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
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