JP6649716B2 - Detection method, measurement method and measurement device - Google Patents

Description

  The present invention relates to a technique for inspecting and measuring raw wood.

  Even if the logs are grown and collected on the same land, the growth conditions such as sunshine and soil conditions differ for each log. In addition, it grows under the influence of various natural environments, such as different weather conditions every year. Logs that have grown in each of the locations where such growth conditions are different are cut down, roughly trimmed to predetermined dimensions for transportation and processing, and collected at a factory for processing. After that, the collected raw wood is subjected to a predetermined process to be processed into various wood products. Some wood products are manufactured by adopting a predetermined part of the wood suitable for the wood product based on the characteristics of the wood as a raw material.

  As a technique for inspecting the characteristics of the raw wood, a technique for inspecting the characteristics of the raw wood without contact has been proposed. For example, Patent Literature 1 and Patent Literature 2 disclose techniques for measuring the water content of raw wood in a non-contact manner using microwaves. Patent Document 3 discloses a technique for automatically detecting the position of the center of the annual ring of a log. In the technique of Patent Document 3, a plurality of search start points are set, and the intersection of the movement trajectory when the search filter is moved in the normal direction of the annual ring from the search start point is set as the center of the annual ring.

JP 2001-289760 A JP-A-10-68701 JP 2011-88436 A

  The log has characteristics that vary from position to position on the cut surface, which is the cut surface. For example, the water content at each position of the annual ring formed in the radial direction may be significantly different between the core material near the center of the annual ring (near the pulp center) and the sapwood near the outer side of the annual ring (near the outer skin). When measuring with microwaves as in Patent Literature 1 and Patent Literature 2, the measurement results are averaged, and the measurement accuracy of each moisture content at a different position on the wood surface may be low. In order to automate the measurement of the characteristic at different positions on the lip end, it is necessary to automate the position identification on the lip end, for example, the identification of the pith position. Patent Literature 3 discloses a technology for automatically detecting the center of the annual ring (that is, the pith) of a log, but there is a concern that sufficient detection accuracy may not be obtained depending on the position of the search start point. In addition, if the number of search start points (the number of movement trajectories) is increased to improve detection accuracy, it is estimated that the processing load increases.

  A first object of the present invention is to automate detection of a medullar position.

  A second object of the present invention is to improve the measurement accuracy of the characteristics of a log.

  In order to achieve the first object, according to the first aspect of the present invention, a photographing step of photographing a cut surface, which is a cut surface of raw wood, and a plurality of annual rings from the image of the cut surface photographed in the photographing process. An extraction step of extracting, a virtual circle identification step of identifying a circle approximating each annual ring extracted in the extraction step, and identification of a virtual circle having a predetermined radius concentric with the circle, and identification in the virtual circle identification step A determining step of determining the position of the medulla of the kiguchi surface based on the degree of overlap between the virtual circles thus determined.

  In order to achieve a second object, according to a second aspect of the present invention, there is provided a method for measuring a raw wood in which a position of a nucleus of a lip is detected by the detection method, wherein a probe is brought into contact with the lip. And a step of moving one of the tracing stylus or the log in the radial direction of the cleave surface so as to pass through the position of the pith, with the tracing stylus in contact with the cleaver surface, A featured measurement method is provided.

According to a third aspect of the present invention, in order to achieve a second object, a photographing means for photographing a woodcut surface of a log, and the woodcut surface based on an image of the woodcut surface taken by the photographing means. Detecting means for detecting the position of the pith, a tracing stylus for measuring a predetermined property of the raw wood in contact with the kiguchi face, and the kiguchi face so as to pass through the position of the pith detected by the detecting means Moving means for moving one of the raw wood including the tracing stylus or the kiguchi surface in the radial direction, and the photographing means comprises illumination means for irradiating red light toward the kiguchi surface. A featured measurement device is provided.

  According to the first aspect of the present invention, the detection of the medullar position can be automated.

  According to the second and third aspects of the present invention, it is possible to improve the measurement accuracy of the characteristics of the raw wood.

The figure which looked at the measuring device concerning one embodiment of the present invention from the side. The figure which looked at the measuring device of FIG. 1 from the top. 2A is a diagram of the measuring device of FIG. 1 as viewed from the front, and FIG. 2B is a block diagram of a control unit of the measuring device of FIG. 4A is a perspective view of the support unit, and FIG. 4B is a cross-sectional view taken along line II of FIG. FIG. (A)-(C) are three views of a tracing stylus. (A) And (B) is explanatory drawing of the measuring aspect of a tracing stylus. 4A and 4B are flowcharts illustrating a processing example of a control unit. 4A and 4B are flowcharts illustrating a processing example of a control unit. (A) is an explanatory diagram of a kiguchi surface, (B) is an explanatory diagram showing an example of detecting a pith position. Explanatory drawing which shows the example of detection of a pulp position. Explanatory drawing which shows the example of detection of a pulp position.

  An embodiment of the present invention will be described with reference to the drawings. In each of the drawings, X and Y indicate horizontal directions orthogonal to each other, and Z indicates a vertical direction.

<Measuring device>
A measuring device A according to an embodiment of the present invention will be described with reference to FIGS. 1 is a diagram of the measuring device A viewed from the side, FIG. 2 is a diagram of the measuring device A viewed from above, and FIG. 3A is a diagram of the measuring device A viewed from the front.

  The measuring device A is a device that measures the characteristics of a log W placed on the rack R in a substantially horizontal posture. The log W is arranged so that the cut surface W0, which is a cut surface thereof, faces the measuring device A. Generally, in wood obtained by artificially drying raw wood, it is necessary to control the moisture content of the wood. In particular, since the cedar wood has a large variation in the water content after artificial drying, it is indispensable to inspect the water content at the start of drying (initial water content). The measuring device A can measure the water content of the raw wood W.

  The measurement device A includes a measurement unit 1, a photographing unit 2, an illumination unit 3, a slide unit 4, a lifting unit 5, a slide table 6, a drive unit 7, and a base plate 8.

  The measurement unit 1 is a unit that measures the characteristics of the log W. Details will be described later. The photographing unit 2 is a digital camera unit for photographing the wooden surface W0, and includes an image pickup device such as a CCD sensor and an optical system such as a lens for forming a subject image on the image pickup device.

  The photographing unit 2 is disposed so as to face the kiguchi surface W0 so that the kiguchi surface W0 is located within the photographable range, and is located at the center of the measurement range of the measurement unit 1 and deviated from the measurement trajectory (the measurement unit 1). In the upper center of the measurement direction). Therefore, if the woodcut WO of the log W is placed outside the measurement range of the photographing unit 2, the log W is regarded as unmeasurable (deformed so as to have no commercial value) and the measurement by the measurement unit 1 is stopped. .

  The illumination unit 3 is a unit that irradiates light to the cut edge W0 when the shot unit 2 shoots the cut edge W0, and includes a light emitting element such as an LED. In the case of the present embodiment, the lighting unit 3 irradiates light of a predetermined color toward the front end face W0. The predetermined color is, for example, red. By photographing the front edge W0 while irradiating the front edge W0 with light of a predetermined color, it is possible to improve the extraction accuracy of the image of the front edge W0 in the captured image (a detailed example will be described later).

  The measurement unit 1, the photographing unit 2, and the illumination unit 3 are supported by a slide unit 4. The slide unit 4 is moved up and down by a lifting unit 5. By moving the slide unit 4 up and down, it is possible to adjust the height of the measuring unit 1 and the photographing unit 2 with respect to the cutting edge W0. At the time of photographing the frontal edge W0, the height of the slide unit 4 is adjusted so that the photographing unit 2 is located at a height facing the frontal edge W0. Further, when measuring the characteristics of the log W, the height of the slide unit 4 is adjusted so that the measurement unit 1 is positioned at a height opposed to the cutout surface W0.

  The slide unit 4 includes a support unit 41 and a support plate 42. The support unit 41 supports the measurement unit 1 so as to swing freely. In the case of the present embodiment, the support unit 41 supports the measurement unit 1 so as to swing freely within a predetermined range. The measurement unit 1 is swingable in the direction of arrow Dz in FIG. 1 and in the direction of arrow Dy in FIG. FIG. 4A is a perspective view of the support unit 41, and FIG. 4B is a cross-sectional view of the support unit 41 taken along line II of FIG. 4A.

  The support unit 41 includes two mounting portions 410, a supporting portion 411, a mounting portion 412, a hollow supporting portion 413, an arm portion 414, a shaft 415, and a spherical body 416. The two mounting portions 410 are portions fixed to the slider 54 of the lifting unit 5. The support part 411 is located between the two attachment parts 410. A hole in the Z direction 411a is formed in the support portion 411, and the ball nut unit 55 of the lifting unit 5 is fixed to the hole 411a. In addition, the support portion 413 is fixed to one side surface of the two mounting portions 410 and the support portion 411 (the surface of the measurement unit 1 on the side of the cylinder 11: the right side surface in FIG. 4B).

  The spherical body 416 is a substantially cylindrical member having a through hole 416a therein, and the shaft 415 is inserted into and fixed to the through hole 416a. The arm 414 is fixed to both ends of the shaft 415. The arm portion 414 is a C-shaped member, and both ends on the open side are fixed to the shaft 415, and the mounting portion 412 is fixed to an intermediate portion thereof. The cylindrical body 11 (described later) of the measurement unit 1 is fixed to the mounting portion 412.

  The support portion 413 has a cavity inside thereof, and has a concave portion 413 a that comes into surface contact with the surface of the spherical body 416. The spherical body 416 has its surface rotatably supported along the surface of the concave portion 413a, and the mounting portion 412 is three-dimensionally swingable (floating state). For this reason, the measuring unit 1 fixed to the mounting portion 412 is also supported in a three-dimensionally swingable manner. However, a buffer unit ABR described later comes into contact with the measuring unit 1 and the measuring unit 1 1 is constantly urged in the X direction, the swing in the X direction is restricted, and the measurement unit 1 is swingable in the Z direction (Dz direction in FIG. 1) and the Y direction (Dy direction in FIG. 2). ing.

  A buffer unit ABR is fixed to each lower portion of the two mounting portions 410 via a bracket 417a. The two buffer units ABR are spaced apart in the Y direction.

  The buffer unit ABR includes a rod 417 that is a shaft-like member extending in the X direction, and the tip of the rod 417 is inserted into a hole 418b (FIG. 4B) of a bracket 418a fixed to the back of the measurement unit 1. Is done. The hole 418b is a hole having a diameter larger than the diameter of the rod 417 so as to allow the measurement unit 1 to swing in the Dz direction within a predetermined range.

  A ring-shaped stopper 418 is attached to the distal end side of the rod 417. The stopper 418 has a hole through which the rod 417 passes, and is movable with respect to the rod 417 in the axial direction of the rod 417 (that is, in the X direction). A spring receiver 417b is fixed to the root side of the rod 417, and an elastic member 419 is provided between the spring receiver 417b and the stopper 418. The elastic member 419 is a coil spring in the present embodiment, and the elastic member 419 is wound around the rod 417.

  The stopper 418 is in contact with the back of the bracket 418a. When the measurement unit 1 swings from the swing center (neutral position) in the Dy direction in FIG. 2, one of the two elastic members 419 is compressed, and an urging force (elasticity) is applied to return the measurement unit 1 to the swing center. Force). Thus, the two elastic members 419 urge the measurement unit 1 so as to maintain the measurement unit 1 at the swing center. The support plate 42 is a plate-shaped member, and is fixed to two mounting portions 410. The photographing unit 2 and the lighting unit 3 are fixed to the front of a support plate 42 (the surface facing the log W: the right side in FIG. 1).

  Returning to FIGS. 1 to 3A, the lifting unit 5 will be described. The elevating unit 5 includes a main body (post member) 51 extending in the Z direction. Two rail members 52 are provided on the front surface of the main body 51 (the surface facing the log W: the right side in FIG. 1). The rail member 52 extends in the Z direction. A slider 54 is engaged with each rail member 52, and the two mounting portions 410 (support unit 41) described above are fixed to the slider 54. The slider 54 is slidable on the rail member 52 by the guide of the rail member 52. For this reason, the support unit 41 and the entire slide unit 4 can slide along the rail member 52.

  A ball screw shaft 53 extending in the Z direction is arranged between the two rail members 52. The ball screw shaft 53 is supported by the main body 51 so as to be rotatable around the axis. The upper end of the ball screw shaft 53 is connected to the output shaft of the motor 50. The motor 50 is fixed to the top of the main body 51, and rotates the ball screw shaft 53 by its drive. A ball nut unit 55 is screwed to the ball screw shaft 53, and the ball nut unit 55 is fixed to the support portion 411 as described above. The ball nut unit 55 is moved up and down along the ball screw shaft 53 by the rotation of the ball screw 53, whereby the entire slide unit 4 is moved up and down. That is, the rotation of the ball screw 53 causes the slide unit 4, the measurement unit 1, the imaging unit 2, and the illumination unit 3 to move up and down integrally. In this embodiment, a ball screw mechanism is employed as the drive mechanism of the elevating unit 5, but another drive mechanism such as a rack and pinion mechanism, a belt transmission mechanism, or a linear motor may be used.

  The lifting unit 5 is provided on a slide table 6. The slide table 6 is a plate-shaped member, and a plurality of sliders 61 are provided on a lower surface thereof. The slider 61 is engaged with the rail member 81. The slider 61 is slidable along the rail member 81 by the guide of the rail member 81, and the entire slide table 6 is slidable on the rail member 81.

  The two rail members 81 are fixed to the base plate 8. The rail member 81 extends in the X direction, and the two rail members 81 are provided apart from each other in the Y direction. The drive unit 7 is fixed to the base plate 8. The drive unit 7 is, for example, an air cylinder or an electric cylinder, and the tip of the rod is fixed to the slide table 6. By driving the drive unit 7, the base plate 8 can be moved forward and backward in the X direction.

  With the above configuration, the measurement unit 1, the photographing unit 2, and the illumination unit 3 are moved in the X direction by the drive of the drive unit 7, and are moved up and down by the drive of the motor 50.

<Measurement unit>
The measurement unit 1 will be described with reference to FIGS. 1 to 3A and FIGS. 5 to 7B. FIG. 5 is a cutaway view of the measuring unit 1, and is a view of the internal structure of the measuring unit 1 as viewed from above. FIGS. 6A to 6C are three views of the tracing stylus 12 included in the measuring unit 1. FIGS. 7A and 7B are explanatory diagrams of the measurement mode of the tracing stylus 12.

  The measuring unit 1 includes a cylindrical body 11 forming an outer wall thereof, a tracing stylus 12, and a moving unit 13.

  The cylindrical body 11 has a rectangular hollow body extending in the Y direction as a whole, and is composed of four walls, that is, up and down and front and back, and left and right sides thereof are closed by cover members. The front wall constitutes an abutment member 11a that comes into contact with the cut surface W0 during measurement. The contact member 11a is a plate-like member extending in the Y direction, and its surface forms a flat contact surface that contacts the cut edge surface W0. The contact surface defines an opening 11b extending in parallel with the extending direction (Y direction) of the contact member 11a. The opening 11b is a slit that penetrates the contact member 11a, and exposes the tracing stylus 12 arranged inside the cylindrical body 11 to the kiguchi surface W0 side and moves in the Y direction with the tracing stylus 12 exposed. Enable.

  The moving unit 13 is a mechanism for moving the tracing stylus 12 in the direction in which the cylindrical body 11 extends (Y direction), and includes a motor 131, a ball screw shaft 132, a ball nut unit 133, a rail member 134, and a slider 135. And The ball screw shaft 132 and the rail member 134 extend in the direction in which the cylinder 11 extends (Y direction), and the ball screw shaft 132 is rotatably supported around the axis. The end of the ball screw shaft 132 is connected to the output shaft of the motor 131, and the ball screw shaft 132 is rotated by the driving force of the motor 131. The slider 135 is engaged with the rail member 134 and is slidable on the rail member 134 by the guide of the rail member 134. The rail member 134 moves the tracing stylus 12 while the positional relationship between the contact surface of the abutting member 11a and the tracing stylus 12 in the X direction is maintained at a constant distance in the extending direction (Y direction). It is arranged as parallel as possible.

  The ball nut unit 133 is formed integrally with the slider 135, and is screwed with the ball screw shaft 132. When the ball screw shaft 132 is rotated, the slider 135 fixed to the ball nut unit 133 is moved in the direction in which the cylindrical body 11 extends (Y direction).

  The measuring element 12 is fixed to the front side of the slider 135. Therefore, when the slider 135 moves, the tracing stylus 12 moves together with the slider 135. This makes it possible to move the tracing stylus 12 relative to the log W in the radial direction of the cutting edge W0. In the case of the present embodiment, the tracing stylus 12 is relatively moved with respect to the raw wood W by the moving unit 13, but conversely, a configuration in which the raw wood W is moved with respect to the measuring stylus 12 can also be adopted. In the present embodiment, a ball screw mechanism is employed as the drive mechanism of the moving unit 13, but another drive mechanism such as a rack and pinion mechanism, a belt transmission mechanism, or a linear motor may be used. In addition, although the contact surface of the contact member 11a is defined to be in contact with the cut surface W, the contact surface may be defined by at least three contact points, and may be defined by three contact members.

  In the case of the present embodiment, the tracing stylus 12 is a contact-type sensor unit including the load cell 123 as a sensor. The sensor included in the tracing stylus 12 may be a contact-type sensor other than the load cell.

  The tracing stylus 12 includes a main body 121 and a housing 122. The main body 121 is a plate-shaped member.

  The accommodation section 122 is a cylindrical member formed integrally with the main body section 121, and the load cell 123 is fixed therein. A circular opening 121 a is formed in the center of the main body 121. A disk 124 having a smaller diameter than the opening 121a is arranged in the opening 121a. The disk 124 is connected to the main body 121 via a plurality of leaf springs 127 and is located at the center of the opening 121a. Each leaf spring 127 is fixed to the disk 124 and the main body 121 by a plurality of screws 127a. The disk 124 can be displaced in the X direction by elastic deformation of the leaf spring 127.

  The detection unit of the load cell 123 is in contact with the back surface of the disk 124. When the disk 124 receives an external force toward the load cell 123 in the X direction, the disk 124 is displaced toward the load cell 123 by the elastic deformation of the leaf spring 127, and the load cell 123 detects this displacement. Thus, the load acting on the disk 124 is detected by the load cell 123.

  The disk 124 is provided with a pair of arm members 125 integrally. A hard sphere 126 is supported at the distal ends of the pair of arm members 125 via a pin 125a. When the hard sphere 126 is brought into contact with the cut surface W0 and receives a reaction force from the cut surface W0, the reaction force is transmitted to the load cell 123 via the pair of arm members 125 and the disk 124 and detected. In a natural state of the leaf spring 127, the hard sphere 126 is in a state of protruding outward (to the side of the wooden edge W0) from the opening 11b. The pin 125a is an axis extending in the Z direction, and the hard sphere 126 is supported rotatably about the pin 125a.

  With reference to FIGS. 7A and 7B, a description will be given of a manner of measuring the characteristics of the raw wood W with the tracing stylus 12. When detecting the characteristics of the raw wood W, the drive unit 7 is driven to bring the contact member 11a into contact with the cut surface W0 as shown in FIG. Since the measuring unit 1 is swingably supported in the Dz direction and the Dy direction by the support unit 41, the measuring unit 1 follows the surface direction of the kiguchi surface W0 by contacting the contact member 11a with the kiguchi surface W0. Swings, so that the extending direction of the measuring unit 1 (that is, the moving direction of the tracing stylus 12) and the surface direction of the cutting edge W0 become the same (or substantially the same). In this way, by bringing the contact member 11a into contact with the cut edge surface W0, it becomes easy to move the tracing stylus 12 in parallel with the surface direction of the cut edge surface W0.

  As described above, in the natural state of the leaf spring 127, the rigid sphere 126 is in a state of protruding from the opening 11b toward the kiguchi surface W0, and the rigid ball 126 is brought into contact with the kiguchi surface W0 by bringing the contact member 11a into contact with the kiguchi surface W0. Contact W0. The tracing stylus 12 is displaced so as to be pressed inside the cylinder 11 and retracted inside the cylinder 11, so that a load is input to the load cell 123, and the leaf spring 127 is elastically deformed. Due to the elastic deformation of the leaf spring 127, after the measurement is completed, the contact member 11a returns to the natural state when the contact member 11a moves away from the cut edge surface W0, and the rigid ball 126 can be returned to the original position.

  As shown in FIG. 7B, the measurement of the characteristics is performed by sampling the detection result of the load cell 123 while moving the tracing stylus 12 in the radial direction (Y direction) of the kerf surface W0 by the moving unit 13. As described above, since the hard sphere 126 is supported rotatably about the pin 125a, it rolls on the kerf surface W0, whereby the tracing stylus 12 moves smoothly on the kerf surface W0.

  When the tracing stylus 12 is moved, the tracing stylus 12 is moved in the radial direction of the cleave surface W0 so that the hard sphere 126 passes through the position of the medulla of the cleave surface W0. Is obtained. A line H in FIG. 7A indicates the position (height) of the medulla.

  Here, the nucleus of the kiguchi surface W0 will be described. FIG. 10A shows an example of the cut surface W0. The pith W1 means the central part of the annual ring. There is a heartwood W2 around the pith W1, a sapwood W3 around the heartwood W2, and an outer bark W4 around it. The core material W2 and the sapwood W3 may differ greatly in moisture content and the like. As shown by the one-dot chain line in FIG. 10A, by measuring the characteristic distribution on the line passing through the medulla W1, the difference in the characteristics of the core material W2 and the sapwood W3 can also be clarified.

  The amount of displacement of the tracing stylus 12 in the X direction is affected by the hardness of the cut surface W0. In a soft part, the tracing stylus 12 is relatively located on the side of the cutting edge W0, and in a hard part, the tracing stylus 12 is relatively located in the slider 135 side. By converting the detection result of the load cell 123 by a predetermined conversion formula, it is possible to calculate the hardness or the water content of the cut surface W0. In the case of the present embodiment, since the tracing stylus 12 is brought into direct contact with the kerf face W0 and its characteristics are measured, it is possible to directly obtain characteristic values at a plurality of positions on the kerf face W0. In particular, it is possible to obtain a distribution of characteristic values on a line that crosses the woodcut surface W0 in the radial direction. Thus, in the present embodiment, the measurement accuracy of the characteristics of the raw wood W can be improved as compared with the non-contact type measurement using microwaves or the like.

  In FIG. 7B, the entire range from the one end to the other end in the radial direction of the cut surface W0 is set as the measurement range, but the present invention is not limited to this. For example, only the distance corresponding to the radius from the medulla W1 to one end in the radial direction of the wood surface W0 may be set as the measurement range. At that time, the measurement start point may be the pith W1 or may be near the outer bark W4.

<Control unit>
A control unit for controlling the measurement device A will be described with reference to FIG. FIG. 3B is a block diagram of the control unit 100. The control unit 100 includes a processing unit 101 such as a CPU, a storage unit 102 such as a RAM and a ROM, and an interface unit 103 for interfacing the processing unit 101 with an external device. The interface unit 103 also includes a communication interface for performing communication with the host computer. The host computer is, for example, a computer that controls the entire manufacturing facility in which the measuring device A is arranged.

  The processing unit 101 executes a program stored in the storage unit 102, and controls various actuators 104 based on detection results of various sensors 105 and instructions from a host computer or the like. The various sensors 105 include, for example, various sensors such as a sensor for detecting the position of the slider 4, a sensor for detecting the position of the tracing stylus 12, and an image sensor of the imaging unit 2. Note that an image processor that processes an image captured by the image sensor may be provided. The various actuators 104 include, for example, the motors 54 and 131 and the cylinder 7.

<Control example>
An example of a process executed by the processing unit 101 will be described. FIG. 8A is a flowchart illustrating an example of a process executed by the processing unit 101. In S1, the position of the medulla of the kiguchi surface W0 is automatically detected. Details will be described later. In S2, as described with reference to FIGS. 7 (A) and 7 (B), the tracing stylus 12 is moved in the radial direction of the cut surface W0 so that the rigid sphere 126 passes through the position of the medulla of the cut surface W0. Then, the characteristics of the raw wood W are measured. Details will be described later. Thus, one unit process is completed.

<Detection of pith position>
An example of the process of detecting the position of the medulla W1 in S1 will be described. FIG. 8B is a flowchart showing an example of the processing. In step S1, an image of the kiguchi surface W0 is taken. Here, first, the photographing unit 2 is moved up and down to a height opposed to the opening surface W0. The illumination unit 3 illuminates the kiguchi surface W0, and the photographing unit 2 images the kiguchi surface W0. The image IMO in FIG. 10B shows an example of the photographed image. The image IMO includes an image other than the kiguchi W0, for example, a background. Specifically, in the factory where the measuring device A is installed, an image of an object existing around or behind the kiguchi surface W0 is also reflected. At the time of photographing, the illumination unit 3 illuminates the wooden surface W0 with a predetermined color, so that it is possible to easily distinguish the image of the wooden surface W0 from the background image. Here, as an example, a case where red light is irradiated will be described. Illumination may be other than red light, but the edge of the wood generally has a higher luminance value of R among RGB (red, green, blue), and irradiation of red light is advantageous in distinguishing from the background image. It is.

  The image IMO may have distortion inherent to the photographing unit 2. Further, it is necessary to match the coordinate space of the imaging system with the position coordinate space of the measurement unit 1. Thus, an image IM1 (FIG. 10B) obtained by correcting the coordinate space conversion and the image distortion is obtained. The image IM1 becomes a reference image.

  In S12, a range for extracting the annual rings is set as a pre-process of the process (S13) for extracting the annual rings of the kiguchi surface W0. Annual rings may be extracted over the entire area of the wood edge W0, but the processing time becomes longer or the processing load becomes larger. In the present embodiment, the extraction range of the annual ring is set to a certain area around the medulla W1 to reduce the processing time or the processing load.

  The process of S12 includes a contour extraction step of extracting a contour of the cut edge W0 based on the image IM1 of the cut edge W0, a circle approximating the extracted contour of the cut edge W0, and a predetermined radius concentric with the circle. And a step of setting a circle having a circle as an extraction range. First, in order to extract a contour, the image IM1 is separated into a red component (R), a green component (G), and a blue component (B), which are the three primary colors of light, as shown in FIG. Since the entrance edge W0 is illuminated in red during photographing, the R image is an image in which the entrance edge W0 has high luminance. Subsequently, as shown in FIG. 10B, each of the separated components is converted into a hue component (H), a saturation component (S), and a lightness component (V) (RGB → HSV conversion). , H image, S image and V image, respectively.

  Next, the H image is binarized according to whether the red component (R) is within a predetermined value range, and the V image is binarized according to whether the brightness is within a predetermined value range. The wood edge W0 utilizes the fact that the red color is strong and that the brightness is high due to illumination. Further, a logical product of pixel values is obtained between the binarized H image and the binarized V image, and an image IM2 in FIG. 11 is generated. As a result, an image IM2 in which the influence of disturbance light is reduced can be obtained.

  With respect to the image IM2, the “hole filling” of the area surrounded by the pixels is performed to generate the image IM3. In order to remove noise from the image IM3, an opening process is performed on the image IM3 to generate an image IM4. When the image IM4 includes a plurality of images that are separated from each other, the largest image among them is regarded as the image of the cut edge W0, and the other images are deleted. Since the image IM4 includes two images (the large image b1 and the small image s1), the small image s1 is deleted. Further, a convex hull process is performed on the image of the tip surface W0 to generate an image IM5 that approximates the image of the tip surface W0 to a circular shape.

  In the image IM5, an image IM6 is generated by converting the image of the kiguchi surface W0 into data in which the outline is represented by a line. Further, a true circle approximate to the image IM6 is specified. Here, for example, a straight line portion is deleted from the contour line of the cutting edge W0, and a true circle approximating the largest arc line among the plurality of remaining arc lines is specified. In the image IM7, an example of the specified perfect circle is indicated by an arrow. Note that the image IM7 is an explanatory image, and it is not necessary to actually generate this image.

  Subsequently, a virtual circle having a common center with the specified true circle and having a predetermined radius is specified, and the range of the virtual circle is set as an annual ring extraction range. The radius can be, for example, 50% of the radius of the perfect circle. In the image IM8, the extraction range of the annual ring is indicated by an arrow. Thus, the extraction range setting process in S12 ends.

  Returning to FIG. 8B, in S13, annual ring extraction processing is performed. First, an image is generated by cutting out the extraction range set in S12 from the reference image IM1. Further, annual rings are extracted from the extracted image. The image IM9 in FIG. 12 shows an image obtained by cutting out the extraction range from the reference image IM1 and displaying the image with the annual rings emphasized. It is not necessary to generate this image itself, but it is sufficient that annual rings can be extracted. The annual rings can be identified by specifying the boundaries of the rings based on changes in the density of the image. Even if it is recognized as the same annual ring in image recognition, if the change in curvature reaches a certain value or more, it may be divided and recognized as another annual ring. Further, annual rings smaller than a certain size may be regarded as noise and deleted.

  In S14, a virtual circle specifying process is performed. Here, first, a true circle approximate to each annual ring extracted in S13 is specified. Image IM10 in FIG. 12 shows an image displaying a true circle approximating each annual ring. It is not necessary to generate this image itself, but it is sufficient that each perfect circle can be extracted. Here, for example, a straight line portion is deleted from the extracted annual rings, and a true circle approximating the largest arc line among a plurality of remaining arc lines is specified. Next, a virtual circle having a predetermined radius concentric with the specified true circle is specified.

  Returning to FIG. 8B, in S15, a process of determining the position of the medulla W1 is performed. Here, the position of the medulla W1 of the kiguchi surface W0 is determined based on the degree of overlap between the virtual circles specified in S14. Although various methods can be adopted as the evaluation method of the degree of overlap, a luminance value is used here. FIG. 9A is a flowchart illustrating a processing example of S15.

  In S21, a process of adding a luminance value to a portion where the virtual circles overlap is performed. A specific example will be described. The image IM11 in FIG. 12 shows an image in which each virtual circle is displayed as indicated by a broken arrow. Each virtual circle is not a contour but an image of a filled circle, and the brightness values of each virtual circle are assumed to be the same. For example, a circle having a luminance value of 1 and a radius of 20 pixels is used. Then, the luminance value is added to the portion where the virtual circles overlap. It can be seen that the portion indicated by the solid arrow in the image IM11 has a high luminance value. That is, the portion where the luminance value is high is a portion that is the center of more annual rings.

  Returning to FIG. 9A, in S22, an area extraction process is performed. Here, an area where the luminance value is equal to or more than a predetermined value is extracted after the addition of the luminance value in S21. For example, a region of a pixel having a luminance value of 60% or more of the maximum luminance value after the addition is extracted. In the image IM12 of FIG. 12, the extracted area is indicated by an arrow. An image IM13 obtained by performing an opening process or the like on the image IM12 for noise removal is generated.

  Returning to FIG. 9A, in S23, the area selection processing and the centroid calculation processing are performed. In the region extraction process of S22, there is a possibility that a plurality of regions are extracted. If a plurality of areas are extracted, the largest area is selected. Then, the centroid of the selected area is calculated, and the position of the centroid is determined as the position of the medulla W1 as shown in FIG.

  Thus, one unit process is completed. In this manner, in the present embodiment, the detection of the position of the pith on the kiguchi surface can be automated. In the present embodiment, a circle approximating each annual ring is specified, and further, a virtual circle having a predetermined radius concentric with the circle is specified. Then, the position of the pith was determined from the degree of overlap of the virtual circles. By performing fitting of a circle substantially similar to the annual ring, the position of the medulla can be determined, so that the position of the medulla can be detected by relatively simple processing. Further, since the position of the pith is near the center of the annual ring, the position of the pith is determined from the degree of overlap of the virtual circles, thereby improving the detection accuracy of the specified position of the pith. In particular, the closer to the marrow, the more the marrow tends to be located at the center of the annual ring.Therefore, setting the extraction range of the annual ring to an area near the marrow not only reduces the processing load but also improves the detection accuracy of the marrow position. Can be improved.

<Measurement of characteristics of raw wood>
A processing example of S2 in FIG. 8A will be described. FIG. 9B is a flowchart showing an example of the processing. In S31, the position of the tracing stylus 12 is adjusted. Here, the measurement unit 1 is moved up and down so that the tracing stylus 12 is positioned at the height of the medulla W1 detected in S1. In FIG. 7A, the measurement unit 1 is moved up and down so that the hard sphere 126 is positioned at the height of the line H. Further, the tracing stylus 12 is moved by the moving unit 13 so that the position of the tracing stylus 12 in the Y direction matches the measurement start position on the cutout surface W0.

  In S32, the contact member 11a is brought into contact with the cut surface W0. As a result, the tracing stylus 12 comes into contact with the measurement start position on the cut surface W0. At this time, since the measurement unit 1 is swingably supported in the Dz direction and the Dy direction by the support unit 41, the measurement unit 1 floats following the surface direction of the cut surface W0. In S33, while the tracing stylus 12 is moved by the moving unit 13, the detection result of the load cell 123 is acquired, and the characteristic of the cut surface W0 is measured. The tracing stylus 12 is moved in the radial direction of the wooden surface W0, passes through the position of the pulp W1 in the course of the movement, and the characteristics of each part of the pulp W1, the core W2, and the sap W3 are measured. Thus, one unit process is completed.

A measuring device, 1 measuring unit, 2 photographing unit, 3 lighting unit, 12 measuring elements

Claims (17)

A photographing process of photographing the cut end of the log,
An extracting step of extracting a plurality of annual rings from the image of the kiguchi taken in the photographing step,
A virtual circle specifying step of specifying a circle approximating each annual ring extracted in the extraction step, and specifying a virtual circle having a predetermined radius concentric with the circle;
Based on the degree of overlap between the virtual circles specified in the virtual circle specifying step, based on the determining step of determining the position of the pulp of the kiguchi surface,
A detection method characterized in that: The detection method according to claim 1, wherein
In the photographing step, irradiating the kiguchi surface with red light to photograph the kiguchi surface,
A detection method characterized in that: The detection method according to claim 1, wherein
Further comprising a setting step of setting an extraction range for extracting annual rings in the extraction step, of the woody surface,
The setting step includes:
A contour extraction step of extracting a contour of the cleave surface based on the image of the cleave surface photographed in the photographing step,
Identifying a circle approximating the extracted contour of the woodcut surface, and setting a circle having a predetermined radius concentric with the circle in the extraction range,
A detection method characterized in that: The detection method according to claim 3, wherein
The contour extraction step includes:
A step of separating the image photographed in the photographing step into a red component, a green component, and a blue component, which are components of the three primary colors of light,
A conversion step of converting each separated component into a hue component, a saturation component, and a lightness component,
A detection method characterized in that: The detection method according to claim 4, wherein
The contour extraction step includes a component extraction step of extracting an image of a hue component and an image of a lightness component from among the HSV-converted images in the conversion step.
A detection method characterized in that: The detection method according to claim 5, wherein
The contour extraction step includes a step of performing a binarization process on each image extracted in the component extraction step, and extracting a contour of the lip surface based on a result of the binarization process.
A detection method characterized in that: The detection method according to claim 1, wherein
The determining step includes:
An adding step of adding a luminance value of an overlapping portion between the virtual circles specified in the specifying step,
After the addition in the addition step, an area extraction step of extracting an area whose luminance value is equal to or greater than a predetermined value,
A detection method characterized in that: The detection method according to claim 7, wherein
The determining step includes:
In the area extracting step, when there are a plurality of areas having a brightness value equal to or more than a predetermined value, the area extracting step includes a selecting step of selecting a maximum area.
A detection method characterized in that: The detection method according to claim 7, wherein
The determining step includes:
The centroid of the region where the luminance value is equal to or greater than the predetermined value is determined as the position of the pith on the Kiguchi surface,
A detection method characterized in that: A method for measuring a raw wood in which a position of a pulp of a lip is detected by the detection method according to claim 1,
Contacting a probe with the tip of the tip,
In the state where the tracing stylus is in contact with the cleave surface, comprising a step of moving one of the tracing stylus or the raw wood over the radial direction of the cleave surface to pass through the position of the pith.
A measuring method characterized by the above-mentioned. A photographing means for photographing the front of a log,
Based on the image of the Kiguchi surface photographed by the photographing means, detecting means for detecting the position of the pith of the Kiguchi surface,
A tracing stylus for measuring a predetermined characteristic of the log,
E Bei and a moving means for moving one of the timber containing the said feeler in a radial direction of the butt end face so that the detection means passes the position of the medullary detected or the end grain surface,
The detection means,
Extraction means for extracting a plurality of annual rings from the image of the kiguchi surface photographed by the photographing means,
Virtual circle specifying means for specifying a circle approximating each annual ring extracted by the extraction means, and specifying a virtual circle having a predetermined radius concentric with the circle;
Based on the degree of overlap between the virtual circles specified by the virtual circle specifying means, determining means for determining the position of the pulp of the Kiguchi surface,
A measuring device characterized by the above-mentioned. A photographing means for photographing the front of a log,
Based on the image of the Kiguchi surface photographed by the photographing means, detecting means for detecting the position of the pith of the Kiguchi surface,
A tracing stylus for measuring a predetermined characteristic of the log,
Moving means for moving one of the tracing stylus or the log including the kiguchi face in the radial direction of the kiguchi face so as to pass through the position of the pith detected by the detection means,
The photographing means,
It comprises illumination means for irradiating red light toward the front of the wood,
A measuring device characterized by the above-mentioned. It is a measuring device according to claim 11 or claim 12 ,
The moving means is a tracing stylus moving mechanism that moves the tracing stylus in a predetermined direction,
The measuring device includes a measuring unit including the tracing stylus and the tracing stylus moving mechanism,
The measurement unit is
A contact member extending in parallel with the predetermined direction and abutting on the front end face,
A measuring device characterized by the above-mentioned. The measuring device according to claim 13 ,
The contact member,
An opening extending parallel to the predetermined direction and exposing the probe,
An abutment surface that defines the opening and abuts against the lip surface.
A measuring device characterized by the above-mentioned. The measuring device according to claim 11,
The photographing means,
Comprising illumination means for irradiating red light toward the front of the wood,
A measuring device characterized by the above-mentioned. The measuring device according to claim 14 ,
Further comprising a support means for swingably supporting the measurement unit,
The support unit includes an elastic unit that urges the measurement unit to maintain the measurement unit at a swing center.
A measuring device characterized by the above-mentioned. It is a measuring device according to claim 11 or claim 12 ,
The property is hardness or water content,
A measuring device characterized by the above-mentioned.