PanCam true color images from Spirit and Opportuniy Mars Exploration Rover

Spirit

Connection to Rover was lost on March 22, 2010 (Sol 2210).

Final command sent on May 25, 2011 (Sol 2628).

more: all Spirit images

older images at list of all Spirit images

Opportunity

Last reconnection attempt was made on February 12, 2019 (Sol 5352).

Final image was received on June 4, 2018 (Sol 5105).

more: all Opportunity images

older images at list of all Opportunity images

New Features

2016-01-27

Use keys ↑ ↓ ← → ↵ for navigation in album pages.

What you see here

On this website you find true color images taken by the Panoramic Camera on each of the Marsrovers Spirit and Opportunity. This is how images would look like, if an astronaut on the surface of Mars took images with a 1 Megapixel digital camera and sent them back to Earth via a planet wide Internet. That means, the colors appear the same as the astronaut would see them.

On the left you see two columns of number pairs. The number before the colon represents the Martian solar day (Sol) since the landing of each Rover. The link leads to an album page with almost all color images taken on that day. The number behind the colon is the number of images available on that album page.

Note, that the color images are created automatically from all raw color data available. That means, there are also images which do not represent true color as they have been taken with filters outside the wavelength range of the human eye.

Those images marked with a dark grey border (name suffix _L4L5L5L5L6) are the true color ones.

The color and contrast of these images appear different than those shown on the official NASA JPL Marsrovers Website. If you like to know why, continue reading below.

How the images are created

The images are automatically created daily from raw data available at JPL Marsrovers Gallery.

Fig.1: The image creation process applied to all images on this website (MER2RGB-process): 3 raw images are taken through the red (L4), green (L5) and blue (L6) filter with the Rover Panoramic Camera. The red and green images are combined (each pixel value summarized) with weighting 70/30; the same is done with blue and green. The results from step 2 are combined into one color image.

Every Martian day (Sol) new raw images are downloaded. The raw images are black & white images, each taken through a colored glass (filter) by the Panoramic Camera on the Rover. By using 3 filters, each one only letting pass red, green and blue light, a true color image can be created. This is in principle the same as every common photo or video camera creates color images.

The Rover Panoramic Camera differs from normal digital cameras by having filters with smaller bandwidth resulting in images with appear as having too much color saturation. To counteract this effect a special but simple processing is done as follows:

By combining the black & white images from two filters a visual effect is created as the image would have been taken through one filter with wider bandwidth. The result is a good approximation to true natural colors.

As the Rover Panoramic Camera contains more than only red, green and blue filters there are more combinations available to create color images. The images created with these additional filters (L2, L3 and L7) show slightly different colorizations as L2 and L3 pass only light of near infrared wavelengths and L7 pass only violet light. However, with the MER2RGB-process described above the overall colors approximate true colors sufficiently. That means, the soil looks still "Earth-like" and the sky is still blue to white.

You can find more detailed explanations about the Panoramic Camera and its filters on pages at cornell.edu, planetary.org and highmars.org.

How precise the true colors are reproduced

There has been much discussion on the Internet how complicated the reproduction of true color images from Mars would be. Of course, a 100% precise reproduction is not possible as the human visual system can only be approximated by technical devices. Taking this fact, some scientist claim, that it is impossible to recreate the Martian colors. These scientists forget that on Mars the same Sun is shining as on Earth with just reduced intensity by 40% and the same optical and physical laws are valid.

Nobody with enough common knowledge would claim that you cannot create true color pictures on any location on Earth. Color is not always 100% correct, but the general colorization is represented so we can get the impression how it would look like on that location when viewing it with our own eyes.

However, with the image data from Mars there was controversy about its colorization since the first color image was taken by the Viking Lander in 1976. The color calibration problem seems to be unsolvable. Even today, more than one year after Spirit landed, the calibration information given at the NASA PDS MER Atlas is still preliminary. Furthermore, a small error which happened during the calibration of the Viking Lander cameras seems to be used as base for calibrations of all later missions. As the investigation on this presumably unintentional errornous Viking calibration document is still ongoing, a concluding report cannot be given yet. For a scientific approach to the calibration of the MER cameras the publication of pre-flight raw image data would also be needed, which isn't available yet.

The current documentation on the calibration of MER images is available as the Data Processing User's Guide.

What the image numbers mean

The image IDs shown on this website are derived from the original image IDs of the raw data. For example the suffix _L3L4L5L6L7 means that the filters L3+L4 for red, L5 for green and L6+L7 for blue are used.

The first part of the ID is a copy of the green filtered (L5) original image ID. A description to decode that number is given on marsrovers.jpl.nasa.gov.

Images with suffix _L4L5L5L5L6 give the best available color reproduction.

Recommended MER image archives and software

• Red Planet Report
  panoramic color images created by Robert Burnham
• Midnight Mars Browser
  A program to download Mars Exploration Rover (MER) images and view them in slideshow and panorama format.
  You can select the different camera datasets, view Pancam images in raw RGB color and move along the Rovers' tracks from Sol to Sol.

Who is offering this service

All Mars surface images are derived from original data published by NASA and JPL on Marsrover Image Gallery and exploratorium.edu.

Mars-Earth Logo © 2013 Holger Isenberg

Image processing framework: Holger Isenberg ([email protected]) using NetPBM, Perl and Album. Impressum on main page: areo.info