From Tracker Software PDF SDK
The method applies Noise filter to the image page or its specified area.
HRESULT FilterNoise([in] RECT* pRect, [in] ULONG nLevel, [in] ULONG nFlags);
- [in] Pointer to the RECT structure which defines the rectangular area where the function should be applied. If this parameter is NULL, the entire page will be processed.
Note:Please note that partial processing of an area of a page is not supported for all image formats. For example, it is not supported for indexed images, because pixels in such images do not contain a color, but an index into a color table (or palette) which is common for the entire page
- [in] Specifies noise level.
- [in] Specifies the type of the filter. Could be one of the following Noise types.
Returns S_OK if operation was successful or error code in other cases.