Forest resource measurement system and forest resource calculation method

Abstract

Provided is a forest resource measurement system that calculates the tree height and trunk diameter for each tree with high precision. 【Solution means】 A system having a ground laser scanner 2 and a forest resource measurement device 10 that calculates the tree height and trunk diameter for each tree based on the three-dimensional point cloud data obtained from the ground laser scanner 2. The forest resource measurement device 10 segments the three-dimensional point cloud data for each tree included in the three-dimensional point cloud data obtained by irradiating the tree with laser light by the ground laser scanner 2, and after performing a filtering process of extracting only the portion corresponding to the trunk from the segmented three-dimensional point cloud data for each tree, from the three-dimensional point cloud data corresponding to the trunk, the diameter of the trunk is calculated by performing circle fitting using at least two or more three-dimensional point cloud data at a predetermined height from the ground, and by obtaining a conical shape passing through the two circles, the diameter or tree height of the trunk at an arbitrary height is calculated.

Description

Technical Field

[0001] The present invention relates to a technique for calculating the tree height or the diameter of the tree trunk for each tree based on three-dimensional point cloud data obtained by irradiating a tree with laser light from the ground using a laser scanner.

Background Art

[0002] Conventionally, as a method for forest measurement, a laser device is mounted on an aircraft, and the laser is irradiated onto the ground using this laser device, and the reflection is measured to obtain three-dimensional data on the ground including the ground, buildings, trees, etc. On the other hand, when performing forest measurement using a laser device from above, although three-dimensional point cloud data of the crown part of the forest can be obtained, since the laser light is blocked by the leaves of the trees, etc., it may be difficult to obtain three-dimensional point cloud data of the tree trunk part.

[0003] For example, Patent Document 1 discloses a forest resource measurement device that calculates the tree height and the diameter of the tree trunk for each tree based on three-dimensional point cloud data obtained by irradiating a forest area with laser light from a laser scanner mounted on an aircraft. The forest resource measurement device segments the three-dimensional point cloud data for each tree included in the three-dimensional point cloud data obtained by three-dimensionally measuring the forest area with the laser scanner, and after performing a filtering process to extract only the part corresponding to the tree trunk from the segmented three-dimensional point cloud data for each tree, a conical shape is searched from the three-dimensional point cloud data corresponding to the tree trunk extracted by the filtering process unit, and a conical formula that best fits the conical shape as the tree trunk is obtained, and the diameter of the tree trunk at an arbitrary height is calculated based on the conical formula.

Prior Art Documents

Patent Documents

[0004]

Patent Document 1

Summary of the Invention

Problems to be Solved by the Invention

[0005] However, in the technology of Patent Document 1, since laser light is irradiated onto trees from above by a laser scanner, three-dimensional point cloud data of the canopy part at the upper part of the trees can be obtained. However, since the laser light is blocked by branches and leaves of the trees, it may be difficult to acquire three-dimensional point cloud data of the trunk part.

[0006] An object of the present invention is to provide a forest resource measurement system that calculates the tree height or the diameter of the tree trunk for each tree with high accuracy based on three-dimensional point cloud data obtained by irradiating trees with laser light from the ground using a laser scanner.

Means for Solving the Problems

[0007] To achieve the above object, a forest resource measurement system according to a first invention includes a laser scanner that irradiates trees with laser light from the ground to acquire three-dimensional point cloud data, and a forest resource measurement device that calculates the tree height and the diameter of the tree trunk for each tree based on the three-dimensional point cloud data, wherein the forest resource measurement device includes a data acquisition unit that acquires three-dimensional point cloud data obtained by irradiating trees with laser light by the laser scanner, a segment processing unit that extracts and segments three-dimensional point cloud data determined to be the trunk for each tree included in the three-dimensional point cloud data acquired by the data acquisition unit, a filtering processing unit that extracts only a portion corresponding to the trunk from the three-dimensional point cloud data for each tree segmented by the segment processing unit, and a trunk diameter calculation unit that calculates , by performing circle fitting using at least two or more three-dimensional point cloud data at a predetermined height from the ground, the diameter of the tree trunk is calculated, and further, by obtaining a conical shape passing through the circles at the two locations, at any height the diameter or the tree height of the trunk from the three-dimensional point cloud data corresponding to the trunk extracted by the filtering processing unit, and is characterized by The circle fitting in the tree trunk diameter calculation unit repeats creating a circle passing through the three-dimensional point cloud data of three randomly selected points from the three-dimensional point cloud data at a predetermined height from the ground. After that, among the plurality of created circles, the circle with the largest number of points within a predetermined range inside and outside the circumference is extracted, and that circle is specified as the circle representing the cross-section of the tree trunk. this.

[0008] The forest resource measurement system according to the second invention, in the first invention, The trunk diameter calculation unit Among the three-dimensional point cloud data corresponding to the trunk extracted by the filtering processing unit, by performing circular fitting for tree inclination correction using the three-dimensional point cloud data within a predetermined range, after calculating the axial direction of the tree, it has correction means for performing inclination correction of the tree so that the axial direction of the tree is perpendicular to the ground. This is the characteristic.

[0009] The forest resource measurement system according to the third invention, in the second invention, The trunk diameter calculation unit After performing inclination correction of the tree by the correction means, using the three-dimensional point cloud data, by performing circular fitting for calculating the tree diameter, after calculating the circular radii of the trees at a plurality of locations, by calculating an approximate straight line showing the relationship between the circular radius of the tree and the height of the tree, it has calculation means for calculating the diameter or height of the trunk at an arbitrary height. This is the characteristic.

[0010] The forest resource measurement system according to the fourth invention, in the first invention, The filtering processing unit sets a threshold for the crown part and a threshold for the underbrush part for each tree from the three-dimensional point cloud data for each tree segmented by the segmentation processing unit, and removes the three-dimensional point cloud data existing in the range corresponding to the crown part and the underbrush part as noise. Furthermore, from the three-dimensional point cloud data for each tree segmented by the segmentation processing unit, one three-dimensional point cloud data corresponding to the tree top point for each tree is obtained, a cone is assumed toward the ground surface with this three-dimensional point cloud data as the apex of the cone, and by setting a threshold for the cone, the three-dimensional point cloud data existing outside the cone is removed as noise. This is the characteristic.

[0011] The forest resource measurement system according to the fifth invention, in the first invention, For the three-dimensional point cloud data acquired by the data acquisition unit, it is provided with a normalization processing unit that horizontally converts the ground surface and converts it to the actual height from the ground surface. The segment processing unit is characterized by segmenting the three-dimensional point cloud data for each tree included in the three-dimensional point cloud data converted by the normalization processing unit.

[0012] The forest resource measurement system according to the sixth invention is, in the first invention, The forest resource measurement device is characterized by including a volume calculation unit that calculates the volume of each tree based on the diameter at breast height of the trunk of each tree calculated by the trunk diameter calculation unit and the height of the tree.

[0013] The forest resource calculation method according to the seventh invention is a method for calculating the height of each tree or the diameter of the trunk based on three-dimensional point cloud data obtained by irradiating a tree with laser light from the ground using a laser scanner, which is executed by a computer, a data acquisition step of acquiring three-dimensional point cloud data obtained by irradiating a tree with laser light by the laser scanner; a segment processing step of extracting and segmenting the three-dimensional point cloud data determined as the trunk for each tree included in the three-dimensional point cloud data acquired in the data acquisition step; a filtering processing step of extracting only the portion corresponding to the trunk from the three-dimensional point cloud data for each tree segmented in the segment processing step; from the three-dimensional point cloud data corresponding to the trunk extracted in the filtering processing step , by performing circle fitting using at least two or more three-dimensional point cloud data at a predetermined height from the ground, the diameter of the tree trunk is calculated, and further, by obtaining a conical shape passing through the circles at the two locations, at any height a trunk diameter calculation step of calculating the diameter or height of the trunk; and includes The circle fitting in the tree trunk diameter calculation step repeats creating a circle passing through the three-dimensional point cloud data of three randomly selected points from the three-dimensional point cloud data at a predetermined height from the ground. After that, among the plurality of created circles, the circle with the largest number of points within a predetermined range inside and outside the circumference is extracted, and that circle is specified as the circle representing the cross-section of the tree trunk. which is characterized by this.

Effect of the Invention

[0014] According to the present invention, in forest measurement, based on three-dimensional point cloud data obtained by irradiating trees with laser light from the ground using a laser scanner, it becomes possible to calculate the tree height or the diameter of the tree trunk for each tree with high accuracy, and to calculate the volume of each tree. In particular, even when it is not possible to obtain three-dimensional point cloud data of the tree top blocked by branches and leaves, etc., or when it is not possible to obtain effective three-dimensional point cloud data due to understory vegetation, it becomes possible to calculate the tree height or the diameter of the tree trunk for each tree with high accuracy, and to calculate the volume of each tree. As a result, it is expected that the speed of forest measurement work can be increased and the work efficiency can be improved, leading to the efficiency improvement of the entire forest measurement business.

Brief Description of the Drawings

[0015]

Figure 1

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Figure 7A

Figure 7B

Figure 7C

Figure 7D

Figure 7E

Figure 7F

Embodiments for Carrying Out the Invention

[0016] Hereinafter, embodiments for carrying out the present invention will be described in detail with reference to the drawings. It should be noted that the present invention is not limited to the embodiments described below.

[0017] FIG. 1 shows an example of a system configuration diagram of a forest resource measurement system according to an embodiment of the present invention. As shown in FIG. 1, the forest resource measurement system 1 includes a ground laser scanner 2 and a forest resource measurement device 10 that calculates the tree height or the diameter of the tree trunk for each tree based on the three-dimensional point cloud data obtained by irradiating the tree with laser light from the ground laser scanner 2.

[0018] In FIG. 1, the ground laser scanner 2 is used. In addition to this, as a laser scanner for irradiating the tree with laser light from the ground to acquire three-dimensional point cloud data, for example, a handy laser scanner, a pack-type laser scanner, etc. can also be used.

[0019] In the ground laser scanner 2, distance calculation and ground surface determination are performed based on the reflection intensity and reflection signals of the laser light obtained by irradiating the trees to be measured with the laser light.

[0020] The forest resource measurement device 10 acquires the three-dimensional point cloud data obtained by irradiating the trees with the laser light from the ground laser scanner 2, and calculates the tree height or the diameter of the tree trunk for each tree. The three-dimensional point cloud data includes point cloud data corresponding to the vertices of the trees, point cloud data corresponding to the crown parts of the trees, point cloud data corresponding to the trunk parts of the trees, and point cloud data corresponding to the underbrush parts.

[0021] Also, the forest resource measurement device 10 is a general computer device, and may be configured to have a function of performing communication control so as to be able to acquire the three-dimensional point cloud data from the ground laser scanner 2 via a network such as the Internet.

[0022] Next, the functional configuration of the forest resource measurement device 10 will be described using the functional block diagram shown in FIG. 2. As shown in FIG. 2, the forest resource measurement device 10 includes a data acquisition unit 11, a normalization processing unit 12, a segmentation processing unit 13, a filtering processing unit 14, a tree trunk diameter calculation unit 15, and a volume calculation unit 16.

[0023] The data acquisition unit 11 acquires the three-dimensional point cloud data obtained by irradiating the trees with the laser light by the ground laser scanner 2.

[0024] The normalization processing unit 12 performs a normalization process of horizontally converting the ground surface and converting it to the actual height from the ground surface for the three-dimensional point cloud data acquired by the data acquisition unit 11. By performing this normalization process, there is an advantage that the complexity in subsequent processes can be eliminated. Also, since this normalization process itself is not an essential process, it is also possible to configure the forest resource measurement device 10 to omit the normalization processing unit 12.

[0025] The segment processing unit 13 extracts and segments the 3D point cloud data determined as the trunk for each tree, which is included in the 3D point cloud data acquired by the data acquisition unit 11 or the 3D point cloud data converted by the normalization processing unit 12. Here, as a method for segmenting the 3D point cloud data, for example, there is a method of segmenting individual trees according to the height of the tree crown part.

[0026] The filtering processing unit 14 extracts only the part corresponding to the trunk from the 3D point cloud data for each tree segmented by the segment processing unit 13. As this extraction method, for example, it can be performed in the following two steps.

[0027] <First step> From the 3D point cloud data for each tree segmented by the segment processing unit 13, a threshold value for the tree crown part and a threshold value for the underbrush part are set for each tree, and the 3D point cloud data existing in the ranges corresponding to the tree crown part and the underbrush part are removed as noise.

[0028] <Second step> From the 3D point cloud data for each tree segmented by the segment processing unit 13, 3D point cloud data of one point corresponding to the tree top point is obtained for each tree. Assuming a cone with this 3D point cloud data as the vertex towards the ground surface, a threshold value of the cone is set, and the 3D point cloud data existing outside the cone is removed as noise.

[0029] By performing the above first-step and second-step processes, it becomes possible to extract only the part corresponding to the trunk from the 3D point cloud data for each tree segmented by the segment processing unit 13.

[0030] The trunk diameter calculation unit 15 calculates the tree height or the diameter of the trunk for each tree from the 3D point cloud data corresponding to the trunk extracted by the filtering processing unit 14.

[0031] Specifically, the trunk diameter calculation unit 15 calculates the diameter of the trunk by performing circular fitting using at least two or more three-dimensional point cloud data at a predetermined height from the ground among the three-dimensional point cloud data corresponding to the trunk extracted by the filtering processing unit 14, and obtains a conical shape passing through the two circles, thereby calculating the diameter or tree height of the trunk at an arbitrary height.

[0032] FIG. 3 is a schematic diagram showing an outline of the procedure for calculating the diameter of the trunk by the trunk diameter calculation unit 15 through circular fitting. In the example of FIG. 3, in order to exclude the influence of the branches and leaves of the tree and the understory plants, for example, the diameter of the trunk is calculated by performing circular fitting using the three-dimensional point cloud data at two positions at heights of 11 m and 3 m from the ground. Then, by obtaining a conical shape passing through the two circles, it becomes possible to calculate the diameter or tree height of the trunk at an arbitrary height. Furthermore, it becomes possible to easily calculate the breast height diameter (the diameter of the tree at a height of 1.2 m from the ground) using the conical shape.

[0033] Also, before executing the calculation process of the diameter or tree height of the trunk described above, the trunk diameter calculation unit 15 executes a correction process for correcting the inclination of the tree. Specifically, the trunk diameter calculation unit 15 calculates the axial direction of the tree by performing circular fitting for tree inclination correction using the three-dimensional point cloud data within a predetermined range among the three-dimensional point cloud data corresponding to the trunk extracted by the filtering processing unit 14, and then executes a correction process for correcting the inclination of the tree so that the axial direction of the tree is perpendicular to the ground.

[0034] After that, the trunk diameter calculation unit 15 calculates the circular radii of the tree at a plurality of locations by performing circular fitting for calculating the tree diameter using the three-dimensional point cloud data after correcting the inclination of the tree in the correction process, and then calculates an approximate straight line showing the relationship between the circular radius of the tree and the height of the tree, thereby making it possible to calculate the diameter or tree height of the trunk at an arbitrary height. The detailed procedure will be described later.

[0035] The volume calculation unit 16 calculates the volume of each tree based on the diameter of the tree trunk including the breast height diameter of each tree calculated by the tree trunk diameter calculation unit 15 and the tree height.

[0036] Next, the process executed by this system will be described using the flowchart shown in FIG. 4. FIG. 4 is a flowchart showing the data processing procedure executed by the forest resource measurement device 10.

[0037] <Data acquisition step S10> Acquire the three-dimensional point cloud data obtained by irradiating the trees with laser light using a ground laser scanner.

[0038] <Normalization processing step S20> Perform normalization processing on the three-dimensional point cloud data obtained in the data acquisition step S10 to horizontally transform the ground surface and convert it to the actual height from the ground surface. By performing this normalization processing, there is an advantage that the complexity in subsequent processing can be eliminated. Also, since this normalization processing itself is not an essential process, it is possible to omit this normalization processing step S20.

[0039] <Segmentation processing step S30> Segment the three-dimensional point cloud data for each tree in the three-dimensional point cloud data converted in the normalization processing step S20. Note that when omitting the above normalization processing step S20, segment the three-dimensional point cloud data for each tree in the three-dimensional point cloud data obtained in the data acquisition step S10. Here, as a method for segmenting the three-dimensional point cloud data, for example, there is a method of segmenting individual trees according to the height of the tree crown part.

[0040] <Filtering processing step S40> Perform filtering processing to extract only the part corresponding to the tree trunk from the three-dimensional point cloud data for each tree segmented in the segmentation processing step S30. A specific example of this filtering processing will be described later.

[0041] <Trunk diameter calculation step S50> Calculate the diameter of the trunk for each tree from the three-dimensional point cloud data corresponding to the trunk extracted in the filtering process step S40. The detailed procedure of this trunk diameter calculation process will be described later.

[0042] <Volume calculation section step S60> Calculate the volume of each tree based on the diameter and tree height of the trunk including the breast height diameter of each tree calculated in the trunk diameter calculation step S50.

[0043] By executing the data processing procedure from step S10 to step S60 above, in forest measurement, it becomes possible to calculate the tree height and the diameter of the trunk for each tree with high precision and calculate the volume of each tree, and it is expected that the efficiency of the entire forest measurement work can be improved by speeding up the measurement work and improving the work efficiency.

[0044] Also, the data processing procedure from step S10 to step S60 may be realized as a method executed by a computer, or may be realized as a program for execution by a computer.

[0045] Next, a specific example of the filtering process in the filtering process step S40 described above will be described with reference to FIG. 5. FIG. 5 is a schematic diagram showing the outline of the filtering process procedure.

[0046] <Specific example of filtering process> In the filtering process step S40, when extracting only the part corresponding to the trunk from the three-dimensional point cloud data for each tree segmented in the segmentation process step S30, as shown in FIG. 5, for example, it can be performed in the following two steps.

[0047] <First stage> From the three-dimensional point cloud data for each tree segmented in the segment processing step S30, a threshold value for the tree crown part and a threshold value for the underbrush part are set for each tree, and the three-dimensional point cloud data existing in the ranges corresponding to the tree crown part and the underbrush part are removed as noise.

[0048] <Second stage> From the three-dimensional point cloud data for each tree segmented in the segment processing step S30, one piece of three-dimensional point cloud data corresponding to the tree top point is obtained for each tree. Assuming a cone toward the ground with this point cloud data as the apex of the cone, a threshold value for the cone is set, and the three-dimensional point cloud data existing outside the cone is removed as noise.

[0049] By performing the above-described first and second stage processes, only the part corresponding to the tree trunk can be extracted from the three-dimensional point cloud data for each tree segmented in the segment processing step S30.

[0050] Next, regarding the process of calculating the diameter or height of the tree trunk from the three-dimensional point cloud data corresponding to the tree trunk extracted by the filtering process step S40, it will be described with reference to FIGS. 6 and 7. FIG. 6 is a flowchart showing an example of the tree trunk diameter calculation process procedure, and FIG. 7 is a schematic diagram for explaining the tree trunk diameter calculation process procedure.

[0051] <Step S51> As shown in FIG. 7A, circular fitting for tree inclination correction is performed using the three-dimensional point cloud data within a predetermined range from the three-dimensional point cloud data corresponding to the tree trunk. (1) For example, the three-dimensional point cloud data for circular fitting within the range of 4 m to 11 m above the ground is extracted. (2) Looking at the extracted three-dimensional point cloud data from above, circles are repeatedly created from three randomly acquired points, and the number of points, for example, within 1 cm inside and outside the circle, close to the circle created by the circular fitting is counted, and the circle with the largest number of points is taken as the circle.

[0052] <Step S52> As shown in FIG. 7B, the axial direction of the tree is calculated from the circle obtained in step S51. (1) The circle obtained in step S51 is shown. (2) Determine the straight lines passing through the center points of two circles for all combinations of circles. (3) Determine the number of center points of the circles within the threshold range from the straight lines obtained from the circle center points. (4) Set the straight line with the largest number of center points as the axial direction of the tree.

[0053] <Step S53> As shown in FIG. 7C, perform tilt correction of the tree from the axial direction obtained in step S52. (1) Align the axial direction of the tree obtained in step S52 with the Z-axis (height) direction. (2) Calculate the angles between the axial direction of the tree and the Z-axis (the angles around the X-axis and the Y-axis). (3) Rotate the three-dimensional point cloud data first around the X-axis and then around the Y-axis by the angles calculated above to align the axial direction of the tree with the Z-axis direction.

[0054] <Step S54> As shown in FIG. 7D, perform circle fitting for calculating the diameter of the tree using the three-dimensional point cloud data with the tilt correction of the tree performed in step S53. (1) Looking at the extracted three-dimensional point cloud data from above, repeatedly create a circle from three randomly acquired points, count the number of points close to the circle created by circle fitting, for example, within 1 cm inside and outside the circle, and determine the circle with the largest number of points as the circle.

[0055] <Step S55> As shown in FIG. 7E, calculate an approximate straight line from the circle radius of the circle obtained in step S54. (1) For the circle obtained in step S54, plot the coordinates with the circle radius at regular intervals on the horizontal axis and the height on the vertical axis. (2) Determine the straight lines passing through two points for all combinations of points. (3) Determine the number of points within the threshold range from the straight lines created from the coordinates of the circle radius and the height. Use the straight line with the largest number of points as the approximate straight line of interest.

[0056] <Step S56> As shown in FIG. 7F, calculate the trunk diameter or tree height from the approximate straight line obtained in step S55. (1) From the approximate straight line obtained in step S55, obtain the circle radius at a height of 1.2 m, and calculate twice that as the breast height diameter. Furthermore, the diameter of the trunk at any height can be calculated from the approximate straight line obtained in step S55.

[0057] As shown in FIG. 7F, calculate the tree height from the approximate straight line obtained in step S55. (2) From the approximate straight line obtained in step S55, obtain the height when the circle radius is "0", and calculate that as the tree height.

[0058] According to this embodiment, in forest measurement, based on the three-dimensional point cloud data obtained by irradiating laser light on trees with a laser scanner from the ground, the tree height or the trunk diameter of each tree can be calculated with high precision, and the volume of each tree can be calculated. Furthermore, it is expected to speed up the measurement work and improve the work efficiency in forest measurement.

[0059] Also, the data processing procedures (steps S10 to S60, steps S51 to S56) described above may be realized as a method executed by a computer, or may be realized as a program for execution by a computer.

Explanation of Signs

[0060] 1... Forest resource measurement system 2... Laser scanner 10... Forest resource measurement device 11... Data acquisition unit 12... Normalization processing unit, 13... Segment processing unit 14... Filtering processing unit 15... Trunk diameter calculation unit 16... Volume calculation unit

Claims

1. A laser scanner that irradiates a tree with laser light from the ground to obtain three-dimensional point cloud data, and a forest resource measurement device that calculates the tree height and the diameter of the tree trunk for each tree based on the three-dimensional point cloud data, The forest resource measurement device is A data acquisition unit that acquires three-dimensional point cloud data obtained by irradiating a tree with laser light by the laser scanner, A segment processing unit that extracts and segments the three-dimensional point cloud data determined to be the trunk for each tree included in the three-dimensional point cloud data acquired by the data acquisition unit, A filtering processing unit that extracts only the portion corresponding to the tree trunk from the three-dimensional point cloud data for each tree segmented by the segment processing unit, From the three-dimensional point cloud data corresponding to the tree trunk extracted by the filtering processing unit, by performing circular fitting using at least two or more three-dimensional point cloud data at a predetermined height from the ground, the diameter of the tree trunk is calculated, and further, by obtaining a conical shape passing through the two circles, the diameter or tree height of the tree trunk at an arbitrary height is calculated. A tree trunk diameter calculation unit, Comprising The circular fitting in the tree trunk diameter calculation unit repeatedly creates a circle passing through the three-dimensional point cloud data of three randomly selected points from the three-dimensional point cloud data at a predetermined height from the ground, and then, among the plurality of created circles, extracts the circle with the largest number of points within a predetermined range inside and outside the circumference, and identifies the circle as the circle representing the cross-section of the tree trunk. A forest resource measurement system characterized by the above.

2. In the forest resource measurement system according to Claim 1, The tree trunk diameter calculation unit is After calculating the axial direction of the tree by performing circular fitting for tree inclination correction using the three-dimensional point cloud data within a predetermined range from the three-dimensional point cloud data corresponding to the tree trunk extracted by the filtering processing unit, it has correction means for correcting the inclination of the tree so that the axial direction of the tree is perpendicular to the ground. A forest resource measurement system characterized by the above.

3. In the forest resource measurement system according to Claim 2, The tree trunk diameter calculation unit is After correcting the inclination of the tree by the correction means, using the three-dimensional point cloud data, by performing circular fitting for calculating the tree diameter, the circular radii of the tree at a plurality of locations are calculated, and then, by calculating an approximate straight line showing the relationship between the circular radius of the tree and the height of the tree, it has calculation means for calculating the diameter or tree height of the tree trunk at an arbitrary height. A forest resource measurement system characterized by the above.

4. In the forest resource measurement system according to Claim 1, the filtering processing unit sets a threshold value for the crown part and a threshold value for the underbrush part for each tree from the three-dimensional point cloud data for each tree segmented by the segment processing unit, and removes the three-dimensional point cloud data existing in the range corresponding to the crown part and the underbrush part as noise, further, obtains one three-dimensional point cloud data corresponding to the tree top point for each tree from the three-dimensional point cloud data for each tree segmented by the segment processing unit, assumes a cone toward the ground surface with the three-dimensional point cloud data as the vertex of the cone, sets a threshold value for the cone, and removes the three-dimensional point cloud data existing outside the cone as noise. A forest resource measurement system characterized by this.

5. In the forest resource measurement system according to Claim 1, the forest resource measurement device, is provided with a normalization processing unit that horizontally converts the ground surface of the three-dimensional point cloud data acquired by the data acquisition unit and converts it to the actual height from the ground surface, and the segment processing unit segments the three-dimensional point cloud data for each tree included in the three-dimensional point cloud data converted by the normalization processing unit. A forest resource measurement system characterized by this.

6. In the forest resource measurement system according to Claim 1, the forest resource measurement device, is provided with a volume calculation unit that calculates the volume for each tree based on the diameter of the tree trunk including the breast height diameter for each tree calculated by the tree trunk diameter calculation unit and the tree height. A forest resource measurement system characterized by this.

7. A method for calculating the tree height or the diameter of the tree trunk for each tree based on the three-dimensional point cloud data obtained by irradiating a tree with laser light from the ground by a laser scanner, which is executed by a computer, a data acquisition step of acquiring the three-dimensional point cloud data obtained by irradiating a tree with laser light by the laser scanner, a segment processing step of extracting and segmenting the three-dimensional point cloud data determined to be the trunk for each tree included in the three-dimensional point cloud data acquired in the data acquisition step, a filtering processing step of extracting only the part corresponding to the tree trunk from the three-dimensional point cloud data for each tree segmented in the segment processing step From the three-dimensional point cloud data corresponding to the tree trunk extracted in the filtering processing step, by performing circle fitting using at least two or more three-dimensional point cloud data at a predetermined height from the ground, the diameter of the tree trunk is calculated, and further, by obtaining a conical shape passing through the circles at the two locations, a tree trunk diameter calculation step of calculating the diameter or tree height of the tree trunk at an arbitrary height; including; In the circle fitting in the tree trunk diameter calculation step, after repeatedly creating a circle passing through the three-dimensional point cloud data of three randomly selected points from the three-dimensional point cloud data at a predetermined height from the ground, among the plurality of created circles, the circle with the largest number of points within a predetermined range inside and outside the circumference is extracted, and the circle is specified as the circle representing the cross-section of the tree trunk. A forest resource calculation method characterized by the above.

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