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| | [2.0] JPEG Image Compression |
 | | Compression could be increased by using some type of lossless compression on the coded bytes. | | | The image would be analyzed to determine the fractal patterns that make it up and transformed into relatively small and compact sets of parameters that define the proper fractal algorithms, The parameters could then be further compressed with some lossless compression algorithm, in principle resulting in a very compact graphics file. | | | It would be possible to obtain an 8:1 compression ratio by matching each block in the image with a block in the library, and just sending a code byte designating which block in the library matches the image block. |
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http://www.vectorsite.net/ttdcmp2.html#m3
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| | Image Compression using Backprop |
| | To compute the amount of image compression (measured in bits-per-pixel) for this level of quantization, we compute the ratio of the total number of bits transmitted: to the total number of pixels in the original image: 64; so in this case, the compression rate is given as bits/pixel. | | | For each such 8x8 chunk, the output the network can be computed and displayed on the screen to visually observe the performance of neural net image compression. | | | Then, a tiny image presented to the network as input would appear exactly the same at the output layer. |
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http://neuron.eng.wayne.edu/bpImageCompression9PLUS/bp9PLUS.html
(740 words)
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| | Image and Video Compression Techniques |
| | The images appearing on the output monitor are therefore mostly approximations or simulations created by a computer rather than the actual images seen by the camera. | | | A pixel data stream from an input image is divided into several sub-bands by a tree of bandpass filters. | | | The image encoding and retrieval process may be achieved using software only. |
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http://www.autosophy.com/videcomp.htm
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| | Optimizing Web Graphics: Compression - webreference.com |
| | While the LZW compression algorithm used by GIFs is one of the better general purpose compression algorithms, it wasn't designed specifically for graphics. | | | The developers of PNG are currently working on formats for lossy image compression and animation, using the overall design and technologies of PNG and applying them to those tasks. | | | The compressor employs a fuzzy logic engine to analyze the image -- looking at factors such as color depth, size, and whether the image is a photo or synthetic graphic -- before selecting the appropriate compression algorithms to use on the image. |
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http://www.webreference.com/dev/graphics/compress.html
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| | An Introduction to Image Compression |
| | Of course, general purpose compression programs can be used to compress images, but the result is less than optimal. | | | Compressing an image is significantly different than compressing raw binary data. | | | The algorithms explained can be easily extended to colour images, either by processing each of the colour planes separately, or by transforming the image from RGB representation to other convenient representations like YUV in which the processing is much easier. |
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http://www.debugmode.com/imagecmp
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| | JPEG image compression FAQ, part 1/2 |
| | The disadvantages of MPEG are (1) it requires far more computation to generate the compressed sequence (since detecting visual similarities is hard for a computer), and (2) it's difficult to edit an MPEG sequence on a frame-by-frame basis (since each frame is intimately tied to the ones around it). | | | When I say "lossless", I mean mathematically lossless: a lossless compression algorithm is one that guarantees its decompressed output is bit-for-bit identical to the original input. | | | The speed and image quality of a JPEG viewer running on such hardware are largely determined by its quantization algorithm. |
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http://www.faqs.org/faqs/jpeg-faq/part1
(9116 words)
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| | Fractal Image Encoding |
| | The Waterloo Fractal Compression Project is part of a general research programme dedicated to the study of fractal analysis and Iterated Function Systems/Fractal Transforms from both theoretical as well as practical perspectives. | | | Image can also be saved t-the clipboard; input file must also be in RAW image format. | | | Fractal compression of single images and image sequences using genetic algorithms, L. Vences, I. Rudomin. |
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http://inls.ucsd.edu/~fisher/Fractals
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| | Compression: Digital Imaging: Glossary: Learn: Digital Photography Review |
| | Lossy compression reduces the image size by discarding information and is similar to summarizing a document. | | | For example, you can summarize a 10 page document into a 9 page or 1 page document that represents the original, but you cannot create the original out of the summary as information was discarded during summarization. | | | For example, the table shows 1.3 MB as file size for an 80% Quality JPEG five megapixel image. |
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http://www.dpreview.com/learn?/Glossary/Digital_Imaging/Compression_01.htm
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| | Image Compression |
| | Although the errors are introduced mainly in the higher frequencies, this means that at lower quality images might not have sufficient high frequancies to "join-up" at the 8x8 block edges. | | | This corrupts the image but only where there are big steps, where the eye can not see errors anyway (visual masking occurs). | | | However a difference image actually starts with more values than the original image (-255 to 255 instead of 0 to 255) which could make the compressed data bigger than the original! |
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http://www.ecs.soton.ac.uk/~km/teaching/compression
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| | Compression Research |
| | A set of experiments found this algorithm to be, on average, 2.5 dB worse in terms of PSNR than an image compressed by JPEG for the same bit rate. | | | Decompression was significantly faster, 10x to 20x than a DCT based algorithm, however compression was two to three times slower. | | | Some investigation was also made into utilizing the compressed data storage format to aid in other common processing tasks. |
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http://www.cs.cmu.edu/~chuck/nsipg/nsi.html
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| | Freeware downloads Graphics Tools - Image Compression at SnapFiles.com |
| | GIFeq is a small utility that allows you to optimize your GIF files, and reduce the size of them by removing comments and interlacing, optimizing palettes and more. | | | The program can process selected files or entire folders (with subfolders) and process images and HTML files at the same time, allowing webmasters to optimize their entire site in a single run. | | | The optimized files can be saved to a new folder, so your original images remain unchanged. |
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http://www.snapfiles.com/freeware/gmm/fwgcomp.html
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| | The FBI Fingerprint Image Compression Standard |
| | Since these details are just a couple pixels wide, our compression method needs to preserve features right at the resolution of the scan, a VERY tough problem since most lossy algorithms work by throwing out the smallest (or highest frequency) details in the image. | | | The standard is a discrete wavelet transform-based algorithm referred to as Wavelet/Scalar Quantization (WSQ). | | | Next take a look at the same image compressed 12.9:1 by the WSQ method (the algorithm chosen over JPEG for this project). |
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http://www.c3.lanl.gov/~brislawn/FBI/FBI.html
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| | Image Compression Toolbox v1.2 |
| | Quantization of the image data using a uniform quantizer, which is implemented as the UniformQuant class. | | | Optimal bit allocation for the various classes of image data, using Rate-Distortion optimization methods. | | | Entropy coding of the quantized data using an arithmetic coder, described in the paper |
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http://www.debugmode.com/imagecmp/icomptbx.htm
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| | SPINWAVE -- GIF and JPEG Compression and Optimization |
| | Click here for free, low compression crunches using JPEG Cruncher and GIF Cruncher, the most popular optimization software tools on the web. | | | Subscribe to the Spinwave image optimization newsletter for tips and tutorials on how to get the most from your GIF and JPEG images. | | | SPINWAVE -- GIF and JPEG Compression and Optimization |
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http://www.spinwave.com
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| | Image compression - Wikipedia, the free encyclopedia |
| | Lossless compression is sometimes preferred for artificial images such as technical drawings, icons or comics. | | | Image compression is the application of data compression on digital images. | | | A Fourier-related transform such as DCT or the wavelet transform are applied, followed by quantization and entropy coding. |
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http://en.wikipedia.org/wiki/Image_compression
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| | SPIHT Image Compression |
| | These pages are being served from the Center for Image Processing Research (CIPR) at the Rensselaer Polytechnic Institute (RPI). | | | Now available is a fast arithmetic coding algorithm, called FastAC, authored by Amir Said. | | | We utilize this homepage as a general resource for signal compression, so will make available programs other than SPIHT. |
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http://www.cipr.rpi.edu/research/SPIHT
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| | Amazon.com: Fractal Image Compression: Theory and Application: Books: Yuval Fisher |
| | The first chapter, probably better known as the "SIGGRAPH '92 Course Notes", can be understand easily even by non-scientist and be used to code your own basic compression engine. | | | Unfortunately, you sometimes need to read between the math to get the necessary information. | | | Borrowed this book from from my instructor and saw that it was much better than any standard image processing coursebook to learn some ideas from... |
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http://www.amazon.com/exec/obidos/tg/detail/-/0387942114?v=glance
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| | Lossless Image Compression Links |
| | Wotsit's Format: The programmer's file formats and data formats resource. | | | MG System - mg system, described in the book Managing Gigabytes contains the implementation of FELICS | | | List of Image and Graphics File Archives from Graphic File Formats FAQ |
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http://theory.cs.uni-bonn.de/~yasha/limcomplinks.html
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| | Catalog Page for PIA07585 |
| | Despite these artifacts, such compression can be useful for increasing the number of images that can be taken and relayed back to Earth. | | | They are stored on its flight data recorder, which has limited space - at the expense of some data quality. | | | This image was taken using a compression scheme that allows more images to be taken by Cassini. |
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http://photojournal.jpl.nasa.gov/catalog/PIA07585
(284 words)
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| | StuffIt - NEW Image Compression Technology! |
| | The only solution was to further reduce the quality of the image in a graphic editing application. | | | The exclusive new image compression technology in StuffIt Deluxe now allows you to reduce the file size of your JPEG images WITHOUT reducing the quality of the image! | | | StuffIt Deluxe version 9.0 for Windows will introduce new, patent pending, compression technology that allows you to compress JPEG images! |
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http://www.stuffit.com/imagecompression
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