libs/gil/example/threshold.cpp

//
// Copyright 2019 Miral Shah <miralshah2211@gmail.com>
//
// Use, modification and distribution are subject to the Boost Software License,
// Version 1.0. (See accompanying file LICENSE_1_0.txt or copy at
// http://www.boost.org/LICENSE_1_0.txt)
//

#include <boost/gil/extension/io/jpeg.hpp>
#include <boost/gil/image_processing/threshold.hpp>

using namespace boost::gil;

// Demonstrates thresholding
// Thresholding can either attribute an arbitrary value to pixels whose values are greater than the threshold
// or can truncate the pixel values at an arbitrary maximum.
// In particular, the function threshold_truncate accepts a mode and a direction.
// Passing threshold_truncate_mode::threshold effectively truncates the values to the threshold, whereas
// threshold_truncate_mode::zero sets them to 0.
// The combination of mode and direction controls which pixels are modified:
//     - threshold and regular: truncates the pixels whose values are greater than the threshold
//     - threshold and inverse: truncates the pixels whose values are less than the threshold
//     - zero and regular: zeroes the pixels whose values are less than the threshold
//     - zero and inverse: zeroes the pixels whose values are greater than the threshold
// See also:
// adaptive_threshold.cpp - Adaptive thresholding

int main()
{
    rgb8_image_t img;
    read_image("test.jpg",img, jpeg_tag{});
    rgb8_image_t img_out(img.dimensions());

//    performing binary threshold on each channel of the image
//    if the pixel value is more than 150 than it will be set to 255 else to 0
    boost::gil::threshold_binary(const_view(img), view(img_out), 150, 255);
    write_view("out-threshold-binary.jpg", view(img_out), jpeg_tag{});

//    if the pixel value is more than 150 than it will be set to 150 else no change
    boost::gil::threshold_truncate(const_view(img), view(img_out), 150, threshold_truncate_mode::threshold);
    write_view("out-threshold-binary_inv.jpg", view(img_out), jpeg_tag{});

    return 0;
}
Boost C++ Libraries

libs/gil/example/threshold.cpp
