| 摘要 |
PROBLEM TO BE SOLVED: To extract star data necessary for highly accurate star position computation by logically adding data output from a data selector to data output from a level comparator, and outputting an extraction signal. SOLUTION: A star extraction circuit for a fixed star sensor is summarily constituted of a level comparator 2 and a data selector 5, and a logical adder 7. The level comparator 2 checks the signal levels of the respective picture elements of an input CCD image signal 1, and passes only the picture elements over a prescribed threshold value 3. The data selector 5 passes only the picture elements designated by a window gate signal 6 within the input CCD image signal 1. The logical adder 7 logically adds window selected data D1 selected by the data selector 5 to level selected data D2 passing the level comparator 2, either of the window selected data D1 or the level selected data D2 is selected, and the data is sent to a succeeding process as an extraction signal 4.
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