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/*
* Copyright (C) 2017 European Synchrotron Radiation Facility
* Grenoble, France
*
*
* Permission is hereby granted, free of charge, to any person obtaining a copy
* of this software and associated documentation files (the "Software"), to deal
* in the Software without restriction, including without limitation the rights
* to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
* copies of the Software, and to permit persons to whom the Software is
* furnished to do so, subject to the following conditions:
*
* The above copyright notice and this permission notice shall be included in
* all copies or substantial portions of the Software.
*
* THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
* IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
* FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
* AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
* LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
* OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN
* THE SOFTWARE.
*
*/
/**
*
* Compute the spatial gradient of an image.
*
* slice: input image
* slice_grad: output gradient
* sizeX: number of columns of the image
* sizeY: number of rows of the image
*
**/
__kernel void kern_gradient2D(
__global float* slice,
__global float2* slice_grad,
int sizeX,
int sizeY)
{
uint gidx = get_global_id(0);
uint gidy = get_global_id(1);
float val_x = 0, val_y = 0;
if (gidx < sizeX && gidy < sizeY) {
if (gidx == sizeX-1) val_y = 0;
else val_y = slice[(gidy)*sizeX+gidx+1] - slice[(gidy)*sizeX+gidx];
if (gidy == sizeY-1) val_x = 0;
else val_x = slice[(gidy+1)*sizeX+gidx] - slice[(gidy)*sizeX+gidx];
slice_grad[(gidy)*sizeX+gidx].x = val_x;
slice_grad[(gidy)*sizeX+gidx].y = val_y;
}
}
/**
*
* Compute the spatial divergence of an image gradient.
*
* slice_grad: input gradient-like image
* slice: output image
* sizeX: number of columns of the input
* sizeY: number of rows of the input
*
**/
__kernel void kern_divergence2D(
__global float2* slice_grad,
__global float* slice,
int sizeX,
int sizeY)
{
uint gidx = get_global_id(0);
uint gidy = get_global_id(1);
float val_x = 0, val_y = 0;
if (gidx < sizeX && gidy < sizeY) {
if (gidx == 0) val_y = slice_grad[(gidy)*sizeX+gidx].y;
else val_y = slice_grad[(gidy)*sizeX+gidx].y - slice_grad[(gidy)*sizeX+gidx-1].y;
if (gidy == 0) val_x = slice_grad[(gidy)*sizeX+gidx].x;
else val_x = slice_grad[(gidy)*sizeX+gidx].x - slice_grad[(gidy-1)*sizeX+gidx].x;
slice[(gidy)*sizeX+gidx] = val_x + val_y;
}
}
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