MFBdjvu is a simple project for easy converting pgm and ppm to (MASK+FG+BG)-djvu. It uses djvulibre for all technichal work and compression. The breakdown of the image into components is done using DjVuL and DjVuL wiki.
MFBdjvu based of simpledjvu.
See MFBdjvu demo
submodules:
$ git submodule init
$ git submodule updateType:
$ makeIf you want, you can change your PATH variable or copy mfbdjvu binary to any directory already included in your PATH.
You need g++ version supports c++0x standard flag.
mfbdjvu [options] input.pnm output.djvuwhere options =
-mask mask.pbm {NULL} exist mask file.
-dpi n {300} DPI output djvu.
-loss n {1} Use n as cjb2 loss level (see djvulibre cjb2 tool description).
-quality n {75} Use n as parameter {0 - Inf} for generate slices, see down.
-slices_bg n1,n2,... {74,84,88,97}. Use n1,n2,... as number of slices for c44 for background (see djvulibre c44 tool description) {== -quality 75}.
-slices_fg n1,n2,... {100} Use n1,n2,... as number of slices for c44 for foreground {== -quality 75}.
-threshold str {djvul} threshold: djvul, bimod, sauvola, blur, edgeplus
-levels n {0} Level DjVuL block, 0 - auto.
-bgs n {3} Background and Foreground downsample.
-fgs n {2} Foreground more downsample.
-overlay n {50} Block overlay DjVuL in percent.
-anisotropic n {0} The main regulator DjVuL in percent. More than zero - more details, less than zero - less details.
-contrast n {0} Auxiliary regulator DjVuL in percent (sharpen).
-fbs n {100} and -delta n {0} Additional regulation DjVuL of BG/FG according to the linear law: FG * fbs + delta != BG
-sensitivity n {20} Sensitivity regulation for Sauvola and Blur threshold
-black Using black BG as the base, not white.
You can use Netpbm or any other similar tool to obtain pgm or ppm from other format.
The base of the algorithm was obtained in 2016 by studying the works monday2000 and adapting them to Linux. The prerequisite was the BookScanLib project and the algorithm DjVu Thresholding Binarization. This algorithm embodied good ideas, but had a recursive structure, was a "function with discontinuities" and had a hard color limit. The result of this algorithm, due to the indicated shortcomings and the absence of regulators, was doubtful. After careful study, all the foundations of the specified algorithm were rejected. The new algorithm is based on levels instead of recursion, a smooth weight function is used instead of a "discontinuous" one, no color restriction, BG/FG selection controls are enabled. The new algorithm allowed not only to obtain a much more adequate result, but also gave derivative functions: image division into BG/FG according to the existing mask.