net.sf.jaer.eventprocessing.filter
Class OnOffProximityLineFilter

java.lang.Object
  net.sf.jaer.eventprocessing.EventFilter
      net.sf.jaer.eventprocessing.EventFilter2D
          net.sf.jaer.eventprocessing.filter.OnOffProximityLineFilter

All Implemented Interfaces:

java.util.Observer

public class OnOffProximityLineFilter
extends EventFilter2D
implements java.util.Observer

An AE filter that outputs only events that are supported by a nearby event of the opposite polarity in the neighborhood. The neighborhood is defined by a subsampling bit shift. This filter can be used to do try to filter out shadows, which produce only one polarity events for an extended shadow. Only thin lines that produce both ON and OFF events in a spatio-temporal neighborhood should pass through. Subsamples space part of address, checks if delta t of current event to opposite polarity is within dt. if so, output event. in either case write subsampled event to lastTimestamps map.

Author:

tobi

Field Summary

protected int

dt the time in timestamp ticks (1us at present) that a spike needs to be supported by a prior event in the neighborhood by to pass through

Fields inherited from class net.sf.jaer.eventprocessing.EventFilter2D

enclosedFilter, out

Fields inherited from class net.sf.jaer.eventprocessing.EventFilter

annotationEnabled, chip, enclosedFilterChain, filterEnabled, log, perf, propertyTooltipMap, support

Constructor Summary

OnOffProximityLineFilter(AEChip chip)

Method Summary

EventPacket	filterPacket(EventPacket in) filters in to out.
static java.lang.String	getDescription()
int	getDt() gets the background allowed delay in us
java.lang.Object	getFilterState() should return the filter state in some useful form
int	getSubsampleBy()
void	initFilter() this should allocate and initialize memory: it may be called when the chip e.g.
void	resetFilter() should reset the filter to initial state
void	setDt(int dt) sets the background delay in us
void	setSubsampleBy(int subsampleBy) Sets the number of bits to subsample by when storing events into the map of past events.
void	update(java.util.Observable o, java.lang.Object arg)

Methods inherited from class net.sf.jaer.eventprocessing.EventFilter2D

checkOutputPacketEventType, checkOutputPacketEventType, getEnclosedFilter, resetOut, setEnclosedFilter, setFilterEnabled

Methods inherited from class net.sf.jaer.eventprocessing.EventFilter

getChip, getEnclosedFilterChain, getEnclosingFilter, getPrefs, getPropertyChangeSupport, getPropertyTooltip, isAnnotationEnabled, isEnclosed, isFilterEnabled, prefsEnabledKey, setAnnotationEnabled, setChip, setEnclosed, setEnclosedFilter, setEnclosedFilterChain, setEnclosingFilter, setPreferredEnabledState, setPrefs, setPropertyTooltip

Methods inherited from class java.lang.Object

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

Field Detail

dt

protected int dt

the time in timestamp ticks (1us at present) that a spike needs to be supported by a prior event in the neighborhood by to pass through

Constructor Detail

OnOffProximityLineFilter

public OnOffProximityLineFilter(AEChip chip)

Method Detail

getDescription

public static java.lang.String getDescription()

filterPacket

public EventPacket filterPacket(EventPacket in)

filters in to out. if filtering is enabled, the number of out may be less than the number put in

Specified by:

filterPacket in class EventFilter2D

Parameters:

in - input events can be null or empty.

Returns:

the processed events, may be fewer in number. filtering may occur in place in the in packet.

getDt

public int getDt()

gets the background allowed delay in us

Returns:

delay allowed for spike since last in neighborhood to pass (us)

setDt

public void setDt(int dt)

sets the background delay in us

Fires a PropertyChangeEvent "dt"

Parameters:

dt - delay in us

See Also:

getDt()

getFilterState

public java.lang.Object getFilterState()

Description copied from class: EventFilter

should return the filter state in some useful form

Specified by:

getFilterState in class EventFilter

resetFilter

public void resetFilter()

Description copied from class: EventFilter

should reset the filter to initial state

Specified by:

resetFilter in class EventFilter

update

public void update(java.util.Observable o,
                   java.lang.Object arg)

Specified by:

update in interface java.util.Observer

initFilter

public void initFilter()

Description copied from class: EventFilter

this should allocate and initialize memory: it may be called when the chip e.g. size parameters are changed after creation of the filter

Specified by:

initFilter in class EventFilter

getSubsampleBy

public int getSubsampleBy()

setSubsampleBy

public void setSubsampleBy(int subsampleBy)

Sets the number of bits to subsample by when storing events into the map of past events. Increasing this value will increase the number of events that pass through and will also allow passing events from small sources that do not stimulate every pixel.

Parameters:

subsampleBy - the number of bits, 0 means no subsampling, 1 means cut event time map resolution by a factor of two in x and in y