Performance and Progress Report - John Doe FIX: put in the authors ...

The collection of new sediment samples and SPI images in August 2006 (with grain size
analysis in 0.5 phi steps) roughly at the same time as a new multibeam survey will allow
for a better correlation between backscatter and grain size and also the determination of
to what extent grain size extracted from profile images is a reliable parameter. Sediment
analyses are underway. When these are complete, the ARA analyses will be done and the
results compared with the grain size analysis and SPI images. The ARA model will be
applied in the standard mode with a fixed number of pings over the entire swath of each
multibeam line and also in the supervised segmentation mode (described above), where
the mosaic is first segmented in classes and then the ARA model is applied for the each
segmented theme independently.
LIDAR Waveform Analysis: Finally, we continue our efforts to explore the potential of
LIDAR data as a means to characterize the shallow coastal seafloor. Shachack Peeri who
has recently been promoted to Research Scientist has led this effort which has included
the investigation of the use of special characteristics of the Raman waveform for the
robust identification of returns from very shallow waveforms. Peeri has noticed that in
very shallow water, the head and rise of the waveform shape are the same as the basic
Raman waveform, but along with a decrease in the digital number values of the tail and
the fall, the peak shifts toward the head of the waveform and decreases. In support of
this research as well is in support of the upcoming Shallow Survey 2008 Conference (see
below), we have, in collaboration with NOAA, the Army Corps of Engineers, and our
industrial partners LADS/TENIX, collected three new LIDAR datasets in the Portsmouth
Harbor region. These data sets include SHOALS 1000, SHOALS 3000 and LADS II
data and will play an important role in future study exploring the capabilities of LIDAR
as a hydrographic tool.
Also in support of this research, a LIDAR simulator project has been initiated. The
objective of this study is to simulate both a bathymetric LIDAR system and the realistic
environmental factors that might be present in various coastal areas. By conducting this
study in a laboratory environment, the relative importance of the various scattering
components on LIDAR waveforms can be investigated individually. It is important to
note that this study is focusing on both the elastic (Mie) and inelastic (Raman and
fluorescence) scattering regimes and the ability to leverage the excitation of the different
scattering phenomena. This research will provide the basis for using airborne LIDAR
systems to make quantitative measurements of a variety of environmental factors in the
coastal areas in addition to the bathymetry.
The first step of this study is configuring the LIDAR simulator. At the moment we are
using a surplus Copper Vapor Laser (511 nm) that that is similar to but is not precisely
the 532 nm Nd: YAG green laser used for bathymetric applications. To date, we have
conditioned the laser and conducted two feasibility tests. These tests aid us in
understanding what types of instrumentation are needed and the configurations needed
for each type of experiment. The preliminary results of the tests show that the spreading
of laser beam through the very clear water is linear and that the tank’s bottom scatters
light in a manner that upwelling was not noticed by the naked eye. When placing a mirror
on the tank’s bottom, the upwelling radiation was visible. The laser beam was captured
JHC Performance Report 42 30 January 2007