People who use "super-compressed" files can appreciate the convenience when it comes to saving space on their PC. It is a great technology though even today.WinDjView is a fast, lightweight, compact and powerful viewer for DjVu files and documents. DjVu at the time it was released, was not much use in scanning applications for OCR. If we were working with color images back then, then DjVu would have been a very good solution. So it was not feasible to perform greyscale or color image processing and most solutions were B/W for speed reasons. When it first came out, most computers had a difficult enough time processing, deskewing and despeckle of B/W images. The fact the B/W separation is not supported possibly points to part of the reason DjVu did not take off in the document management industry many years ago. I do not have enough scanned images to test how well it performs though. Fore/Back separation works on Gray and Colour images. When you choose B/W you lose the background processing option which supports my theory the B/W is not supported for automatic background separation. When you upload to any2djvu, it first asks you if it is a B/W or color document. The whole page of a B/W converted image is contained in the foreground only. 300dpi B/W images are not able to be processed by DjVu into fore/back layers. I uploaded about 10 more documents and have come to the following conclusions. I looked a DjVu when it first came out and overlooked this feature for some reason. I hope this answers your question a little better than my first attempt. I wonder what the licensing fees are for commercial apps ? I will have to do some more testing myself. " - If you perform a Google search with "vincent djvu segmentation" and then click on "Quick View" link of the 1st result then you can read the PDF.
#WINDJVIEW VS DJVULIBRE PDF#
Source code for WinDjView is available at - RenderThread.cpp - The function CRenderThread::Render() is the layer splitting/viewing code for the foreground/background viewing functions in WinDjView.Īlso there is a PDF document explaining how the algorithm works - "A GENERAL SEGMENTATION SCHEME FOR DJVU DOCUMENT COMPRESSION. I uploaded 1 color JPEG document and was quite impressed with the results. I would recommend uploading some scanned TIFF / JPEG files to and then using WinDjView to see the results of the fore / back separation. So this would be a good way to test how good the algorithm is before digging into c++ code. It has an option to View either Foreground or Background objects. WinDjView - is a nice DjVu file viewer built on DjVuLibre. DjViLibre is a C++ library that will do what you need. The tells the encode to use a special image processing algorithm to search for foreground and background objects and it save them to separate layers. The layering option needs to be turned on in the DjVu encoding settings though. To make a DjVu into layered document it would have to be generated as a layered document. If the document is scanned from a scanner then the image is just a flat bitmap like image. DjVuLayered - color documents such as magazines, catalogs, historical documents, etc.Ĭompressing to DjVu with the DjVuLayered mode will produce files between 30KB and 100KB, of which 5 to 40KB will be used for the foreground layer, and the rest for the backgrounds and pictures.ĭjVuLibre includes a standalone viewer, a browser plug-in (for Mozilla, Firefox, Konqueror, Netscape, Galeon, and Opera), and command line tools (decoders, encoders, utilities).Īny ideas how I can work with the DjVu tools to separate the background and foreground of a given scanned document?.DjVuPhoto - continuous-tone images such as photos, scanned graphic art, etc.DjVuText - black and white (bitonal) documents.
#WINDJVIEW VS DJVULIBRE HOW TO#
I was initially looking at developing my own background removal algorithm but it appears that the popular document format DjVu has its own foreground / background separation functions if I can only understand how to work with it.
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