| 摘要 |
A method and apparatus are provided for compensating for spatial non-uniformities in a printer by deriving a true spatial non-uniformity tone response curve (TRC) that characterizes the printer in terms of color output variation for each addressable pixel location in a spatial range. In a one-time offline process, the "true average" tone response curve is determined for a color channel and stored. The "true average" tone response curve defines an average true response for the printer across the printed output spatial range. A prediction of the true response as a function of the spatial location is derived by printing and scanning a specially designed halftone-independent target of binary patterns. The predicted tone response curve for each color channel and halftone is predicted using a binary printer model and stored, wherein the "predicted tone response curve" provides a model based approximation of the actual response for the printer for each addressable pixel location in the spatial range. Also stored is an "average predicted tone response" by averaging the "predicted tone response curve" over the spatial range of the printer. With the "true average" tone response curve, the "predicted tone response curve", and the "average predicted tone response curve", an estimate of the true tone response curve for the color channel can then be mathematically obtained, wherein the true tone response curve defines a predicted actual response for the printer for each addressable print location in the spatial range. The "predicted" and "average" tone response curves are obtained using the 2x2 binary printer model.
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