Package lejos.robotics.filter

Class AbstractCalibrationFilter

java.lang.Object

lejos.robotics.filter.AbstractFilter

lejos.robotics.filter.AbstractCalibrationFilter

All Implemented Interfaces:

Calibrate, SampleProvider

Direct Known Subclasses:

LinearCalibrationFilter

public abstract class AbstractCalibrationFilter
extends AbstractFilter
implements Calibrate

Nested Class Summary

Nested Classes

Modifier and Type	Class and Description
class	AbstractCalibrationFilter.CalibrationFileException

Field Summary

Fields

Modifier and Type	Field and Description
protected boolean	calibrating
private static java.lang.String	DIRECTORY
private static java.lang.String	EXT
protected LowPassFilter	lowPassFilter
protected float[]	max
protected float[]	min
protected int	numberOfSamplesInCalibration
private java.util.Properties	props
protected float[]	sum
private float	timeConstant

Fields inherited from class lejos.robotics.filter.AbstractFilter

sampleSize, source

Constructor Summary

Constructors

Constructor and Description
AbstractCalibrationFilter(SampleProvider source)

Method Summary

Modifier and Type	Method and Description
void	fetchSample(float[] dst, int off) Fetches a sample from the sensors and updates array with minimum and maximum values when the calibration process is running.
private java.io.File	getFile(java.lang.String filename)
protected float	getProperty(java.lang.String key)
protected float[]	getPropertyArray(java.lang.String key)
protected void	load(java.lang.String filename) Loads calibration parameters from the file system.
void	resumeCalibration() Resumes the process of updating calibration parameters after a stop.
protected void	setProperty(java.lang.String key, float value)
protected void	setPropertyArray(java.lang.String key, float[] values)
void	setTimeConstant(float timeConstant) Sets the time constant for the lowpass filter that is used when calibrating.
void	startCalibration() Starts a calibration proces.
void	stopCalibration() Halts the process of updating calibration parameters.
protected void	store(java.lang.String filename) Saves the current set of calibration parameters to the file system.
void	suspendCalibration() Halts the process of updating calibration parameters.

Methods inherited from class lejos.robotics.filter.AbstractFilter

sampleSize

Methods inherited from class java.lang.Object

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

Field Detail

lowPassFilter

protected LowPassFilter lowPassFilter

min

protected float[] min

max

protected float[] max

sum

protected float[] sum

calibrating

protected boolean calibrating

DIRECTORY

private static final java.lang.String DIRECTORY

See Also:

Constant Field Values

EXT

private static final java.lang.String EXT

See Also:

Constant Field Values

props

private final java.util.Properties props

numberOfSamplesInCalibration

protected int numberOfSamplesInCalibration

timeConstant

private float timeConstant

Constructor Detail

AbstractCalibrationFilter

public AbstractCalibrationFilter(SampleProvider source)

Method Detail

fetchSample

public void fetchSample(float[] dst,
                        int off)

Fetches a sample from the sensors and updates array with minimum and maximum values when the calibration process is running.

Specified by:

fetchSample in interface SampleProvider

Overrides:

fetchSample in class AbstractFilter

Parameters:

dst - The array to store the sample in.

off - The elements of the sample are stored in the array starting at the offset position.

setTimeConstant

public void setTimeConstant(float timeConstant)

Sets the time constant for the lowpass filter that is used when calibrating.
A value of zero will effectivly disable the lowpass filter. Higher values will remove more noise from the signal and give better results, especially when calibraating for scale. The downside of higher timeConstants is that calibrating takes more time.

Parameters:

timeConstant - between 0 and 1

startCalibration

public void startCalibration()

Starts a calibration proces. Resets collected minimum and maximum values. After starting calibration new minimum and maximum values are calculated on each fetched sample. From this calibration parameters can be calculated.

Specified by:

startCalibration in interface Calibrate

stopCalibration

public void stopCalibration()

Halts the process of updating calibration parameters.

Specified by:

stopCalibration in interface Calibrate

suspendCalibration

public void suspendCalibration()

Halts the process of updating calibration parameters.

resumeCalibration

public void resumeCalibration()

Resumes the process of updating calibration parameters after a stop.

getFile

private java.io.File getFile(java.lang.String filename)

load

protected void load(java.lang.String filename)
             throws java.io.IOException

Loads calibration parameters from the file system.
This method raises an exception when the stored calibration parameters do not match the sensors or the calibration class.

Parameters:

filename - filename of the stored calibration parameters

Throws:

java.io.IOException - Exception

store

protected void store(java.lang.String filename)

Saves the current set of calibration parameters to the file system.

Calibration files are stored in /home/root/sensorCalibration/filename

Parameters:

filename - Name of the file to store calibration parameters in.

getPropertyArray

protected float[] getPropertyArray(java.lang.String key)

setPropertyArray

protected void setPropertyArray(java.lang.String key,
                                float[] values)

setProperty

protected void setProperty(java.lang.String key,
                           float value)

getProperty

protected float getProperty(java.lang.String key)