diff options
Diffstat (limited to 'cuda/2d/fan_bp.cu')
| -rw-r--r-- | cuda/2d/fan_bp.cu | 11 |
1 files changed, 7 insertions, 4 deletions
diff --git a/cuda/2d/fan_bp.cu b/cuda/2d/fan_bp.cu index 0d21897..428485c 100644 --- a/cuda/2d/fan_bp.cu +++ b/cuda/2d/fan_bp.cu @@ -271,11 +271,14 @@ __global__ void devFanBP_FBPWeighted(float* D_volData, unsigned int volPitch, un const float fNum = fDetSY * fXD - fDetSX * fYD + fX*fSrcY - fY*fSrcX; const float fDen = fDetUX * fYD - fDetUY * fXD; + const float fr = __fdividef(1.0f, fDen); + + // fDen = || u (x-s) || + // Required scale factor is ( || u s || / || u (x-s) || ) ^ 2. + // The factor || u s || ^ 2 is handled by the preweighting - const float fWeight = fXD*fXD + fYD*fYD; - - const float fT = fNum / fDen; - fVal += tex2D(gT_FanProjTexture, fT, fA) / fWeight; + const float fT = fNum * fr; + fVal += tex2D(gT_FanProjTexture, fT, fA) * fr * fr; fA += 1.0f; } |