FilterAlphaTrimmedMean  Method

Description         This function will filter the image by the nonlinear alpha-trimmed mean method. This function works for only monochrome, 8 bit per pixel and 24 bit per pixel images. The alpha-trimmed mean filter is based on order statistics and varies between a median and a mean filter. It is used when an image contains both short and long tailed types of noise (e.g. both Gaussian and salt and pepper noise). To define the alpha-trimmed mean filter, all pixels surrounding the pixel at the coordinate (x,y) in the image A which are specified by an input N x N size square mask A(i) are ordered from minimum to maximum value. The alpha-trimmed mean filter is given as:

                                   

Examples

Description: Gauss                             Description: alpha

Syntax                 RetVal = [BiFilter.]FilterAlphaTrimmedMean  hDib N P iShowProgress hWnd

Returns               RetVal                    LONGLONG The handle of new filtered DIB, 0 if an error occurred, or -1 if the BIFilter.dll does not installed.

Remarks             hDib                       LONGLONG Handle of the image to filter.

                            N                             short                This parameter specifies the size of the square mask. N cannot be less than 1. See the description and examples above for further information and a possible value. See the description and examples above for further information and a possible value.

                            P                             short                This parameter specifies the value P in the equation above. P cannot be greater than . See the description and examples above for further information and a possible value.

                            iShowProgress       short                This parameter specifies the displaying of the progressbar and the preview dialog.

Available values:

DISPLAY_NONE (0) - The progressbar and the preview dialog will not display before filtering.

DISPLAY_PROGRESS (1) - The progressbar will display during filtering procedure.

DISPLAY_DIALOG (2) - The preview dialog will display before filtering. This dialog shows the part of the image before and after filtering.

DISPLAY_BOTH (3) - The progressbar and the preview dialog will display.

IMPORTANT: The preview dialog will only display, if there is BIDlgs32.dll installed.

                            hWnd                     LONGLONG Handler of the parent window.

See Also