| 摘要 |
PURPOSE:To obtain a recording picture with high quality by changing the weight at the center value of a Laplacian filter in response to digital picture information to correct the degradation in frequency characteristic caused due to the transmission characteristic of luminous amount versus picture density in a printer. CONSTITUTION:The median Z of the 3X3-constitution Laplacian filter (figure 1 (a)) is positive and a function of digital picture information at a noted picture element D(2,2) being a processing object among a prescribed picture element area extracted in response to the Laplacial filter constitution as shown in a figure (b). Thus, new digital picture information processed by the spatial filter is obtained by multiplying matrix elements corresponding to the Laplacian filter and an input picture element, summing the products and normalizing the sum. Thus, the deterioration in frequency characteristic due to nonlinear transmission characteristics in the luminous amount versus picture density of the printer is compensated and a recording picture with high quality is obtained.
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