'Declaration

Public Property IsPreviewScan As Boolean

public bool IsPreviewScan { get; set; }

public: __property bool get_IsPreviewScan();
public: __property void set_IsPreviewScan(
   bool value
);

public:
property bool IsPreviewScan {
   bool get();
   void set(bool value);
}

True - image scanner should do the low-resolution overview pass, which is optimized for speed and drawing visual bounds;
false - image scanner should do the standard operational scan and deliver the final production image.
Default value is false.