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Vehicle based laser range finding in crops.

Ehlert D, Adamek R, Horn HJ - Sensors (Basel) (2009)

Bottom Line: In scientific papers the measurement of these parameters by low cost laser rangefinders with one echo has been presented for short ranges.Lab tests under defined conditions and a real field test were performed to assess the measuring properties under such difficult conditions of a chosen low cost sensor.Based on lab tests it was shown that the accuracy was reduced, but the successful use of the sensor under field conditions demonstrated the potential to meet the demands for agricultural applications, Insights resulting from investigations made in the paper contribute to facilitating the choice or the development of laser rangefinder sensors for vehicle based measurement of crop parameters for optimisation of production processes.

View Article: PubMed Central - PubMed

Affiliation: Leibniz-Institute for Agricultural Engineering Potsdam-Bornim, Max-Eyth-Allee 100, 14469 Potsdam, Germany; E-Mails: radamek@atb-potsdam.de ; jhorn@atb-potsdam.de.

ABSTRACT
Laser rangefinders and laser scanners are widely used for industrial purposes and for remote sensing. In agriculture information about crop parameters like volume, height, and density can support the optimisation of production processes. In scientific papers the measurement of these parameters by low cost laser rangefinders with one echo has been presented for short ranges. Because the cross section area of the beam increases with the measuring range, it can be expected that laser rangefinders will have a reduced measuring accuracy in small sized crops and when measuring far distances. These problems are caused by target areas smaller than the beam and by the beam striking the edges of crop objects. Lab tests under defined conditions and a real field test were performed to assess the measuring properties under such difficult conditions of a chosen low cost sensor. Based on lab tests it was shown that the accuracy was reduced, but the successful use of the sensor under field conditions demonstrated the potential to meet the demands for agricultural applications, Insights resulting from investigations made in the paper contribute to facilitating the choice or the development of laser rangefinder sensors for vehicle based measurement of crop parameters for optimisation of production processes.

No MeSH data available.


Distribution of light intensity inside the laser beam for three measuring distances.
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f5-sensors-09-03679: Distribution of light intensity inside the laser beam for three measuring distances.

Mentions: According to the manufacturers' information the diameter of the laser spot (Dspot) can be calculated approximately: Dspot ≈ 2.5 mm + 0.0005×(measuring range in mm). That means e.g. the spot has a theoretical diameter of about 7.5 mm in the range of 10.00 m. The measurements (Figure 5) confirmed the magnitude of beam cross section given by the manufacturer. Figure 5 demonstrates however that the distribution of light intensity differs from the concentric shape and therefore from the ideal Gauss beam cross section distribution. From this irregular distribution it results that the laser rangefinder has specific beam parameters and therefore specific measuring features. As a consequence of this the theoretical considerations on measuring properties will suffer.


Vehicle based laser range finding in crops.

Ehlert D, Adamek R, Horn HJ - Sensors (Basel) (2009)

Distribution of light intensity inside the laser beam for three measuring distances.
© Copyright Policy
Related In: Results  -  Collection

License
Show All Figures
getmorefigures.php?uid=PMC3297142&req=5

f5-sensors-09-03679: Distribution of light intensity inside the laser beam for three measuring distances.
Mentions: According to the manufacturers' information the diameter of the laser spot (Dspot) can be calculated approximately: Dspot ≈ 2.5 mm + 0.0005×(measuring range in mm). That means e.g. the spot has a theoretical diameter of about 7.5 mm in the range of 10.00 m. The measurements (Figure 5) confirmed the magnitude of beam cross section given by the manufacturer. Figure 5 demonstrates however that the distribution of light intensity differs from the concentric shape and therefore from the ideal Gauss beam cross section distribution. From this irregular distribution it results that the laser rangefinder has specific beam parameters and therefore specific measuring features. As a consequence of this the theoretical considerations on measuring properties will suffer.

Bottom Line: In scientific papers the measurement of these parameters by low cost laser rangefinders with one echo has been presented for short ranges.Lab tests under defined conditions and a real field test were performed to assess the measuring properties under such difficult conditions of a chosen low cost sensor.Based on lab tests it was shown that the accuracy was reduced, but the successful use of the sensor under field conditions demonstrated the potential to meet the demands for agricultural applications, Insights resulting from investigations made in the paper contribute to facilitating the choice or the development of laser rangefinder sensors for vehicle based measurement of crop parameters for optimisation of production processes.

View Article: PubMed Central - PubMed

Affiliation: Leibniz-Institute for Agricultural Engineering Potsdam-Bornim, Max-Eyth-Allee 100, 14469 Potsdam, Germany; E-Mails: radamek@atb-potsdam.de ; jhorn@atb-potsdam.de.

ABSTRACT
Laser rangefinders and laser scanners are widely used for industrial purposes and for remote sensing. In agriculture information about crop parameters like volume, height, and density can support the optimisation of production processes. In scientific papers the measurement of these parameters by low cost laser rangefinders with one echo has been presented for short ranges. Because the cross section area of the beam increases with the measuring range, it can be expected that laser rangefinders will have a reduced measuring accuracy in small sized crops and when measuring far distances. These problems are caused by target areas smaller than the beam and by the beam striking the edges of crop objects. Lab tests under defined conditions and a real field test were performed to assess the measuring properties under such difficult conditions of a chosen low cost sensor. Based on lab tests it was shown that the accuracy was reduced, but the successful use of the sensor under field conditions demonstrated the potential to meet the demands for agricultural applications, Insights resulting from investigations made in the paper contribute to facilitating the choice or the development of laser rangefinder sensors for vehicle based measurement of crop parameters for optimisation of production processes.

No MeSH data available.