| 摘要 |
<p>An input scanner is disclosed which is adapted to scan an image on an original, such as a radiographic film, and to form a digital representation of the image. The scanner (10) comprises a transparent platen (12) for supporting the film (22), a light source (14) under the platen (12), and a plurality of linear arrays (18) of photosensitive elements (31) located above the platen (12) for receiving light transmitted through the film (22). In order to improve the signal-to-noise ratio and the dynamic range of the scanner (10), the signals from adjacent photosensitive elements (31) in the arrays are processed by a combination of analog and digital summing. Different levels of spatial resolution can be selected electronically without changing the physical disposition of the photosensitive elements (31).</p> |
