image_processing/morphing.cpp

/*******************************************************
 * Copyright (c) 2014, ArrayFire
 * All rights reserved.
 *
 * This file is distributed under 3-clause BSD license.
 * The complete license agreement can be obtained at:
 * http://arrayfire.com/licenses/BSD-3-Clause
 ********************************************************/
 
#include <arrayfire.h>
#include <stdio.h>
#include <af/util.h>
#include <cstdlib>
 
using namespace af;
 
array morphopen(const array& img, const array& mask) {
    return dilate(erode(img, mask), mask);
}
 
array morphclose(const array& img, const array& mask) {
    return erode(dilate(img, mask), mask);
}
 
array morphgrad(const array& img, const array& mask) {
    return (dilate(img, mask) - erode(img, mask));
}
 
array tophat(const array& img, const array& mask) {
    return (img - morphopen(img, mask));
}
 
array bottomhat(const array& img, const array& mask) {
    return (morphclose(img, mask) - img);
}
 
array border(const array& img, const int left, const int right, const int top,
             const int bottom, const float value = 0.0) {
    if ((int)img.dims(0) < (top + bottom))
        printf("input does not have enough rows\n");
    if ((int)img.dims(1) < (left + right))
        fprintf(stderr, "input does not have enough columns\n");
 
    dim4 imgDims = img.dims();
    array ret    = constant(value, imgDims);
    ret(seq(top, imgDims[0] - bottom), seq(left, imgDims[1] - right), span,
        span)    = img(seq(top, imgDims[0] - bottom),
                       seq(left, imgDims[1] - right), span, span);
 
    return ret;
}
 
array border(const array& img, const int w, const int h,
             const float value = 0.0) {
    return border(img, w, w, h, h, value);
}
 
array border(const array& img, const int size, const float value = 0.0) {
    return border(img, size, size, size, size, value);
}
 
array blur(const array& img, const array mask = gaussianKernel(3, 3)) {
    array blurred = array(img.dims(), img.type());
    for (int i = 0; i < (int)blurred.dims(2); i++)
        blurred(span, span, i) = convolve(img(span, span, i), mask);
    return blurred;
}
 
// Demonstrates various image morphing manipulations.
static void morphing_demo() {
    af::Window wnd(1280, 720, "Morphological Operations");
    // load images
    array img_rgb = loadImage(ASSETS_DIR "/examples/images/man.jpg", true) /
                    255.f;  // 3 channel RGB       [0-1]
 
    array mask = constant(1, 5, 5);
 
    array er = erode(img_rgb, mask);
    array di = dilate(img_rgb, mask);
    array op = morphopen(img_rgb, mask);
    array cl = morphclose(img_rgb, mask);
    array gr = morphgrad(img_rgb, mask);
    array th = tophat(img_rgb, mask);
    array bh = bottomhat(img_rgb, mask);
    array bl = blur(img_rgb, gaussianKernel(5, 5));
    array bp = border(img_rgb, 20, 30, 40, 50, 0.5);
    array bo = border(img_rgb, 20);
 
    while (!wnd.close()) {
        wnd.grid(3, 4);
 
        wnd(0, 0).image(img_rgb, "Input");
        wnd(1, 0).image(er, "Erosion");
        wnd(2, 0).image(di, "Dilation");
 
        wnd(0, 1).image(op, "Opening");
        wnd(1, 1).image(cl, "Closing");
        wnd(2, 1).image(gr, "Gradient");
 
        wnd(0, 2).image(th, "TopHat");
        wnd(1, 2).image(bh, "BottomHat");
        wnd(2, 2).image(bl, "Blur");
 
        wnd(0, 3).image(bp, "Border to Gray");
        wnd(1, 3).image(bo, "Border to black");
 
        wnd.show();
    }
}
 
int main(int argc, char** argv) {
    int device = argc > 1 ? atoi(argv[1]) : 0;
 
    try {
        af::info();
        af::setDevice(device);
        printf("** ArrayFire Image Morphing Demo **\n\n");
        morphing_demo();
 
    } catch (af::exception& e) {
        fprintf(stderr, "%s\n", e.what());
        throw;
    }
 
    return 0;
}