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New Hybrid Algorithms for Estimating Tree Stem Diameters at Breast Height Using a Two Dimensional Terrestrial Laser Scanner.

Kong J, Ding X, Liu J, Yan L, Wang J - Sensors (Basel) (2015)

Bottom Line: In this paper, a new algorithm to improve the accuracy of estimating diameter at breast height (DBH) for tree trunks in forest areas is proposed.Compared with previous works, this proposed method improves the accuracy of diameter estimation of trees significantly and effectively reduces the calculation time.Moreover, the experimental results indicate that this method is stable and suitable for the most challenging conditions, which has practical significance in improving the operating efficiency of forest harvester and reducing the risk of causing accidents.

View Article: PubMed Central - PubMed

Affiliation: School of Technology, Beijing Forestry University, Beijing 100083, China. kongjianlei_slgc@163.com.

ABSTRACT
In this paper, a new algorithm to improve the accuracy of estimating diameter at breast height (DBH) for tree trunks in forest areas is proposed. First, the information is collected by a two-dimensional terrestrial laser scanner (2DTLS), which emits laser pulses to generate a point cloud. After extraction and filtration, the laser point clusters of the trunks are obtained, which are optimized by an arithmetic means method. Then, an algebraic circle fitting algorithm in polar form is non-linearly optimized by the Levenberg-Marquardt method to form a new hybrid algorithm, which is used to acquire the diameters and positions of the trees. Compared with previous works, this proposed method improves the accuracy of diameter estimation of trees significantly and effectively reduces the calculation time. Moreover, the experimental results indicate that this method is stable and suitable for the most challenging conditions, which has practical significance in improving the operating efficiency of forest harvester and reducing the risk of causing accidents.

No MeSH data available.


The changes in the relationship between the distance and the estimation error.
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sensors-15-15661-f011: The changes in the relationship between the distance and the estimation error.

Mentions: However, the Figure 10 also revealed that the errors of diameter estimation were very different for different targets, which had diverse diameters and were located at different distances from the 2DTLS. Therefore, a further outdoor experiment was performed to reveal the influence of the distance on the average absolute error of diameter estimation. For each abovementioned birch, the 2DTLS was placed at a distance ranging from 2 m to 12.2 m to the tree in 0.6 m steps. Then the device scanned all eight targets 20 times to achieve the optimized laser data. In order to increase the quantity of targets, thirteen tree trunk sections with diameters in the range of 9–35 cm and lengths in the range of 40–49 cm were used for the indoor experiment as recorded in Table 1. Considering that the measured trees in outdoor experiment were all silver birches, the distinguishing species were placed in an indoor corridor, at distances varying between 2 m and 12.2 m every 0.6 m, with varying sides facing the laser scanner. Then the 2DTLS was set at the same height of 35 cm above the ground and all observations were scanned 20 times in various combinations. In total, 378 sets of laser data integrating the outside and indoor measurement experiments were scanned to calculate the diameter estimation errors for a better statistical determination. When analyzing the effects on one treatment combination (distance-error) in the proposed methods, the laser data at same distance (21 sets every distance) were applied to compute the fitting diameters in all the methods mentioned above. For each algorithm, the average of diameter estimation errors in one distance was performed to draw the distance-error curve as illustrated in Figure 11, where the x-axis represented the distance between the trees and the laser scanner, and the y-axis represented the average of estimated errors.


New Hybrid Algorithms for Estimating Tree Stem Diameters at Breast Height Using a Two Dimensional Terrestrial Laser Scanner.

Kong J, Ding X, Liu J, Yan L, Wang J - Sensors (Basel) (2015)

The changes in the relationship between the distance and the estimation error.
© Copyright Policy
Related In: Results  -  Collection

License
Show All Figures
getmorefigures.php?uid=PMC4541849&req=5

sensors-15-15661-f011: The changes in the relationship between the distance and the estimation error.
Mentions: However, the Figure 10 also revealed that the errors of diameter estimation were very different for different targets, which had diverse diameters and were located at different distances from the 2DTLS. Therefore, a further outdoor experiment was performed to reveal the influence of the distance on the average absolute error of diameter estimation. For each abovementioned birch, the 2DTLS was placed at a distance ranging from 2 m to 12.2 m to the tree in 0.6 m steps. Then the device scanned all eight targets 20 times to achieve the optimized laser data. In order to increase the quantity of targets, thirteen tree trunk sections with diameters in the range of 9–35 cm and lengths in the range of 40–49 cm were used for the indoor experiment as recorded in Table 1. Considering that the measured trees in outdoor experiment were all silver birches, the distinguishing species were placed in an indoor corridor, at distances varying between 2 m and 12.2 m every 0.6 m, with varying sides facing the laser scanner. Then the 2DTLS was set at the same height of 35 cm above the ground and all observations were scanned 20 times in various combinations. In total, 378 sets of laser data integrating the outside and indoor measurement experiments were scanned to calculate the diameter estimation errors for a better statistical determination. When analyzing the effects on one treatment combination (distance-error) in the proposed methods, the laser data at same distance (21 sets every distance) were applied to compute the fitting diameters in all the methods mentioned above. For each algorithm, the average of diameter estimation errors in one distance was performed to draw the distance-error curve as illustrated in Figure 11, where the x-axis represented the distance between the trees and the laser scanner, and the y-axis represented the average of estimated errors.

Bottom Line: In this paper, a new algorithm to improve the accuracy of estimating diameter at breast height (DBH) for tree trunks in forest areas is proposed.Compared with previous works, this proposed method improves the accuracy of diameter estimation of trees significantly and effectively reduces the calculation time.Moreover, the experimental results indicate that this method is stable and suitable for the most challenging conditions, which has practical significance in improving the operating efficiency of forest harvester and reducing the risk of causing accidents.

View Article: PubMed Central - PubMed

Affiliation: School of Technology, Beijing Forestry University, Beijing 100083, China. kongjianlei_slgc@163.com.

ABSTRACT
In this paper, a new algorithm to improve the accuracy of estimating diameter at breast height (DBH) for tree trunks in forest areas is proposed. First, the information is collected by a two-dimensional terrestrial laser scanner (2DTLS), which emits laser pulses to generate a point cloud. After extraction and filtration, the laser point clusters of the trunks are obtained, which are optimized by an arithmetic means method. Then, an algebraic circle fitting algorithm in polar form is non-linearly optimized by the Levenberg-Marquardt method to form a new hybrid algorithm, which is used to acquire the diameters and positions of the trees. Compared with previous works, this proposed method improves the accuracy of diameter estimation of trees significantly and effectively reduces the calculation time. Moreover, the experimental results indicate that this method is stable and suitable for the most challenging conditions, which has practical significance in improving the operating efficiency of forest harvester and reducing the risk of causing accidents.

No MeSH data available.