float Noise::interpolateNoise(float x, float y)
{
int wholePartX = (int) x; // Same as flooring.
float fractionPartX = x - wholePartX;
int wholePartY = (int) y;
float fractionPartY = y - wholePartY;
float v1 = nextFloat(wholePartX, wholePartY);
float v2 = nextFloat(wholePartX + 1, wholePartY);
float v3 = nextFloat(wholePartX, wholePartY + 1);
float v4 = nextFloat(wholePartX + 1, wholePartY + 1);
float i1 = InterpolateCubic(v1, v2, fractionPartX);
float i2 = InterpolateCubic(v3, v4, fractionPartX);
return InterpolateCubic(i1, i2, fractionPartY);
}
__kernel void SliceTimingCorrection(__global float* Corrected_Volumes,
__global const float* Volumes,
__private float delta,
__private int DATA_W,
__private int DATA_H,
__private int DATA_D,
__private int DATA_T)
{
int x = get_global_id(0);
int y = get_global_id(1);
int3 tIdx = {get_local_id(0), get_local_id(1), get_local_id(2)};
if (x >= DATA_W || y >= DATA_H)
return;
float t0, t1, t2, t3;
// Forward interpolation
if (delta > 0.0f)
{
t0 = Volumes[Calculate3DIndex(x,y,0,DATA_W,DATA_H)];
t1 = t0;
t2 = Volumes[Calculate3DIndex(x,y,1,DATA_W,DATA_H)];
t3 = Volumes[Calculate3DIndex(x,y,2,DATA_W,DATA_H)];
// Loop over timepoints
for (int t = 0; t < DATA_T - 3; t++)
{
// Cubic interpolation in time
Corrected_Volumes[Calculate3DIndex(x,y,t,DATA_W,DATA_H)] = InterpolateCubic(t0,t1,t2,t3,delta);
// Shift old values backwards
t0 = t1;
t1 = t2;
t2 = t3;
// Read one new value
t3 = Volumes[Calculate3DIndex(x,y,t+3,DATA_W,DATA_H)];
}
int t = DATA_T - 3;
Corrected_Volumes[Calculate3DIndex(x,y,t,DATA_W,DATA_H)] = InterpolateCubic(t0,t1,t2,t3,delta);
t = DATA_T - 2;
t0 = t1;
t1 = t2;
t2 = t3;
Corrected_Volumes[Calculate3DIndex(x,y,t,DATA_W,DATA_H)] = InterpolateCubic(t0,t1,t2,t3,delta);
t = DATA_T - 1;
t0 = t1;
t1 = t2;
Corrected_Volumes[Calculate3DIndex(x,y,t,DATA_W,DATA_H)] = InterpolateCubic(t0,t1,t2,t3,delta);
}
// Backward interpolation
else
{
delta = 1.0f - (-delta);
t0 = Volumes[Calculate3DIndex(x,y,0,DATA_W,DATA_H)];
t1 = t0;
t2 = t0;
t3 = Volumes[Calculate3DIndex(x,y,1,DATA_W,DATA_H)];
// Loop over timepoints
for (int t = 0; t < DATA_T - 2; t++)
{
// Cubic interpolation in time
Corrected_Volumes[Calculate3DIndex(x,y,t,DATA_W,DATA_H)] = InterpolateCubic(t0,t1,t2,t3,delta);
// Shift old values backwards
t0 = t1;
t1 = t2;
t2 = t3;
// Read one new value
t3 = Volumes[Calculate3DIndex(x,y,t+2,DATA_W,DATA_H)];
}
int t = DATA_T - 2;
Corrected_Volumes[Calculate3DIndex(x,y,t,DATA_W,DATA_H)] = InterpolateCubic(t0,t1,t2,t3,delta);
t = DATA_T - 1;
t0 = t1;
t1 = t2;
t2 = t3;
Corrected_Volumes[Calculate3DIndex(x,y,t,DATA_W,DATA_H)] = InterpolateCubic(t0,t1,t2,t3,delta);
}
T InterpolateCubic (T prev, T start, T end, T after, float startT, float endT, float time)
{
return InterpolateCubic(prev, start, end, after, (time-startT)/(endT-startT));
};