| 摘要 |
The checkered black/white test pattern used during a television camera setup mode for the automatic correction of spatial registration, shading, and gamma errors, is also used to obtain digital data for automatically focusing the camera. The system detects the variation of the optical and the electrical focus by detecting the corresponding variation in the risetime of the signal generated as the electron beam spot scans across a transition in the test pattern. At an optimum focus condition the digital data is at a maximum value, i.e., the risetime is at a maximum rate. The focus data is stored for subsequent use during the camera operating mode.
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