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Image Compression: Putting your Images on a Diet with Akamai CTO Guy Podjarny
Image Compression: Putting your Images on a Diet with Akamai CTO Guy Podjarny
Published: 2013/12/02
Channel: Akamai Technologies
JPEG DCT, Discrete Cosine Transform (JPEG Pt2)- Computerphile
JPEG DCT, Discrete Cosine Transform (JPEG Pt2)- Computerphile
Published: 2015/05/22
Channel: Computerphile
JPEG image compression
JPEG image compression
Published: 2014/09/10
Channel: vishal kumar
JPEG IMAGE COMPRESSION STEPS
JPEG IMAGE COMPRESSION STEPS
Published: 2016/12/03
Channel: IP University CSE/IT
Image compression for Android developers - Google I/O 2016
Image compression for Android developers - Google I/O 2016
Published: 2016/05/19
Channel: Android Developers
Lecture - 17 Lossy Image Compression : DCT
Lecture - 17 Lossy Image Compression : DCT
Published: 2008/10/14
Channel: nptelhrd
Digital image processing: p007 The why and how of compression
Digital image processing: p007 The why and how of compression
Published: 2013/03/15
Channel: Alireza Saberi
Image Compression Formats
Image Compression Formats
Published: 2013/09/20
Channel: hundredvisionsguy
Understanding lossy and lossless compression
Understanding lossy and lossless compression
Published: 2009/10/05
Channel: butterscotchcom
How to Compress Images for Websites using Photoshop
How to Compress Images for Websites using Photoshop
Published: 2016/01/11
Channel: Web3
Facebook Image Compression - how to get the best results
Facebook Image Compression - how to get the best results
Published: 2015/07/29
Channel: Matt Granger
Image compression | Digital Signal Processing
Image compression | Digital Signal Processing
Published: 2014/08/23
Channel: Free Engineering Lectures
Image Compression - Making Contact
Image Compression - Making Contact
Published: 2009/12/09
Channel: csunplugged
Introduction to Lossy Image Data Compression Part1
Introduction to Lossy Image Data Compression Part1
Published: 2011/11/08
Channel: AccusoftPegasus
How JPEG Works
How JPEG Works
Published: 2013/02/17
Channel: Cihan Chen
Best Website Image Compression Tool - Thats right, FREE image compression
Best Website Image Compression Tool - Thats right, FREE image compression
Published: 2016/06/11
Channel: Ultimate Web Design
Learning Gulp #9 - Easy Image Compression
Learning Gulp #9 - Easy Image Compression
Published: 2014/08/08
Channel: LevelUpTuts
Matlab codes for Image compression ( part 4)
Matlab codes for Image compression ( part 4)
Published: 2014/12/02
Channel: rashi agrawal
Lecture: FFT and Image Compression
Lecture: FFT and Image Compression
Published: 2016/02/19
Channel: AMATH 301
Understanding Image Compression
Understanding Image Compression
Published: 2013/06/21
Channel: Blender HD
The Huffman Coding (Image Compression-Part II)
The Huffman Coding (Image Compression-Part II)
Published: 2014/11/20
Channel: rashi agrawal
Latest Image compression techniques
Latest Image compression techniques
Published: 2013/05/11
Channel: RAVI CHANDRA MADDALI
How to Change WordPress JPEG Image Compression
How to Change WordPress JPEG Image Compression
Published: 2016/05/31
Channel: WPBeginner - WordPress Tutorials
How to batch compress images without loss of quality
How to batch compress images without loss of quality
Published: 2011/01/15
Channel: Amiya Patanaik
WordPress Image Compression Using The WP Smush.it Plugin | WP Learning Lab
WordPress Image Compression Using The WP Smush.it Plugin | WP Learning Lab
Published: 2015/12/23
Channel: WordPress Tutorials - WPLearningLab
Image Compression Tutorial
Image Compression Tutorial
Published: 2016/06/15
Channel: DCP Web Designers
Squash for Mac — Image Compression Tutorial
Squash for Mac — Image Compression Tutorial
Published: 2017/02/21
Channel: Realmac Software
how to compress images/Photos without losing quality in Hindi / Urdu 2016
how to compress images/Photos without losing quality in Hindi / Urdu 2016
Published: 2016/04/25
Channel: Crazuals
Image compression race: PNG Adam7 vs FLIF
Image compression race: PNG Adam7 vs FLIF
Published: 2015/09/06
Channel: Jon Sneyers
Image Compressing using Discrete Cosine Transform in Matlab- Part 1
Image Compressing using Discrete Cosine Transform in Matlab- Part 1
Published: 2014/11/19
Channel: rashi agrawal
💫 3 Wordpress Image Optimisation Plugins That Can Make Your Site 899% Faster 💫
💫 3 Wordpress Image Optimisation Plugins That Can Make Your Site 899% Faster 💫
Published: 2015/07/21
Channel: TRUE MILLER
Compress Image Size Without Losing Quality | Bulk Image Compression
Compress Image Size Without Losing Quality | Bulk Image Compression
Published: 2017/03/29
Channel: All Time Geeks
Swift: Firebase 3 - Lets Fix some Bugs and Use JPEG Image Compression (Ep 7)
Swift: Firebase 3 - Lets Fix some Bugs and Use JPEG Image Compression (Ep 7)
Published: 2016/07/06
Channel: Lets Build That App
JavaScript Image Compression
JavaScript Image Compression
Published: 2017/04/08
Channel: examsmyantra
10   4   Fractal Image Compression 18 07
10 4 Fractal Image Compression 18 07
Published: 2017/02/23
Channel: shahid mobin
How to compress an image using GIMP
How to compress an image using GIMP
Published: 2012/11/19
Channel: linuxforever
Java Tutorials - JPEG image compression
Java Tutorials - JPEG image compression
Published: 2017/05/08
Channel: Zoran Davidović
PowerPoint 2010 Tips - How to Compress Photo Size and Increase Image Resolution in PowerPoint 2010
PowerPoint 2010 Tips - How to Compress Photo Size and Increase Image Resolution in PowerPoint 2010
Published: 2013/03/04
Channel: Moyea Software
upload and compress image php
upload and compress image php
Published: 2015/12/04
Channel: rspate.com
JPEG Image Compression in WordPress
JPEG Image Compression in WordPress
Published: 2016/06/11
Channel: Helpfolder
Fourier Transforms: Image Compression, Part 1
Fourier Transforms: Image Compression, Part 1
Published: 2016/06/11
Channel: Data4Bio
Image Compression for the Web using Photoshop
Image Compression for the Web using Photoshop
Published: 2013/03/08
Channel: curtis stage
Images:Ep 1: How To Compress Image Sizes.
Images:Ep 1: How To Compress Image Sizes.
Published: 2012/04/04
Channel: Reeds Tuts
Implementation of DWT for Image compression using EHRCA
Implementation of DWT for Image compression using EHRCA
Published: 2016/04/11
Channel: kaushik krishna
An Efficient Quadtree-based Block Truncation Coding for Digital Image Compression
An Efficient Quadtree-based Block Truncation Coding for Digital Image Compression
Published: 2016/12/12
Channel: IEEE Projects , Ecruitment Solutions
Optimus - WordPress Image Compression Plugin Review
Optimus - WordPress Image Compression Plugin Review
Published: 2016/03/04
Channel: WP Smackdown
For when someone posts a compressed image/uses Windows XP to save a jpeg...
For when someone posts a compressed image/uses Windows XP to save a jpeg...
Published: 2013/05/27
Channel: BobRoberts
Unplugged: The show. Part 5: Image compression - run-length coding
Unplugged: The show. Part 5: Image compression - run-length coding
Published: 2008/10/24
Channel: csunplugged
Progressive JPEG vs lossy FLIF: image compression race
Progressive JPEG vs lossy FLIF: image compression race
Published: 2016/09/08
Channel: Jon Sneyers
image compression matlab
image compression matlab
Published: 2015/12/20
Channel: MATLAB tutor
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WIKIPEDIA ARTICLE

From Wikipedia, the free encyclopedia
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Image compression is a type of data compression applied to digital images, to reduce their cost for storage or transmission. Algorithms may take advantage of visual perception and the statistical properties of image data to provide superior results compared with generic compression methods.[1]

Comparison of JPEG images saved by Adobe Photoshop at different quality levels and with or without "save for web"

Lossy and lossless Image compression[edit]

Image compression may be lossy or lossless. Lossless compression is preferred for archival purposes and often for medical imaging, technical drawings, clip art, or comics. Lossy compression methods, especially when used at low bit rates, introduce compression artifacts. Lossy methods are especially suitable for natural images such as photographs in applications where minor (sometimes imperceptible) loss of fidelity is acceptable to achieve a substantial reduction in bit rate. Lossy compression that produces negligible differences may be called visually lossless.

Methods for lossless image compression are:

Methods for lossy compression:


Other properties[edit]

The best image quality at a given bit-rate (or compression rate) is the main goal of image compression, however, there are other important properties of image compression schemes:

Scalability generally refers to a quality reduction achieved by manipulation of the bitstream or file (without decompression and re-compression). Other names for scalability are progressive coding or embedded bitstreams. Despite its contrary nature, scalability also may be found in lossless codecs, usually in form of coarse-to-fine pixel scans. Scalability is especially useful for previewing images while downloading them (e.g., in a web browser) or for providing variable quality access to e.g., databases. There are several types of scalability:

  • Quality progressive or layer progressive: The bitstream successively refines the reconstructed image.
  • Resolution progressive: First encode a lower image resolution; then encode the difference to higher resolutions.[2][3]
  • Component progressive: First encode grey; then color.

Region of interest coding. Certain parts of the image are encoded with higher quality than others. This may be combined with scalability (encode these parts first, others later).

Meta information. Compressed data may contain information about the image which may be used to categorize, search, or browse images. Such information may include color and texture statistics, small preview images, and author or copyright information.

Processing power. Compression algorithms require different amounts of processing power to encode and decode. Some high compression algorithms require high processing power.

The quality of a compression method often is measured by the Peak signal-to-noise ratio. It measures the amount of noise introduced through a lossy compression of the image, however, the subjective judgment of the viewer also is regarded as an important measure, perhaps, being the most important measure.

Notes and references[edit]

  1. ^ "Image Data Compression". 
  2. ^ Burt, P.; Adelson, E. (1 April 1983). "The Laplacian Pyramid as a Compact Image Code". IEEE Transactions on Communications. 31 (4): 532–540. doi:10.1109/TCOM.1983.1095851. 
  3. ^ Shao, Dan; Kropatsch, Walter G. (February 3–5, 2010). "Irregular Laplacian Graph Pyramid" (PDF). Computer Vision Winter Workshop 2010. Nove Hrady, Czech Republic: Czech Pattern Recognition Society.  |first1= missing |last1= in Editors list (help)

External links[edit]

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