| 摘要 |
PROBLEM TO BE SOLVED: To obtain the image-processing unit in which image quality is emphasized by applying stepwise background elimination to digital image information, after adaptive edge enhancement. SOLUTION: A density conversion section 2 converts digital image information into a signal P which is linear in density with log transformation equation or the like. An edge amount calculation section 31 obtains an edge amountδfrom the density linear signal P. A correction value selection section 32 selects a correction values S, corresponding to the edge amountδ, to conduct nonlinear edge correction from a lockup table, an edge density arithmetic section 33 multiplies the edge amountδwith the selected correction value S, and the product is added to the signal P which is linear in density to calculate the corrected signal P1. A background elimination section 4 applies stepwise background elimination to the correction signal P1, based on the threshold level and the tilt of the background elimination characteristic, to calculate a correction signal P2.
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