A specific threshold-based pixel clustering algorithm. More...

#include <PixelThresholdClusterizer.h>

Inheritance diagram for PixelThresholdClusterizer:

Public Member Functions
void	clusterizeDetUnit (const edm::DetSet< PixelDigi > &input, const PixelGeomDetUnit *pixDet, const std::vector< short > &badChannels, edmNew::DetSetVector< SiPixelCluster >::FastFiller &output)
	Cluster pixels. This method operates on a matrix of pixels and finds the largest contiguous cluster around each seed pixel. Input and output data stored in DetSet. More...

	PixelThresholdClusterizer (edm::ParameterSet const &conf)

	~PixelThresholdClusterizer ()

Public Member Functions inherited from PixelClusterizerBase
void	setSiPixelGainCalibrationService (SiPixelGainCalibrationServiceBase *in)

virtual	~PixelClusterizerBase ()

Private Member Functions
int	calibrate (int adc, int col, int row)

void	clear_buffer (DigiIterator begin, DigiIterator end)
	Clear the internal buffer array. More...

void	copy_to_buffer (DigiIterator begin, DigiIterator end)
	Copy adc counts from PixelDigis into the buffer, identify seeds. More...

SiPixelCluster	make_cluster (const SiPixelCluster::PixelPos &pix, edmNew::DetSetVector< SiPixelCluster >::FastFiller &output)
	The actual clustering algorithm: group the neighboring pixels around the seed. More...

bool	setup (const PixelGeomDetUnit *pixDet)
	Private helper methods: More...

Private Attributes
bool	bufferAlreadySet

edm::ParameterSet	conf_

bool	dead_flag

uint32_t	detid_

bool	doMissCalibrate

bool	doSplitClusters

SiPixelArrayBuffer	theBuffer
	Data storage. More...

std::vector< SiPixelCluster >	theClusters

float	theClusterThreshold

float	theClusterThresholdInNoiseUnits

int	theConversionFactor

int	theFirstStack_

int	theNumOfCols

int	theNumOfRows
	Geometry-related information. More...

int	theOffset

int	thePixelThreshold

float	thePixelThresholdInNoiseUnits
	Clustering-related quantities: More...

std::vector < SiPixelCluster::PixelPos >	theSeeds

int	theSeedThreshold

float	theSeedThresholdInNoiseUnits

int	theStackADC_

Additional Inherited Members
Public Types inherited from PixelClusterizerBase
typedef edm::DetSet< PixelDigi > ::const_iterator	DigiIterator

Protected Attributes inherited from PixelClusterizerBase
SiPixelGainCalibrationServiceBase *	theSiPixelGainCalibrationService_

Detailed Description

A specific threshold-based pixel clustering algorithm.

An explicit threshold-based clustering algorithm.

General logic of PixelThresholdClusterizer:

The clusterization is performed on a matrix with size equal to the size of the pixel detector, each cell containing the ADC count of the corresponding pixel. The matrix is reset after each clusterization.

The search starts from seed pixels, i.e. pixels with sufficiently large amplitudes, found at the time of filling of the matrix and stored in a SiPixelArrayBuffer.

Translate the pixel charge to electrons, we are suppose to do the calibrations ADC->electrons here. Modify the thresholds to be in electrons, convert adc to electrons. d.k. 20/3/06 Get rid of the noiseVector. d.k. 28/3/06

A threshold-based clustering algorithm which clusters SiPixelDigis into SiPixelClusters for each DetUnit. The algorithm is straightforward and purely topological: the clustering process starts with seed pixels and continues by adding adjacent pixels above the pixel threshold. Once the cluster is made, it has to be above the cluster threshold as well.

The clusterization is performed on a matrix with size equal to the size of the pixel detector, each cell containing the ADC count of the corresponding pixel. The matrix is reset after each clusterization.

The search starts from seed pixels, i.e. pixels with sufficiently large amplitudes, found at the time of filling of the matrix and stored in a

At this point the noise and dead channels are ignored, but soon they won't be.

SiPixelCluster contains a barrycenter, but it should be noted that that information is largely useless. One must use a PositionEstimator class to compute the RecHit position and its error for every given cluster.

Author: Largely copied from NewPixelClusterizer in ORCA written by Danek Kotlinski (PSI). Ported to CMSSW by Petar Maksimovic (JHU). DetSetVector data container implemented by V.Chiochia (Uni Zurich)

Sets the PixelArrayBuffer dimensions and pixel thresholds. Makes clusters and stores them in theCache if the option useCache has been set.

Definition at line 56 of file PixelThresholdClusterizer.h.

Constructor & Destructor Documentation

PixelThresholdClusterizer::PixelThresholdClusterizer ( edm::ParameterSet const & conf )

Constructor: Initilize the buffer to hold pixels from a detector module. This is a vector of 44k ints, stays valid all the time.

Definition at line 45 of file PixelThresholdClusterizer.cc.

PixelThresholdClusterizer::~PixelThresholdClusterizer ( )

Definition at line 72 of file PixelThresholdClusterizer.cc.

Member Function Documentation

int PixelThresholdClusterizer::calibrate	(	int	adc,
		int	col,
		int	row
	)

private

Definition at line 242 of file PixelThresholdClusterizer.cc.

void PixelThresholdClusterizer::clear_buffer	(	DigiIterator	begin,
		DigiIterator	end
	)

private

Clear the internal buffer array.

Pixels which are not part of recognized clusters are NOT ERASED during the cluster finding. Erase them now.

TO DO: ask Danek... wouldn't it be faster to simply memcopy() zeros into the whole buffer array?

Definition at line 172 of file PixelThresholdClusterizer.cc.

void PixelThresholdClusterizer::clusterizeDetUnit	(	const edm::DetSet< PixelDigi > &	input,
		const PixelGeomDetUnit *	pixDet,
		const std::vector< short > &	badChannels,
		edmNew::DetSetVector< SiPixelCluster >::FastFiller &	output
	)

virtual

Cluster pixels. This method operates on a matrix of pixels and finds the largest contiguous cluster around each seed pixel. Input and output data stored in DetSet.

Implements PixelClusterizerBase.

Definition at line 112 of file PixelThresholdClusterizer.cc.

void PixelThresholdClusterizer::copy_to_buffer	(	DigiIterator	begin,
		DigiIterator	end
	)

private

Copy adc counts from PixelDigis into the buffer, identify seeds.

Definition at line 183 of file PixelThresholdClusterizer.cc.

SiPixelCluster PixelThresholdClusterizer::make_cluster	(	const SiPixelCluster::PixelPos &	pix,
		edmNew::DetSetVector< SiPixelCluster >::FastFiller &	output
	)