (or try any other object) is illuminated from the light above, and the shadow is not necessarily needed. Expecting a light source from the top is wired to our brains, naturally.

[djellison]

I've never struggled with this, once I read "illumination from the left" - I'm fine...BUT

I've NEVER been able to watch the Apollo 11 landing and see 'craters' on the surface, it's always been domes....it really annoys me

Doug

[RedSky]

I really tried to make that work, using various light sources at different positions. But I don't see how I would create the shadow of my finger on my bright screen, short of using a blinding light. It sounds like a good idea, though.

In keeping with the theme of illusions, here is something different. When I first saw North Sinus Meridiani Landforms from Release 6, I knew instantly how it needed to be "enhanced." The f@ce and pyr@mids of the Cydonia region are nothing compared to this place. Kick me, if I am bad, but I thought we made allowances for artistic impression here.

The detail that HiRise is able to capture is amazing. I've named this image, "Mars...Land of Change."

Nice joke, there CR. I almost didn't notice the Jefferson Nickel until I saw the words "trust" and "liberty" on the crater rim. Oh, and the FDR dime makes for nice "change" also...

[Nirgal]

First of all, A Happy New Year to all of you

Let me share the latest finding of my "HiRISE Mars Sightseeing Flights": a colorized crop of the "Ius Chasma" image of the PSP5 release (original image here)
Included is a 50-meter scale symbolized as the shadow of an "imaginary" passenger-jet, just for a better "sense of scale" of the
scenery ...



(usual disclaimer: the synthetic colors are based on "real-color" palettes and guesses about
probable surface composition (i.e. "blackish" dark basaltic sand dunes with light colored, more reddisch/yellowish exposed rocks etc.)

[Bob Shaw]

First of all, A Happy New Year to all of you

Let me share the latest finding of my "HiRISE Mars Sightseeing Flights": a colorized crop of the "Ius Chasma" image of the PSP5 releaseIncluded is a 50-meter scale symbolized as the shadow of an "imaginary" passenger-jet, just for a better "sense of scale" of the scenery ...

Ahaa! Caught you! You're obviously posting in the style of that last image post - down in the corner, it's a Jefferson Airplane...


Bob Shaw

[CosmicRocker]

I wasn't sure which thread would be best to post this in, since it is an anaglyph made from the color image of Eberswalde delta from release 1 and a grayscale image from release 8. I like the concept of a HiPOD thread, so here it is.

This full-scale anaglyph is from an area north of the oxbow anaglyph of release 8. It has a lot of relief and a nice view of the polygonal blocks eroding from these sedimentary layers. The scale bar is 100 pixels/25 meters long, and 2 pixels/50 centimeters wide.

Edit: I just wanted to note that this is a progressive jpeg, to give a false sense of instant gratification to those of you on dialup, like myself. A low resolution version builds relatively quickly, and the details fill in painfully slower.

[dilo]

Great works, Tom and Bernhard!

[ustrax]

Great works, Tom and Bernhard!

I subscribe that!
Nirgal...How do you do that?!
You know I'm saving them all...
In the end I'll print them all and keep your work as a treasure...

[CosmicRocker]

Thanks for your kind comments, Marco and ustrax.

I've been experimenting with color anaglyphs where only one image from the stereo pair is in color. It seems that it works much better when the colored image is for the right eye. The Eberswalde pair fortunately matched that criterion. I now find myself wishing that the rovers' Pancams had the color filters on the right side.

Anyway, that exercise started me wondering if there were any other HiRise stereo pairs where one of them was in color...and that led me to collect a listing of released HiRise images, and to learn how to decipher the HiRise image names. I haven't yet found any other stereo pairs that would make interesting false-color anaglyphs, but I thought the image catalog I collected might be useful to others.

I am posting an Excel spreadsheet that contains all of the images and their descriptions. It is easily sortable, and you can use the auto-filter buttons to filter the data fields in many convenient ways. I have also included links to the images, and a field indicating if color or stereo is available. (If I missed any, perhaps someone will let me know.) Thanks to the HiBlog, I learned that the file names are composed from the Mission Phase, Orbit #, and Target Code. I could not use that information to identify the location of the images, but I was able to use the Target Code to calculate the latitude of the center of each image.
 MRO_HiRise_Image_Catalog1_posted.xls ( 152.5K ) Number of downloads: 356