| 摘要 |
<p>An input scanner scans documents on a platen (112) and converts detected reflected light from the document into a series of electrical signals representative of the image. In such an arrangement, an array (64) of photosensitive elements is supported on a scanning carriage (60) for scanning past a document on the platen for the acquisition of image information therefrom, arranged on the carriage transverse to the direction of carriage movement and parallel to the document supporting platen. Along the path of the scanning carriage, at a position for detection by photosensitive elements positioned outside the area of image acquisition, a series of indicia (198) are placed for detection by such normally unused photosensitive elements. The indicia, which may take the form of a series of printed lines are arranged at a known frequency. Detection of a line at such a position on the array is useful for position detection and velocity measurement. Once detected by the photosensitive elements, the images of the indicia are converted to transition values, and counted to obtain a positional value.</p> |
