/// <summary>
 /// Create a filter object with a kernel from the builtin ones.
 /// </summary>
 /// <param name="type"> Builtin kernel desired </param>
 /// <returns> Filter object </returns>
 public static Filter BuiltinFilter(BuiltinKernel type)
 {
     float[] values = BuiltinFilters.Kernel(type);
     Filter filter = CustomFilter(values.Length, values);
     return filter;
 }
 public static float[] Kernel(BuiltinKernel type)
 {
     float[] kernel = Map[BuiltinKernel.Identity3X3];
     Map.TryGetValue(type, out kernel);
     return kernel;
 }