image_processing/gradient_diffusion.cpp
/*******************************************************
* Copyright (c) 2017, ArrayFire
* All rights reserved.
*
* This file is distributed under 3-clause BSD license.
* The complete license agreement can be obtained at:
* https://arrayfire.com/licenses/BSD-3-Clause
********************************************************/
#include <arrayfire.h>
#include <stdio.h>
#include <af/util.h>
#include <cstdlib>
using namespace af;
static const unsigned ITERS = 64;
array normalize(const array &p_in) {
float mx = max<float>(p_in);
float mn = min<float>(p_in);
return (p_in - mn) / (mx - mn);
}
array sobelFilter(const array &p_in) {
int w = 5;
if (p_in.dims(0) < 512) w = 3;
if (p_in.dims(0) > 2048) w = 7;
int h = 5;
if (p_in.dims(0) < 512) h = 3;
if (p_in.dims(0) > 2048) h = 7;
array ker = gaussianKernel(w, h);
array smooth = convolve(p_in, ker);
for (unsigned i = 1; i < ITERS; ++i) smooth = convolve(smooth, ker);
array Gx, Gy;
sobel(Gx, Gy, smooth, 3);
return normalize(hypot(Gx, Gy));
}
array in, edges, smoothed;
void anisotropicSmoothing() {
smoothed = anisotropicDiffusion(in, 0.125, 0.35f, ITERS);
}
int main(int argc, char *argv[]) {
int device = argc > 1 ? atoi(argv[1]) : 0;
try {
setDevice(device);
info();
printf("** ArrayFire Gradient Anisotropic Smoothing Demo **\n");
Window myWindow("Gradient Anisotropic Smoothing");
in = loadImage(ASSETS_DIR "/examples/images/man.jpg", false);
array sEdges = sobelFilter(in);
anisotropicSmoothing();
array Gx, Gy;
sobel(Gx, Gy, smoothed, 3);
edges = normalize(hypot(Gx, Gy));
while (!myWindow.close()) {
myWindow.grid(2, 2);
myWindow(0, 0).image(in / 255.0f, "Input Image");
myWindow(0, 1).image(normalize(smoothed),
"Anisotropically smooted Input");
myWindow(1, 0).image(normalize(sEdges),
"Gradient Magnitude after gaussian blur t=64");
myWindow(1, 1).image(normalize(edges),
"Gradient Magnitude after diffusion t=64");
myWindow.show();
}
printf(
"\nAnisotropic Diffusion avg runtime for current image in Seconds: "
"%g\n",
timeit(anisotropicSmoothing));
} catch (af::exception &e) {
fprintf(stderr, "%s\n", e.what());
throw;
}
return 0;
}