recob::OpWaveform Class Reference

Class holding the regions of interest of signal from a photon detector channel. More...

#include <OpWaveform.h>

Public Types
typedef lar::sparse_vector< float >	RegionsOfInterest_t
	a region of interest is a pair (TDC offset, readings) More...

Public Member Functions
	OpWaveform ()
	Default constructor: a wire with no signal information. More...
	OpWaveform (raw::RDTimeStamp time, raw::ChannelID_t channel, RegionsOfInterest_t const &sigROIlist)
	Constructor: uses specified signal in regions of interest. More...
	OpWaveform (raw::RDTimeStamp time, raw::ChannelID_t channel, RegionsOfInterest_t &&sigROIlist)
	Constructor: uses specified signal in regions of interest. More...
Accessors
std::vector< float >	Signal () const
	Return a zero-padded full length vector filled with RoI signal. More...
const RegionsOfInterest_t &	SignalROI () const
	Returns the list of regions of interest. More...
std::size_t	NSignal () const
	Returns the number of time ticks, or samples, in the channel. More...
raw::ChannelID_t	Channel () const
	Returns the ID of the channel (or InvalidChannelID) More...
raw::RDTimeStamp	TimeStamp () const
	Returns the time stamp. More...
Sorting and comparison operations
bool	operator< (const OpWaveform &than) const
	Returns whether this channel ID is smaller than the other. More...

Private Attributes
raw::RDTimeStamp	fTimeStamp
	Time stamp. More...
raw::ChannelID_t	fChannel
	ID of the associated channel. More...
RegionsOfInterest_t	fSignalROI
	Signal on the channel as function of time tick. More...

Detailed Description

Class holding the regions of interest of signal from a photon detector channel.

Note

The class is designed based on recob::Wire.

The channel content is expected to have been filtered from noise and corrected for electronics response, a process often called in jargon "deconvolution".

The content is presented as calibrated ADC counts, pedestal removed, as function of time in discrete TDC units. The time is expected to be the same as for the raw::OpDetWaveform that originates it.

The content is organized as time intervals where some signal is present ("regions of interest", RoI), outside which we assume no signal. By principle, the definition of the regions of interest is a negative one: we determine time intervals where we are confident no signal is present; the rest will constitute regions of interest where there might be signal. The identification of such regions is responsibility of the algorithm creating the OpWaveform object. In the simplest approach, the whole readout window is stored in a single region of interest, meaning that we don't claim any of the channel signal to be definitely signal free. More generally, the first tick of the waveform is #0, and if the first region of interest starts after that tick, it implies that the region between tick #0 and the start of that first region lacks signal. Likewise, any samples in the end of the covered time window (defined above) which lack signal are indicated by the overall size of the content, while the last region of interest ends earlier.

Algorithms using the regions of interest can access the channel signal information either ignoring the regions of interest, and being potentially flooded by zeroes from the non-signal regions:

for (float ADCcount: opwf.Signal()) ...

or they can analyze region by region:

for (auto iROI = opwf.begin_range(); iROI != opwf.end_range(); ++iROI) {
  const datarange_t& ROI = *iROI;
  const int FirstTick = ROI.begin_index();
  const int EndTick = ROI.end_index();
  const float FirstADC = ROI[FirstTick]; // index access is by absolute tick number
  for (float ADC: ROI) // ... or you can just iterate through
  // ...
} // for

An alternative to the first form is:

for (float ADCcount: opwf.SignalROI()) ...

which does not create a temporary dense vector, as Signal() does instead.

Note that the indexed access is always by absolute tick number. More examples of the use of SignalROI() return value are documented in lar::sparse_vector.

Each channel is associated with a raw::OpDetWaveform object. These associations should be stored together with recob::OpWaveform by the producer in a art::Assns data product.

Creating recob::OpWaveform objects

LArSoft "protocol" prescribes:

• creation of an association of each recob::OpWaveform with the raw::OpDetWaveform it comes from; the association should be created by the same art module producing the recob::OpWaveform collection
• recob::OpWaveform time span should be the same as its raw::OpDetWaveform Please read the documentation of recob::OpWaveform constructors.

Definition at line 97 of file OpWaveform.h.

Member Typedef Documentation

typedef lar::sparse_vector<float> recob::OpWaveform::RegionsOfInterest_t

a region of interest is a pair (TDC offset, readings)

Definition at line 100 of file OpWaveform.h.

Constructor & Destructor Documentation

recob::OpWaveform::OpWaveform

(

)

Default constructor: a wire with no signal information.

Definition at line 17 of file OpWaveform.cxx.

    : fTimeStamp(0)
    , fChannel(raw::InvalidChannelID)
    , fSignalROI()
    {}

recob::OpWaveform::OpWaveform	(	raw::RDTimeStamp	time,
		raw::ChannelID_t	channel,
		RegionsOfInterest_t const &	sigROIlist
	)

Constructor: uses specified signal in regions of interest.

Parameters

time	time stamp of the signal
channel	the ID of the channel
sigROIlist	signal organized in regions of interest

Signal is copied into the recob::OpWaveform object, including the sparse region of interest structure within sigROIlist. If possible, use the other constructor that moves the data instead.

For more details, see the other constructor documentation.

Definition at line 24 of file OpWaveform.cxx.

    : fTimeStamp(time)
    , fChannel(channel)
    , fSignalROI(sigROIlist)
    {}

recob::OpWaveform::OpWaveform	(	raw::RDTimeStamp	time,
		raw::ChannelID_t	channel,
		RegionsOfInterest_t &&	sigROIlist
	)

Constructor: uses specified signal in regions of interest.

Parameters

time	time stamp of the signal
channel	the ID of the channel
sigROIlist	signal organized in regions of interest

The recob::OpWaveform object is constructed with the waveform information in sigROIlist and assigned the specified channel and view.

The signal is stored in a sparse vector, each entry corresponding to a tick in the calibrated waveform. The tick range of the sparse vector reflects the one in the wire, i.e. the first sample in sigROIlist becomes the sample #0 of the recob::OpWaveform waveform. The total length of the waveform (that is, its duration in ticks) is also learned from the (nominal) size of sigROIlist (see also lar::sparse_vector::resize()), which can and should extend beyond the last region of interest.

This constructor moves the signal information is moved sigROIlist, that becomes invalid. This also preserves the sparse region of interest structure within sigROIlist.

Definition at line 35 of file OpWaveform.cxx.

    : fTimeStamp(time)
    , fChannel(channel)
    , fSignalROI(std::move(sigROIlist))
    {}

Member Function Documentation

raw::ChannelID_t recob::OpWaveform::Channel ( ) const

inline

Returns the ID of the channel (or InvalidChannelID)

Definition at line 208 of file OpWaveform.h.

{ return fChannel;          }

std::size_t recob::OpWaveform::NSignal ( ) const

inline

Returns the number of time ticks, or samples, in the channel.

Definition at line 207 of file OpWaveform.h.

{ return fSignalROI.size(); }

bool recob::OpWaveform::operator< ( const OpWaveform &  than ) const

inline

Returns whether this channel ID is smaller than the other.

Definition at line 210 of file OpWaveform.h.

  { return Channel() < than.Channel(); }

std::vector< float > recob::OpWaveform::Signal

(

)

const

Return a zero-padded full length vector filled with RoI signal.

Definition at line 47 of file OpWaveform.cxx.

                                            {
    return { fSignalROI.begin(), fSignalROI.end() };
  } // OpWaveform::Signal()

const recob::OpWaveform::RegionsOfInterest_t & recob::OpWaveform::SignalROI ( ) const

inline

Returns the list of regions of interest.

Definition at line 206 of file OpWaveform.h.

{ return fSignalROI;        }

raw::RDTimeStamp recob::OpWaveform::TimeStamp ( ) const

inline

Returns the time stamp.

Definition at line 209 of file OpWaveform.h.

{ return fTimeStamp;          }

Member Data Documentation

raw::ChannelID_t recob::OpWaveform::fChannel

private

ID of the associated channel.

Definition at line 107 of file OpWaveform.h.

RegionsOfInterest_t recob::OpWaveform::fSignalROI

private

Signal on the channel as function of time tick.

Definition at line 108 of file OpWaveform.h.

raw::RDTimeStamp recob::OpWaveform::fTimeStamp

private

Time stamp.

Definition at line 106 of file OpWaveform.h.

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

• OpWaveform.h
• OpWaveform.cxx