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Curiosity Transmits First 360-Degree Panorama From Mars
redletterdave writes with this snippet from the IB Times: "Five days after NASA's Curiosity rover successfully landed on Mars, the one-ton robot sent another postcard back to Earth, this one a 360-degree doozy. Curiosity's first panorama, albeit black-and-white, gives Earthlings a great high-quality glimpse at the surface on Mars, specifically within the 96-mile Gale Crater."
That's not a picture of Mars. I've been where this picture was taken... It's in southern Nevada. They're probably embarassed that the lens cap was left on, so they're showing us this instead. :)
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Here is NASA's version
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Curiosity is a hipster, color photographs are too mainstream.
This rover actually does have color cameras on it. The primary navigation cameras are B&W, but there are two color 2-mpixel cameras used for sending back photos. NASA has some information on that. Not sure why the linked image here is in B&W. Perhaps they sometimes take B&W photos to save bandwidth? The MarsEarth link is 29 kbit, basically '90s modem speed.
10 PRINT CHR$(205.5+RND(1)); : GOTO 10
That may be color, but it is the wrong rover! For those wondering why they don't take color photos...they do, but they take much longer to downlink. They are transmitting small thumbnails first, then full size B&W images, then they will do the full res color photos and videos, over the coming days/weeks/months. This way they can get initial images to check for any damage, etc as quickly as possible.
I know adding color would increase bandwidth, but I can't imagine that alone is the problem.
Actually, that alone is the problem. It's a 1mbit / 256kbit stream to a satellite in LEO that's only overhead for 18 minutes every day. I guess it's something about the transmitter being a few billion miles away that makes it hard, or something...
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Since these are science missions, the camera isn't equipped with a fixed Bayer pattern filter in front of the sensor. Instead it uses exchangeable filters. You can't make an interchangeable Bayer pattern filter, so they have to take three pictures to capture the red, green and blue channels separately. In addition to "sciency" filters, Curiosity also has filters for "human perception" color photography, whereas the spectra that were combined into color pictures from earlier missions did not match human perception because they were optimized just for the science. Curiosity should give us a first glimpse of what Mars would like like to human eyes (although it appears that they were not that far off before, see here.
Here is the Raw Archive of Engineering Camera's and improved EDL sequence with Yaketty Sax for soundtrack ;)
I am not an astrophysicist, but this is my understanding. The cameras are not like normal digital cameras. Regular digital cameras use 4 sensors per pixel (with different color filters) to take color pictures. This causes artifacts in the image because the different colors in a pixel are actually measuring different parts of the image, so some demosaicing algorithms are used to remove the artifacts. Additionally, the spectral bandwidth of the color filters (how much of what wavelengths they let through) in the camera is fixed (and generally set to approximate the human eye response -- color is not an objective measurement and is generally defined based on measurements of how people perceive different wavelengths of light).
Cameras used for scientific work are less concerned with making things look like the human eye would perceive them and more concerned with obtaining accurate and well-controlled images. Such cameras generally consist of an array of unfiltered sensors with an external, exchangeable, color filter. These color filters may vary from wide-bandwidth filters (for grayscale), to extremely narrow-band filters that only pass wavelengths within a few nanometers of the center frequency (useful for verifying structure or composition of objects).
Look for some pseudo-color images later. They just need to take the same picture 3 or more times with the appropriate sets of filters and then combine them into an image that approximates what someone would see.
Nasa's web site is the first place I look. There's a treasure trove of beautiful high resolution photos, movies, data. The photo you're looking for is there. I linked the panoramic shot in a comment farther down.
Free Martian Whores!
They have already downloaded a number of color photos you can find online, including a color panorama. http://mars.jpl.nasa.gov/msl/multimedia/raw/
Correction: The older rovers had to take three pictures for a color picture and lacked the human perception filters. Curiosity has color cameras: the Mastcams on the same mast as the black-and-white navigation cameras, a downward pointing camera for taking pictures of the descent, and a camera on the instrument arm. The Mastcams have filter wheels with narrowband and neutral density filters that can be added on top of the fixed Bayer pattern filter.
It's because of how cameras work.
The CCD sensors that make up each pixel can't sense color, they only sense light intensity. Putting a filter in front of them lets one get light of a single color. In a consumer camera every CCD is filtered by a red, green, or blue filter. In a scientific camera the full resolution is desired, instead of 1/3 resolution, so they use swappable filters and take 3 images; one red, one green, and one blue. These are then composed into a single color image. They can also use different filters (IR, UV, etc) depending on what data they want to capture (and the sensitivity range of the CCD in the camera). When color data isn't needed, full-spectrum luminance info is desired, or just to save bandwidth, they take unfiltered pictures.
Not a sentence!