CandHitStandard_tool.cc

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////////////////////////////////////////////////////////////////////////
/// \file   CandHitStandard.cc
/// \author T. Usher
////////////////////////////////////////////////////////////////////////

#include "larreco/HitFinder/HitFinderTools/ICandidateHitFinder.h"

#include "art/Utilities/ToolMacros.h"
#include "larcore/CoreUtils/ServiceUtil.h"
#include "larcore/Geometry/Geometry.h"

#include <algorithm>

namespace reco_tool {

  class CandHitStandard : ICandidateHitFinder {
  public:
    explicit CandHitStandard(const fhicl::ParameterSet& pset);

    void findHitCandidates(const recob::Wire::RegionsOfInterest_t::datarange_t&,
                           const size_t,
                           const size_t,
                           const size_t,
                           HitCandidateVec&) const override;

    void MergeHitCandidates(const recob::Wire::RegionsOfInterest_t::datarange_t&,
                            const HitCandidateVec&,
                            MergeHitCandidateVec&) const override;

  private:
    void findHitCandidates(std::vector<float>::const_iterator,
                           std::vector<float>::const_iterator,
                           const size_t,
                           const size_t,
                           HitCandidateVec&) const;

    // Member variables from the fhicl file
    const float fRoiThreshold; ///< minimum maximum to minimum peak distance

    const geo::GeometryCore* fGeometry = lar::providerFrom<geo::Geometry>();
  };

  //----------------------------------------------------------------------
  // Constructor.
  CandHitStandard::CandHitStandard(const fhicl::ParameterSet& pset)
    : fRoiThreshold(pset.get<float>("RoiThreshold", 5.))
  {}

  void
  CandHitStandard::findHitCandidates(const recob::Wire::RegionsOfInterest_t::datarange_t& dataRange,
                                     const size_t roiStartTick,
                                     const size_t channel,
                                     const size_t eventCount,
                                     HitCandidateVec& hitCandidateVec) const
  {
    // Recover the actual waveform
    const Waveform& waveform = dataRange.data();

    // Recover the plane index for this method
    std::vector<geo::WireID> wids = fGeometry->ChannelToWire(channel);
    const size_t plane = wids[0].Plane;

    // Use the recursive version to find the candidate hits
    findHitCandidates(waveform.begin(), waveform.end(), roiStartTick, plane, hitCandidateVec);

    return;
  }

  void
  CandHitStandard::findHitCandidates(std::vector<float>::const_iterator startItr,
                                     std::vector<float>::const_iterator stopItr,
                                     const size_t roiStartTick,
                                     const size_t planeIdx,
                                     HitCandidateVec& hitCandidateVec) const
  {
    // Need a minimum number of ticks to do any work here
    if (std::distance(startItr, stopItr) > 4) {
      // Find the highest peak in the range given
      auto maxItr = std::max_element(startItr, stopItr);

      float maxValue = *maxItr;
      int maxTime = std::distance(startItr, maxItr);

      if (maxValue > fRoiThreshold) {
        // backwards to find first bin for this candidate hit
        auto firstItr = std::distance(startItr, maxItr) > 2 ? maxItr - 1 : startItr;

        while (firstItr != startItr) {
          // Check for pathology where waveform goes too negative
          if (*firstItr < -fRoiThreshold) break;

          // Check both sides of firstItr and look for min/inflection point
          if (*firstItr < *(firstItr + 1) && *firstItr <= *(firstItr - 1)) break;

          firstItr--;
        }

        int firstTime = std::distance(startItr, firstItr);

        // Recursive call to find all candidate hits earlier than this peak
        findHitCandidates(startItr, firstItr + 1, roiStartTick, planeIdx, hitCandidateVec);

        // forwards to find last bin for this candidate hit
        auto lastItr = std::distance(maxItr, stopItr) > 2 ? maxItr + 1 : stopItr - 1;

        while (lastItr != stopItr - 1) {
          // Check for pathology where waveform goes too negative
          if (*lastItr < -fRoiThreshold) break;

          // Check both sides of firstItr and look for min/inflection point
          if (*lastItr <= *(lastItr + 1) && *lastItr < *(lastItr - 1)) break;

          lastItr++;
        }

        int lastTime = std::distance(startItr, lastItr);

        // Now save this candidate's start and max time info
        HitCandidate hitCandidate;
        hitCandidate.startTick = roiStartTick + firstTime;
        hitCandidate.stopTick = roiStartTick + lastTime;
        hitCandidate.maxTick = roiStartTick + firstTime;
        hitCandidate.minTick = roiStartTick + lastTime;
        hitCandidate.maxDerivative = *(startItr + firstTime);
        hitCandidate.minDerivative = *(startItr + lastTime);
        hitCandidate.hitCenter = roiStartTick + maxTime;
        hitCandidate.hitSigma = std::max(2., float(lastTime - firstTime) / 6.);
        hitCandidate.hitHeight = maxValue;

        hitCandidateVec.push_back(hitCandidate);

        // Recursive call to find all candidate hits later than this peak
        findHitCandidates(lastItr + 1,
                          stopItr,
                          roiStartTick + std::distance(startItr, lastItr + 1),
                          planeIdx,
                          hitCandidateVec);
      }
    }

    return;
  }

  void
  CandHitStandard::MergeHitCandidates(
    const recob::Wire::RegionsOfInterest_t::datarange_t& rangeData,
    const HitCandidateVec& hitCandidateVec,
    MergeHitCandidateVec& mergedHitsVec) const
  {
    // If no hits then nothing to do here
    if (hitCandidateVec.empty()) return;

    // The idea is to group hits that "touch" so they can be part of common fit, those that
    // don't "touch" are fit independently. So here we build the output vector to achieve that
    HitCandidateVec groupedHitVec;
    int lastTick = hitCandidateVec.front().stopTick;

    // Step through the input hit candidates and group them by proximity
    for (const auto& hitCandidate : hitCandidateVec) {
      // Check condition that we have a new grouping
      if (int(hitCandidate.startTick) - lastTick > 1) {
        mergedHitsVec.emplace_back(groupedHitVec);

        groupedHitVec.clear();
      }

      // Add the current hit to the current group
      groupedHitVec.emplace_back(hitCandidate);

      lastTick = hitCandidate.stopTick;
    }

    // Check end condition
    if (!groupedHitVec.empty()) mergedHitsVec.emplace_back(groupedHitVec);

    return;
  }

  DEFINE_ART_CLASS_TOOL(CandHitStandard)
}