PulsWave profile values are mod(256)

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Andres Kuusk

Feb 20, 2018, 3:49:41 AM2/20/18
to PulseWaves - no pulse left behind

Dear all,

We have ALS FWF data over a hemiboreal forest in LAS-1.4WDP and PulsWave formats.
If the profile values are less than 256 then the profiles in two formats coincide.
The large profile values are different, the PW values are mod(WDP, 256).

ALS is Riegel VQ-1560i, data were collected at flight height 350 m,
ground surface is about 30 m asl, stand height 30 m.

ALS data were provided in LAS-1.4 wdp and PulseWaves 0.3 r11 (150617) by rapidlasso formats.
Seven sample profiles I extracted working on a Linux PC, using LAStools  09-Feb-2018:
las2las -keep_gps_time t1 t2
las2txt -parse xyzirndecauptRGBwWV -o wdata.txt

PulseWaves from https://github.com/PulseWaves/PulseWaves version 0.3 rev 11
using in Wine:
pulse2pulse -keep_T T1 T2
pulse2pulse -i data.pls -o pdata.txt

Profile values in pdata.txt do not exceed 255.
In the attached plot is a sample waveform of 128 readings which had 4 discrete returns
at heights 48.85, 51.44, 57.27, and 59.45 m.
Differences of wdp and pw data are 0 and 256.
In other profiles I have differences 0, 256, 512, 768.

Is I doing something wrong or are the PW data erroneous?

Andres Kuusk
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