A.4.3 JPEG-LS Image Compression
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### A.4.3 JPEG-LS Image Compression

The International Standards Organization ISO/IEC JTC1 has developed an International Standard, ISO/IS-14495-1 (JPEG-LS Part 1), for digital compression and coding of continuous-tone still images (see Annex F for further details).

A DICOM Transfer Syntax for JPEG-LS Image Compression shall be identified by a UID value, appropriate to its JPEG-LS coding process.

Two Transfer Syntaxes are specified for JPEG-LS:

1. A Transfer Syntax with a UID of "1.2.840.10008.1.2.4.80 ", which specifies the use of the lossless mode of JPEG-LS. In this mode the absolute error between the source and reconstructed images will be zero.

2. A Transfer Syntax with a UID of "1.2.840.10008.1.2.4.81 ", which specifies the use of the near-lossless mode of JPEG-LS. In this mode, the absolute error between the source and reconstructed images will be constrained to a finite value that is conveyed in the compressed bit stream. Note that this process can, at the discretion of the encoder, be used to compress images with an error constrained to a value of zero, resulting in no loss of information.

If the object allows multi-frame images in the pixel data field, then each frame shall be encoded separately. Each fragment shall contain encoded data from a single-frame image.

### Note

Though a fragment may not contain encoded data from more than one frame, the encoded data from one frame may span multiple fragments. See note in Section 8.2.

For all images, including all frames of a multi-frame image, the JPEG-LS Interchange Format shall be used (all parameter specifications shall be included).

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