org.openimaj.audio.filters

Class FeedForwardCombFilter

java.lang.Object

org.openimaj.audio.Audio

org.openimaj.audio.AudioStream

org.openimaj.audio.processor.AudioProcessor

org.openimaj.audio.processor.FixedSizeSampleAudioProcessor

org.openimaj.audio.filters.FeedForwardCombFilter

All Implemented Interfaces:

Iterable<SampleChunk>

public class FeedForwardCombFilter
extends FixedSizeSampleAudioProcessor

A basic feed-forward comb filter. A buffer is used to buffer the samples during the overlap of the sample chunks and it is initialised lazily, so the first time through the filter will take slightly longer. This filter extends the FixedSizeSampleAudioProcessor to ensure that the sample chunks are the same length as the required delay; this means that the buffer need only be copied in between each iteration.

Author:

David Dupplaw (dpd@ecs.soton.ac.uk)

Created:

27 Apr 2012

Field Summary

Fields inherited from class org.openimaj.audio.Audio

format

Constructor Summary

Constructors

Constructor and Description
FeedForwardCombFilter(double frequency, double sampleRate, double gain) Constructor that takes the frequency at which the comb filter will operate and the gain to apply to the delayed signal.
FeedForwardCombFilter(int nSamplesDelay, double gain) Constructor that takes the number of samples delay to apply to the signal.

Method Summary

Modifier and Type	Method and Description
double	getFrequency() This returns the frequency that this comb filter is set to detect.
double	getHarmonicity() Returns the harmonicity power.
double	getInputPower() Returns the input power for the last processed frame.
double	getOutputPower() Returns the output power for the last processed frame.
SampleChunk	process(SampleChunk sample) Function that takes a sample chunk and processes the chunk.

Methods inherited from class org.openimaj.audio.processor.FixedSizeSampleAudioProcessor

getWindowSize, getWindowStep, isOverlapping, nextSampleChunk, setWindowSize, setWindowStep

Methods inherited from class org.openimaj.audio.processor.AudioProcessor

getLength, getUnderlyingStream, process, processingComplete, reset, setUnderlyingStream

Methods inherited from class org.openimaj.audio.AudioStream

iterator, seek

Methods inherited from class org.openimaj.audio.Audio

getFormat, setFormat

Methods inherited from class java.lang.Object

clone, equals, finalize, getClass, hashCode, notify, notifyAll, toString, wait, wait, wait

Methods inherited from interface java.lang.Iterable

forEach, spliterator

Constructor Detail

FeedForwardCombFilter

public FeedForwardCombFilter(int nSamplesDelay,
                             double gain)

Constructor that takes the number of samples delay to apply to the signal.

Parameters:

nSamplesDelay - The number of delay samples

gain - The gain of the delayed signal

FeedForwardCombFilter

public FeedForwardCombFilter(double frequency,
                             double sampleRate,
                             double gain)

Constructor that takes the frequency at which the comb filter will operate and the gain to apply to the delayed signal.

Parameters:

frequency - The frequency

sampleRate - The sample rate of the signal in Hz

gain - the gain of the delayed signal

Method Detail

getFrequency

public double getFrequency()

This returns the frequency that this comb filter is set to detect. This is only available if the frequency was used during construction.

Returns:

The frequency.

process

public SampleChunk process(SampleChunk sample)
                    throws Exception

Function that takes a sample chunk and processes the chunk. It should also return a sample chunk containing the processed data. If wished, the chunk may be side-affected and the input chunk returned. It should not be assumed that the input chunk will be side-affected, but it must be noted that it is possible that it could be. This process function may also return null. If null is returned it means that the rest of the audio stream is not required to be processed by this processing function. Whether the rest of the sample chunks are copied or ignored is up to the caller. The default operation of the FixedSizeSampleAudioProcessor is simply to change the shape of the sample chunk. You may override this method to process the samples directly.

Overrides:

process in class FixedSizeSampleAudioProcessor

Parameters:

sample - The sample chunk to process.

Returns:

A sample chunk containing processed data.

Throws:

Exception - If the processing could not take place

See Also:

AudioProcessor.process(org.openimaj.audio.SampleChunk)

getOutputPower

public double getOutputPower()

Returns the output power for the last processed frame.

Returns:

the output power for the last processed frame.

getInputPower

public double getInputPower()

Returns the input power for the last processed frame.

Returns:

the input power for the last processed frame.

getHarmonicity

public double getHarmonicity()

Returns the harmonicity power.

Returns:

the harmonicity power.