Active methods of early forest fire detection (original) (raw)
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Lidar Technique for Early Forest Fire Detection : Design and Development Aspects
AIP Conference Proceedings, 2008
Many countries suffer from forest fires every summer, a phenomenon which wreaks havoc on both local and global environment. As well, it causes enormous damage to public health especially for people living in surrounding areas. For fighting against forest fires, ocular surveillance, in spite of its wide use, is not efficient owing to the costly mobilization of a great number of forest agents and to the fact that most of forest regions are not accessible. Other passive techniques such as infrared camera remote sensing are neither efficient under unfavorable weather conditions. An efficient way to early detect forest fires even under worse environmental conditions and in inaccessible mountainous regions uses the backscattering Lidar technique. This consists of the emission of monowavelength laser pulses spanning azimuthally the entire region subject to surveillance and the detection of the backscattered signal. The detection parameter is the signal to noise ration SNR. In this contribution, we will deal with approach and design aspects inherent to the development task of such a Lidar.
Detection of small forest fires by lidar
Applied Physics B-lasers and Optics, 2002
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.
Application of lidar in ultraviolet, visible and infrared ranges for early forest fire detection
Applied Physics B: Lasers and Optics, 2003
The efficiency of directs lidar operating at 355, 532, 1064, and 1540 nm radiation wavelengths for early forest-fire detection was compared. For each wavelength the range for reliable smoke plume detection was estimated on the basis of computer simulation plume using a one-dimensional "top hat" gas dynamic model for the calculation of the backscattering and extinction coefficient profiles within the plume. The agreement between the predicted signal-to-noise ratio (SNR) and experimental results for 532 and 1064 nm wavelength radiation is good. The decrease of the signalto-noise ratio with distance is maximum for 355 nm and minimum for 1064 nm. At 1540 nm the decay of SNR with distance is slightly faster, but the SNR is higher than for other wavelengths, leading to the highest detection efficiency for the same energy of the probing laser pulse. For a burning rate of 2 kg/s and a laser beam divergence of 2.5 mr, the maximum distance for reliable detection varies between 6 and 12 km, depending on the wavelength.
Fire Surveillance and Evaluation by Means of Lidar Technique
Lidar (light detection and ranging) is an active remote detection technique that uses a pulsed laser beam to probe the atmosphere. When the laser radiation illuminates a target, such as a smoke plume originating from a forest fire, part of the incident radiation is backscattered, the intensity of this radiation is measured as a function of time by a suitable detector, and the resulting signal is analyzed by artificial intelligence methods. If the signature of a smoke plume is identified, an alarm is emitted. Precise position of the smoke plume is derived from the current azimuth/elevation angles of the laser beam (provided by the scanning system) and the distance to the target (calculated from the detection time).
Proceedings of SPIE, 2004
It has recently been shown that lidar (LIght Detection And Ranging) can effectively detect smoke plumes from small bonfires up to distances of 6.5 km, so that the technique can be used for wildfire surveillance. The aim of the present work is to describe a method for calculating the optimal location and minimum number of lidar stations required for the surveillance of a given forest area, taking the hilly terrain of Sintra-Cascais Nature Park (Portugal) as an example. The placement and horizontal scanning of the lidar sensors must be such that the laser beam passes over the ground, while keeping sufficiently low to enable early smoke plume detection, before the smoke is dispersed by the wind. Simultaneously, the laser beam should not hit the ground at distances shorter than the instrument range. To solve the problem, a terrain rendering was created and the best laser-beam zenith angle for each azimuth and the effective range covered by each lidar were calculated. The computations showed that 95.2% of the 146 km 2 of the Nature Park area can be covered by seven detectors with the laser beams scanning at a height of 50 m or less above ground.
Application of lidar at 1.54 um for forest fire detection
1999
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.
Feasibility of forest-fire smoke detection using lidar
International Journal of Wildland Fire, 2003
The feasibility and fundamentals of forest fire detection by smoke sensing with single-wavelength lidar are discussed with reference to results of 532-nm lidar measurements of smoke plumes from experimental forest fires in Portugal within the scope of the Gestosa 2001 project. The investigations included tracing smoke-plume evolution, estimating forest-fire alarm promptness, and smoke-plume location by azimuth rastering of the lidar optical axis. The possibility of locating a smoke plume whose source is out of line of sight and detection under extremely unfavourable visibility conditions was also demonstrated. The eye hazard problem is addressed and three possibilities of providing eye-safety conditions without loss of lidar sensitivity (namely, using a low energy-per-pulse and high repetition-rate laser, an expanded laser beam, or eye-safe radiation) are discussed.
XVII International Symposium on Gas Flow, Chemical Lasers, and High-Power Lasers, 2008
The possibility of early forest fire detection within a range up to ~2 km using a portable eye-safe 1540 nm lidar is demonstrated in this paper, both on experimental and theoretical ground. An estimation of the detection efficiency using a mathematical model based on the 3D system of Navier-Stokes equations describing the smoke plume evolution in the presence of wind, agrees reasonably well with experimental results. Calculations made using the model show that a detection range up to ~5.5 km can be achieved by accumulating lidar return signals.
Application of lidar at 1.54 μm for forest fire detection
Remote Sensing for Earth Science, Ocean, and Sea Ice Applications, 1999
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 m. 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 20cm diameter and an avalanche photodiode are used. Particle size distributions in the smoke from experiments in the literature are utilised 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.
A portable LIDAR system for the early detection: FfED system - a casestudy
2012
Forest fires can be the cause of serious environmental and economic damage. For this reason considerable effort has been devoted to forest protection and fire-fighting. Experimental and theoretical investigations have already shown that the LIDAR (Light Detection and Ranging) technique is a powerful tool to detect the tenuous smoke plumes produced by forest fires at an early stage In this paper the capability of a LIDAR system to detect a forest fire is explained and an upgrade of the LIDAR technique to reduce the number of false alarms is described. It is based on the comparison between the backscattered signal due to the orography, acquired in absence of any fire, and the signal obtained during surveying. The first experimental results, acquired by FfED (Forest fire Early Detection) system, will be shown. Forest fires can be the cause of serious environmental and economic damage. For this reason considerable effort has been devoted to forest protection and fire-fighting. Experimen...