Merge branch 'master' into FDK

1 files changed, 31 insertions, 39 deletions

diff --git a/cuda/2d/fft.cu b/cuda/2d/fft.cu
index aab755a..3dd1c22 100644
--- a/cuda/2d/fft.cu
+++ b/cuda/2d/fft.cu
@@ -304,44 +304,42 @@ void genFilter(E_FBPFILTER _eFilter, float _fD, int _iProjectionCount,
 	float * pfFilt = new float[_iFFTFourierDetectorCount];
 	float * pfW = new float[_iFFTFourierDetectorCount];
 
-#if 1
+	// We cache one Fourier transform for repeated FBP's of the same size
+	static float *pfData = 0;
+	static int iFilterCacheSize = 0;
+
+	if (!pfData || iFilterCacheSize != _iFFTRealDetectorCount) {
+		// Compute filter in spatial domain
+
+		delete[] pfData;
+		pfData = new float[2*_iFFTRealDetectorCount];
+		int *ip = new int[int(2+sqrt(_iFFTRealDetectorCount)+1)];
+		ip[0] = 0;
+		float32 *w = new float32[_iFFTRealDetectorCount/2];
+
+		for (int i = 0; i < _iFFTRealDetectorCount; ++i) {
+			pfData[2*i+1] = 0.0f;
+
+			if (i & 1) {
+				int j = i;
+				if (2*j > _iFFTRealDetectorCount)
+					j = _iFFTRealDetectorCount - j;
+				float f = M_PI * j;
+				pfData[2*i] = -1 / (f*f);
+			} else {
+				pfData[2*i] = 0.0f;
+			}
+		}
 
-	for(int iDetectorIndex = 0; iDetectorIndex < _iFFTFourierDetectorCount; iDetectorIndex++)
-	{
-		float fRelIndex = (float)iDetectorIndex / (float)_iFFTRealDetectorCount;
+		pfData[0] = 0.25f;
 
-		// filt = 2*( 0:(order/2) )./order;
-		pfFilt[iDetectorIndex] = 2.0f * fRelIndex;
-		//pfFilt[iDetectorIndex] = 1.0f;
+		cdft(2*_iFFTRealDetectorCount, -1, pfData, ip, w);
+		delete[] ip;
+		delete[] w;
 
-		// w = 2*pi*(0:size(filt,2)-1)/order
-		pfW[iDetectorIndex] = 3.1415f * 2.0f * fRelIndex;
-	}
-#else
-
-	float *pfData = new float[2*_iFFTRealDetectorCount];
-	int *ip = new int[int(2+sqrt(_iFFTRealDetectorCount)+1)];
-	ip[0]=0;
-	float32 *w = new float32[_iFFTRealDetectorCount/2];
-
-	for (int i = 0; i < _iFFTRealDetectorCount; ++i) {
-		pfData[2*i+1] = 0.0f;
-
-		if (i & 1) {
-			int j = i;
-			if (2*j > _iFFTRealDetectorCount)
-				j = _iFFTRealDetectorCount - j;
-			float f = M_PI * j;
-			pfData[2*i] = -1 / (f*f);
-		} else {
-			pfData[2*i] = 0.0f;
-		}
+		iFilterCacheSize = _iFFTRealDetectorCount;
 	}
 
-	pfData[0] = 0.25f;
-
-	cdft(2*_iFFTRealDetectorCount, -1, pfData, ip, w);
-
 	for(int iDetectorIndex = 0; iDetectorIndex < _iFFTFourierDetectorCount; iDetectorIndex++)
 	{
 		float fRelIndex = (float)iDetectorIndex / (float)_iFFTRealDetectorCount;
@@ -350,11 +348,6 @@ void genFilter(E_FBPFILTER _eFilter, float _fD, int _iProjectionCount,
 		pfW[iDetectorIndex] = M_PI * 2.0f * fRelIndex;
 	}
 
-	delete[] pfData;
-	delete[] ip;
-	delete[] w;
-#endif
-
 	switch(_eFilter)
 	{
 		case FILTER_RAMLAK:
@@ -906,5 +899,4 @@ void downloadDebugFilterReal(float * _pfHostSinogram, int _iProjectionCount,
 	free(pfHostFilter);
 }
 
-
 #endif