ImageGear .NET
BandPassFilter Method




ImageGear.Core.ImGearRasterPage class object to be processed.
Brand of the filter to use. Constants are listed in the ImGearFreqIPFilterBrands enumeration.
Lower cutoff frequency for the band-pass filter.
Higher cutoff frequency for the band-pass filter.
Filter order to use, applicable to all except Ideal filter.
A factor which determines the pass-band ripple for Chebyshev filters, with value between [0, 1].
Filters the input image using a band-pass filter, with the specified parameters.
Syntax
'Declaration
 
Public Shared Sub BandPassFilter( _
   ByVal page As ImGearRasterPage, _
   ByVal filterBrand As ImGearFreqIPFilterBrands, _
   ByVal lowerCutoffFrequency As Double, _
   ByVal higherCutoffFrequency As Double, _
   ByVal filterOrder As Integer, _
   ByVal rippleFactor As Double _
) 
'Usage
 
Dim page As ImGearRasterPage
Dim filterBrand As ImGearFreqIPFilterBrands
Dim lowerCutoffFrequency As Double
Dim higherCutoffFrequency As Double
Dim filterOrder As Integer
Dim rippleFactor As Double
 
ImGearFrequencyProcessing.BandPassFilter(page, filterBrand, lowerCutoffFrequency, higherCutoffFrequency, filterOrder, rippleFactor)

Parameters

page
ImageGear.Core.ImGearRasterPage class object to be processed.
filterBrand
Brand of the filter to use. Constants are listed in the ImGearFreqIPFilterBrands enumeration.
lowerCutoffFrequency
Lower cutoff frequency for the band-pass filter.
higherCutoffFrequency
Higher cutoff frequency for the band-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 value between [0, 1].
Remarks
This method filters the input image using a band-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.

Parameters lowerCutoffFrequency and higherCutoffFrequency specify the lower and upper cutoff frequencies for the band-pass filter. The parameters 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.

ImGearFrequencyProcessingVerifier.CanApplyBandPassFilter 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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