'Declaration

Public Property overlayAlpha As Single

public float overlayAlpha { get; set; }

public: __property float get_overlayAlpha();
public: __property void set_overlayAlpha(
   float value
);

public:
property float overlayAlpha {
   float get();
   void set(float value);
}

1 - High Pass result is overlayed without transparency;
otherwise, output image is converted to Bgra32 and High Pass result is overlayed using selected Alpha value.
Default value is 1.