PS3.5​ DICOM PS3.5 2021d - Data Structures and Encoding​ Page 2​ PS3.5: DICOM PS3.5 2021d - Data Structures and Encoding​ Copyright © 2021 NEMA​ A DICOM® publication​ - Standard -​ DICOM PS3.5 2021d - Data Structures and Encoding​ Page 3​ Table of Contents​ Notice and Disclaimer ........................................................................................................................................... 13​ Foreword ............................................................................................................................................................ 15​ 1. Scope and Field of Application ............................................................................................................................. 17​ 2. Normative References ....................................................................................................................................... 19​ 3. Definitions ....................................................................................................................................................... 23​ 4. Symbols and Abbreviations ................................................................................................................................. 27​ 5. Conventions ..................................................................................................................................................... 29​ 6. Value Encoding ................................................................................................................................................ 31​ 6.1. Support of Character Repertoires ................................................................................................................... 31​ 6.1.1. Representation of Encoded Character Values ............................................................................................ 31​ 6.1.2. Graphic Characters .............................................................................................................................. 32​ 6.1.2.1. Default Character Repertoire ........................................................................................................... 32​ 6.1.2.2. Extension or Replacement of the Default Character Repertoire ............................................................... 32​ 6.1.2.3. Encoding of Character Repertoires .................................................................................................... 33​ 6.1.2.4. Code Extension Techniques ............................................................................................................ 34​ 6.1.2.5. Usage of Code Extension ................................................................................................................ 34​ 6.1.2.5.1. Assumed Initial States .............................................................................................................. 35​ 6.1.2.5.2. Restrictions for Code Extension ................................................................................................. 35​ 6.1.2.5.3. Requirements ......................................................................................................................... 35​ 6.1.2.5.4. Levels of Implementation and Initial Designation ............................................................................ 35​ 6.1.3. Control Characters ............................................................................................................................... 36​ 6.2. Value Representation (VR) ........................................................................................................................... 37​ 6.2.1. Person Name (PN) Value Representation ................................................................................................. 47​ 6.2.1.1. Examples of PN VR and Notes ......................................................................................................... 47​ 6.2.1.2. Ideographic and Phonetic Characters in Data Elements with VR of PN ..................................................... 47​ 6.2.2. Unknown (UN) Value Representation ....................................................................................................... 48​ 6.2.3. URI/URL (UR) Value Representation ....................................................................................................... 49​ 6.3. Enumerated Values and Defined Terms .......................................................................................................... 49​ 6.4. Value Multiplicity (VM) and Delimitation ........................................................................................................... 50​ 7. The Data Set .................................................................................................................................................... 51​ 7.1. Data Elements ........................................................................................................................................... 51​ 7.1.1. Data Element Fields ............................................................................................................................. 52​ 7.1.2. Data Element Structure with Explicit VR .................................................................................................... 52​ 7.1.3. Data Element Structure with Implicit VR .................................................................................................... 53​ 7.2. Group Length ............................................................................................................................................ 53​ 7.3. Little Endian Byte Ordering ........................................................................................................................... 54​ 7.4. Data Element Type ..................................................................................................................................... 54​ 7.4.1. Type 1 Required Data Elements .............................................................................................................. 54​ 7.4.2. Type 1C Conditional Data Elements ......................................................................................................... 55​ 7.4.3. Type 2 Required Data Elements .............................................................................................................. 55​ 7.4.4. Type 2C Conditional Data Elements ......................................................................................................... 55​ 7.4.5. Type 3 Optional Data Elements ............................................................................................................... 55​ 7.4.6. Data Element Types Within A Sequence ................................................................................................... 55​ 7.5. Nesting of Data Sets ................................................................................................................................... 56​ 7.5.1. Item Encoding Rules ............................................................................................................................. 56​ 7.5.2. Delimitation of The Sequence of Items ..................................................................................................... 57​ 7.5.3. Sequence Inheritance ........................................................................................................................... 59​ 7.6. Repeating Groups ...................................................................................................................................... 59​ 7.7. Retired Data Elements ................................................................................................................................. 59​ 7.8. Private Data Elements ................................................................................................................................. 59​ 7.8.1. Private Data Element Tags .................................................................................................................... 59​ 7.8.2. Encoding of Private Elements ................................................................................................................. 61​ 8. Encoding of Pixel, Overlay and Waveform Data ....................................................................................................... 63​ 8.1. Pixel and Overlay Data, and Related Data Elements .......................................................................................... 63​ 8.1.1. Pixel Data Encoding of Related Data Elements .......................................................................................... 63​ 8.1.2. Overlay Data Encoding of Related Data Elements ...................................................................................... 64​ 8.2. Native or Encapsulated Format Encoding ........................................................................................................ 65​ - Standard -​ Page 4​ DICOM PS3.5 2021d - Data Structures and Encoding​ 8.2.1. JPEG Image Compression ..................................................................................................................... 66​ 8.2.2. Run Length Encoding Image Compression ................................................................................................ 68​ 8.2.3. JPEG-LS Image Compression ................................................................................................................ 69​ 8.2.4.