Questions about the interpolation of laser point.

[cpkingw]

It seems that _scanTime is the timestamp of the previous laser frame, because the update of the _scanTime or _sweepStart in the reset() is behind the the interpolation of laser point via projectPointToStartOfSweep(). When doing interpolation of point in current laser frame, Shouldn't it be the timestamp of the current frame?

void BasicScanRegistration::interpolateIMUStateFor(const float &relTime, IMUState &outputState)
{
  double timeDiff = toSec(_scanTime - _imuHistory[_imuIdx].stamp) + relTime;
  while (_imuIdx < _imuHistory.size() - 1 && timeDiff > 0) {
    _imuIdx++;
    timeDiff = toSec(_scanTime - _imuHistory[_imuIdx].stamp) + relTime;
  }
  ...
}

void BasicScanRegistration::reset(const Time& scanTime)
{
  _scanTime = scanTime;

  // re-initialize IMU start index and state
  _imuIdx = 0;
  if (hasIMUData()) {
    interpolateIMUStateFor(0, _imuStart);
  }

  // clear internal cloud buffers at the beginning of a sweep
  if (true/*newSweep*/) {
    _sweepStart = scanTime;
    ...
  }
}

[arshhhly]

I think it is a mistake.

[gackes]

Have you solved the problem? I have the same doubt. @cpkingw

[cpkingw]

Have you solved the problem? I have the same doubt. @cpkingw

I think you can try to update the _scanTime in projectPointToStartOfSweep() firstly by adding scanTime as a new argument like processScanlines(scanTime, _laserCloudScans)