univurshul wrote:I did wonder about compression now that you mention it: what apps are you using to compress your TIFFs post-Scan Tailor?
Depends on the image, which is partly why I wrote djvubind. The djvulibre tool for black-and-white images is cjb2, which uses pattern matching and can be set to either lossless compression or a lossy method that will allow small changes to create more matches. I use minidjvu, which from what I know does the same thing as cjb2 but uses a shared dictionary of matches for several pages (djvubind is set to 100 pages per dict, I think). An image with more colors get separated, the black-and-white portions being sent to cjb2 before being merged back to the original with csepdjvu. I actually have a lot more to learn about the different compression methods and what might work even better, but there some more pressing areas of development for djvubind before I start fine-tuning things that already work very well.
I work with the djvu format mainly because the opensource toolset for it is quite capable (that or I know more about it and it just seems more capable!). I guess Misty is working on a pdf maker script, and I'm really looking forward to seeing direct comparisons of djvu and pdf files produced from the same set of images.
univurshul wrote:What would you recommend for iPad displays?
I'm not sure what your concern is, but I probably can't answer the question. Things like power consumption and render speeds would depend on the method of compression used in the image (and generally it is a trade off between power, speed, and size). Audio and video codecs are compared all the time for those things, but I haven't looked for a comparison of image compression and I doubt there would be a significant difference. Image quality would only be degraded with lossy compression. So long as it is a lossy compression designed for images of text, there shouldn't be a difference easily noticeable to the human eye (jpg compression, for example, is made for photo image and should never be used on a text image like we work with here).
univurshul wrote:Looking forward to djvubind once ported to the Mac OS.
I recently learned that minidjvu doesn't build on Mac. I made minidjvu a dependency because I've seen it cut file sizes almost in half on files that were already impressively small. I have two major things I still want to get into djvubind: cuneiform ocr engine (essentially done), and multicore improvements. Once those are out of the way, I plan to make minidjvu used only if present and cjb2 otherwise, and then post something here looking for people with macs to tell me if the code even runs, let alone how to package it for easy installation.
...and a little closer to the original topic, I would encourage you, recaptcha, that there is no need to build a book scanner before trying out the the software side firsthand. Take a quick picture of a book held open with your hand or a piece of paper or something; forget about getting the angle right and eliminating page curvature - that's half of what the book scanner is for. Toss the image on your computer, see how Scantailor works (and the things you can't expect it to fix!), try different formats like pdf, djvu, etc.