369         const in_image_type& in_img_,  in threshold_image()  argument
379         const_image_view<in_image_type> in_img(in_img_);  in threshold_image()
447         const in_image_type& in_img_,  in auto_threshold_image()  argument
461         if (image_size(in_img_) == 0)  in auto_threshold_image()
470         get_histogram(in_img_,hist);  in auto_threshold_image()
472         const_image_view<in_image_type> in_img(in_img_);  in auto_threshold_image()
549         threshold_image(in_img_,out_img_,thresh);  in auto_threshold_image()
569         const in_image_type& in_img_,  in hysteresis_threshold()  argument
580         DLIB_ASSERT(is_same_object(in_img_, out_img_) == false,  in hysteresis_threshold()
582             << "\n\tis_same_object(in_img_,out_img_): " << is_same_object(in_img_,out_img_)   in hysteresis_threshold()
585         const_image_view<in_image_type> in_img(in_img_);  in hysteresis_threshold()