ImageGear for C and C++ on Windows v20.3 - Updated
IG_FIP_filter_highpass
API Reference Guide > FreqIP Component API Reference > FreqIP Component Functions Reference > Filter Functions > IG_FIP_filter_highpass

This function filters the input image using a high-pass filter, with the specified parameters.

Declaration:

 
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AT_ERRCOUNT ACCUAPI IG_FIP_filter_highpass(
        HIGEAR hIGear, 
        const LPAT_RECT lpRect, 
        const AT_MODE nFilterBrand, 
        const AT_DOUBLE dCutoffFreq, 
        const AT_INT nFilterOrder, 
        const AT_DOUBLE dRippleFactor 
);

Arguments:

Name Type Description
hIGear HIGEAR Handle of the input image, also pass out filtered image.
lpRect const LPAT_RECT Far pointer to an AT_RECT structure specifying the rectangular portion of the image on which to operate. If NULL, this operation will be performed on the entire image.
nFilterBrand const AT_MODE Brand of the filter to use. Constants IG_FREQIP_FILTER_BRAND_* are listed in file i_FreqIP.h.
dCutoffFreq const AT_DOUBLE Cutoff frequency for the high-pass filter.
nFilterOrder const AT_INT Filter order to use, applicable to all except Ideal filter.
dRippleFactor const AT_DOUBLE A factor which determines the pass-band ripple for Chebyshev filters, with value between [0, 1].

Return Value:

Returns the number of ImageGear errors that occurred during this function call.

Supported Raster Image Formats:

Grayscale - 8 bpp.

Sample:

FreqIP

Example:

 
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HIGEAR hIGear;                   /* Handle of the input image */
...
IG_FIP_filter_highpass(hIGear, NULL, IG_FREQIP_FILTER_BRAND_GAUSSIAN, 0.3, 1, 0.5);
...

Remarks:

Parameter nFilterBrand specifies the brand of filter to use, with available brands being Ideal, Butterworth, Gaussian, Chebyshev I, and Chebyshev II.

Parameter dCutoffFreq specifies the cutoff frequency for the high-pass filter. This parameter should have value within the range of [0, 1], where 0 is DC and 1 is the Nyquist frequency.

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