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3rdparty/boost_1_81_0/libs/gil/example/threshold.cpp 1.97 KB
977ed18d   Hu Chunming   提交三方库
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  //
  // 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;
  }