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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 schematic of the difference calculation for clustering the raw laser data.
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sensors-15-15661-f005: The schematic of the difference calculation for clustering the raw laser data.

Mentions: As the measurement data is processed in increasing order of the bearing angle from 40° to 140° with the chosen angular resolution, a vector Li = [Di, θi] in polar form is supposed to describe the single laser beam, where i is the sequence of laser beam distribution from 1 to 601, θi is the angular position and Di is the value of the horizontal distance between the laser reflecting point and the device. Before filtering, the raw laser data are passed through the clustering algorithm based on difference calculation to form a difference vector satisfying the following equation:(1)ΔD(i)=D(i+1)−D(i)where ∆D(i) is the new difference vector representing the range between two adjacent laser beams Li and Li+1. As shown in Figure 5, dramatic changes will occur in the value of the difference vector when the edges of objects are detected in the original laser data [37]. After calculation of the difference, the independent objects are separated from the background in the vector curve as follows.


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 schematic of the difference calculation for clustering the raw laser data.
© Copyright Policy
Related In: Results  -  Collection

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

sensors-15-15661-f005: The schematic of the difference calculation for clustering the raw laser data.
Mentions: As the measurement data is processed in increasing order of the bearing angle from 40° to 140° with the chosen angular resolution, a vector Li = [Di, θi] in polar form is supposed to describe the single laser beam, where i is the sequence of laser beam distribution from 1 to 601, θi is the angular position and Di is the value of the horizontal distance between the laser reflecting point and the device. Before filtering, the raw laser data are passed through the clustering algorithm based on difference calculation to form a difference vector satisfying the following equation:(1)ΔD(i)=D(i+1)−D(i)where ∆D(i) is the new difference vector representing the range between two adjacent laser beams Li and Li+1. As shown in Figure 5, dramatic changes will occur in the value of the difference vector when the edges of objects are detected in the original laser data [37]. After calculation of the difference, the independent objects are separated from the background in the vector curve as follows.

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.