"number of segments" and "number of samples" are zero

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Ahmad Hojjati

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Aug 19, 2020, 8:08:04 PM8/19/20
to PulseWaves - no pulse left behind
Hi Martin,

I'm trying to extract the waveforms from a pulse-wave data (.pls/.wvs) and I see both "number of segments" and "number of samples" are zero for the "descriptor index" 13.
As I read from https://github.com/PulseWaves/Specification/blob/master/specification.rst this means that segmenting and sampling are variable. The question is how I can access individual waveforms without knowing the number of segments and/or samples?

I attached the pulse info results here.

Thanks,
Ahmad 
lidar.txt

Martin Isenburg

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Sep 9, 2020, 1:46:22 PM9/9/20
to PulseWaves - no pulse left behind
Hello,

this is an odd looking PulseWaves file. It seems to contain ***ONLY*** outgoing waveforms but no returning waveforms. Furthermore these outgoing waveforms (those that leave the rotating polygon mirror) use a descriptors that specifies they are sampled with a varying number of segments (which makes ZERO sense) and a varying number of samples per segment (which makes also little sense). The outgoing waveforms are very uniform and are usually sampled with one short segment with a fixed number of samples (such as 20 or 32).

Regards,

Martin

============

variable length header record 19 of 20:
  reserved             0
  user ID              'PulseWaves_Spec'
  record ID            200013
  length after header  196
  description          'PulseWaves 0.3 r11 (150617) by rapidlasso'
    PULSEdescriptor 13
      optical_center_to_anchor_point:  0x0 ('coincide')
      number_of_extra_waves_bytes:     0
      number_of_samplings:             1
      sample_units:                    1.00503 [nanoseconds]
      scanner_index:                   1
      compression:                     0
      description:                     'returns(s), vary'
        sampling[0]
          type:        1 ('outgoing')
          channel:     3
          bits_for_duration_from_anchor:            32
          scale_for_duration_from_anchor:            0.00165993
          offset_for_duration_from_anchor:           0
          bits_for_number_of_segments:               8
          bits_for_number_of_samples:               16

          number_of_segments:   0
          number_of_samples:    0
          bits_per_sample:      8
          lookup_table_index:   1
          sample_units:       1.0 [nanoseconds]
          compression:          0
          description:        'outgoing, reference, vary'

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