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 ?
Processing video data streams with JPEG XS generates the crucial bandwidth savings needed to move more pixels over wired or wireless transmission (Wifi, WiGig, 5G), but also reduces the need for many internal links within a device.
Smallest block size considered is 8x8 in accordance with the JPEG standard.
In the case of the JPEG data stream, the AC coefficients in the 8 x 8 DCT block correspond to the detail.
Caption: Figure 9: BER(%) after JPEG compression using different message lengths at different PSNR values (a) 40 dB and (b) 45 dB.
It is used dissimilar algorithm like DWT, 3D Spiral JPEG and K-means determine performance parameter of these algorithm.
CUTLINE: Comparison of JPEG quality on this close-up of a train.
Please clearly label jpeg of each entry (category, subject).
A progressive Discrete Cosine Transform (DCT) based JPEG coder with spectral selection mode is used.
El objetivo de este trabajo es demostrar que la transmision utilizando un esquema basado en capas de calidad, como la codificacion de bloques embebidos con optimizacion truncada (EBCOT), produce mejores resultados que el esquema JPEG, basado en indices de calidad.
That's like a JPEG: if there is too much contrast or saturation, it's difficult to remove.