| 摘要 |
A profile detector in a scanning system measures spacing of an original non-planar image from a reference image plane of the scanning system. The sp acing is measured by projecting a spot of light, with a collimated light source, onto a scan line of the original non-planar image at an angle that is oblique with respect to th e fast scan direction of the scanning system. A first photosensor converts optical infor mation reflecting off of the original non-planar image at a first slow scan positio n into electrical profile data. A position along the fast scan direction is identified for the first slow scan position by locating the spot of light in the electrical profile data. The l ocated position is compared with a pre-recorded position along the fast scan direction for the first slow scan position. The pre-recorded position defines a position where the first photo sensor would have detected the spot of light if it reflected off of a planar image. The d ifference between the located position and the pre-recorded position is used to determ ine the value for the spacing between the original non-planar image and the reference imag e plane at the first slow scan position. In a one pass scanning system, a second photos ensor records image data at a second slow scan position that is offset from the first slow scan position.The offset provides sufficient time for the scanning system t o calculate the spacing of the original non-planar image from the reference image plane before the second p hotosensor records image data at the first slow scan position. In a two-pass scanning s ystem, the first photosensor records the image data during the second pass. The scanning syst em compensates for image distortion caused by the calculated spacing by either adjusting system scan parameters or by performing image processing techniques.
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