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Applied hyperspectral LIDAR for monitoring fauna dispersal in aquatic environments

Rydhmer, Klas LU and Strand, Alfred (2016) PHYM01 20161
Combustion Physics
Department of Physics
Abstract
This thesis work has been focused on evaluation and further development of a hyperspectral LIDAR (Light Detection And Ranging) system made by Ljungholm et. al. [1] for monitoring of aquatic fauna, and in particular zooplankton. The project, which was a ”proof-of-concept”, showed the possibility to create a relatively compact and low-cost LIDAR with both spectral, temporal and range resolution. Experiments were developed with the help of the Department of Limnology, Lund University and performed with the LIDAR system. The dispersal rate of the zooplankton genus Daphnia in a water tank was measured, and was found to be largely dependent on background light and laser duty cycle of the LIDAR. The intrusive degree of the laser was determined to... (More)
This thesis work has been focused on evaluation and further development of a hyperspectral LIDAR (Light Detection And Ranging) system made by Ljungholm et. al. [1] for monitoring of aquatic fauna, and in particular zooplankton. The project, which was a ”proof-of-concept”, showed the possibility to create a relatively compact and low-cost LIDAR with both spectral, temporal and range resolution. Experiments were developed with the help of the Department of Limnology, Lund University and performed with the LIDAR system. The dispersal rate of the zooplankton genus Daphnia in a water tank was measured, and was found to be largely dependent on background light and laser duty cycle of the LIDAR. The intrusive degree of the laser was determined to be large, since the zooplankton genus Daphnia was attracted to the laser light source, but reduced by employing a low duty cycle. The laser intensity stabilisation was ensured by a ramp time before each duty cycle.
Range resolution measurements showed that the modelled resolution was not achieved, and this was determined to be due to defocusing and misalignment of the LIDAR system. The defocusing problem also lead to a weakening of the signal by approximately a factor 102, and artifacts were introduced on the detector.
Measurements on the interaction kinetics between the Daphnia and the midge larvae Chaoborus were performed, and species distinction was made by labelling the different species with different dyes and recording the wavelength spectrum. No interaction statistics could be deduced from the results, mainly due to the inactivity of Chaoborus. However, the dyeing of the aquatic fauna using marker pens were shown to be an easy way to label different species for spectral distinction.
Lastly, 3D-scanning of a terrestrial plant was performed, with the aid of a simple robot acting as a whiskbroom LIDAR. The results were promising and the chlorophyll was readily distinguished from the branch, although the range resolution and uneven movement of the robot resulted in a relatively low image resolution. (Less)
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author
Rydhmer, Klas LU and Strand, Alfred
supervisor
organization
course
PHYM01 20161
year
type
H2 - Master's Degree (Two Years)
subject
ISSN
1102-8718
language
English
id
8891971
date added to LUP
2016-09-19 11:23:18
date last changed
2016-11-15 13:29:57
@misc{8891971,
  abstract     = {This thesis work has been focused on evaluation and further development of a hyperspectral LIDAR (Light Detection And Ranging) system made by Ljungholm et. al. [1] for monitoring of aquatic fauna, and in particular zooplankton. The project, which was a ”proof-of-concept”, showed the possibility to create a relatively compact and low-cost LIDAR with both spectral, temporal and range resolution. Experiments were developed with the help of the Department of Limnology, Lund University and performed with the LIDAR system. The dispersal rate of the zooplankton genus Daphnia in a water tank was measured, and was found to be largely dependent on background light and laser duty cycle of the LIDAR. The intrusive degree of the laser was determined to be large, since the zooplankton genus Daphnia was attracted to the laser light source, but reduced by employing a low duty cycle. The laser intensity stabilisation was ensured by a ramp time before each duty cycle.
Range resolution measurements showed that the modelled resolution was not achieved, and this was determined to be due to defocusing and misalignment of the LIDAR system. The defocusing problem also lead to a weakening of the signal by approximately a factor 102, and artifacts were introduced on the detector.
Measurements on the interaction kinetics between the Daphnia and the midge larvae Chaoborus were performed, and species distinction was made by labelling the different species with different dyes and recording the wavelength spectrum. No interaction statistics could be deduced from the results, mainly due to the inactivity of Chaoborus. However, the dyeing of the aquatic fauna using marker pens were shown to be an easy way to label different species for spectral distinction.
Lastly, 3D-scanning of a terrestrial plant was performed, with the aid of a simple robot acting as a whiskbroom LIDAR. The results were promising and the chlorophyll was readily distinguished from the branch, although the range resolution and uneven movement of the robot resulted in a relatively low image resolution.},
  author       = {Rydhmer, Klas and Strand, Alfred},
  issn         = {1102-8718},
  language     = {eng},
  note         = {Student Paper},
  title        = {Applied hyperspectral LIDAR for monitoring fauna dispersal in aquatic environments},
  year         = {2016},
}