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comparison OrthancFramework/Sources/DicomParsing/ParsedDicomFile.cpp @ 5322:a904a4caf5b7

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unit testing ParsedDicomFile::GuessPixelDataValueRepresentation()
author Sebastien Jodogne <s.jodogne@gmail.com>
date Sun, 25 Jun 2023 11:48:47 +0200
parents f2e1ad71e49c
children 138e9d0c08c1
comparison
equal deleted inserted replaced
5321:5fae323b11ed 5322:a904a4caf5b7
2178 2178
2179 2179
2180 ValueRepresentation ParsedDicomFile::GuessPixelDataValueRepresentation() const 2180 ValueRepresentation ParsedDicomFile::GuessPixelDataValueRepresentation() const
2181 { 2181 {
2182 /** 2182 /**
2183 * DICOM specification is at: 2183 * This approach is validated in "Tests/GuessPixelDataVR.py":
2184 * https://dicom.nema.org/medical/dicom/current/output/chtml/part05/chapter_d.html 2184 * https://hg.orthanc-server.com/orthanc-tests/file/tip/Tests/GuessPixelDataVR.py
2185 *
2186 * Our algorithm for guessing the pixel data VR is imperfect, and
2187 * inspired from: https://forum.dcmtk.org/viewtopic.php?t=4961
2188 *
2189 * "The baseline for Little Endian Implicit/Explicit is: (a) if
2190 * the TS is Explicit Little Endian and the pixeldata is <= 8bpp,
2191 * VR of pixel data shall be VR_OB, and (b) in all other cases, VR
2192 * of pixel data shall be VR_OW."
2193 **/ 2185 **/
2194 2186
2195 DicomTransferSyntax ts; 2187 DicomTransferSyntax ts;
2196 if (LookupTransferSyntax(ts)) 2188 if (LookupTransferSyntax(ts))
2197 { 2189 {
2198 if (ts == DicomTransferSyntax_LittleEndianExplicit || 2190 if (ts == DicomTransferSyntax_LittleEndianExplicit ||
2199 ts == DicomTransferSyntax_BigEndianExplicit) 2191 ts == DicomTransferSyntax_BigEndianExplicit)
2200 { 2192 {
2193 /**
2194 * Same rules apply to Little Endian Explicit and Big Endian
2195 * Explicit (now retired). The VR of the pixel data directly
2196 * depends upon the "Bits Allocated (0028,0100)" tag:
2197 * https://dicom.nema.org/medical/dicom/current/output/chtml/part05/sect_A.2.html
2198 * https://dicom.nema.org/medical/dicom/2016b/output/chtml/part05/sect_A.3.html
2199 **/
2201 DcmItem& dataset = *GetDcmtkObjectConst().getDataset(); 2200 DcmItem& dataset = *GetDcmtkObjectConst().getDataset();
2202 2201
2203 uint16_t bitsAllocated; 2202 uint16_t bitsAllocated;
2204 if (dataset.findAndGetUint16(DCM_BitsAllocated, bitsAllocated).good() && 2203 if (dataset.findAndGetUint16(DCM_BitsAllocated, bitsAllocated).good() &&
2205 bitsAllocated > 8) 2204 bitsAllocated > 8)
2211 return ValueRepresentation_OtherByte; 2210 return ValueRepresentation_OtherByte;
2212 } 2211 }
2213 } 2212 }
2214 else if (ts == DicomTransferSyntax_LittleEndianImplicit) 2213 else if (ts == DicomTransferSyntax_LittleEndianImplicit)
2215 { 2214 {
2215 // Assume "OW" for DICOM Implicit VR Little Endian Transfer Syntax
2216 // https://dicom.nema.org/medical/dicom/current/output/chtml/part05/chapter_A.html#sect_A.1
2216 return ValueRepresentation_OtherWord; 2217 return ValueRepresentation_OtherWord;
2217 } 2218 }
2218 else 2219 else
2219 { 2220 {
2220 // Assume "OB" for all the compressed transfer syntaxes 2221 // Assume "OB" for all the compressed transfer syntaxes
2222 // https://dicom.nema.org/medical/dicom/current/output/chtml/part05/sect_A.4.html
2221 return ValueRepresentation_OtherByte; 2223 return ValueRepresentation_OtherByte;
2222 } 2224 }
2223 } 2225 }
2224 else 2226 else
2225 { 2227 {
2226 // Assume "OB" if transfer syntax is not available 2228 // Assume "OB" if the transfer syntax is unknown
2227 return ValueRepresentation_OtherByte; 2229 return ValueRepresentation_OtherByte;
2228 } 2230 }
2229 } 2231 }
2230 2232
2231 2233