Hello,
first let me post a challenge:
Who is able to use either C or C++ and the latest PulseWaves DLL to
convert the provided NEON sample from the set of ENVI-style BIL + HDR
into proper PulseWaves files? The geolocation is already provided. Can
you correctly handle all time and range offsets to get to the first
sample of each segment, reverse compute the optical origin as the
anchor point, and getting the pulse directions right? If you like IDL
better you can also the IDL PulseWaves API that was developed by
Carbomap Ltd as part of their technology partnership with us here at
rapidlasso. Fame and glory awaits ... (-;
now on to the great news:
Keith Krause who is the algorithm scientist for the airborne efforts
of NEON has put together the first sample release of full waveform
LiDAR. Get the data here by clicking on the "Sample AOP Data" link (~
230 MB):
http://neoninc.org/data-resources/get-data/airborne-data
Below a short summary of Keith's document provided part of the release
in which he describes the full waveform part in details. His document
also serves as a great reference on how to interpret time stamps,
ranges, and - ultimately - extract also discrete LiDAR returns from
the provided format:
The format is a series of flat binary files for reading into IDL or Matlab.
Optech Gemini collected data at nominal range of 1000 m (the aircraft
flew at 1000 m AGL), wide divergence (0.8 mrad), 100 kHz PRF, and a
mirror scan frequency of 50 Hz and full scan angle of 37 degrees.
Pulse density of 3.82 pulse per meter squared at Nadir with a 0.8 m
diameter spot and a spot spacing of about 0.524 m in the across-track
direction and 0.5 m in the along-track direction.
Outgoing pulse width is around 15 nsec and the waveform is digitized
with 1 nsec bins and a 12 bit A/D.
Two flight lines of data are provided and each waveform sample is a
cropped area of 250 m x 250 m centered around NEON distributed plot
AOP116. Area is open woodland dominated by blue oak, interior live
oak, and gray pine with scattered shrubs and a nearly continuous cover
of herbaceous plants.
Here a look at the contents:
>> dir NEON_AOP_sample_data_v2\LiDAR\Waveform_LiDAR\FL03\
9,353,064 2013_SJER_AOP_FL03_waveform_ephemeris_array_img
431 2013_SJER_AOP_FL03_waveform_ephemeris_array_img.hdr
4,676,862 2013_SJER_AOP_FL03_waveform_first_return.las
21,378,432 2013_SJER_AOP_FL03_waveform_geolocation_array_img
712 2013_SJER_AOP_FL03_waveform_geolocation_array_img.hdr
16,033,824 2013_SJER_AOP_FL03_waveform_observation_array_img
690 2013_SJER_AOP_FL03_waveform_observation_array_img.hdr
33,403,800 2013_SJER_AOP_FL03_waveform_outgoing_pulse_array_img
303 2013_SJER_AOP_FL03_waveform_outgoing_pulse_array_img.hdr
83,509,500 2013_SJER_AOP_FL03_waveform_return_pulse_array_img
299 2013_SJER_AOP_FL03_waveform_return_pulse_array_img.hdr
200 2013_SJER_AOP_waveform_impulse_response_img
488 2013_SJER_AOP_waveform_impulse_response_img.hdr
200 2013_SJER_AOP_waveform_impulse_response_T0_img
519 2013_SJER_AOP_waveform_impulse_response_T0_img.hdr
15 File(s) 168,359,324 bytes