JP7478998B2 - Method and device for imaging and measuring the diameter of cut end surface of wood - Google Patents

Description

The present invention relates to a method and device for imaging and measuring the diameter of cut end surfaces of timber, which can image and measure the diameter of timber felled at the felling site, convert the diameter class indication, and store and use the measurement data.

At forestry harvesting sites, the smallest point on each felled tree is measured with a tape measure or similar tool when viewed from the cut circular end surface. Diameters up to 14 cm are measured in 1 cm increments - for example, 9 cm to 9.9 cm is assigned a diameter class of 9 cm, and diameters over 14 cm are measured in 2 cm increments - for example, 14 cm to 15.9 cm is assigned a diameter class of 14 cm. The measurement data is recorded on a recording sheet and also directly on the cut circular end surface of the tree that was measured.
The measurement data, including the number of pieces and timber volume for each diameter class, is recorded on a delivery note specified by each company, and the timber and delivery note are delivered to the customer as a set.
The customer compares the measurement data of the actual timber with that on the delivery note, sorts and stores the actual timber by diameter class, and issues work instructions for each diameter class.

Conventionally, a processor device used to mechanize the felling and timber construction work of cutting down timber resources in forests and turning them into wood products, and a method of felling and timber construction using such a processor device are known (see Patent Document 1).
This known technology is a processor device that is fitted to a work vehicle with a movable arm and holds felled timber and cuts it to a specified length, the processor device comprising: a main body section arranged at the tip of the movable arm; a gripping section arranged on the main body section for gripping the timber; a feeding section arranged to feed the timber gripped by the gripping section in the lengthwise direction; a cutting section arranged to cut the timber at an adjacent end of the feeding section; an imaging device that images the portion of the timber gripped by the gripping section that extends from the gripping section along the centre line of the timber, along the axial direction of the timber in a direction away from the portion adjacent to the gripping section; a display device arranged on the work vehicle and that receives and displays imaging information of the timber sent from the imaging device; and information transmission means for transmitting the imaging information from the imaging device to the display device.

In this way, the processor for felling and timber making can inspect the timber for defects based on the image information captured by an imaging device from a different direction in addition to the worker's visual observation, and can reliably cut out only the defect-free, good parts of the timber to obtain wood products with high commercial value.
On the other hand, this invention is a post-process in which the diameter of timber felled at the felling site is photographed and measured, and measurement data is obtained that records the number and volume of timber tallied by diameter class on a delivery note specified by each company, allowing the timber and delivery note to be delivered to the customer as a set.

JP 2003-193096 A

The present invention aims to provide a method and device for imaging and measuring the diameter of cut end faces of timber that can accurately image and measure the diameter of timber felled at the felling site, excluding parts that are not used for diameter measurement (hereinafter referred to as "defective parts"), and convert the diameter class indication to store and use the measurement data.

The method of the present invention for imaging and measuring the diameter of cut end faces of wood involves using a camera to photograph the cross section of the end grain of each felled piece of wood and two light spots illuminated by an illumination device attached to the camera, eliminating defective parts through image processing, setting a virtual contour on the captured image and performing image processing to determine the circular shape, determining the center of gravity from the image-processed circular shape, determining the minimum value of the circular shape centered on the center of gravity, determining the actual measurement by comparing the minimum value of the circular shape with the distance between the two light spots, calculating a diameter class value from the actual measurement value of the captured image, and recording the number and volume of timber tallied for each diameter class.

The imaging and measuring device for wood cut end diameter of the present invention comprises a camera that images the cut circular end surface of each felled piece of wood, an illumination device attached to the camera and displays two light spots that serve as measurement standards for image processing, an image processing device that eliminates defective parts from the image captured by the camera and determines the circular shape, a calculation device that determines the center of gravity from the captured image and the minimum value of the circular shape centered on the center of gravity, an actual measurement calculation device that determines the actual measurement value by relative comparison between the minimum value of the circular shape and the distance between the two light spots, a diameter class calculation device that calculates a diameter class value from the actual measurement value of the captured image, a memory device that records the number and volume of timber tallied for each diameter class, and a display device that displays the calculation results of the diameter class.

The imaging and measuring method and device of the present invention for measuring the diameter of cut ends of wood can measure the diameter of cut ends of wood accurately with little discrepancy from the actual measured value simply by photographing the diameter of the cut ends of wood, can sort the diameter into different grades, and allows customers to store and use the collected data.

FIG. 2 is a flow chart showing the operation of the imaging and measuring device for measuring the diameter of a cut end surface of wood according to the

An embodiment of the imaging and measuring device for measuring the diameter of a cut end surface of wood according to the present invention will be described below.
The imaging and measuring device for wood cut end diameter of the present invention comprises a camera that images the cut circular end surface of each felled piece of wood, a pair of illumination devices attached to the camera that illuminate light that serves as a measurement standard for image processing, an image processing device that determines the circular shape of the image captured by the camera by excluding any defective parts, a calculation device that determines the center of gravity from the captured image and the minimum value of the circular shape centered on the center of gravity, an actual measurement calculation device that determines an actual measurement value by relative comparison between the minimum value of the circular shape and the distance between two light points, a diameter class calculation device that calculates a diameter class value from the actual measurement value of the captured image, a memory device that records the number and volume of timber tallied for each diameter class, and a display device that displays the calculation results of the diameter class.

The camera is a handy, portable photographing device that can be substituted with the camera function of a mobile phone and has an internal data processing function and data transmission function. An imaging and measuring device is provided in which at least one pair of irradiation devices that irradiate light that is a reference for measuring the diameter of the cut end surface of the wood is fixed to the camera, and the imaging and measuring device simultaneously captures the irradiation point of the reference light and the cut end surface of the wood , and processes the image thus obtained to measure the diameter of the cut circular end surface.
The cut circular end of the wood is photographed from a certain distance away, and the image is converted into actual measurements inside the photography device. The data is then uploaded to a cloud server as appropriate, and the data is downloaded to a calculation device such as a computer at a remote location that converts the diameter class.

The image processing device performs image processing to determine the circular shape from the outline of the image captured by the camera, excluding any defective parts. By calculating the diameter of the cut end face of the wood after excluding the defective parts through image analysis using machine learning, the measurement accuracy is greatly improved.
The calculation device determines a center of gravity from the circular shape image-processed by the image processing device, and determines a minimum value of the circular shape centered on the center of gravity.
The irradiation device is provided with a pair of laser emission modules that irradiate light that serves as a measurement standard in image processing. Both an image captured with and without the light that serves as a reference for measuring the cut end surface of the wood are used in the processing, thereby accurately determining the position of the irradiated light in the image. The light that serves as a reference for measuring the diameter of the cut end surface of the wood is provided by installing two laser emission modules so that the light is parallel, and the two light points reflected on the cut end surface of the wood to be measured maintain a constant distance regardless of the distance from the cut end surface of the wood to be measured, providing a highly reliable length standard.

The actual measurement calculation device obtains an actual measurement value by relative comparison between the minimum value of the circle and the distance between two light spots, and the diameter class calculation device calculates a diameter class value from the actual measurement value of the captured image.
The storage device records the number and volume of timber calculated by each diameter class based on the calculation results sent from the calculation device.
The display device is a CRT or a monitor screen, and displays the results of the diameter class calculation.

By storing and managing the measured values on a cloud server, data can be exchanged between multiple workers (multiple imaging devices and processing devices), and the data can be transferred to customers for use as management materials and inspection materials.

Next, the operation of the method for photographing and measuring the diameter of a cut end surface of wood according to the present invention will be described with reference to (1) to (4) in FIG.
(1) Timber felled in a mountain forest is piled up at a logging site which is a flat, open area, and a camera is used to photograph the cross section of the end of each piece of felled wood as well as two light spots illuminated by an illumination device such as a laser emission module attached to the camera.
(2) By using both an image taken with two lights shining on the wood as a reference for measuring the cut end surface, and an image taken without shining the lights on, the distance between the positions of the two lights shining on the image is stored on the image and used as the measurement reference.
(3) The cut end surface of the wood is subjected to image analysis using machine learning (AI) to remove defects (cracks, knots, etc.) that should not be used for diameter measurement, and then image processing is performed to determine the circular shape from the contour of the captured image.
(4) The center of gravity is determined from the image-processed circular shape, the minimum value of the circular shape centered on the center of gravity is determined, and an actual measurement value is determined by relative comparison with the two light spot distances , and the actual measurement value is recorded on the cross section of the measured wood.

The use of the measurement data will be explained below with reference to (5) to (12) in FIG.
(5) The measured timber is transported to a loading area for the truck, and the measurement data from the captured images is uploaded to a dedicated cloud server.
(6) For each truck loading operation, the actual measurements recorded on the cross section of the timber are read from the cloud and the data is stored in the device. The actual measurements are then displayed once the truck loading operation is completed and compared with the actual timber loaded onto the truck.
(7) At the same time as storing the actual measured value, the diameter class value is calculated on the reading device.
(8) Display the number of trees and volume totaled by diameter class.
(9) The number and volume of trees are registered, and the diameter class value is entered directly for the trees photographed. The diameter class value is automatically converted into 1 cm increments for trees under 14 cm, for example, 9 cm to 9.9 cm is classified as a "9 cm" diameter class, and 2 cm increments for trees over 14 cm, for example, 14 cm to 15.9 cm is classified as a "14 cm" diameter class.
(10) The reading device automatically performs the specified compilation and calculation for each customer's file and registers it.
(11) Deliver the lumber to the customer.
(12) The customer compares the actual products with the electronic records, sorts and stores the actual products by diameter class, and issues work instructions for each class.
In this way, the present invention can automate the diameter classification process at felling sites, and allows customers to easily use the compiled data in electronic files.

Claims (5)

A method for imaging and measuring the diameter of cut end faces of timber, comprising the steps of: photographing the cross section of the end grain of each felled timber tree with a camera and two light spots illuminated by an illumination device attached to the camera; eliminating defective parts through image processing; setting a virtual outline on the captured image and performing image processing to determine the circular shape; determining the center of gravity from the image-processed circular shape; determining the minimum value of the circular shape centered on the center of gravity; determining an actual measurement value by comparing the minimum value of the circular shape with the distance between the two light spots; calculating a diameter class value from the actual measurement value of the captured image; and recording the number and volume of timber tallied for each diameter class. 2. The method for imaging and measuring the diameter of a cut end surface of wood as described in claim 1, further comprising an imaging and measuring device for fixing to the camera at least one pair of illumination devices for irradiating light that serves as a reference for measuring the diameter of the cut end surface of wood, and simultaneously imaging the illumination point of the reference light and the cut end surface of wood in conjunction with the imaging and measuring device, and measuring the diameter of the cut circular end surface by processing the image thus obtained. The method for imaging and measuring the diameter of a cut end surface of wood described in claim 2 is characterized in that the light used as the reference for measuring the diameter of the cut end surface of wood is provided by installing two laser emission modules so that the light is parallel, and the two light points projected onto the cut end surface of the wood to be measured maintain a constant distance regardless of the distance from the cut end surface of the wood to be measured, thereby providing a highly reliable reference for length. The method for imaging and measuring the diameter of a cut end surface of wood described in claim 2 is characterized in that, in the imaging and measuring of the cut end surface of wood, both an image captured by irradiating the cut end surface with light that is a reference for measuring the cut end surface of wood and an image captured without irradiating the cut end surface are used for processing, thereby accurately determining the position of the irradiated light in the image. an illumination device attached to the camera and displaying two light spots that serve as measurement standards for image processing; an image processing device that determines the circular shape by eliminating defective parts from the image captured by the camera; a calculation device that determines the center of gravity from the captured image and the minimum value of the circular shape centered on the center of gravity; an actual measurement calculation device that determines the actual measurement value by relative comparison between the minimum value of the circular shape and the distance between the two light spots; a diameter class calculation device that calculates a diameter class value from the actual measurement value of the captured image; a memory device that records the number and volume of timber collected by diameter class; and a display device that displays the calculation results of the diameter class.

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