ImageGear for .NET
HighPassFilter Method




ImageGear.Core.ImGearRasterPage class object to be processed.
Brand of the filter to use. Constants are listed in ImGearFreqIPFilterBrands enumeration.
Cutoff frequency for the high-pass filter.
Filter order to use, applicable to all except Ideal filter.
A factor which determines the pass-band ripple for Chebyshev filters, with vaule between [0, 1].
Filters the input image using a high-pass filter, with the specified parameters.
Syntax
'Declaration
 
Public Shared Sub HighPassFilter( _
   ByVal page As ImGearRasterPage, _
   ByVal filterBrand As ImGearFreqIPFilterBrands, _
   ByVal cutoffFrequency As Double, _
   ByVal filterOrder As Integer, _
   ByVal rippleFactor As Double _
) 
'Usage
 
Dim page As ImGearRasterPage
Dim filterBrand As ImGearFreqIPFilterBrands
Dim cutoffFrequency As Double
Dim filterOrder As Integer
Dim rippleFactor As Double
 
ImGearFrequencyProcessing.HighPassFilter(page, filterBrand, cutoffFrequency, filterOrder, rippleFactor)
public static void HighPassFilter( 
   ImGearRasterPage page,
   ImGearFreqIPFilterBrands filterBrand,
   double cutoffFrequency,
   int filterOrder,
   double rippleFactor
)
public: static void HighPassFilter( 
   ImGearRasterPage* page,
   ImGearFreqIPFilterBrands filterBrand,
   double cutoffFrequency,
   int filterOrder,
   double rippleFactor
) 
public:
static void HighPassFilter( 
   ImGearRasterPage^ page,
   ImGearFreqIPFilterBrands filterBrand,
   double cutoffFrequency,
   int filterOrder,
   double rippleFactor
) 

Parameters

page
ImageGear.Core.ImGearRasterPage class object to be processed.
filterBrand
Brand of the filter to use. Constants are listed in ImGearFreqIPFilterBrands enumeration.
cutoffFrequency
Cutoff frequency for the high-pass filter.
filterOrder
Filter order to use, applicable to all except Ideal filter.
rippleFactor
A factor which determines the pass-band ripple for Chebyshev filters, with vaule between [0, 1].
Remarks
This method filters the input image using a high-pass filter, with the specified parameters.

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

Parameter cutoffFrequency 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.

Before using this method, like other frequency processing methods, InitializeFFTW method must be called first to initialize the support for FFTW.

Can be applied only to 8bit grayscale images with one channel.

Method ImGearFrequencyProcessingVerifier.CanApplyHighPassFilter method can be called to check whether the operation can be performed or not.

See Also

Reference

ImGearFrequencyProcessing Class
ImGearFrequencyProcessing Members
ImGearRasterPage Class
ImGearFreqIPFilterBrands Enumeration

 

 


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