A simple and robust eye-safe lidar was developed on the basis of a rangefinder optical scheme com... more A simple and robust eye-safe lidar was developed on the basis of a rangefinder optical scheme comprising an Er:glass laser which generates 8 mJ pulses of 1540-nm radiation with the pulse repetition rate of 0.17 Hz and a 38-mm-diameter telescope. Reliable measurements of the cloud height up to 3700 m and early forest-fire detection with a range of 3000 m were experimentally demonstrated. Theoretical estimations indicate that using an optical scheme built around a 10 Hz Er:glass lasers and 150 mm light gathering optics early forest fire detection in a range up to 6500 m can be achieved.
The possibility of detecting small forest fires with the help of a simple and cheap lidar operati... more The possibility of detecting small forest fires with the help of a simple and cheap lidar operating at 0.532-μm wavelength up to distances of about 6.5 km is demonstrated. The values of the signal-to-noise ratio (SNR) achieved in the experiments are consistent with theoretical estimations obtained by computational modeling of the lidar detection process, including simulation of the smoke-plume shape and of the laser beam-plume interaction. This model was used to assess the potential of the lidar technique for fire surveillance in large forest areas. In particular, the upper limiting range for effective detection (SNR>5) of small localized fires in dry- and clear-weather conditions is estimated at 7-15 km depending on operation mode, burning rate, and observation geometry.
A mathematical model for computation of parameters of eyesafe lidar for detection of forest fire ... more A mathematical model for computation of parameters of eyesafe lidar for detection of forest fire smoke has been developed. It is assumed that the lidar uses a wavelength of 1.54 micrometer. This wavelength can be obtained from Er:glass lasers, from Nd:YAG lasers with an optical parametric oscillator, or from Nd:YAG lasers with a Raman cell. It is assumed that receiver optics of 20 cm diameter and an avalanche photodiode are used. Particle size distributions in the smoke from experiments in the literature are utilized for calculation of backscattering efficiency. The backscattering cross section is calculated on the basis of Mie formulae. Diffusion of the smoke plume is estimated on the basis of an analytical solution of the relevant hydrodynamics equations. Results of the calculations show that for detection of forest fires with fuel mass burned in unit time 2 kg/s at a distance of 10 km it is necessary to have a laser pulse energy of 120 mJ.
The problem of eye safety in lidar-assisted wildland fire detection and investigation is consider... more The problem of eye safety in lidar-assisted wildland fire detection and investigation is considered as a problem of reduction of the hazard range within which the laser beam is dangerous for direct eye exposure. The dependence of this hazard range on the lidar characteristics is ...
Proceedings of SPIE - The International Society for Optical Engineering, 2006
Detection of fire smoke plume with a compact cheap rangefinder based on 905 nm laser diode (2 μJ ... more Detection of fire smoke plume with a compact cheap rangefinder based on 905 nm laser diode (2 μJ pulse energy, slashed oh 2 cm telescope and 720 m solid-target range) is demonstrated. Reliable detection of small experimental fires (20×25 m 2 fire plot, burning ...
A simple and robust eye-safe lidar was developed on the basis of a rangefinder optical scheme com... more A simple and robust eye-safe lidar was developed on the basis of a rangefinder optical scheme comprising an Er:glass laser which generates 8 mJ pulses of 1540-nm radiation with the pulse repetition rate of 0.17 Hz and a 38-mm-diameter telescope. Reliable measurements of the cloud height up to 3700 m and early forest-fire detection with a range of 3000 m were experimentally demonstrated. Theoretical estimations indicate that using an optical scheme built around a 10 Hz Er:glass lasers and 150 mm light gathering optics early forest fire detection in a range up to 6500 m can be achieved.
The possibility of detecting small forest fires with the help of a simple and cheap lidar operati... more The possibility of detecting small forest fires with the help of a simple and cheap lidar operating at 0.532-μm wavelength up to distances of about 6.5 km is demonstrated. The values of the signal-to-noise ratio (SNR) achieved in the experiments are consistent with theoretical estimations obtained by computational modeling of the lidar detection process, including simulation of the smoke-plume shape and of the laser beam-plume interaction. This model was used to assess the potential of the lidar technique for fire surveillance in large forest areas. In particular, the upper limiting range for effective detection (SNR>5) of small localized fires in dry- and clear-weather conditions is estimated at 7-15 km depending on operation mode, burning rate, and observation geometry.
A mathematical model for computation of parameters of eyesafe lidar for detection of forest fire ... more A mathematical model for computation of parameters of eyesafe lidar for detection of forest fire smoke has been developed. It is assumed that the lidar uses a wavelength of 1.54 micrometer. This wavelength can be obtained from Er:glass lasers, from Nd:YAG lasers with an optical parametric oscillator, or from Nd:YAG lasers with a Raman cell. It is assumed that receiver optics of 20 cm diameter and an avalanche photodiode are used. Particle size distributions in the smoke from experiments in the literature are utilized for calculation of backscattering efficiency. The backscattering cross section is calculated on the basis of Mie formulae. Diffusion of the smoke plume is estimated on the basis of an analytical solution of the relevant hydrodynamics equations. Results of the calculations show that for detection of forest fires with fuel mass burned in unit time 2 kg/s at a distance of 10 km it is necessary to have a laser pulse energy of 120 mJ.
The problem of eye safety in lidar-assisted wildland fire detection and investigation is consider... more The problem of eye safety in lidar-assisted wildland fire detection and investigation is considered as a problem of reduction of the hazard range within which the laser beam is dangerous for direct eye exposure. The dependence of this hazard range on the lidar characteristics is ...
Proceedings of SPIE - The International Society for Optical Engineering, 2006
Detection of fire smoke plume with a compact cheap rangefinder based on 905 nm laser diode (2 μJ ... more Detection of fire smoke plume with a compact cheap rangefinder based on 905 nm laser diode (2 μJ pulse energy, slashed oh 2 cm telescope and 720 m solid-target range) is demonstrated. Reliable detection of small experimental fires (20×25 m 2 fire plot, burning ...
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Papers by Alexander Lavrov