Page:Advanced Automation for Space Missions.djvu/37

 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