Harmonic Mean Filter

#include "BIFILTER.H"


HANDLE CALLBACK FilterHarmonicMean( HDIB   hDIB,
int         N,
int         iShowProgress,
HWND hParent)


This function will filter the image by the nonlinear harmonic mean method. This function works for only monochrome, 8 bit per bixel and 24 bit per pixel images. The harmonic mean filter is member of a set of nonlinear mean filters which are better at removing Gaussian type noise and preserving edge features than the arithmetic mean filter. The harmonic mean filter is very good at removing positive outliers. The definition of  harmonic mean filter is :

where the coordinate (x+i, y+j ) is defined over the image A and the coordinate  (i, j) is defined over the N x N size square mask.


Description: 8bitgray                                                  Description: harmonic

The original 180 x 210 pixel image and the harmonic mean filtered image using a 2 x 2 pixel square mask.




Handle of the DIB to filter.



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.



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 BiDlgs.dll installed.



Handler of the parent window.

Return values

The handle of the new filtered DIB or NULL if an error occurred.

Programming notes

The function will not free the input DIB.


Header :    Declared in BIFilter.h; include BIFilter.h.

Library :    Use BIFilter.lib.

DLLs :       BIFilter.dll , BIDlgs32.dl.