interp::InterpFilter Class Reference

Provides methods to generate interpolation filters using Kaiser windows. More...

#include "interpolation_filter.h"

Public Member Functions
	InterpFilter (const InterpFilter &)=delete
	InterpFilter (InterpFilter &&)=delete
InterpFilter &	operator= (const InterpFilter &)=delete
InterpFilter &	operator= (InterpFilter &&)=delete
	~InterpFilter ()=default
std::expected< RealType, std::string >	kaiserWinCompute (RealType x) const noexcept
	Computes the Kaiser window function for a given input.
std::expected< RealType, std::string >	interpFilter (RealType x) const noexcept
	Computes the interpolation filter value for a given input.
std::span< const RealType >	getFilter (RealType delay) const
	Retrieves a span of precomputed filter values for a given delay.

Static Public Member Functions
static constexpr RealType	sinc (const RealType x) noexcept
	Computes the sinc function for a given input.
static InterpFilter &	getInstance () noexcept
	Retrieves the singleton instance of the InterpFilter class.

Detailed Description

Provides methods to generate interpolation filters using Kaiser windows.

Definition at line 28 of file interpolation_filter.h.

Constructor & Destructor Documentation

InterpFilter() [1/2]

interp::InterpFilter::InterpFilter ( const InterpFilter &  )

delete

InterpFilter() [2/2]

interp::InterpFilter::InterpFilter ( InterpFilter &&  )

delete

~InterpFilter()

interp::InterpFilter::~InterpFilter ( )

default

Member Function Documentation

getFilter()

std::span< const RealType > interp::InterpFilter::getFilter

(

RealType

delay

)

const

Retrieves a span of precomputed filter values for a given delay.

Parameters

delay

The delay value for which the filter is retrieved.

Returns

A span of precomputed filter values.

Exceptions

std::runtime_error

If the delay value is out of range.

Definition at line 138 of file interpolation_filter.cpp.

    {
        if (delay < -1 || delay > 1)
        {
            LOG(Level::FATAL, "Requested delay filter value out of range: {}", delay);
            throw std::runtime_error("Requested delay filter value out of range");
        }
 
        const auto filt =
            std::min(static_cast<std::size_t>((delay + 1.0) * (static_cast<RealType>(_table_filters) / 2.0)),
                     _table_filters - 1);
        return std::span{_filter_table.data() + filt * _length, _length};
    }

References LOG, and max.

getInstance()

InterpFilter & interp::InterpFilter::getInstance ( )

staticnoexcept

Retrieves the singleton instance of the InterpFilter class.

Returns

The singleton instance of the InterpFilter class.

Definition at line 64 of file interpolation_filter.cpp.

    {
        static InterpFilter instance;
        return instance;
    }

Referenced by fers_signal::Signal::renderSlice().

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interpFilter()

std::expected< RealType, std::string > interp::InterpFilter::interpFilter ( RealType  x ) const

noexcept

Computes the interpolation filter value for a given input.

Parameters

x	The input value for which the interpolation filter is computed.

Returns

The computed filter value, or an error message if computation fails.

Definition at line 85 of file interpolation_filter.cpp.

    {
        auto kaiser = kaiserWinCompute(x + _alpha);
        if (kaiser)
        {
            return *kaiser * sinc(x);
        }
 
        return std::unexpected(kaiser.error());
    }

References max.

kaiserWinCompute()

std::expected< RealType, std::string > interp::InterpFilter::kaiserWinCompute ( RealType  x ) const

noexcept

Computes the Kaiser window function for a given input.

Parameters

x	The input value for the Kaiser window calculation.

Returns

The computed window value, or an error message if computation fails.

Definition at line 70 of file interpolation_filter.cpp.

    {
        if (x < 0 || x > _alpha * 2)
        {
            return 0;
        }
        auto bessel = besselI0(_beta * std::sqrt(1 - std::pow((x - _alpha) / _alpha, 2)));
        if (bessel)
        {
            return *bessel / _bessel_beta;
        }
 
        return std::unexpected(bessel.error());
    }

References max.

operator=() [1/2]

InterpFilter & interp::InterpFilter::operator= ( const InterpFilter &  )

delete

operator=() [2/2]

InterpFilter & interp::InterpFilter::operator= ( InterpFilter &&  )

delete

sinc()

static constexpr RealType interp::InterpFilter::sinc ( const RealType  x )

staticconstexprnoexcept

Computes the sinc function for a given input.

Parameters

x	The input value for which the sinc function is computed.

Returns

The computed sinc value.

Definition at line 43 of file interpolation_filter.h.

        {
            return x == 0.0 ? 1.0 : std::sin(x * PI) / (x * PI);
        }

References PI.

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The documentation for this class was generated from the following files:

• packages/libfers/src/interpolation/interpolation_filter.h
• packages/libfers/src/interpolation/interpolation_filter.cpp