// Copyright (C) 2006 Davis E. King (davis@dlib.net) // License: Boost Software License See LICENSE.txt for the full license. #undef DLIB_THRESHOLDINg_ABSTRACT_ #ifdef DLIB_THRESHOLDINg_ABSTRACT_ #include "../pixel.h" namespace dlib { // ---------------------------------------------------------------------------------------- const unsigned char on_pixel = 255; const unsigned char off_pixel = 0; // ---------------------------------------------------------------------------------------- template < typename in_image_type, typename out_image_type > void threshold_image ( const in_image_type& in_img, out_image_type& out_img, unsigned long thresh ); /*! requires - in_image_type == is an implementation of array2d/array2d_kernel_abstract.h - out_image_type == is an implementation of array2d/array2d_kernel_abstract.h - pixel_traits<typename out_image_type::type>::grayscale == true - pixel_traits<typename in_image_type::type>::has_alpha == false - pixel_traits<typename out_image_type::type>::has_alpha == false ensures - #out_img == the thresholded version of in_img (in_img is converted to a grayscale intensity image if it is color). Pixels in in_img with grayscale values >= thresh have an output value of on_pixel and all others have a value of off_pixel. - #out_img.nc() == in_img.nc() - #out_img.nr() == in_img.nr() !*/ // ---------------------------------------------------------------------------------------- template < typename in_image_type, typename out_image_type > void auto_threshold_image ( const in_image_type& in_img, out_image_type& out_img ); /*! requires - in_image_type == is an implementation of array2d/array2d_kernel_abstract.h - out_image_type == is an implementation of array2d/array2d_kernel_abstract.h - pixel_traits<typename out_image_type::type>::grayscale == true - pixel_traits<typename in_image_type::type>::has_alpha == false - pixel_traits<typename out_image_type::type>::has_alpha == false - pixel_traits<typename in_image_type::type>::is_unsigned == true - pixel_traits<typename out_image_type::type>::is_unsigned == true ensures - #out_img == the thresholded version of in_img (in_img is converted to a grayscale intensity image if it is color). Pixels in in_img with grayscale values >= thresh have an output value of on_pixel and all others have a value of off_pixel. - The thresh value used is determined by performing a k-means clustering on the input image histogram with a k of 2. The point between the two means found is used as the thresh value. - #out_img.nc() == in_img.nc() - #out_img.nr() == in_img.nr() !*/ // ---------------------------------------------------------------------------------------- template < typename in_image_type, typename out_image_type > void hysteresis_threshold ( const in_image_type& in_img, const out_image_type& out_img, unsigned long lower_thresh, unsigned long upper_thresh ); /*! requires - in_image_type == is an implementation of array2d/array2d_kernel_abstract.h - out_image_type == is an implementation of array2d/array2d_kernel_abstract.h - pixel_traits<typename out_image_type::type>::grayscale == true - pixel_traits<typename in_image_type::type>::has_alpha == false - pixel_traits<typename out_image_type::type>::has_alpha == false - lower_thresh <= upper_thresh ensures - #out_img == the hysteresis thresholded version of in_img (in_img is converted to a grayscale intensity image if it is color). Pixels in in_img with grayscale values >= upper_thresh have an output value of on_pixel and all others have a value of off_pixel unless they are >= lower_thresh and are adjacent to a pixel with a value >= upper_thresh in which case they have a value of on_pixel. - #out_img.nc() == in_img.nc() - #out_img.nr() == in_img.nr() !*/ // ---------------------------------------------------------------------------------------- } #endif // DLIB_THRESHOLDINg_ABSTRACT_