| 摘要 |
A method and apparatus for exposure calibration of a recording device for pixel-by-pixel and line-by-line exposure of rastered areas on a recording material. A correction function (transfer function) is calculated, and picture signal values that are to be recorded, and which represent nominal gray scale values, are corrected according to the correction function so that the real gray scale values that are recorded correspond to the nominal gray scale values. For calculating the transfer function, check rasters having line patterns are exposed pixel-by-pixel and line-by-line on the recording material and the surface coverage values of the developed check rasters are measured. Relative increases in the optical density of the check raster are calculated from the measured surface coverage values. The effective increase in optical density of a dot or picture element is calculated from the relative increases in optical density of the check raster, taking the raster parameters provided for the recording into consideration. Subsequently, an increase in the optical density function is calculated for the nominal gray scale values of the gray scale range and the transfer function is calculated from the increase in the optical density function.
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