Preprocessing functions including extremely rapid rectification of images, formatting, noise removal, imbalance, and radiometric correcting can be performed best by manipulating data in parallel rather than serially. Projections for serial onboard image processing range up to 109 operations per second (Opportunity for Space Exploration to Year 2000. Address delivered by A. Adelman at Goddard Space Flight Center, 1980), whereas, those for parallel processors extend up to 1011 operations per second per pixel (assuming 100 clock cycles per operation). Another capability expected to be using parallel processing is a 1000 X 1000 parallel input array operating at up to 100 MHz clock rates (James Strong, personal communication, 1980). In one proposed 1000 X 1000 input array, as shown in figure 2.17, threshold photosensors on a wafer lead directly to massively parallel processing elements which in turn are connected (also through the wafers) to memories. Processing rates expected for massively parallel
SENSOR DATA UV VIS NEAR IR FAR IR SAR LIDAR ADJUST SENSORS
ACQUIRE DATA
CONVERT A TO D
PRELIMINARY
ANALYSIS FOR OBSERV. QUALITY REQUEST CAN BE MET ABORT NEXT PASS SCHEDULE AND WORLD { MODEL SEGMENT J4LE REQUEST CANNOT? BE MET
REGISTER MODIFY OR
RECTIFY ABORT
PROCESS
PROCESSING
COMPARE TO WORLD MODEL
Figure 2.14. - Onboard processing flowchart.
processors (MPP) are tabulated in table 2.7. Further information and technical descriptions are available in Gilmore et
