“ What worries me is that I can't see how this would have happened unless the Internet Archive's DjVu encoder knows something about what kind of glyphs to expect to find on a page, and is willing to take a guess as to which one is correct—a process tantamount to low-level OCR. If it is the case that the Internet Archive's DjVu processing is guessing glyphs rather than faithfully reproducing whatever it sees, then this casts serious doubt upon how we do our work here. What is the point of using scans to ensure fidelity, if the scans themselves lack fidelity? ”
Summary
“DjVu files/other pages”, is a work by . It explores elements such as DjVu, files and encoder.
Quotes from DjVu files/other pages ()
“ For typical black-text-on-white-paper pages, use ImageMagick to convert the tif/jp2/whatever to pbm format. PBM format is bitonal - every pixel is either fully black or fully white. Thus converting the bulk of a scan to this format gives you huge compression. Generally "convert page1.tif page1.pbm" gives you a sensible result, though you can fiddle around with manual thresholding if you want. It all depends on how much effort you are willing to invest in learning ImageMagick. DjVuLibre's cjb2 encoder will convert a PBM image into a DjVu file for you. ”
“ It’s important to emphasize that this is a consequence of the specific compression settings IA has chosen for their djvu encoder. More reasonable settings can produce better results. I grabbed the topmost png image from this post, converted to PAM, and ran it through the c44 djvu encoder at the default settings. ”
