| 摘要 |
<p>The present invention is a system that includes a quadrant detector with an axis between the detector elements aligned with the direction of film motion. The output of the detector is used by an analog signal processor composed of adders and subtractors to produce signals for detecting the center of the perforation and lateral displacement of the perforation and to provide an illumination adjustment signal. Control logic connected to the analog processor produces signals indicating perforation edge crossings. The center crossing signal is used to control sampling of an illumination adjustment signal and a lateral displacement signal while the edge crossing signals are used for a timing reference for the bottom edge of the film frame. The control logic also detects these trigger signals, controls the capture of the illumination and displacement signals and provides an interrupt to a computer to indicate the capture operation is complete. The computer then retrieves the captured values and uses the values to adjust the position of the image from the film captured by a video detector.</p> |
