Update generate_octave template function implementation

Update generate_octave template function implementation

Author: Jimmy-Hu

image_operations.h

@@ -6159,7 +6159,9 @@ namespace TinyDIP
         //  generate_octave template function implementation (Multi-Channel Overload)
         template<typename ElementT, typename SigmaT = double>
         requires((std::floating_point<SigmaT> || std::integral<SigmaT>) and
-                 ((std::same_as<ElementT, RGB>) || (std::same_as<ElementT, RGB_DOUBLE>) || (std::same_as<ElementT, HSV>) || (is_MultiChannel<ElementT>::value))
+                 ((std::same_as<ElementT, RGB>) || (std::same_as<ElementT, RGB_DOUBLE>) || (std::same_as<ElementT, HSV>) || (is_MultiChannel<ElementT>::value)) and
+                 (!is_bool_data_v<ElementT>) and
+                 (!is_complex_data_v<ElementT>)
         )
         static auto generate_octave(
             const Image<ElementT>& input,
@@ -6180,6 +6182,11 @@ namespace TinyDIP
                     // Force floating-point precision on the plane before DoG evaluation
                     return TinyDIP::difference_of_gaussian(TinyDIP::im2double(std::forward<decltype(each_plane)>(each_plane)), initial_sigma, initial_sigma);
                 }
+                else
+                {
+                    // Compile-time firewall preventing cryptic void deduction errors on unsupported raw types
+                    static_assert(!std::same_as<ScalarT, ScalarT>, "The underlying channel type of the multi-channel image is not supported by difference_of_gaussian or im2double.");
+                }
             };
             using MultiChannelDiffT = decltype(apply_each(input, deduce_type_lambda));
 
@@ -6206,19 +6213,23 @@ namespace TinyDIP
                     if constexpr (std::same_as<ScalarT, double>)
                     {
                         return TinyDIP::difference_of_gaussian(
-                            each_plane,
+                            std::forward<decltype(each_plane)>(each_plane),
                             sig1,
                             sig2
                         );
                     }
-                    else
+                    else if constexpr (requires { TinyDIP::im2double(std::forward<decltype(each_plane)>(each_plane)); })
                     {
                         return TinyDIP::difference_of_gaussian(
-                            TinyDIP::im2double(each_plane),
+                            TinyDIP::im2double(std::forward<decltype(each_plane)>(each_plane)),
                             sig1,
                             sig2
                         );
                     }
+                    else
+                    {
+                        static_assert(!std::same_as<ScalarT, ScalarT>, "The underlying channel type of the multi-channel image is not supported by difference_of_gaussian or im2double.");
+                    }
                 });
             }