JPEG

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JPEG

Computing a standard file format for compressing pictures by disposing of redundant pixels

JPEG

[′jā‚peg]
(graphic arts)
Graphics file format for compressed still images, particularly photographic images found on the World Wide Web; developed by the Joint Photographic Experts Group.

JPEG

JPEG

(Joint Photographic Experts Group) An ISO/ITU standard for compressing still images. Pronounced "jay-peg," the JPEG format is very popular due to its variable compression range. JPEGs are saved on a sliding resolution scale based on the quality desired. For example, an image can be saved in high quality for photo printing, in medium quality for the Web and in low quality for attaching to emails, the latter providing the smallest file size for fastest transmission over slow connections.

Not Great for Text
JPEGs are not suitable for graphs, charts and explanatory illustrations because the text appears fuzzy, especially at low resolutions. Compressing images in the GIF format is much better for such material (see GIF).

JPEGs Are Lossy
Using discrete cosine transform, JPEG is a lossy compression method, wherein some data from the original image is lost. It depends on the image, but ratios of 10:1 to 20:1 may provide little noticeable loss. The more the loss can be tolerated, the more the image can be compressed.

Compression is achieved by dividing the picture into tiny pixel blocks, which are halved over and over until the desired amount of compression is achieved. JPEGs can be created in software or hardware, the latter providing sufficient speed for real-time, on-the-fly compression. C-Cube Microsystems introduced the first JPEG chip. See JPEG2000, JPE file and GIF.

File Extensions
JPEGs use the JPEG File Interchange Format (JFIF), and file extensions are .JPG or .JFF. M-JPEG and MPEG are variations of JPEG used for full-motion digital video (see MPEG). See graphics formats.


Saving JPEGs
At first glance, these two dialogs seem contradictory because the larger number means high quality in one and low quality in the other. Photoshop (top) uses a 1-to-12 scale for quality, while Epson (bottom) uses a percentage for the amount of compression. The more compression, the more loss in the result. Standard is the original JPEG format, while Optimized compresses more effectively. Progressive causes the image to display incrementally from top to bottom. Web users with slow connections see the image form on screen right away rather than wait for the entire file to download first.


Saving JPEGs
At first glance, these two dialogs seem contradictory because the larger number means high quality in one and low quality in the other. Photoshop (top) uses a 1-to-12 scale for quality, while Epson (bottom) uses a percentage for the amount of compression. The more compression, the more loss in the result. Standard is the original JPEG format, while Optimized compresses more effectively. Progressive causes the image to display incrementally from top to bottom. Web users with slow connections see the image form on screen right away rather than wait for the entire file to download first.
References in periodicals archive ?
Google has announced a new open source algorithm that will encode high-quality JPEG with 35 percent smaller files, without the loss of quality.
Guetzli, meaning 'cookie' in Swiss German, is a JPEG encoder for digital images and web graphics that can enable faster online experiences by producing smaller JPEG files while still maintaining compatibility with existing browsers, image processing applications and the JPEG standard," the company said Thursday on its (https://research.
It takes about a tenth of a second, so we can extract 100 JPEGs from 100 RAW files in 10 seconds.
When they get that magic photo, they don't want to risk capturing it on JPEG and not having it be as qood as it could be," he says.
TELECOMWORLDWIRE-6 October 2004-Aladdin says its eSafe is only gateway-based product to protect against JPEG threats(C)1994-2004 M2 COMMUNICATIONS LTD http://www.
The RAW images can be saved in slot one and the JPEGs, in any of ten quality levels, in slot two, or vice versa.
Imaging quality in the EOS 5D is enhanced with the addition of the DIGIC II image processor, which provides detailed and natural color reproduction and fast image processing, including an incredible burst performance of 60 Large/Fine JPEGs or 17 RAW images at 3 fps.
These files allow for in-camera JPEG and TIFF extraction, as well as RAW editing within new KODAK EASYSHARE software v5.
What's more, where the original Digital Rebel camera required dedicated software to extract embedded middle/fine resolution JPEGs from the larger, uncompressed RAW image file, the new Rebel XT model saves RAW and large/fine resolution images as separate files on the Compact Flash
3 seconds after its power switch is clicked on and fires a fast four frames per second at full resolution for bursts of up to 32 JPEG or 11 RAW images (compared with 3 fps for up to 10 frames on the original EOS-1Ds camera).
By running a simple file transfer protocol (FTP) script on a PC connected to either of Pico's low-cost EnviroMon data loggers (the EL005 and EL008) users can post JPEG versions of EnviroMon's graphs onto a web site.
Images made with the EOS-1D can be recorded as 12-bit RAW files or in one of three JPEG formats (Large/Fine, Large/Normal, and Small/Fine).