COPYRIGHT © 2000 CANON INC. 2000 2000 2000 2000 CANON iR5000/iR6000 REV.0 JULY 2000CHAPTER 2 MAIN CONTROLLER2-9 S2.2 Input Image ProcessingThe input image data from the reader unit is processed as follows:2.2.1 Image Data from the Reader UnitThe image data from the reader unit is 8-bit, 256-gradation luminance signals which havebeen subjected to shading correction.Further, the input is from two signal lines (odd-/even-number pixels).2.2.2 Enlargement/Reduction (main scanning direction)An image is enlarged/reduced by processing image data when writing it to the imagememory or reading it from the image memory.2.2.3 Edge EmphasisEdge emphasis is performed to enhance the crispness of text, text/photo, film photo, andprint photo modes while reducing moire as much as possible.2.2.4 EditingThe machine’s editing functions include the following: blanking/framing, negative/posi-tive reversal, slant, mirror, fold, repeat.2.2.5 Density Conversion (LUT)In this block, luminance image signals are converted into density image signals, and pro-cessing is performed so that the output density curve best suited to each mode may be ob-tained.a. LOG ConversionA LOG conversion table is used to convert luminance image signals possessing lumi-nance data based on reflected light into density image signals possessing density data oftoner.b. Density Adjustment (F-value conversion)An F-value table suited to the setting of the Copy Density key on the control panel isused to perform density adjustment. It, however, is not performed in memory copy mode.c. Density Correction (ϒ conversion)The ϒ conversion table for text, text photo, film photo, or print photo is used to performdensity correction.2.2.6 Binary Processing (error diffusion; T-BIC)The machine’s error diffusion method (T-BIC) ensures the best binary processing by con-trolling texture for best printing results. The 8-bit image density signal of text, text/photo, orprint photo mode is converted into a 1-bit image density signal (binary).Download Free Service Manual at http://printer1.blogspot.com
