| 摘要 |
<p>A video camera generates an approximation of the dark current or black shading distortion signals based on scan position in the image, and subtracts the approximation signal from the signal generated by the camera during normal image-sensing operation to reduce the black shading distortion. In a particular embodiment of the invention, counters generate location signals representative of the location of pixel currently being read, and the location signals are processed by functions such as squaring or raising to a constant power, and by weighting, to produce components of the approximation of the dark signal. The components are subtracted from the imager signal, to reduce the dark shading. In one embodiment of the invention, the functions are automatically selected from among a plurality of preselected functions, and implemented by look-up tables. <IMAGE></p> |
