Материал: part05

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ATransferSyntaxSpecifications(Normative)​

A.1 DICOM Implicit VR Little Endian Transfer Syntax​

ThisTransferSyntaxappliestotheencodingoftheentireDICOMDataSet.ThisimpliesthatwhenaDICOMDataSetisbeingencoded​ with the DICOM Implicit VR Little Endian Transfer Syntax the following requirements shall be met:​

a.​The Data Elements contained in the Data Set structure shall be encoded with Implicit VR (without a VR Field) as specified in​ Section 7.1.3.​

b.​TheencodingoftheoverallDataSetstructure(DataElementTags,ValueLength,andValue)shallbeinLittleEndianasspecified​ in Section 7.3.​

c.​The encoding of the Data Elements of the Data Set shall be as follows according to their Value Representations:​

•​For all Value Representations defined in this Part, except for the Value Representations OB and OW, the encoding shall be​ in Little Endian as specified in Section 7.3.​

•​For the Value Representations OB, OL, OV and OW, the encoding shall meet the following specification depending on the​ Data Element Tag:​

•​Pixel Data (7FE0,0010) has the Value Representation OW and shall be encoded in Little Endian.​

Note​

i.​ The OL and OV Value Representations are not used for Pixel Data, even if it has a Bits Allocated (0028,0100)​ of32or64,sinceOLandOVwereaddedtotheStandardaftertheencodingofPixelDatahadbeenestablished​

ii.​ The 32-bit Value Length Field limits the maximum size of the Pixel Data that can be encoded in Implicit VR​ Little Endian Transfer Syntax, since they are sent in a Native Format.​

•​Overlay Data (60xx,3000) has the Value Representation OW and shall be encoded in Little Endian.​

•​Waveform Data (5400,1010) shall have Value Representation OW and shall be encoded in Little Endian.​

•​Red Palette Color Lookup Table Data (0028,1201), Green Palette Color Lookup Table Data (0028,1202), Blue Color Palette​ Lookup Table Data (0028,1203) and Alpha Palette Color Lookup Table Data (0028,1204) have the Value Representation​ OW and shall be encoded in Little Endian.​

Note​

Previous versions of the Standard either did not specify the encoding of Red Palette Color Lookup Table Data​ (0028,1201), Green Palette Color Lookup Table Data (0028,1202) and Blue Color Palette Lookup Table Data​ (0028,1203) in this Part, but specified a VR of US or SS in PS3.6-1993, or specified OW in this Part but a VR of​ US, SS or OW in PS3.6-1996. The actual encoding of the values and their byte order would be identical in each​ case.​

•​Red Palette Color Lookup Table Descriptor (0028,1101), Green Palette Color Lookup Table Descriptor (0028,1102) and Blue​ Palette Color Lookup Table Descriptor (0028,1103) have the Value Representation SS or US (depending on rules specified​ in the IOD in PS3.3), and shall be encoded in Little Endian. The first and third values are always interpreted as unsigned, re-​ gardless of the Value Representation.​

•​Data Elements (0028,1221),(0028,1222),(0028,1223) Segmented Red, Green, Blue Palette Color Lookup Table Data have​ the Value Representation OW and shall be encoded in Little Endian.​

•​LUT Data (0028,3006) has the Value Representation US or OW and shall be encoded in Little Endian.​

Note​

Previous versions of the Standard did not specify the encoding of these Data Elements in this Part, but specified a​ VR of US or SS in PS3.6-1998. A VR of OW has been added to support explicit VR Transfer Syntaxes. Moreover this​

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element is always unsigned, therefore the VR of SS has been removed. The actual encoding of the values and their​ byte order would be identical in each case.​

•​LUT Descriptor (0028,3002) has the Value Representation SS or US (depending on rules specified in the IOD in PS3.3), and​ shall be encoded in Little Endian. The first and third values are always interpreted as unsigned, regardless of the Value Rep-​ resentation.​

•​Blending Lookup Table Data (0028,1408) has the Value Representation OW and shall be encoded in Little Endian.​

•​Track Point Index List (0066,0129) has the Value Representation OL and shall be encoded in Little Endian and is always inter-​ preted as unsigned.​

Note​

1.​Encoding of Curve Data (5000,3000) and Audio Sample Data (5000,200C) was previously defined but has been retired.​ See PS3.5-2004.​

2.​Vertex Point Index List (0066,0025), Edge Point Index List (0066,0024), Triangle Point Index List (0066,0023) and​ PrimitivePointIndexList(0066,0029)werepreviouslydefinedwithavaluerepresentationofOWandalwaysinterpreted​ as unsigned, but have been retired. These have been replaced by corresponding OL data elements, which allow values​ larger than 65535 to index the full range of points that can be encoded in Point Coordinates Data (0066,0016). See​ PS3.5-2015c.​

This DICOM Implicit VR Little Endian Transfer Syntax shall be identified by a UID of Value "1.2.840.10008.1.2".​

A.2 DICOM Little Endian Transfer Syntax (Explicit VR)​

ThisTransferSyntaxappliestotheencodingoftheentireDICOMDataSet.ThisimpliesthatwhenaDICOMDataSetisbeingencoded​ with the DICOM Little Endian Transfer Syntax the following requirements shall be met:​

a.​The Data Elements contained in the Data Set structure shall be encoded with Explicit VR (with a VR Field) as specified in Sec-​ tion 7.1.2.​

b.​TheencodingoftheoverallDataSetstructure(DataElementTags,ValueLength,andValue)shallbeinLittleEndianasspecified​ in Section 7.3.​

c.​The encoding of the Data Elements of the Data Set shall be as follows according to their Value Representations:​

•​For all Value Representations defined in this Part, except for the Value Representations OB and OW, the encoding shall be​ in Little Endian as specified in Section 7.3.​

•​For the Value Representations OB, OL, OV and OW, the encoding shall meet the following specification depending on the​ Data Element Tag:​

•​Pixel Data (7FE0,0010)​

•​where Bits Allocated (0028,0100) has a value greater than 8 shall have Value Representation OW and shall be encoded​ in Little Endian;​

•​where Bits Allocated (0028,0100) has a value less than or equal to 8 shall have the Value Representation OB or OW and​ shall be encoded in Little Endian.​

Note​

i.​ The OL and OV Value Representations are not used for Pixel Data, even if it has a Bits Allocated (0028,0100)​ of32or64,sinceOLandOVwereaddedtotheStandardaftertheencodingofPixelDatahadbeenestablished​

ii.​ The 32-bit Value Length Field limits the maximum size of the Pixel Data that can be encoded in Little Endian​ Transfer Syntax (Explicit VR) since they are sent in a Native Format.​

•​Overlay Data (60xx,3000)​

•​shall have the Value Representation OB or OW and shall be encoded in Little Endian.​

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Note​

Previous versions of the Standard specified that the choice of OB or OW VR was based on whether or not​ Overlay Bits Allocated (60xx,0100) was greater than, or less than or equal to, 8. However, since only one bit​ plane can be encoded in each Overlay Data (60xx,3000) Element, no value of Overlay Bits Allocated other than​ 1 makes sense. Such a restriction is now present in PS3.3.​

•​Waveform Data (5400,1010) has the Value Representation specified in its Explicit VR Field. The component points shall be​ encoded in Little Endian.​

•​Red Palette Color Lookup Table Data (0028,1201), Green Palette Color Lookup Table Data (0028,1202), Blue Color Palette​ Lookup Table Data (0028,1203) and Alpha Palette Color Lookup Table Data (0028,1204) have the Value Representation​ OW and shall be encoded in Little Endian.​

Note​

Previous versions of the Standard either did not specify the encoding of Red Palette Color Lookup Table Data​ (0028,1201), Green Palette Color Lookup Table Data (0028,1202) and Blue Color Palette Lookup Table Data​ (0028,1203) in this Part, but specified a VR of US or SS in PS3.6-1993, or specified OW in this Part but a VR of​ US, SS or OW in PS3.6-1996. The actual encoding of the values and their byte order would be identical in each​ case, though the explicitly encoded VR field would be different. However, an explicit VR of US or SS cannot be​ used to encode a table of 216 elements, since the Value Length is restricted to 16 bits.​

•​Red Palette Color Lookup Table Descriptor (0028,1101), Green Palette Color Lookup Table Descriptor (0028,1102) and​ Blue Palette Color Lookup Table Descriptor (0028,1103) have the Value Representation SS or US (depending on rules​ specified in the IOD in PS3.3), and shall be encoded in Little Endian. The first and third values are always interpreted as​ unsigned, regardless of the Value Representation.​

•​Segmented Red Palette Color Lookup Table Data (0028,1221), Segmented Green Palette Color Lookup Table Data​ (0028,1222) and Segmented Blue Palette Color Lookup Table Data (0028,1223) have the Value Representation OW and​ shall be encoded in Little Endian.​

•​LUT Data (0028,3006) has the Value Representation US or OW and shall be encoded in Little Endian.​

Note​

Previous versions of the Standard did not specify the encoding of these Data Elements in this Part, but specified​ a VR of US or SS in PS3.6-1998. However, an explicit VR of US or SS cannot be used to encode a table of 216​

elements,sincetheValueLengthisrestrictedto16bits.HenceaVRofOWhasbeenadded.Moreoverthiselement​ is always unsigned, therefore the VR of SS has been removed. The actual encoding of the values and their byte​ order would be identical in each case, though the explicitly encoded VR field would be different.​

•​LUT Descriptor (0028,3002) has the Value Representation SS or US (depending on rules specified in the IOD in PS3.3),​ and shall be encoded in Little Endian. The first and third values are always interpreted as unsigned, regardless of the Value​ Representation.​

•​Blending Lookup Table Data (0028,1408) has the Value Representation OW and shall be encoded in Little Endian.​

•​Track Point Index List (0066,0129) has the Value Representation OL and shall be encoded in Little Endian and is always​ interpreted as unsigned.​

Note​

1.​For Data encoded with the Value Representation OB, the Data encoding is unaffected by byte ordering.​

2.​Encoding of Curve Data (5000,3000) and Audio Sample Data (5000,200C) was previously defined but has been retired.​ See PS3.5-2004.​

3.​Vertex Point Index List (0066,0025), Edge Point Index List (0066,0024), Triangle Point Index List (0066,0023) and​ PrimitivePointIndexList(0066,0029)werepreviouslydefinedwithavaluerepresentationofOWandalwaysinterpreted​ as unsigned, but have been retired. These have been replaced by corresponding OL data elements, which allow values​

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larger than 65535 to index the full range of points that can be encoded in Point Coordinates Data (0066,0016). See​ PS3.5-2015c.​

This DICOM Explicit VR Little Endian Transfer Syntax shall be identified by a UID of Value "1.2.840.10008.1.2.1".​

A.3 DICOM Big Endian Transfer Syntax (Explicit VR)​

This Transfer Syntax was retired in 2006. For the most recent description of it, see PS3.5 2016b.​

A.4 Transfer Syntaxes For Encapsulation of Encoded Pixel Data​

These Transfer Syntaxes apply to the encoding of the entire DICOM Data Set, even though the image Pixel Data (7FE0,0010) portion​ of the DICOM Data Set is the only portion that is encoded by an encapsulated format. These Transfer Syntaxes shall only be used​ when Pixel Data (7FE0,0010) is present in the top level Data Set, and hence shall not be used when Float Pixel Data (7FE0,0008)​ or Double Float Pixel Data (7FE0,0009) are present. This implies that when a DICOM Message is being encoded according to an​ encapsulation Transfer Syntax the following requirements shall be met:​

1.​The Data Elements contained in the Data Set structure shall be encoded with Explicit VR (with a VR Field) as specified in Sec-​ tion 7.1.2.​

2.​The encoding of the overall Data Set structure (Data Element Tags, Value Length, etc.) shall be in Little Endian as specified in​ Section 7.3.​

3.​The encoding of the Data Elements of the Data Set shall be as follows according to their Value Representations:​

•​For all Value Representations defined in this Part of the DICOM Standard, except for the Value Representations OB and OW,​ the encoding shall be in Little Endian as specified in Section 7.3.​

•​For the Value Representations OB, OL, OV and OW, the encoding shall meet the following specification depending on the​ Data Element Tag:​

•​Pixel Data (7FE0,0010) may be encapsulated or native.​

It shall be encapsulated if present in the top-level Data Set (i.e., not nested within a Sequence Data Element).​

Note​

The distinction between fixed value length (native) and undefined value length (encapsulated) is present so that​ the top level Data Set Pixel Data can be compressed (and hence encapsulated), but the Pixel Data within an Icon​ Image Sequence may or may not be compressed.​

If native, it shall have a defined Value Length, and be encoded as follows:​

•​where Bits Allocated (0028,0100) has a value greater than 8 shall have Value Representation OW and shall be encoded​ in Little Endian;​

•​where Bits Allocated (0028,0100) has a value less than or equal to 8 shall have the Value Representation OB or OW and​ shall be encoded in Little Endian.​

Note​

a.​The OL and OV Value Representations are not used for Pixel Data, even if it has a Bits Allocated (0028,0100)​ of32or64,sinceOLandOVwereaddedtotheStandardaftertheencodingofPixelDatahadbeenestablished​

b.​That is, as if the Transfer Syntax were Explicit VR Little Endian.​

If encapsulated, it has the Value Representation OB and is an octet-stream resulting from one of the encoding processes.​ It contains the encoded pixel data stream fragmented into one or more Item(s). This Pixel Data Stream may represent a​ Single or Multi-frame Image. See Table A.4-1 and Table A.4-2.​

•​The Length of the Data Element (7FE0,0010) shall be set to the Value for Undefined Length (FFFFFFFFH).​

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