Single frame images are sometimes acquired for the purpose of creating a mosaic or panorama. In some cases, mosaics are generated as archive products.
There are three types of mosaics in the Notebook.
- Archive mosaics are data products created from Navcam data by the science team and are part of the NASA PDS archive.
- Context mosaics are created from Navcam, MSL Mastcam, and MSL MAHLI data as part of Notebook processing to provide context when archive mosaics do not exist.
- Special product mosaics are created by instrument teams. MSL ChemCam RMI mosaics with links to associated LIBS data are provided. Note that these mosaics appear in the sol summary block as "Special products" and not as "Mosaics". See ChemCam RMI mosaics.
Finding mosaics in the Notebook
How mosaics are made
Archive mosaics are made by the Multi-mission Image Processing Lab at JPL. Camera pointing information is used to create well-controlled mosaics with known geometric properties. In some cases, inputs to the process are updated by hand to favor a particular image where there is overlap or to provide better image quality.
Context mosaics are generated using Microsoft Research Image Composite Editor (ICE) in either perspective or simple horizontal cylindrical projection. Navcam context mosaics are created by stitching images radiometrically calibrated images and then applying a linear 2% stretch. MSL Mastcam and MAHLI context mosaics use DRCL products as sources.
Microsoft Research ICE is an advanced panoramic image stitcher and available as a free download. Generated images may be uploaded to Photosynth or exported for use with Deep Zoom, Seadragon, and HD View. A load of thanks goes out to Matt Uyttendaele and his team for helping us integrate their code into our process. For more information, see:
- Microsoft Research: http://research.microsoft.com/en-us/
- ICE: http://research.microsoft.com/en-us/um/redmond/groups/ivm/ice/
- Matt Uyttendaele: http://research.microsoft.com/en-us/people/mattu/
Errors in the mosaic image
It is not unusual to see errors in some of the mosaics because of the large field of view of source images and the mosaics. Most mismatches occur at distances relatively close to the camera.
There are five projection types used for mosaics, though not for every particular set of source images: cylindrical, cylindrical-perspective, perspective, polar, and vertical-perspective.
Context mosaics use either cylindrical or perspective projection. Projection geometry, including phi and theta values, are stored in the EXIF header of the mosaic file.
The single frame images used as mosaic sources are listed on the mosaic product detail page. In some cases, stitching software may drop an image that does not "fit" correctly in the mosaic. As a result, there may be source images listed that are not in the mosaic.
Context mosaics use only radiometrically calibrated images as sources. This provides nearly seamless edge matching.
Mosaics and sols
Within the sol summary lists, mosaics are associated with the sol listed in the label. The source frames may or may not be from that particular sol for archive mosaics. Context mosaics are only made with source images from the same sol.