lossless-compression

I am doing a project where I compare different types of Text compression methods such as Huffman and Arithmetic for both static and adaptive form. I make a probability table for both using the number of occurrence of each letter in the text. Now, for adaptive form, the receiver does not need the Probability table but for the static form, we need to transmit this probability table as well to the receiver for decoding the message. Now this storing of the table will need some extra bits, which should be taken into account while comparing. So my question here is: What is the best solution for

I am dealing now with DDSM database (Digital Database for Screening Mammography) .. its disadvantage is its extension. It is extension is ljpeg (lossless jpeg) which it is very poorly supported extension. I want to read them using matlab or converting them to any other type which is widely supported. thank I know there is a working version of DDSM's jpeg program for linux at http://www.cs.unibo.it/~roffilli/sw.html I compiled and tested it. I used the MATLAB code as described here to view the images. It displays correctly only for some scanners. As described in the paper http://citeseerx.ist

Does anyone of you know a lossless compression algorithm, which produces headerless outputs? For example do not store the huffman tree used to compress it? I do not speak about hard coded huffman trees, but I like to know if there is any algorithm that can compress and decompress input without storing some metadata in its output. Or is this even theoretically impossible? Adaptive Huffman coding does exactly that. More generally, the term adaptive coding is used to describe entropy codes with this property. Some dictionary codes have this property too, e.g. run-length encoding (RLE) and Lempel

I've got 100's (maybe 1000's) of products with 10-30 images of each product coming to an online store I've put together. I need to optimize the images' file sizes as much as possible without loosing image quality. I haven't used jpegtran, jpegoptim, or any other jpeg optimizer directly but I have noticed that punypng shrinks file sizes down about 4-6% on the larger jpeg images LOSSLESSLY. Meta data is already stripped from the images during upload (via jumpoader) so that is not an option/problem anymore. Is there any way to get one of the jpeg optimizers to run from C# code? Note: I'm using

In honor of the Hutter Prize , what are the top algorithms (and a quick description of each) for text compression? Note: The intent of this question is to get a description of compression algorithms, not of compression programs. Corbin March The boundary-pushing compressors combine algorithms for insane results. Common algorithms include: The Burrows-Wheeler Transform and here - shuffle characters (or other bit blocks) with a predictable algorithm to increase repeated blocks which makes the source easier to compress. Decompression occurs as normal and the result is un-shuffled with the reverse

This C program is just 143 characters long! But it “decompresses” into the first 10,000 digits of Pi . // Created by cheeseMan on 30/11/13. long a[35014],b,c=35014,d,e,f=1e4,g,h; int main(int argc, const char * argv[]) { for(;(b=c-=14); h=printf("%04ld",e+d/f)) for(e=d%=f;(g=--b*2);d/=g) d=d*b+f*(h?a[b]:f/5), a[b]=d%--g; } I was doing some research on loss-less compression algorithms, still no luck yet, when I came across this pitiny.c . The weird thing is that it compiles successfully no errors or bugs, but like i said i cannot make heads or tales of the code, even its syntax. I just would

I am trying to losslessly compress an image, and in order to take advantage of regularities, I want to convert the image from RGB to Y'CbCr. (The exact details of what I mean by RGB and Y'CbCr are not important here; the RGB data consists of three bytes, and I have three bytes to store the result in.) The conversion process itself is pretty straightforward, but there is one problem: although the transformation is mathematically invertible, in practice there will be rounding errors. Of course these errors are small and virtually unnoticeable, but it does mean that the process is not lossless