The two Mars Exploration Rovers, Spirit and Opportunity, have a large complement of cameras. All cameras can take stereo pictures, in which an image is taken with a left camera and a right camera. The rovers have three sets of camera systems, each with different uses and capabilities.
  • Panoramic Cameras (pancams):
  • The left and right cameras are separated by 30 cm and each one has 8 color filters, which can be used to create color images (see Color Image Processing section). This is the primary science camera and is responsible for all color images from the mission.
  • Navigational Cameras (navcams):
  • The navigational cameras are used for science and by operators on Earth to use the images to drive the rovers to the desired scientific sites.
  • Hazard Avoidance Cameras (hazcams):
  • Two sets (front and rear) of hazcams provide stereo images through fish-eye lenses. Fish eye lenses create distinctive curvature in the output images.
In all cases, when the rover has acquired both a right and left-eye image, we can combine the images in a manner similar to the way the human brain continuously combines the images from our left and right eyes to perceive depth. You can see this effect yourself, when you hold your finger up close to your face and alternately open just one eye. Your finger appears to move against the background you see from the rest of the room. Your brain knows that the larger difference between objects in a view from your left and right eyes is due to the fact that the object is closer. The challenge is to both acquire a left and right eye view of the scene and moreover to display the resulting stereo images in a way that your left eye only sees the left image (taken with the left camera) and the right eye only sees the right image. In our case, we use inexpensive Geowall technology (see Geowall Consortium section).