WO2023287365A1

WO2023287365A1 - Method of determination of the external parameters of the round timber using three-dimensional image

Info

Publication number: WO2023287365A1
Application number: PCT/SK2021/050012
Authority: WO
Inventors: Lukáš HALM ING. MA
Original assignee: VALASAHA Group, a. s.
Priority date: 2021-07-13
Filing date: 2021-09-24
Publication date: 2023-01-19
Also published as: SK500392021A3

Abstract

The invention relates to method for determination of the external parameters of the round timber (length, front diameter, centre diameter, volume, shape) in the round timber warehouse in the acceptance process. The parameters are determined using available smart devices (12) such as tablets / smartphones with LiDAR laser scanner, supplemented by the 3D depth scanning device (13) with dual IR camera technology and designed software. The invention describes the method for scanning the round timber set (10) stored on the pads (11) and the method for determining the external parameters of the round timber using the three- dimensional image. The volume of the round timber is determined based on more detailed scan of the round timber fronts and the automatic calculation of the standardized round timber length. In the second alternative, the volume is determined from the complete scan of the round timber, where the diameter is determined in several sections of the round timber perpendicular to its longitudinal axis. All the obtained parameters are sent to the central database (24), from which the sheet with all the obtained data can be printed directly on site by means of the portable printer (25). The invention is mainly intended for fast and accurate determination of the volume of the round timber with the possibility of storing the 3D model of the scanned round timber. The result of the process is a unique digital footprint of the round timber.

Description

Method of determination of the external parameters of the round timber using three- dimensional image

Technical field

The invention relates to the rapid determination of the external parameters of the round timber (length, diameter of the thinner end, diameter of the thicker end, centre diameter, volume, shape, length) in the round timber warehouse in the process of its acceptance in supplier- customer relations of timber trade. The invention makes it possible to determine the above- mentioned parameters of the round timber without the use of manual measuring devices (measuring tape, diameter). The parameters are determined using available smart devices such as tablets / smartphones with LiDAR (light detection and ranging) laser scanner, supplemented by the scanning device (3D depth scanner with dual IR camera technology) and software with implemented methodology for processing the three-dimensional image of the round timber.

Technical background

Round timber is a part of trees that is to be used to produce the wood products such as the sawn timber in the form of boards and prisms, veneer, plywood, chipboard and others. In today's competitive environment, it is important that round timber volume determination is accurate and provides a good basis for yield estimation. The important factor is also the simplicity of determining the volume of the round timber from the point of view of users.

When selling round timber, it is necessary to create a record of each piece, where its external parameters (dimensions and volume), type of timber, or location of harvest are given. Several standardized methods are used around the world to measure dimensions and determine round timber volume. Many methods add confusion to the international timber trade, which creates inconsistencies in the detection of log volume. For Slovak timber trade, it is recommended to use the standard STN EN 1309-2 Round and sawn timber. Method of measurement of dimensions. Part 2: Round timber. Requirements for measurement and volume calculation rules. The rules for calculating the volume of the round timber try to estimate the total volume of the timber without considering the expected form of post-processing of the round timber (however, there are exceptions). Using different calculation methods, significant differences arise in determining the volume of the round timber. Most calculations assume that the trunk corresponds to the geometric shape of a cylinder, cone or paraboloid and the trunk has a circular diameter. The length of the round timber is given as a nominal value and not a rounded value. This causes further inaccuracies in determining the volume of the round timber, because in some cases the shape of the round timber has significant deviations from the ideal geometric shape.

To calculate the volume of the round timber, as the basic parameter in the trade of the round timber, it is necessary to obtain its parameters (end and middle diameter and its length). These dimensions are most often measured manually using a forest average and a band, which is very time and personnel consuming and the measurement largely depends on the person performing the measurement.

The process of obtaining the necessary parameters can be accelerated by using digital devices that send the dimensions to a special application on the smartphone. However, this does not significantly speed up the whole process, nor does it reduce staffing requirements, but it reduces the risk of error by automation of the data transfer during the measurement.

In practice, these facts present many problems which can be eliminated by determining the volume of the round timber by modern digital methods. Today, various digital systems for detecting the dimensions of round timber are being developed, most often based on image and laser scanning technology. These scanners are fast, accurate and can create a computer model thanks to the three-dimensional reconstruction of the image of the scanned object, which can be further used, for example to determine the dimensions, volume, shape and, to a limited extent, also surface defects of round timber. These scanners are mostly large stationary devices that use a system of cameras and laser measuring systems to evaluate the external parameters of the round timber. Devices of this type are commonly commercially available. Most of these devices are described in patent applications. For example, in patent applications U.S. Pat. No. 6219585 and U.S. Pat. No. 6463402. Devices of this type are rather intended for large and medium-sized wood processing plants, where they are used mainly for optimizing the incision of round timber. The solution according to the invention described in the application CL2009000088A1 is the alternative for quickly and efficiently determining the external parameters of the round timber in supplier-customer relations. This product is a large gate equipped with a scanning device that scans the entire load placed on a truck or train. The main advantage of this device is the rapid detection of a larger volume of the round timber at once. The disadvantage is the lower accuracy of determining the volume of the inner layers.

All these devices have a disadvantage in their large dimensions, which does not allow to determine the volume of the round timber in situ anywhere in the warehouse.

These problems are solved, for example, by the system described in patent application U.S. 10590222. This system comprises a measuring unit using stereo-vision technology located on a vehicle. This circling system scans the complete spatial model of the round timber around the stored round timber. The resulting model is further computer processed to determine the volume. The described method has great demands on the space around the stored round timber, so it cannot be implemented anywhere.

The problem with better mobility of the device is solved by the system described in patent application US 10503943. It is a portable, hand-held device for scanning the round timber in situ. It includes a hand-held scanning unit with stereo cameras for sensing the depth and texture of the fronts of the round timber. Another part is a belt with the battery, data processing unit and mobile phone showing the current scanning area. The device is also designed to read a QR code, to register individual pieces of the round timber. The disadvantage of this device is less compactness, since it consists of several parts connected by a cable. The device also does not contain any internal memory or operating system, so it processes the obtained data in an external device. Another disadvantage of this solution is the determination of the round timber volume only by means of scanned fronts and the calculation of the length, which reduces the overall accuracy.

Subject of the invention

The above-mentioned shortcomings are substantially eliminated by the proposed methodological procedure for determining the external parameters of the round timber with the help of equipment commonly available on the market. This is the portable smart device (tablet or mobile phone) containing LiDAR (light detection and ranging) scanner technology with the connected scanning device (STRUCTURE sensor MARK II). The invention is mainly intended for the accurate and fast determination of the volume of timber in the supplier-customer relations of the timber trade.

Determination of timber volume is always performed during inspection, respectively acceptance of the round timber before loading the trucks, shipping containers, railway wagons or other types of means of transport. The total volume of the raw material is essential for the final price and weight of the cargo. Trading companies and inspection bodies place emphasis on the increasing accuracy of determining the volume and weight of round timber. Therefore, to increase the accuracy of round timber scanning, the IR scanner technology is combined with the camera system of the portable device containing LiDAR (light detection and ranging) laser scanner technology.

To implement the method, the portable smart device with LiDAR laser scanner, rear camera system, operating system is required. The scanning device is connected to it. This scanning device contains the high-quality inertial measurement unit (IMU) containing gyroscopes and accelerometers, which provides monitoring of the position of the sensor in space. The scanning device (13) scans based on deep IR scanning, it is equipped with two IR cameras and one wide- angle camera and holder.

The entire computing device A is supplemented by software for processing the scanned 3D model, calculating the round timber volume, data registration and creating the database of scanned round timber. The smart device is connected via wireless technology to portable printer to print labels with information about the scanned log. The information database is connected to device A using wireless Wi-Fi technologies or mobile networks.

Scanning is performed to determine the parameters of the round timber (external dimensions, volume and shape). The scanning procedure is schematically shown in FIG. 1 and FIG. 2. The worker uses a hydraulic loader to arrange 1 to 5 pieces of the round timber in the row next to each other in the set. To ensure better scanning, the round timber is placed on the pad, such as a prism with a cross section of 100 x 150 mm. The worker marks the fronts with labels with a QR code. The labels are generated using software, which then forms the database with data on the round timber. The worker scans the complete set of the round timber (1 - 5 pieces) with the portable smart device with the scanning device. Using the created application, it inserts the scanned set into the desired area shown on the display and bypasses the entire round timber set in the indicated direction. By combining LiDAR laser scanner and structural sensor, it scans the complete set of the round timber and creates the spatial 3D model of each piece of the round timber with the large number of points. The created spatial model is further worked on according to the proposed procedure shown in the diagram in Fig. 4. The method can be implemented with two equivalent alternatives. In the first alternative, the volume is determined based on a detailed scan of the round timber fronts and automatic calculation of the standardized round timber length. In the second alternative, the volume is determined from a complete scan of the round timber, where the diameter of the round timber is determined in several cross sections perpendicular to the longitudinal axis of the round timber. The length of the round timber will be determined by means of the two points furthest distant in the longitudinal axis of the round timber. The proposed procedures are described in more detail in the examples of invention embodiment.

The input parameter of the processing process is the scanned round timber model. Using the programmed algorithm, the model surface points are categorized into round timber front points and round timber surface points. Then these points are approximated respectively filtered for simplification and for work with the point field of the model. Then, the orientations of the surface points and fronts in space are determined, and further the front cross section planes are determined, and at the same time n-numbers of cross sections of planes are determined for the surface length of the round timber model, which reminds the frustum of cone and these planes serve for detection of points, in these planes, further to determine the content of the described points of the 2D body in the planes, the detection of points is in progress in the planes, respectively in n-planes, whereby the distances of the end planes in the model axis determine the lengths of the round timber models, where based on the obtained contents of bodies in all planes and the length of the round timber model the final volume of the round timber model is calculated, then all parameters are subsequently sent to the central database.

The dimensions among the individual points are obtained by deriving from the distance of the scanning device from the object, when the distance is determined by the time of reflection of the light signal (IR radiation, laser) reflected from the surface of the scanned body. The calibration of the scanning system must be performed at regular intervals, which is monitored by the software. Calibration is performed by scanning a known predefined object. To verify the data, it is necessary to perform a random check of the dimensions manually, using the diameter and the measuring tape.

The output of the application is the length, dimensions of the fronts, but above all the exact volume of the round timber needed to determine the final price of the round timber. The output can also be a simplified 3D model of the round timber. This can be important evidence in the complaint process, or an interesting element for increasing competitiveness within the timber trade. A great advantage of the proposed solution is the possibility to perform measurements directly in the field (in round timber warehouses), in real time. The proposed solution can significantly refine the determination of the volume of the round timber and provide added value of the output in the form of a 3D model of the round timber. The model can be used as input for automated saws. It is also possible to better locate and possibly clarify any errors in the measurement, for example in the process of claiming the goods.

Overview of figures in the drawings

FIG. 1 shows the worker scanning the set of the round timber lying on pads using the scanning system. FIG. 2 shows the same situation as in FIG. 1 in plan view with the depicted scanning path of the round timber set. FIG. 3 shows a more detailed view of the scanning system. FIG. 4 shows the process flow diagram of the scanned 3D model of the round timber for Example 1, where scanning is performed with the focus on scanning the round timber front. FIG. 5 shows the process flow diagram of the scanned 3D model of the round timber for Example 2, in which the complete round timber is scanned in detail. These diagrams simply describe the algorithms used and other operations for processing the scanned image (scatter 3D spatial model) in the proposed application.

Example of embodiment of the invention

To implement the method, the portable smart device 12 with LiDAR laser scanner, the rear camera system 17, the operating system 21 is required. The scanning device 13 is connected to it. This scanning device 13 comprises the high-quality inertial measurement unit (IMU) containing gyroscopes and accelerometers, which provides monitoring of position of the sensor in the room. The scanning device 13 scans based on in-depth IR scanning, it is equipped with two IR cameras and one wide-angle camera, and holder 16.

The whole computing device A is supplemented by software 22 for processing the scanned 3D model, calculating the volume of the round timber, registering the data, and creating the database 24 of the scanned round timber. The smart device 12 is connected with the portable printer 25 via wireless technology 26 for printing labels with information about the scanned round timber. The information database 24 is connected with the device A by means of wireless WIFI technologies or mobile networks 23.

Scanning is performed to determine the parameters of the round timber (external dimensions, volume, and shape). The scanning procedure is schematically shown in FIG. 1 and FIG. 2. Worker 14 uses the hydraulic loader to arrange 1 to 5 pieces of the round timber in the row next to each other in the set 10. To ensure better scanning, the round timbers are placed on pad 11, for example, a prism with the cross-section of 100 x 150 mm. Worker 14 marks the fronts with QR code labels. The labels are generated by software, which then also forms database 24 with data on the round timber. Worker 14 scans a complete set 10 of the round timbers (1-5 pieces) with the portable smart device 12 with the scanning device 13. Using the created application 22 inserts the scanned set 10 into the desired area shown on the display and, following the instructions of application 22, bypasses the entire round timber set 10 in direction 15. By combining LiDAR laser scanner and structural sensor 13 the complete set 10 of the round timber is scanned and it creates the spatial 3D model of each piece of the round timber with many points. The created spatial model is further used according to the proposed procedure shown in the diagram in Fig. 4.

Example 1 - the first alternative

The worker 14 uses the hydraulic loader to arrange 3 round timbers in the row next to each other into the set 10. To ensure better scanning, the round timber is placed on the pad 11. The worker 14 marks the round timber fronts with labels with the QR information code generated from the application 22. The worker 14 takes the portable smart device 12 with the scanning device 13 and scans the complete set 10 of the round timbers. Using the created application 22, it inserts the complete scanned set 10 into the desired area shown on the display and, following the instructions of the application 22, bypasses the entire round timber set 10 according to the given route 15. The scanning is performed with emphasis on scanning the round timber fronts. These are scanned with greater accuracy to determine the more accurate contents of the round timber fronts. The scan creates a spatial 3D model of each piece of the round timber with many points of the round timber fronts and a limited number of points at the surface of the round timber.

For the processing of the 3D model of the round timber to determine the volume of the round timber, the procedure in the diagram (Fig. 5) is shown, focused on the operations concerning the fronts of the round timber. From the incoming scanned model, the model points are categorized using the programmed algorithm. In the first row, the points of the fronts and in the second row, the points of the surface of the round timber model intended only to determine the location of points in space. Furthermore, the approximation (filtering) of the front points is performed to simplify the work with points in the planes of the cross sections of the fronts of the round timber model. These points are located perpendicular to the detected axis of the model in the part of the narrower and wider front of the round timber model. Subsequently, the contents of the described 2D objects of the front cross section are determined. The resulting round timber volume is calculated from the contents of both fronts of the round timber model and the standard predefined round timber lengths. All the obtained parameters are then sent to the central database 24. After scanning the required volume, the delivery note is also printed out by means of the wireless portable printer 25 with data on individual pieces of the round timber obtained from the database 24.

Example 2 - the second alternative

The procedure for preparing the scan does not differ from the procedure in Example 1. The scanning also proceeds in the same way, with the difference of more precise scanning not only of the fronts, but of the whole round timber. Scanning creates a spatial 3D model of each piece of the round timber with many points of the round timber fronts and the surface of the round timber. The processing of the 3D model of the round timber is shown in the diagram (Fig. 4). The model points are categorized from the scanned round timber model. The points are divided into points on the front of the round timber. Next, the approximation (filtering) of the front points is performed to simplify the work with the point field of the model, then the direction and location of the points of the round timber model in space is determined. Determining the points and axes of the model helps to accurate positioning the planes of the cross section of fronts for length of surface of the round timber model. These planes are used to detect points in the plane from which the content of the described points of the created 2D objects is determined. A simplified 3D model of the round timber is then compiled from two 2D objects of the fronts and the length of the round timber model. The resulting length of the round timber model is derived from it by determining the distance of the two end planes in the model axis. Using all the obtained contents of bodies in all planes and lengths, the final volume of the round timber model is calculated.

All the obtained parameters are then sent to the central database 24. After scanning the required volume, the delivery note is also printed out by means of the wireless portable printer 25 with data on individual pieces of the round timber obtained from the database 24. Industrial applicability

The described method of determining the external parameters of the round timber by reconstructing a three-dimensional image obtained using the smartphone or tablet with the specific camera system can be used wherever it is necessary to determine the volume of the round timbers. Its usability is intended for producers as well as buyers of round timber. Specifically, in forest warehouses, which are based at timber harvesting as well as in handling warehouses, where the round timbers are sold. With the introduction of this system, the registration of specific pieces of the round timbers in the wood flow chain in the wood processing industry will be significantly accelerated and more accurate, because a three- dimensional digital record with the necessary parameters is created for each piece of round timbers.

Claims

PATENT CLAIMS

1. Method for determining the external parameters of round timber by means of a three- dimensional image, characterized in that the scanning set (10) is placed on the pad (11), the round timber fronts are marked with QR information code labels, and then this set (10) is scanned by the portable smart device (12) with the scanning device (13), wherein the scanning being performed with emphasis on scanning the round timber fronts, then the model points are categorized from the incoming scanned model, primarily the front points and secondarily the surface points of the round timber model are intended only for determination of location of a points in space, further approximation (filtering) of front points is performed to simplify work with points in the planes of cross sections of fronts of the round timber model, where these points are placed perpendicular to the detected model axis in parts of narrower and wider round timber model front, then the resulting round timber volume is calculated from the content of both fronts of the round timber model and the standard predefined length round timbers, then all the obtained parameters are subsequently sent to the central database (24).

2. Method for determining the external parameters of round timbers by means of a three- dimensional image, characterized in that the scanning set (10) is placed on the pad (11), the round timber fronts are marked with QR information code labels, and then this set (10) is scanned by the portable smart device (12) with the scanning device (13), with emphasis on scanning the whole round timber, then from the scanned round timber model the model points are categorized, the points are divided into round timber front points, approximation (filtering) of front points is performed to simplify work with point field model, then determine the direction and location of the round timber model points in space, determining the points and axis of the model helps to accurate positioning the planes of the front cross sections for the surface length of the round timber model, where these planes are used to detect points in the plane from which the content of the described points created 2D objects, then from two 2D objects of fronts and length of the round timber model is then compiled a simplified 3D model The final length of the round timber model is derived by determining the distance of the two end planes in the model axis, the final volume of the round timber model is calculated from all the obtained body contents in all planes and lengths, then the obtained parameters are subsequently sent to the central database (24).