JP7775552B2 - Method for inspecting wooden products and image acquisition device for inspecting wooden products - Google Patents

Description

The present invention relates to the technical field of manufacturing wooden products.

In recent years, the number of cedar, cypress, and other trees planted in Japan's forests has grown, resulting in an abundant stock of timber in the country. Coupled with the movement toward a decarbonized society, there are high hopes for the use of timber as a building material.
When used as building materials, etc., it is required to inspect the quality and manufacture and supply products that meet the appropriate standards.
Wood is used in two forms: solid wood and laminated wood such as plywood and laminated lumber. Plywood is produced by cutting veneers from raw logs, drying them, gluing the veneers, laminating them, and pressing them. The present applicant has proposed a method and a sorting device for evaluating and sorting veneers for plywood by using transmitted and reflected light, as shown in Patent Document 1 (Japanese Patent No. 6017390) and Patent Document 2 (Japanese Patent Laid-Open No. 2020-144727).
Since irradiated light cannot penetrate plywood made of laminated veneers, inspection methods using transmitted light cannot be used. Therefore, Patent Document 3 (Japanese Patent Application No. 2021-134887) proposes an inspection device for wood products that includes a surface inspection device that uses vertical irradiation light and oblique irradiation light irradiated onto the surface of the wood product, and an end grain inspection device that uses end grain irradiation light irradiated onto the end grain of the wood product.

The inventions proposed in Patent Documents 1 to 3 provide a gap between a leading conveyor and a trailing conveyor in the conveying direction, and irradiate the surface between them with light and take an image to obtain a surface image for evaluation. These inventions target plywood and veneers for plywood, and inspection is possible because there is a width that spans the gap.
Recently, laminated timber and CLT have been attracting attention as structural materials for high-rise buildings. To ensure reliable structural design, it is necessary to evaluate the quality of the lamina, which is the material. With the previously proposed inspection device, it was difficult to obtain images for evaluation of narrow lamina because the position was unstable in the inspection gap.

Patent No. 6017390 Japanese Patent Application Laid-Open No. 2020-144727 Patent application No. 2021-134887

The objective of the present invention is to develop an inspection method that can inspect narrow, long materials such as lamina.

The present invention makes it possible to obtain evaluation images of long wooden materials such as lamina by transporting the long wooden materials in a stable position in the imaging area. To achieve a stable position, the long wooden materials are transported in an oblique position, or the imaging area is set obliquely so that the long wooden materials are gradually transferred from the carry-in conveyor to the carry-out conveyor, thereby ensuring a stable position.
The gist of the present invention is as follows.
1. A method for inspecting long wooden products using surface images, comprising:
An image capturing device for capturing a surface image of a long wooden product, comprising: a carry-in conveyor; a carry-out conveyor; and an imaging area provided between the two conveyors, and imaging means disposed along the imaging area,
The imaging means includes an illumination device and an imaging device,
(A) When the imaging area is provided at an angle to the conveying direction in a plan view , the long wooden product is conveyed in a perpendicular orientation to the conveying direction in a plan view , and an image of the long wooden product is acquired by the imaging means while it passes through the imaging area.
or,
(B) When the imaging area is provided in a direction perpendicular to the conveying direction in a plan view , the long wooden product is conveyed in an oblique position in a plan view with respect to the conveying direction, and an image of the long wooden product is acquired by the imaging means while it passes through the imaging area.
A method for inspecting long wooden products.
2. A device for inspecting long wooden products using surface images,
An image capturing device for a long wooden product, comprising an input conveyor, an output conveyor, and an imaging means disposed between the two conveyors,
The end of the carry-in conveyor and the beginning of the carry-out conveyor are arranged diagonally in a plan view, and the imaging area is arranged diagonally in a plan view,
An image acquisition device for inspecting long wooden products, characterized in that the imaging means comprises an illumination device and an imaging device, and the illumination device and the imaging device are arranged along the direction of the imaging area.
3. The imaging means are arranged above and below,
2. The image acquisition device for inspecting long wooden products according to 2., characterized in that the lighting device has two types of lighting with different illumination angles.
4. The image acquisition device according to 3., wherein the carry-in conveyor and the carry-out conveyor are configured by the same conveyor belt.
5. An image acquisition device for inspecting long wooden products according to any one of 2. to 4., characterized in that the carry-in conveyors and carry-out conveyors are arranged in parallel in at least three rows, and the imaging area formed between the carry-in conveyors and the carry-out conveyors is an oblique linear interval or an interval bent in a "L" shape.
6. A device for inspecting long wooden products using surface images,
An image capturing device for a long wooden product, comprising an input conveyor, an output conveyor, and an imaging means disposed between the two conveyors,
The end of the loading conveyor and the beginning of the unloading conveyor are arranged perpendicular to the conveying direction in a plan view, the loading conveyor is provided with a mechanism for restricting the conveying position of the long wooden products from a perpendicular angle to the conveying direction to an oblique angle, and the unloading conveyor is provided with a mechanism for restricting the conveying position of the long wooden products from an oblique angle to a perpendicular angle to the conveying direction,
The imaging area is located between the infeed conveyor and the discharge conveyor, perpendicular to the conveying direction in a plan view.
An image acquisition device for inspecting long wooden products, characterized in that the imaging means comprises an illumination device and an imaging device, and the illumination device and the imaging device are arranged along the direction of the imaging area.
The image acquisition device having this configuration can be equipped with the devices and mechanisms described in 3. to 5.
7. The image acquisition device for inspecting long wooden products according to 2, 3 or 6, characterized in that the long wooden product is any one of lamina (material for glued laminated lumber, LVL, and CLT), long sawn lumber (columns, beams, and solid boards), glued laminated lumber, plywood, and CLT.
An inspection device for long wooden products, comprising a means for analyzing and evaluating images obtained from an image acquisition device for inspecting long wooden products as set forth in any one of 8.2. to 4.6.
9. The images obtained from the image acquisition device are analyzed and evaluated by the inspection device.
Before and after the image capture device, there are conveying devices and pick-up devices that supply long wooden products to the image capture device. In addition, devices for sorting, conveying, storing, and printing grades are installed according to the evaluation by the inspection device.

1. In the present invention, by conveying long wooden products such as lamina at an angle in a plan view or by setting the interval between the carry-in and carry-out conveyors at an angle, the wooden product straddles both the carry-in and carry-out conveyors in the imaging area, stabilizing its posture and enabling accurate images to be obtained quickly.
In the present invention, an inspection method has been developed that captures images of the surface of narrow, long wooden products in an imaging area without a transport conveyor, and analyzes and evaluates the images.
The present invention makes it possible to obtain evaluation images of long wooden materials such as lamina by transporting the long wooden materials in a stable position in the imaging area. To achieve a stable position, the long wooden materials are transported in an oblique position when viewed from above , or the imaging area is set obliquely when viewed from above , and the long wooden materials are gradually transferred from the carry-in conveyor to the carry-out conveyor, thereby ensuring a stable position.
Although it is possible to transport and photograph long wooden products in the longitudinal direction, it takes time to obtain an image of the entire product, which is inefficient. Since there is a limit to how much imaging can be done by narrowing the gap between the conveyors and capturing images in a small imaging area, by slanting the conveyors in a plan view , sufficient gaps and stability in the transport posture are ensured.
2. The image acquisition device described in claims 2 to 5 is an invention in which the end of the carry-in conveyor and the beginning of the carry-out conveyor are slanted, and the imaging area is the diagonal space formed between the two conveyors in a plan view . By devising the conveyors to form an oblique imaging area and arranging the imaging means along that area, a device is realized that can obtain stable images of long wooden products.
3. The transport conveyor is divided into an inlet and outlet conveyor, so an imaging outlet can be installed below, allowing images of the front and back surfaces of long wooden products to be acquired. By simultaneously evaluating the images of the front and back surfaces, knots that penetrate from the front to the back can be evaluated.
Images captured by irradiating light and capturing reflected light can be used to obtain images of wood products that can be used to evaluate the surface properties of the wood product. Various surface properties can be evaluated by comparing images captured using vertically reflected light and obliquely reflected light. Images are captured using a line sensor camera, stored in memory, and combined to generate a single image of the wood product. Evaluation data can also be accumulated and used for inspection using AI. For example, knots, insect holes, cracks, rot, discoloration, etc. can be detected. By evaluating the front and back surfaces separately and then evaluating properties common to both surfaces, it is possible to determine whether the property penetrates through the thickness.
4. By forming the loading and unloading conveyors from the same conveyor belt, the speeds of the loading and unloading conveyors can be synchronized. The belt can be routed around the area where the imaging device is installed, ensuring space for the imaging device below. In addition, adjustment means such as speed adjustment, tension adjustment, and spacing adjustment can be shared.
5. The loading and unloading conveyors are made up of multiple rows of belt conveyors. Three or more rows are preferable for handover and transport, and four or more rows are usually used for long materials over 2m. A conveyor belt in the center provides stability for handover. On the other hand, for long, warped materials, a central belt can act as a fulcrum, making the material unstable and risking inaccurate images. To avoid this risk, measures can be taken such as not having a central belt or setting the level of the central belt slightly lower.
Furthermore, since any slight warping of the lamina is corrected during the process of applying adhesive and crimping, even warped lamina are subject to quality evaluation.
6. The oblique imaging area can also be shaped like a dogleg. The ends of the infeed conveyors on both sides are long and the center is short, while the outfeed conveyor is long in the center and short on both sides, forming a dogleg-shaped space between them. The imaging means are also arranged on the left and right to form a dogleg shape. In this way, the long material leaves the conveyor at the center, but remains stable because it is supported on both sides, and when both ends of the long material leave the conveyor, the center is supported by the outfeed conveyor, making it more stable.
7. The invention of claim 6 has imaging areas set at a distance from the end of the carry-in conveyor to the beginning of the carry-out conveyor, perpendicular to the conveying direction. Long materials are regulated to maintain an oblique position on the carry-in conveyor, and pass through the imaging area in a diagonal position in a plan view . Then, on the carry-out conveyor, the opposite regulation is applied to correct the conveying position of the wooden products to a position perpendicular to the conveying direction.
In the imaging area, wooden products are transported across both conveyors, so their posture is stable and accurate images can be obtained. This device requires a mechanism to adjust the posture of the wooden products, and also requires a gap between the front and back of the wooden products.
This transport position changing mechanism can also achieve the same effects as those described in 2. to 6. above.
8. The wood products to be inspected by the present invention are long lumber, and mainly consist of long lumber such as lamina, columns, beams, and solid boards, which are materials for laminated lumber, LVL, and CLT, but laminated products such as laminated lumber, plywood, and CLT can also be inspected.
9. Wood products can be inspected by analyzing the images acquired by the image acquisition device of the present invention. Various inspection devices proposed by the present applicant can be used. Then, based on the inspection and evaluation, the wood products are sent to subsequent processes, such as sorting and stockpiling.
Japanese coniferous trees such as cedar, pine, cypress, and larch, which were planted after the war, have grown and are increasing in volume as lumber, but due to low lumber prices and insufficient care such as pruning, there is discoloration due to knots and oil, and the quality varies greatly. By appropriately evaluating these trees using this invention, it is possible to promote the use of these trees.

FIG. FIG. 4 is a diagram showing the transport posture and the arrangement of the image acquisition means. FIG. 1 is an explanatory diagram of a conveyor belt. FIG. 1 shows a perspective view of a first embodiment. FIG. 1 shows a plan view of a first embodiment. 1A and 1B show a front view and a cross-sectional view of a first embodiment. FIG. 10 is a diagram showing a "C"-shaped embodiment of the second embodiment. FIG. 10 is a diagram showing an example of changing the oblique conveying posture according to the third embodiment; FIG. 1 is a diagram showing an example of a wooden product to be inspected.

The present invention is a wood product inspection device that can evaluate the surface properties of long wooden products such as lamina using images captured by irradiating light and capturing reflected light. The inspection method compares images obtained using light reflected from a vertical direction with images obtained using light reflected from an oblique direction to compare the state of shadows caused by unevenness and determine the presence of live knots, knotholes, discoloration, etc.
The invention also proposes an image acquisition device for inspecting wooden products, which is adapted to acquire images of long wooden products.
The image acquisition device is equipped with a device for continuously capturing images of wooden products while they are being transported, with carry-in and carry-out conveying devices provided before and after an imaging area where images are captured using a line sensor-type imaging means. Since it is necessary to stabilize the posture of narrow wooden products in the imaging area, if the imaging area is provided at an angle to the transport direction in a plan view , the posture of the wooden product will be stable even if the wooden product is transported perpendicularly (in the short direction) in a plan view , as it will be supported by the conveying devices before and after. Alternatively, if the imaging area is provided at a right angle to the transport direction in a plan view , the wooden product will be transported at an angle in a plan view , and will be supported by the conveying devices before and after across the imaging area to be stabilized.

An example of a lamina that can be inspected in this invention is shown in Figure 9. Laminae are long, narrow sawn boards approximately 15-60 mm thick, 100-300 mm wide, and 2000-6000 mm long, and are the basic material for laminated lumber and CLT. Evaluating the performance of lamina is an important factor that determines the quality of laminated lumber products. For example, the strength performance of CLT is classified according to its bending performance, and the strength grade of lamina that can be used is determined according to the strength grade of the CLT. Laminae whose constituent layers have different strength grades and are symmetrical about the central axis in the thickness direction of the CLT are called "different-grade construction," while lamina whose constituent layers have the same strength grade are called "same-grade construction." Furthermore, lamina with a specified upper limit for the bending Young's modulus of the lamina used are designated as "Type B construction." If a long, thin lamina is used in the inspection devices proposed in Patent Documents 1 and 2, etc., there is a risk that it may get stuck between the loading and unloading conveyors and fall, making it impossible to obtain a correct image.

The image acquisition device of the present invention will be outlined with reference to FIGS. 1 to 3 and FIG. 6(b).
1 shows an outline of an image acquisition device for inspecting wood products 5, which acquires images of the surfaces of the wood products as they are transported. The transport device 1 is made up of an inlet conveyor 11 and an outlet conveyor 12. An imaging area 13 is provided between the inlet conveyor 11 and the outlet conveyor 12, and an imaging means 6 equipped with a surface illumination means 62 and a surface imaging device 61 is disposed above the imaging area 13. The imaging area 13 is disposed at an angle to the transport direction in a plan view. In order to provide the imaging area 13 at an angle, the ends of the inlet conveyor 11 and the outlet conveyor 12 are formed so as to be inclined in the width direction.
With this configuration, even when the wooden product 5 is transported in the short direction in a plan view , the section supported by one conveyor is shorter, and the wooden product 5 is supported by both the carry-in and carry-out conveyors, allowing it to maintain a stable posture. If the width of the imaging area is set to be approximately the same as the width of the wooden product, when the center of the wooden product is in the imaging area, the leading and trailing ends of the wooden product in the longitudinal direction are supported by the carry-in conveyor and the carry-out conveyor, so the wooden product is passed over in a stable posture. If the wooden product's posture is stable, the reflected light from the illumination does not waver, allowing the surface properties to be accurately imaged.
The image of the wood product 5 obtained by the surface imaging device 61 is analyzed and evaluated for properties by the inspection device 10.

The conveying posture of the wooden product and the arrangement of the imaging means are shown in Figure 2. This is an example of a conveying device using four belt conveyors.
In FIG. 2(a), the four conveyors constituting the carry-in conveyor 11 are set so that the end of the upper conveyor in the figure is to the right of the lower conveyor, and the leading ends of the four conveyors of the carry-out conveyor 12 are set to the left from top to bottom so that they are parallel to the end of the carry-in conveyor.
This arrangement of the conveyor forms the imaging area 13 at an angle in plan view , and the imaging means 6 can be arranged along this imaging area.
Even if the wooden product 51 is transported with its longitudinal direction perpendicular to the carry-in conveyor 11 in a plan view , it will be handed over to the carry-out conveyor 12 earlier on the illustrated lower side of the imaging area 13, and will be handed over later on the illustrated upper side. When the wooden product 51 leaves the carry-in conveyor 11 at the bottom of the illustration, most of it is still supported on the carry-in conveyor 11 side, so its posture is stable, and it will gradually move toward the carry-out conveyor 12 side, so the posture of the wooden product 51 can be stabilized throughout the entire imaging area 13.

In Figure 2(b), of the four conveyors that make up the carry-in conveyor 11, the two central conveyors shown in the figure are set so that their ends are short, and of the four conveyors that make up the carry-out conveyor 12, the two central conveyors are set so that their ends are long.
By arranging the conveyor in this manner, the imaging area 13 is formed in a "L" shape in a plan view , and the imaging means 6 can also be arranged in a "L" shape along the imaging area.
Even if the wooden product 51 is transported with its longitudinal direction perpendicular to the carry-in conveyor 11, it will be taken over by the carry-out conveyor 12 earlier in the illustrated center of the imaging area 13 and later at the top and bottom as illustrated. When the wooden product 51 leaves the carry-in conveyor 11 in the illustrated center, its posture is stable because the top and bottom are still supported by the carry-in conveyor 11 side, and it will gradually move toward the carry-out conveyor 12 side, so the posture of the wooden product 51 can be stabilized throughout the entire imaging area 13.

In FIG. 2(c), the four conveyors constituting the carry-in conveyor 11 and the carry-out conveyor 12 are aligned with their leading and trailing ends at right angles to the conveying direction.
Due to this arrangement of the conveyor, the imaging area 13 is formed perpendicular to the conveying direction in a plan view , and the imaging means 6 is also arranged perpendicular to the imaging area in a plan view .
By transporting the wooden products 51 in an oblique position, they are quickly transferred to the carry-out conveyor 12 on the upper side of the image capturing area 13 as shown, and are slowly transferred to the carry-out conveyor 12 on the lower side as shown. Since the wooden products 51 are transferred sequentially from the carry-out conveyor 11 to the carry-in conveyor 12, the position of the wooden products 51 can be stabilized throughout the entire image capturing area 13.
In addition, a position changing mechanism is provided to change the position of the wooden products during transport to a position perpendicular to the transport direction or an oblique position, so that the wooden products can be matched to the stacking device that takes them out or loads them.

The conveying device 1, which forms the imaging area 13 at an angle in a plan view, can be configured using means such as belts, chains, rollers, etc. It is suitable to use a conveying means using a belt. Although a roller conveyor can be used, there is a risk that the wooden products will bounce off the rollers.
An example of the structure of the transport device will be explained with reference to FIG.
In this example, the carry-in conveyor 11 and the carry-out conveyor 12 are formed by a single common conveyor. By forming them from a common belt, the conveying speed and tension of the carry-in conveyor 11 and the carry-out conveyor 12 are synchronized. Also, in this example, an imaging area 13 is provided, which is formed at the interval between the carry-in conveyor 11 and the carry-out conveyor 12.

The conveying device 1 shown in Fig. 3 is composed of four rows of conveying belts. Fig. 3(a) is a plan view, and Fig. 3(b) shows an example of a side view of the carry-in conveyor and the carry-out conveyor.
There are four rows of carry-in conveyors 11-1 to 11-4 and carry-out conveyors 12-1 to 12-4, and the four rows of conveyors are arranged diagonally opposite each other to form an imaging area 13 diagonally in plan view .
The carry-in conveyor 11 and the carry-out conveyor 12 are formed by a conveyor belt 1A as shown in the side view.
The transport conveyor 1A has a transport surface formed by a carry-in conveyor leading pulley 11A, a carry-in conveyor terminal pulley 11B, a carry-out conveyor leading pulley 12A, and a carry-out conveyor terminal pulley 12B. The carry-in and carry-out transport surfaces are formed at the same height.
In this example, the diameter of the carry-in conveyor terminal pulley 11B is made small. By using a pulley with a small diameter, it is possible to ensure the inclination required for providing oblique lighting for the back side.
The basic configuration is provided with a drive pulley 14 and a tension pulley 16 on the lower side. Six belt detouring pulleys 17 are provided to detour the conveyor belt 1A downwards to form an imaging area 13 between the carry-in conveyor end pulley 11B and the carry-out conveyor start pulley 12A. The belt is routed in a U-shape by the belt detouring pulleys 17, and the resulting space allows for the installation of a lower imaging means.
In this device, a mechanism is provided for changing the position of the input conveyor end pulley 11B back and forth, thereby enabling adjustment of the spacing of the imaging area 13. In response to this position change, the tension of the conveyor belt 1A is maintained by the tension pulley 16.
Since the conveying device 1 is made up of four rows of conveyor belts, the angle of the imaging area 13 can also be adjusted by providing a mechanism that can adjust the positions of both the leading pulley 12A of the output conveyor and the trailing pulley 12B of the output conveyor forward and backward.

In the example of FIG. 3, the carry-in conveyor 11 and the carry-out conveyor 12 are formed by a single belt, but they may also be formed by separate belts and controlled to synchronize their speeds.
In addition, in Figure 3(a), four rows of conveyors are shown in parallel with equal spacing, but if the spacing in the center is wider than on both sides, the probability of stable transport of long materials with warping increases. This is because if warping occurs, transporting the material so that the center where the center of gravity is located is lower will ensure stability. Since slight warping can be corrected, if it is subject to quality inspection, inspection efficiency will improve.
This conveying device 1 is a conveying device for an image acquisition device for inspecting wooden products, and a conveying device that picks up and conveys lamina from a stock is provided in front of this conveying device 1. In addition, after this conveying device 1, a post-process is provided where lamina that have been evaluated by analyzing the images are sorted and stored.

FIG. 6(b) shows the basic configuration of the imaging means.
An imaging area 13 is provided between the transport conveyor 11 and the discharge conveyor 12, and the imaging means 6 is disposed in this imaging area 13.
The imaging means 6 is composed of a front surface imaging device 61, a front surface lighting means 62, a back surface imaging device 71, and a back surface lighting means 72. The imaging devices and lighting means are provided on the front and back surfaces of the wooden product to obtain images of both the front and back surfaces. The lighting means 62 and 72 are composed of reflected light lighting 62A and 72A and oblique light lighting 62A and 72A. The imaging device uses a line sensor type imaging device.
The front surface side is provided above, with the front surface imaging device 61 directly above, the reflected light illuminator 62A at a large angle above, and the oblique light illuminator 62B obliquely above.
Reflected light illumination and oblique illumination utilize the reflection of light at different angles to obtain images, allowing for three-dimensional analysis of the state of unevenness.
The back side is provided at the bottom in the same manner as the front side. In order to ensure the angle of oblique lighting on the back side, in the illustrated example, the terminal pulley of the transfer conveyor 11 is made small. Then, the back side oblique lighting 72B is provided on the side of the terminal pulley of the transfer conveyor 11.

The inspection device that processes and evaluates the image obtained from the imaging device can employ the mechanisms described in Patent Documents 1 to 3 previously proposed by the applicant.
Images captured by irradiating light and capturing reflected light can be used to obtain images of wood products that can be used to evaluate the surface properties of the wood product, and various properties of the surface of the wood product can be evaluated by comparing images obtained using light reflected from a vertical direction and light reflected from an oblique direction. Images are captured using a line sensor camera, stored in memory, and combined to generate a single image of the wood product, and evaluation data can be stored and used to utilize AI for inspection.
The inspection device is equipped with a grade determination device that determines the grade of a wooden product using predetermined determination parameters based on a line image of the wooden product obtained by a color line sensor type camera.
Synchronization processing for generating an image of the entire surface of the wooden product from the line image can be performed by a wooden product detection sensor and encoder installed on the conveying device.
The graded wood products are separated and piled up.
By inspecting the front and back surfaces, it is possible to detect, evaluate, and grade live knots, dead knots, holes, cracks, insect holes, rot, discoloration, blade marks, and poor putty.
By evaluating the front and back surfaces separately and then evaluating the properties common to both surfaces, it is possible to determine whether the properties penetrate through the thickness direction.

The image acquisition device of Example 1 is shown in Figures 4 to 6. Figure 4 is a perspective view, Figure 5 is a plan view, and Figure 6 is a cross-sectional view (a) along the imaging area and a front view (b).
5, the carry-in conveyor 11 and the carry-out conveyor 12 are arranged diagonally with a gap therebetween that forms the imaging area 13. The conveyors are arranged in four parallel rows, with the carry-in conveyor 11 being assigned branch numbers 11-1 to 11-4 and the carry-out conveyor 12 being assigned branch numbers 12-1 to 12-4. Detection sensors 32, 32 that detect wooden products 51 are arranged between the carry-in conveyors 11-1 and 11-2 and between the carry-in conveyors 11-3 and 11-4.
Between the imaging regions 13, there are arranged a surface imaging device 61 consisting of a left surface imaging device 61L and a right surface imaging device 61R, and a surface illumination means 62 consisting of a reflected light illumination device 62A and an oblique light illumination device 62B.
These imaging devices and lighting means are also provided below the transport conveyor for the back side. The state in which they are arranged above and below is shown in Figure 6. In the front view of Figure 6(b), imaging means 6 consisting of an imaging device and lighting means is provided between the carry-in conveyor 11 and the carry-out conveyor 12.
In this example, the conveyor belts for loading and unloading are configured as a single common belt. Therefore, the belt is curved in a U-shape to accommodate the lighting and imaging device underneath. In the front view of Figure 6(b), an imaging means 6 consisting of an imaging device and lighting means is provided between the U-shaped curved loading conveyor 11 and unloading conveyor 12. Reflected light illumination 62A and oblique light illumination 62B are directed toward the conveying levels of the loading conveyor 11 and unloading conveyor 12 that transport the wooden products 51, and surface imaging devices 61L and 61R are positioned with their focus on this conveying level.
Two surface imaging devices 61 are arranged on the left and right to separately photograph the long wooden product 51. The number of imaging devices is not limited to two, and the number can be increased.
The imaging device is installed directly above, and the reflected light is positioned at a distance so as not to hit the imaging device. The oblique light is positioned so that it shines obliquely onto the surface of the wooden product to highlight its unevenness.
For the rear side of the wooden product 51, a reflected light illuminator 72A and an oblique light illuminator 72B are irradiated, and rear side image pickup devices 71L and 71R focused on this conveyance level are arranged.
An encoder 31 is provided on the pulley of the input conveyor 11, and the signal from the detection sensor 32 and the timing of image acquisition by the imaging device are controlled based on the encoder signal to generate image data for the front and back surfaces of a single wooden product.
A cross-sectional view is shown in FIG.

A perspective view of the device configuration is shown in FIG.
The image information captured by the left surface imaging device 61L and the right surface imaging device 61R that form the surface imaging device 61 is processed by the AI controller surface 33A to generate and evaluate a surface image of the wood product.
The image information captured by the left backside imaging device 71L and the right backside imaging device 71R that form the backside imaging device 71 is processed by the AI controller back side 33B to generate a backside image of the wooden product and evaluate it.

The operation is explained as follows:
The wooden products 51 placed on the carry-in conveyor 11 are transported and detected by the detection sensor 32 near the end of the carry-in conveyor 11, and a detection signal is sent to two AI controllers 33A and 33B, which identify the wooden products to be inspected. As the wooden products are transported, they enter the imaging area 13. Once the wooden products enter the imaging area 13, they leave the short carry-in conveyor 11-4 one by one, are illuminated from above and below, and images of the front and back are taken by the imaging means and sent to the AI controllers 33A and 33B.
The wooden products 51 leave the carry-in conveyor in order of length, and are transferred to each of the oppositely disposed carry-out conveyors 12-4 to 12-1. In the illustrated example, the distance between the two conveyors and the inclination of the imaging area 13 are set so that the front end of the wooden product 51 will land on the carry-out conveyor 12-4 before the rear end of the wooden product 51 leaves the carry-in conveyor 11-3. Therefore, the leading end of the wooden product 51 will land on one of the four rows of carry-out conveyors 12 before the rear ends of the wooden products 51 leave two of the four rows of carry-in conveyors 11, allowing the wooden products 51 to pass through the imaging area 13 in a stable position. This makes it possible to acquire undisturbed images.
The timing of transporting the wooden product 51 is managed by an encoder 31 installed on the carry-in conveyor 11, and the detection signal from the detection sensor 32 and image data from a line sensor are integrated by an AI controller to obtain images of the front and back of the wooden product. Quality evaluation is carried out based on these images.

FIG. 7 shows a second embodiment of an image acquisition device in which the imaging region 13 is formed in a "L" shape.
In this embodiment, the two outer conveyors 11-1 and 11-4 that make up the four rows of conveyors 11 are short, and the inner conveyors 11-2 and 11-3 are long, and the opposing conveyors 12 are long on the outside and short on the inside. A U-shaped imaging area 13 is formed between these conveyors, and the imaging means 6 is also U-shaped, bent in the middle. The upper and lower lighting means and imaging devices that make up the imaging means 6 are the same as those in the first embodiment except for their shape.
As in Example 1, the leading edge of the wooden product 51 transported by the input conveyor 11 is detected by the detection sensor 32, and a signal is sent to the AI controller. Images are then captured by the front and back imaging devices 61 and 71, and sent to the AI controller, and images of the front and back surfaces are generated according to the timing signal of the encoder 32.

In this embodiment, the wooden product 51 in the imaging area 13 falls off the outer carry-in conveyors 11-1 and 11-4, but remains stable because the center of the wooden product 51 continues to be supported by the two inner carry-in conveyors 11-2 and 11-3, and the spacing is adjusted so that while more than half the width of the wooden product 51 is on these two carry-in conveyors, it is supported by the outer carry-out conveyors 12-1 and 12-4 of the carry-out conveyor 12. Therefore, the posture of the wooden product 51 moving in the imaging area 13 is stable, and clear images can be acquired.
In this example, the wooden product 51 in the imaging area is supported at the center or both sides, so that its posture is stable.

FIG. 8 shows a third embodiment of an image capturing device in which a wooden product is conveyed in a tilted position and the image capturing area 13 is formed perpendicular to the conveying direction.
In this embodiment, the carry-in conveyor and the carry-out conveyor are each divided into front and rear sections, with a position change mechanism provided between them. The carry-in conveyor and the carry-out conveyor are configured in four rows, as in the first and second embodiments.
The carry-in conveyor 11 is divided into a front carry-in belt conveyor 111 and a rear carry-in belt conveyor 113, between which a carry-in low-friction conveyor 112 and position-changing lifting members 114L and 114R are arranged. A left position-changing lifting member 114L and a right position-changing lifting member 114R are provided at the front and rear and are raised and lowered so as to appear and disappear relative to the conveying level.
The carry-out conveyor 12 is divided into a front carry-out belt conveyor 121 and a rear carry-out belt conveyor 123, between which a carry-out low-friction conveyor 122 and posture return lifting members 124L and 124R are arranged. The left posture return lifting member 124L and the right posture return lifting member 124R are provided at right angles to the conveying direction and are raised and lowered so as to appear and disappear relative to the conveying level.
An imaging area 13 is provided perpendicularly between the rear carry-in belt conveyor 113 and the front carry-out belt conveyor 121. The imaging device and lighting means constituting the imaging means 6 installed in the imaging area 13 are provided perpendicularly to the conveying direction along the imaging area, as in the first embodiment.

The right side of the wooden product 51 comes into contact with the right attitude-changing lifting member 114R during conveyance, and the left side advances and comes into contact with the left attitude-changing lifting member 114L, and at the point when the wooden product 51 becomes inclined with respect to the direction of advancement, the left attitude-changing lifting member 114L and the right attitude-changing lifting member 114R are lowered, the wooden product 51 is conveyed by a rear carry-in belt conveyor 113, sent into an imaging area 13, and images of the front and back are acquired by an imaging means.
The wooden products 51 continue at an angle, are sequentially transferred onto the front discharge belt conveyor 121, and proceed to the discharge low-friction conveyor 122, where the left side of the wooden products 51 abuts against the left posture return lifting member 124L, and then the right side abuts against the right posture return lifting member 124R, and the posture of the wooden products 51 returns to a position perpendicular to the conveying direction. At this point, the left posture return lifting member 124L and the right posture return lifting member 124R are lowered and sent to the rear discharge belt conveyor 123, where they are sent to the subsequent process.
The movement of the components that change their position relative to the conveying surface or return to their original position can be controlled using contact sensors or optical sensors. For example, when a wooden product comes into contact with the left or right components in the extended position, the components are lowered. After that, when the optical sensor detects the passage of the wooden product, the components are raised to prepare for contact with the next wooden product.
The low-friction conveyor 112 and the low-friction conveyor 122, which change the position of the wooden products 51, are formed by belt conveyors or chain conveyors with low friction, so that the position can be easily changed. Chain conveyors tend to have low friction because they have point contact.

1 Conveying device 1A Conveying belt 10 Inspection device 11 Carrying-in conveyor
11A: Leading pulley of carry-in conveyor 11B: End pulley of carry-in conveyor 12: Outgoing conveyor
12A Leading edge pulley of discharge conveyor 12B Ending edge pulley of discharge conveyor 13 Imaging area 14 Drive pulley 15 Imaging interval adjustment mechanism 16 Tension pulley 17 Detour pulley 20 Image acquisition device 3 Control system 31 Encoder
32 detection sensor
33A AI controller front surface 33B AI controller back surface
5, 51 Wooden products 6 Imaging means
61 Surface imaging device
61L: Front surface imaging device left 61R: Front surface imaging device right 62: Front surface illumination means 62A: Reflected light illumination 62B: Oblique light illumination 71: Back surface imaging device
71L: rear surface imaging device left 71R: rear surface imaging device right 72: rear surface illumination means
72A Reflected light illumination 72B Oblique light illumination 111 Front carry-in belt conveyor 112 Carry-in low-friction conveyor 113 Rear carry-in belt conveyor 121 Front carry-out belt conveyor 122 Carry-out low-friction conveyor 123 Rear carry-out belt conveyor 114 Position changeable lifting member 114L Left position changeable lifting member 114R Right position changeable lifting member 124 Position return lifting member 124L Left position return lifting member 124R Right position return lifting member

Claims (8)

1. A method for inspecting long wooden products using surface images, comprising:
An image capturing device for capturing a surface image of a long wooden product, comprising: a carry-in conveyor; a carry-out conveyor; and an imaging area provided between the two conveyors, and imaging means disposed along the imaging area,
The imaging means includes an illumination device and an imaging device,
(A) When the imaging area is provided at an angle to the conveying direction in a plan view , the long wooden product is conveyed in a perpendicular orientation to the conveying direction in a plan view , and an image of the long wooden product is acquired by the imaging means while it passes through the imaging area.
or,
(B) When the imaging area is provided in a direction perpendicular to the conveying direction in a plan view , the long wooden product is conveyed in an oblique position in a plan view with respect to the conveying direction, and an image of the long wooden product is acquired by the imaging means while it passes through the imaging area.
A method for inspecting long wooden products. An apparatus for inspecting long wooden products using surface images,
An image capturing device for a long wooden product, comprising an input conveyor, an output conveyor, and an imaging means disposed between the two conveyors,
The end of the carry-in conveyor and the beginning of the carry-out conveyor are arranged diagonally in a plan view, and the imaging area is arranged diagonally in a plan view,
An image acquisition device for inspecting long wooden products, characterized in that the imaging means comprises an illumination device and an imaging device, and the illumination device and the imaging device are arranged along the direction of the imaging area. The imaging means are arranged above and below,
3. The image acquisition device for inspecting long wooden products according to claim 2, wherein the lighting device has two types of lighting with different illumination angles. The image acquisition device described in claim 3, characterized in that the loading conveyor and the unloading conveyor are composed of the same conveying belt. An image acquisition device for inspecting long wooden products as described in any one of claims 2 to 4, characterized in that the loading conveyors and unloading conveyors are arranged in parallel in at least three rows, and the imaging area formed between the loading conveyors and the unloading conveyors is a diagonal linear interval or a curved "L"-shaped interval. An apparatus for inspecting long wooden products using surface images,
An image capturing device for a long wooden product, comprising an input conveyor, an output conveyor, and an imaging means disposed between the two conveyors,
The end of the loading conveyor and the beginning of the unloading conveyor are arranged perpendicular to the conveying direction in a plan view, the loading conveyor is provided with a mechanism for restricting the conveying position of the long wooden products from a perpendicular angle to the conveying direction to an oblique angle, and the unloading conveyor is provided with a mechanism for restricting the conveying position of the long wooden products from an oblique angle to a perpendicular angle to the conveying direction,
The imaging area is located between the infeed conveyor and the discharge conveyor, perpendicular to the conveying direction in a plan view.
An image acquisition device for inspecting long wooden products, characterized in that the imaging means comprises an illumination device and an imaging device, and the illumination device and the imaging device are arranged along the direction of the imaging area. 7. An image acquisition device for inspecting long wooden products according to claim 2, 3 or 6, wherein the long wooden product is any one of lamina, long lumber, laminated lumber, plywood and CLT. An inspection device for long wooden products, comprising means for analyzing and evaluating images obtained from an image acquisition device for inspecting long wooden products according to any one of claims 2 to 4 and 6.