| 摘要 |
In an electro-optical imaging system an reference background (11) is scanned by an N element charge coupled device array (21) of photosensitive elements both when a lamp (15) is off and when the lamp (15) is on in order to provide a diagnostic test for the array (21). Each pixel output is compared with respective thresholds for the off and on modes and in the event of an unsatisfactory comparison for at least one pixel a respective indicator (69, 77) is illuminated. The number of unsatisfactory photosensitive elements is counted for each mode in respective counters (890, 891) and the addresses of such unsatisfactory photosensitive elements are stored in respective random access memories (950, 951). The detection of an object (17) to be scanned interrupts the diagnostic scanning. |
