image_processing/image_editing.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 <cmath>
#include <cstdio>
#include <cstdlib>
 
using namespace af;
 
array changeContrast(const array &in, const float contrast) {
    float scale = tan((contrast + 1) * Pi / 4);
    return (((in / 255.0f - 0.5f) * scale + 0.5f) * 255.0f);
}
 
array changeBrightness(const array &in, const float brightness,
                       const float channelMax = 255.0f) {
    float factor = brightness * channelMax;
    return (in + factor);
}
 
array clamp(const array &in, float min = 0.0f, float max = 255.0f) {
    return ((in < min) * 0.0f + (in > max) * 255.0f +
            (in >= min && in <= max) * in);
}
 
array usm(const array &in, float radius, float amount) {
    int gKernelLen   = 2 * radius + 1;
    array blurKernel = gaussianKernel(gKernelLen, gKernelLen);
    array blur       = convolve(in, blurKernel);
    return (in + amount * (in - blur));
}
 
array digZoom(const array &in, int x, int y, int width, int height) {
    array cropped = in(seq(x, width - 1), seq(y, height - 1), span);
    return resize(cropped, (unsigned)in.dims(0), (unsigned)in.dims(1));
}
 
array alphaBlend(const array &a, const array &b, const array &mask) {
    array tiledMask;
    if (mask.dims(2) != a.dims(2)) tiledMask = tile(mask, 1, 1, a.dims(2));
    return a * tiledMask + (1.0f - tiledMask) * b;
}
 
void normalizeImage(array &in) {
    float min = af::min<float>(in);
    float max = af::max<float>(in);
    in        = 255.0f * ((in - min) / (max - min));
}
 
array boundary(const array &in, const array &mask) {
    array ret_val = in - erode(in, mask);
    normalizeImage(ret_val);
    return ret_val;
}
 
int main(int argc, char **argv) {
    try {
        int device = argc > 1 ? atoi(argv[1]) : 0;
        af::setDevice(device);
        af::info();
 
        array man   = loadImage(ASSETS_DIR "/examples/images/man.jpg", true);
        array fight = loadImage(ASSETS_DIR "/examples/images/fight.jpg", true);
        array nature =
            resize(loadImage(ASSETS_DIR "/examples/images/nature.jpg", true),
                   fight.dims(0), fight.dims(1));
 
        array intensity  = colorSpace(fight, AF_GRAY, AF_RGB);
        array mask       = clamp(intensity, 10.0f, 255.0f) > 0.0f;
        array blend      = alphaBlend(fight, nature, mask);
        array highcon    = changeContrast(man, 0.3);
        array highbright = changeBrightness(man, 0.2);
        array translated = translate(man, 100, 100, 200, 126);
        array sharp      = usm(man, 3, 1.2);
        array zoom       = digZoom(man, 28, 10, 192, 192);
        array morph_mask = constant(1, 3, 3);
        array bdry       = boundary(man, morph_mask);
 
        af::Window wnd("Image Editing Operations");
        printf("Press ESC while the window is in focus to exit\n");
        while (!wnd.close()) {
            wnd.grid(2, 5);
            wnd(0, 0).image(man / 255, "Input");
            wnd(1, 0).image(highcon / 255, "High Contrast");
            wnd(0, 1).image(highbright / 255, "High Brightness");
            wnd(1, 1).image(translated / 255, "Translation");
            wnd(0, 2).image(sharp / 255, "Unsharp Masking");
            wnd(1, 2).image(zoom / 255, "Digital Zoom");
            wnd(0, 3).image(nature / 255, "Background for blend");
            wnd(1, 3).image(fight / 255, "Foreground for blend");
            wnd(0, 4).image(blend / 255, "Alpha blend");
            wnd(1, 4).image(bdry / 255, "Boundary extraction");
            wnd.show();
        }
    } catch (af::exception &e) {
        fprintf(stderr, "%s\n", e.what());
        throw;
    }
    return 0;
}