FilterEdgeCanny  Method

Description         This function will find edges on the input image by the Canny edge detection method. This function works for 8 and 24 bit per pixel images. Canny edge-detection first filters the image with the derivative of the Gaussian filter mask generated by the standard deviation parameter. The value of standard deviation determines the width of the filter matrix, and controls the amount of smoothing produced by the Gaussian component. The derivative Gaussian filtering will smooth the image and enhance the edges. After filtering the magnitude of the result x and y components is to be computed. The final step of Canny edge-detector is a nonmaximum suppression step, where pixels that are not local maxima are removed. During the nonmaximum suppression step a hysteresis thresholding is applied.

Examples

Description: edge          Description: edgecanny

The original 500 x 400 pixel image and the Canny edge detected image with fSTDV = 1.5, parameter value.

Syntax                 RetVal = [BiFilter.]FilterEdgeCanny  hDib nSTDV bShowDialog

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.

                            nSTDV                   Long                Standard deviation value. The value of standard deviation determines the width of the filter matrix, and controls the amount of smoothing produced by the Gaussian component. STDV cannot be less than 0. See the description and examples above for further information and a possible value.

                            bShowDialog         BOOL             This parameter specifies the displaying of the preview dialog. IMPORTANT: The preview dialog will only display, if there is BiDlgs.dll installed

See Also