Mars Images - 3D Viewer

NASA (actually JPL) is currently publishing raw images from Mars. Many of these images form left-right stereo pairs.

MarsImages.exe was designed specifically to view these images - just download and run it. (It is just a single exe file, it does not modify the registry. However, it will create several files in the same directory that it is stored in.)

To get you started, pick an image from the list provided. The program will display 2 images that form a stereo pair - cross your eyes and force the 2 images to fuse into a single 3D image. (The line between the images is not always obvious.) When you cross your eyes, the Left eye will look directly at the image on the Right side of the monitor and Right eye will look directly at the image on the Left. When the landmarks (rocks and hills) in the 2 images overlap, your brain will interpret the scene as having depth.

Scroll bars are provided so that the entire image can be seen. Notice that there are 2 horizontal scroll bars

For the time being, just use the lower one.

Upper Horizontal Scrollbar

Due to the way stereo photography works, when you zoom in on an image pair there is usually an alignment problem - the upper horizontal scroll bar compensates for that.

This compensation can be enabled (or disabled) via Configure / Auto Horz Offset.

You will notice that the horizonal compensation is different when the image is scrolled to the top and bottom of the range. With your eyes, when you look at items that are close, the angle between the eyes is not the same as when you look at items further away. However, with images, the angle of separation is fixed when the image is taken. The upper horizontal scroll bar compensates for this when only a portion of the image can be seen - it is not necessary when the entire image is visible at one time..

With the images available via the pick list, the horizontal offsets are already set. Without crossing your eyes, move the vertical scroll bar and notice that the upper horizontal scrollbar moves all by itself.

With images that are not compensated, scroll the image to the top, use the upper horizontal scrollbar to adjust the offset, and right click the scrollbar to set the point. Now, scroll the image to the bottom and repeat (be sure to right click the scrollbar to set the compensation). The order of the points is not important.

Notice that, because the program uses a simple linear algorithm to adjust the offset, you don't have to scroll all the way to the top and bottom of the image, any 2 points will do as long as there is a reasonable distance between them.

Its not really very complicated - play with it and you'll see.

Selecting Image Pairs

Almost all the Navigation and Hazard images and many of the Panoramic images are available as stereo pairs. When you examine the url's, you can determine which images are stereo pairs - the url's are identical except for the L & R in the 8th position from the end of the url. For instance, the following urls's are from the Spirit Panoramic Camera and were taken on Sol 010 (the 10th day after landing).
                                                 ^^^ Day image was taken
                                               ^ Camera
                                             ^ 1=Opportunity 2=Spirit  
Most of the better Panoramic camera stereo images are taken with filter 2 (red) on both cameras. Thus L2 and R2 make a good stereo pair. The blue (L7 and R1) filters also make good setero pairs. The Navigation and Hazard cameras do not have changable filters, so they are always L0 and R0.

This provides a complete description of the image names (ie, how to decode them).

Viewing additional images

The main point of this viewer is to simplify viewing additional images. Once you've selected a likely canditate There are several possibilities at this point Assuming that 2 images are displayed, set the horizonal offset and enjoy viewing.

Once you have a pair you like, you can save its data via Configure / Image Data, this will add a link to the image to the pick list. Notice that the List Text value does not need to be unique.

Since this data is stored in the ini file, you can edit that with a text editor (not MS Word) if you need to.

Images from other sites

This program is actually a generic stereo image viewer - as a result it can be used to view images on your hard drive or from other sites on the web.

For instance, Pathfinder images can also be seen in this viewer - just paste the url's into the address field. (The gif's don't work.)

For non-JPL images use Configure / Image Data to enter the fully qualified names of 2 images. In fact, this dialog box will be automatically displayed if the program does not know what to do with url that you paste in the address field.

Over/Under Viewing

By default, the program displays stereo pairs side-by-side for cross-eyed viewing. However, for those with an over/under viewer, there is an option to arrange the images in that way.

I've found that the horizontal offsets I prefer for over/under viewing are not the same as those for side-by-side viewing.

This is a real treat ... if you have a viewer.

Panoramic Camera Filters

To compare Wavelengths to colors, see Spectra Lab Report. The names used in the table above are very approximate. I also suggest checking out Color Science - Eye Sensitivity.

I don't have confirmation that the table and the image filenames use the same filter numbers, but it seems likely. I have noticed that most of the better stereo pairs are L2/R2 and L7/R1.

Notice that only the left camera can be used to produce "true color" images. While that would appear to limit the possibility of color stereo pairs, I once took a roll of stereo pairs using color film for one camera and black and white for the other (well actually, it was an accident). When merged, the final image was in color - I was very suprised.

JPL has published a summarry of the File name code.

Arrow Keys

The 3 scroll bars can be moved using the arrow keys. The Alt and Ctrl keys control how fast the scroll bars move.

The horizontal offset (upper horizontal scroll bar) is moved by holding down the Shift key while using the arrow keys.

Additional Notes

MarsImages.exe is still under development, so new features will be added. Be sure to check for updates.

MarsImages.exe creates the following files in the directory it is stored in

Author: Robert Clemenzi -