| 摘要 |
PURPOSE:To improve the tracking performance of an original picture to a density change and the gradation by applying different weighting to a multi-value picture signal and a binary picture signal when weighted luminance is calculated and making a reference picture element range of a multi-value picture filter narrow. CONSTITUTION:Corrected picture data outputted from an adder 23 are inputted to a correction multi-value picture buffer 25 and a comparator 24. The comparator 24 compares the signal with a threshold level of a threshold level generating section 27 to binarize it and outputs the result to a binary picture buffer 20. A binary picture filter 31 calculates the luminance of the binary picture in the unit of picture elements based on an output of the buffer 30 and an output of a recording dot coefficient setting section 28 to execute weighted addition. Furthermore, a multi-value picture filter 26 implements the weight addition of the luminance of the corrected picture stored in the buffer 25. Then coefficients used for weight addition of the filters 31, 26 are made different and the picture element range referenced by the filter 26 is made narrower than the picture element range referenced by the filter 31. Thus, the tracking performance of the original picture to a density change is improved and the gradation is enhanced. |
