Fix for decoded color photometric interpretation

Author: PantelisGeorgiadis

CMakeLists.txt

@@ -8,7 +8,7 @@ project(
 
 set(DCMTKHTJ2K_VERSION_MAJOR 1)
 set(DCMTKHTJ2K_VERSION_MINOR 0)
-set(DCMTKHTJ2K_VERSION_BUILD 4)
+set(DCMTKHTJ2K_VERSION_BUILD 5)
 set(DCMTKHTJ2K_VERSION
     "${DCMTKHTJ2K_VERSION_MAJOR}.${DCMTKHTJ2K_VERSION_MINOR}.${DCMTKHTJ2K_VERSION_BUILD}"
 )

build.sh

@@ -37,7 +37,7 @@ cmake .. -DCMAKE_BUILD_TYPE=$BUILD_TYPE \
 	-DCMAKE_INSTALL_PREFIX=$OTS_DEV_SPACE/dcmtk/$BUILD_TYPE \
 	-DCMAKE_POLICY_DEFAULT_CMP0091=NEW \
 	-DCMAKE_MSVC_RUNTIME_LIBRARY='MultiThreaded$<$<CONFIG:Debug>:Debug>'
-cmake --build . --parallel $(nproc) --config $BUILD_TYPE
+cmake --build . --parallel $(nproc 2>/dev/null || sysctl -n hw.logicalcpu) --config $BUILD_TYPE
 cmake --install . --config $BUILD_TYPE
 
 cd $OTS_DEV_SPACE
@@ -54,7 +54,7 @@ cmake .. -DCMAKE_BUILD_TYPE=$BUILD_TYPE \
 	-DCMAKE_INSTALL_PREFIX=$OTS_DEV_SPACE/openjph/$BUILD_TYPE \
 	-DCMAKE_POLICY_DEFAULT_CMP0091=NEW \
 	-DCMAKE_MSVC_RUNTIME_LIBRARY='MultiThreaded$<$<CONFIG:Debug>:Debug>'
-cmake --build . --parallel $(nproc) --config $BUILD_TYPE
+cmake --build . --parallel $(nproc 2>/dev/null || sysctl -n hw.logicalcpu) --config $BUILD_TYPE
 cmake --install . --config $BUILD_TYPE
 
 mkdir -p $BUILD_DIR
@@ -70,5 +70,5 @@ cmake .. -DCMAKE_BUILD_TYPE=$BUILD_TYPE \
 	-DCMAKE_INSTALL_PREFIX=$BUILD_DIR_LIB \
 	-DCMAKE_POLICY_DEFAULT_CMP0091=NEW \
 	-DCMAKE_MSVC_RUNTIME_LIBRARY='MultiThreaded$<$<CONFIG:Debug>:Debug>'
-cmake --build . --parallel $(nproc) --config $BUILD_TYPE
+cmake --build . --parallel $(nproc 2>/dev/null || sysctl -n hw.logicalcpu) --config $BUILD_TYPE
 cmake --install . --config $BUILD_TYPE

libsrc/djcodecd.cc

@@ -389,9 +389,12 @@ OFCondition HtJ2kDecoderBase::decodeFrame(
       codestream.read_headers(&mem_file);
 
       ojph::param_siz siz = codestream.access_siz();
+      ojph::param_cod cod = codestream.access_cod();
       int num_comps = siz.get_num_components();
       int width = siz.get_recon_width(0);
       int height = siz.get_recon_height(0);
+      bool usingColorTransform =
+          (num_comps == 3) && cod.is_using_color_transform();
 
       if (width != imageColumns)
         result = EC_HTJ2KImageDataMismatch;
@@ -447,6 +450,11 @@ OFCondition HtJ2kDecoderBase::decodeFrame(
           }
         }
 
+        // Update photometric interpretation
+        if (usingColorTransform) {
+          dataset->putAndInsertString(DCM_PhotometricInterpretation, "RGB");
+        }
+
         // Clean up
         for (int c = 0; c < num_comps; c++) {
           delete[] comps_data[c];
@@ -522,6 +530,12 @@ OFCondition HtJ2kDecoderBase::determineDecompressedColorModel(
     // retrieve color model from given dataset
     result = dataset->findAndGetOFString(DCM_PhotometricInterpretation,
                                          decompressedColorModel);
+    // YBR_ICT (lossy) and YBR_RCT (lossless) are converted to RGB by
+    // OpenJPH's inverse color transform during decompression.
+    if (result.good() && (decompressedColorModel == "YBR_ICT" ||
+                          decompressedColorModel == "YBR_RCT")) {
+      decompressedColorModel = "RGB";
+    }
   }
   return result;
 }

libsrc/djcodece.cc

@@ -530,7 +530,7 @@ OFCondition HtJ2kEncoderBase::losslessRawEncode(
   if (compressedSize > 0) compressionRatio = uncompressedSize / compressedSize;
 
   // update photometric interpretation for color images
-  if (result.good() && samplesPerPixel > 1) {
+  if (result.good() && photometricInterpretation == "RGB") {
     result = dataset->putAndInsertString(
         DCM_PhotometricInterpretation,
         djrp->useLosslessProcess() ? "YBR_RCT" : "YBR_ICT");
@@ -562,7 +562,8 @@ OFCondition HtJ2kEncoderBase::compressRawFrame(
     ojph::codestream codestream;
     ojph::mem_outfile destinationBuffer;
 
-    bool colorTransform = (samplesPerPixel > 1);
+    // Apply color transform only for RGB input
+    bool colorTransform = (photometricInterpretation == "RGB");
     codestream.set_planar(colorTransform == false);
     codestream.set_tilepart_divisions(true, false);
     codestream.request_tlm_marker(true);
@@ -813,7 +814,7 @@ OFCondition HtJ2kEncoderBase::RenderedEncode(
     if (result.good())
       result = dataset->putAndInsertUint16(DCM_HighBit, bitsPerSample - 1);
     // update photometric interpretation for color images
-    if (result.good() && samplesPerPixel > 1) {
+    if (result.good() && photometricInterpretation == "RGB") {
       result = dataset->putAndInsertString(
           DCM_PhotometricInterpretation,
           djrp->useLosslessProcess() ? "YBR_RCT" : "YBR_ICT");
@@ -980,7 +981,8 @@ OFCondition HtJ2kEncoderBase::compressRenderedFrame(
     ojph::codestream codestream;
     ojph::mem_outfile destinationBuffer;
 
-    bool colorTransform = (samplesPerPixel > 1);
+    // Apply color transform only for RGB input
+    bool colorTransform = (photometricInterpretation == "RGB");
     codestream.set_planar(colorTransform == false);
     codestream.set_tilepart_divisions(true, false);
     codestream.request_tlm_marker(true);

tests/test.cc

@@ -394,18 +394,26 @@ TEST(CodecTest, BasicColorCompressDecompressLossless) {
   DcmDataset *readDataset = readFile.getDataset();
   const E_TransferSyntax readXfer = readDataset->getOriginalXfer();
   ASSERT_EQ(readXfer, htj2kLossless);
+
+  // Verify photometric interpretation is updated to YBR_RCT
+  OFString photometricInterpretation;
+  ASSERT_TRUE(readDataset
+                  ->findAndGetOFString(DCM_PhotometricInterpretation,
+                                       photometricInterpretation)
+                  .good());
+  ASSERT_EQ(photometricInterpretation, "YBR_RCT");
+
   ASSERT_TRUE(
       readDataset->chooseRepresentation(EXS_LittleEndianExplicit, nullptr)
           .good());
   ASSERT_TRUE(readDataset->canWriteXfer(EXS_LittleEndianExplicit));
 
-  // Verify photometric interpretation is updated to YBR_RCT
-  OFString photometricInterpretation;
+  // Verify photometric interpretation is updated to RGB
   ASSERT_TRUE(readDataset
                   ->findAndGetOFString(DCM_PhotometricInterpretation,
                                        photometricInterpretation)
                   .good());
-  ASSERT_EQ(photometricInterpretation, "YBR_RCT");
+  ASSERT_EQ(photometricInterpretation, "RGB");
 
   Uint8 const *decoded = nullptr;
   unsigned long decodedCount = 0;