The International Standards Organization ISO/IEC JTC1 has developed an International Standard, ISO/IS-10918-1 (JPEG Part 1) and an International Draft Standard, ISO/IS-10918-2 (JPEG Part 2), known as the JPEG Standard, for digital compression and coding of continuous-tone still images. (See Annex F for further details.)
A DICOM Transfer Syntax for JPEG Image Compression shall be identified by a UID value, appropriate to its JPEG coding process, chosen from Table A.4-3.
Table A.4-3 DICOM TRANSFER SYNTAX UIDS FOR JPEG
|DICOM Transfer Syntax UID||JPEG coding process||JPEG description|
|1.2.840.10008.1.2.4.70||14 (Selection Value 1)||lossless, non-hierarchical, first-order prediction|
Note: DICOM identifies, to increase the likelihood of successful association, three Transfer Syntaxes for Default JPEG Compression Image processes (see Sections 8.2.1 and 10).
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 Interchange Format shall be used (the table specification shall be included).
If images with Photometric Interpretation (0028,0004) YBR_FULL_422 or YBR_PARTIAL_422, are encoded with JPEG coding Process 1 (non hierarchical with Huffman coding), identified by DICOM Transfer Syntax UID "1.2.840.10008.1.2.4.50" the minimum compressible unit is YYCBCR, where Y, CB, and CR are 8 by 8 blocks of pixel values. The data stream encodes two Y blocks followed by the corresponding CB and CR blocks.