Added normalize first option to ImageCaster

Author: smistad

source/FAST/Algorithms/ImageCaster/ImageCaster.cl

@@ -25,8 +25,17 @@ void writeImageAsFloat2D(__write_only image2d_t image, int2 position, float4 val
 __kernel void cast2D(
         __read_only image2d_t input,
         __write_only image2d_t output,
-        __private float scaleFactor
+        __private float scaleFactor,
+        __private char normalize,
+        __private float minimum,
+        __private float maximum
     ) {
     const int2 pos = {get_global_id(0), get_global_id(1)};
-    writeImageAsFloat2D(output, pos, readImageAsFloat2D(input, sampler, pos)*scaleFactor);
+    if(normalize == 1) {
+        float4 value = readImageAsFloat2D(input, sampler, pos);
+        value = (value - minimum) / (maximum - minimum);
+        writeImageAsFloat2D(output, pos, value*scaleFactor);
+    } else {
+        writeImageAsFloat2D(output, pos, readImageAsFloat2D(input, sampler, pos)*scaleFactor);
+    }
 }

source/FAST/Algorithms/ImageCaster/ImageCaster.cpp

@@ -9,15 +9,24 @@ ImageCaster::ImageCaster() {
     createOpenCLProgram(Config::getKernelSourcePath() + "/Algorithms/ImageCaster/ImageCaster.cl");
 }
 
-ImageCaster::ImageCaster(DataType outputType, float scaleFactor) : ImageCaster() {
+ImageCaster::ImageCaster(DataType outputType, float scaleFactor, bool normalizeFirst) : ImageCaster() {
     m_outputType = outputType;
     m_scaleFactor = scaleFactor;
+    m_normalizeFirst = normalizeFirst;
 }
 
 void ImageCaster::execute() {
     auto input = getInputData<Image>();
     if(input->getDimensions() == 3)
         throw Exception("Image caster only supports 2D for now");
+
+    float minimum = 0.0f;
+    float maximum = 0.0f;
+    if(m_normalizeFirst) {
+        minimum = input->calculateMinimumIntensity();
+        maximum = input->calculateMaximumIntensity();
+    }
+
     auto output = Image::create(input->getSize(), m_outputType, input->getNrOfChannels());
     output->setSpacing(input->getSpacing());
     SceneGraph::setParentNode(output, input);
@@ -31,6 +40,9 @@ void ImageCaster::execute() {
     kernel.setArg(0, *inputAccess->get2DImage());
     kernel.setArg(1, *outputAccess->get2DImage());
     kernel.setArg(2, m_scaleFactor);
+    kernel.setArg(3, (char)(m_normalizeFirst ? 1 : 0));
+    kernel.setArg(4, minimum);
+    kernel.setArg(5, maximum);
 
     queue.enqueueNDRangeKernel(
             kernel,

source/FAST/Algorithms/ImageCaster/ImageCaster.hpp

@@ -16,17 +16,21 @@ class FAST_EXPORT ImageCaster : public ProcessObject {
          * @brief Create instance
          * @param outputType The data type to cast the input image to
          * @param scaleFactor Value to multiply each pixel with when casting to other type
+         * @param normalizeFirst Whether to apply [0, 1] intensity normalization (e.g. (value - minimum)/(maximum - minimum))
+         *      on input before casting.
          * @return instance
          */
         FAST_CONSTRUCTOR(ImageCaster,
                          DataType, outputType,,
-                         float, scaleFactor, = 1.0f
+                         float, scaleFactor, = 1.0f,
+                         bool, normalizeFirst, = false
         )
     private:
         ImageCaster();
         void execute() override;
         float m_scaleFactor;
         DataType m_outputType;
+        bool m_normalizeFirst = false;
 };
 
 }