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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.


Related in: MedlinePlus

The measurement equipment includes sensor equipment fixed on the tripod platform as well as the data acquisition PC and lithium batteries providing 24 V for the system. The experiment is used in a birch forest.
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sensors-15-15661-f001: The measurement equipment includes sensor equipment fixed on the tripod platform as well as the data acquisition PC and lithium batteries providing 24 V for the system. The experiment is used in a birch forest.

Mentions: To acquire abundant tree features with adequate resolution from the laser cloud measurements taken in the forest, the scanning angular resolution of the LMS511-pro is set to its minimum value 0.1667°. Then the maximum scanning angle is set to 100° and maximum scanning distance is 32 m. Therefore, the measurement result of LMS511-pro laser scanner is a right ahead semicircle in the front of the device, while its centre is the scanner’s location, the radius is 32 m and the scanning degree is 100° in a range from 40° to 140°. The electronics of the LMS511-pro are directly powered by a 24 V lithium battery. In order to recording the corresponding visual information, a Fluke TI55 type infrared thermal camera with images of 640 × 480 pixels resolution is mounted on the side of the laser scanner. This device can obtain both RGB visible and infrared thermal images simultaneously and regularly. Visible images reflect the visual reality and infrared thermal images record the temperature of the environment. Because of the complicated surroundings in a forest, it is difficult to detect targets guided by any single information source. When it is dark or misty in the forest, it becomes difficult to distinguish the objects in the RGB images without information about temperature, whereas after a period of extensive cooling (e.g., after a long period of rain or early in the morning), the infrared images are less detailed in representing the background due to the low thermal levels compared with visible images. In this situation, the fusion of the visible and thermal image on a single display could enhance the fused images’ clarity and capture more abundant information about the reality. Therefore, an algorithm based on a Contourlet transform and a pulse coupled neural network (PCNN) is used to generate the mutual complementary blending images (the detail description can be found in [36]). Considering that the outdoor experiments are carried out in different places, this paper will apply those fused images to track both the pose of the laser scanner and the measured trees, which will establish a corresponding relationship between the fitted diameter data and the corresponding observed diameter for further accurate data processing. The complete measurement equipment setup is shown in Figure 1.


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 measurement equipment includes sensor equipment fixed on the tripod platform as well as the data acquisition PC and lithium batteries providing 24 V for the system. The experiment is used in a birch forest.
© Copyright Policy
Related In: Results  -  Collection

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

sensors-15-15661-f001: The measurement equipment includes sensor equipment fixed on the tripod platform as well as the data acquisition PC and lithium batteries providing 24 V for the system. The experiment is used in a birch forest.
Mentions: To acquire abundant tree features with adequate resolution from the laser cloud measurements taken in the forest, the scanning angular resolution of the LMS511-pro is set to its minimum value 0.1667°. Then the maximum scanning angle is set to 100° and maximum scanning distance is 32 m. Therefore, the measurement result of LMS511-pro laser scanner is a right ahead semicircle in the front of the device, while its centre is the scanner’s location, the radius is 32 m and the scanning degree is 100° in a range from 40° to 140°. The electronics of the LMS511-pro are directly powered by a 24 V lithium battery. In order to recording the corresponding visual information, a Fluke TI55 type infrared thermal camera with images of 640 × 480 pixels resolution is mounted on the side of the laser scanner. This device can obtain both RGB visible and infrared thermal images simultaneously and regularly. Visible images reflect the visual reality and infrared thermal images record the temperature of the environment. Because of the complicated surroundings in a forest, it is difficult to detect targets guided by any single information source. When it is dark or misty in the forest, it becomes difficult to distinguish the objects in the RGB images without information about temperature, whereas after a period of extensive cooling (e.g., after a long period of rain or early in the morning), the infrared images are less detailed in representing the background due to the low thermal levels compared with visible images. In this situation, the fusion of the visible and thermal image on a single display could enhance the fused images’ clarity and capture more abundant information about the reality. Therefore, an algorithm based on a Contourlet transform and a pulse coupled neural network (PCNN) is used to generate the mutual complementary blending images (the detail description can be found in [36]). Considering that the outdoor experiments are carried out in different places, this paper will apply those fused images to track both the pose of the laser scanner and the measured trees, which will establish a corresponding relationship between the fitted diameter data and the corresponding observed diameter for further accurate data processing. The complete measurement equipment setup is shown in Figure 1.

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.


Related in: MedlinePlus