Browse code
Initial commit
Dario Rodriguez authored on 28/10/2020 22:49:01
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+#!/usr/bin/pike |
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+/* |
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+ * jpgscanclean.pike |
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+ * |
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+ * Utility to clean the background of scanned pages (req. RGB page) |
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+ * |
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+ * Author: Dario Rodriguez dario@softhome.net |
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+ * The program is licensed under the terms of the MIT/X license. |
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+ */ |
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+ |
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+int bgthreshold=64; // from 0 to 255 |
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+int amplitude=15; // from 1 to 255 |
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+ |
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+int |
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+main(int argc, array(string) argv) |
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+{
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+ Image.Image in,out,inhsv,indistance; |
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+ string infile,outfile; |
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+ if(argc!=3 || argv[argc-1]=="--help") {
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+ write("Syntax: "+argv[0]+" infile.jpg outfile.png\n");
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+ return(1); |
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+ } |
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+ write(argv[1]+" -> "+argv[2]+"\n"); |
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+ write("* Generating intermediate representations...");
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+ infile=argv[1]; |
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+ outfile=argv[2]; |
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+ in=Image.load(infile); |
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+ inhsv=in->copy()->rgb_to_hsv(); |
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+ indistance=in->copy()->distancesq(255,255,255); |
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+ out=Image.Image(in.xsize(),in.ysize()); |
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+ // Guess the most used bg color |
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+ write("done.\n* Guessing most used bg hue...");
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+ array(int) hues=allocate(256); |
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+ int x,y; |
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+ int h,n,selh,seln,j; |
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+ int c; |
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+ for(y=0;y<in.ysize();y++) {
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+ for(x=0;x<in.xsize();x++) {
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+ c=indistance.getpixel(x,y)[0]; |
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+ if(c<bgthreshold) {
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+ // possible bg |
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+ c=inhsv.getpixel(x,y)[0]; |
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+ hues[c]++; |
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+ } |
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+ } |
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+ if(!(y%1000)) |
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+ write(".");
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+ } |
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+ for(selh=0,seln=0,h=0;h<256;h++) {
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+ for(n=0,j=-amplitude;j<amplitude;j++) {
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+ n+=hues[(h+256+j)%256]; |
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+ } |
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+ if(n>seln) {
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+ seln=n; |
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+ selh=h; |
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+ } |
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+ } |
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+ write(""+selh);
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+ // Clean image |
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+ write(".\n* Cleaning image...");
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+ int d; |
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+ for(y=0;y<in.ysize();y++) {
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+ for(x=0;x<in.xsize();x++) {
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+ c=indistance.getpixel(x,y)[0]; |
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+ h=inhsv.getpixel(x,y)[0]; |
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+ // calc. hue distance to bg hue wrapping on the color wheel |
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+ if(h<selh) {
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+ if((selh-h)<(h+256-selh)) |
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+ d=selh-h; |
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+ else |
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+ d=h+256-selh; |
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+ } else {
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+ if((h-selh)<(selh+256-h)) |
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+ d=h-selh; |
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+ else |
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+ d=selh+256-h; |
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+ } |
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+ // heuristics |
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+ if(c<bgthreshold && d<bgthreshold) {
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+ out.setpixel(x,y,255,255,255); |
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+ } else {
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+ array(int) rgb=in.getpixel(x,y); |
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+ out.setpixel(x,y,rgb[0],rgb[1],rgb[2]); |
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+ } |
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+ } |
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+ if(!(y%1000)) |
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+ write(".");
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+ } |
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+ // Write result |
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+ write("done.\n* Writing result to disk...");
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+ Stdio.write_file(outfile,Image.PNG.encode(out)); |
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+ write("done.\n* Process finished.\n");
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+} |