JP2017040548A - Detection method, measurement method, and measurement device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To enable automated detection of pith positions.SOLUTION: A detection method of the present invention includes; a photographing step of capturing an image of a cut surface of a raw wood, or butt-end surface; an extraction step of extracting a plurality of annual rings from the image of the butt-end surface captured in the photographing step; a virtual circle identification step for identifying, for each of the annual rings extracted in the extraction step, a circle that approximates an annual ring and then a virtual circle that is concentric with the circle and has a same radius as that of the circle; and a determination step for determining a pith position on the butt-end surface based on a degree of overlap between each pair of adjacent virtual circles identified in the virtual circle identification step.SELECTED DRAWING: Figure 12

Description

  The present invention relates to raw wood inspection technology and measurement technology.

  Even if the raw wood is grown and collected on the same land, the growth conditions such as sunshine and soil condition are different for each raw wood. It also grows under the influence of various natural environments such as different weather conditions every year. Logs that have grown in different places with different growth conditions are cut down, roughly cut to a predetermined size for transportation and processing, and collected in a factory for processing. Thereafter, the collected raw wood is subjected to a predetermined treatment and processed into various wood products. Some timber products may be manufactured using a predetermined portion of the timber suitable for the timber product based on the characteristics of the raw timber.

  As a technique for inspecting the characteristics of the raw wood, a technique for inspecting the characteristics without contacting the raw wood has been proposed. For example, Patent Literature 1 and Patent Literature 2 disclose a technique for measuring the moisture 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 a tree ring. In the technique of Patent Document 3, a plurality of search start points are set, and the intersection of the movement trajectories when the search filter is moved in the normal direction of the annual rings from the search start point is set as the center of the annual ring.

JP 2001-289760 A Japanese Patent Laid-Open No. 10-68701 JP 2011-88436 A

  The characteristics of the raw wood vary depending on the position on the cut end surface as a cut surface. For example, the moisture content at each position of the annual rings formed in the radial direction may differ greatly between the heartwood near the center of the annual ring (near the medullary center) and the sapwood near the outside of the annual ring (near the outer skin). When measuring with a microwave like patent document 1 and patent document 2, a measurement result will be averaged and the measurement accuracy of each moisture content in a different position on a mouth end may be low. In order to automate the measurement of the characteristics at different positions on the face of the mouth, it is necessary to automate the position specification on the face of the mouth, for example, to automate the position of the marrow. Patent Document 3 discloses a technique for automatically detecting the center of an annual ring (ie, the medulla) of a raw tree, but there is a concern that sufficient detection accuracy cannot be obtained depending on the position of the search start point. In addition, it is estimated that the processing load increases when the number of search start points (the number of movement trajectories) is increased in order to improve detection accuracy.

  The first object of the present invention is to automate the detection of the medullary position.

  The second object of the present invention is to improve the measurement accuracy of the characteristics of the raw wood.

  In order to achieve the first object, according to the first aspect of the present invention, a photographing step of photographing a cut end surface that is a cut surface of a raw tree, and a plurality of annual rings from the image of the cut end surface photographed in the photographing step. An extraction step to extract, a circle that approximates each annual ring extracted in the extraction step, a virtual circle specifying step that specifies a virtual circle that is concentric with the circle and has a predetermined radius, and a virtual circle specifying step that is specified And a determining step of determining the position of the medullary surface of the mouth end based on the degree of overlap between the virtual circles.

  In order to achieve the second object, according to the second aspect of the present invention, there is provided a method for measuring a raw wood in which the position of the marrow of the mouth end surface is detected by the above-described detection method, wherein a measuring element is brought into contact with the end face of the end. And a step of moving one of the measuring element or the raw wood over the radial direction of the mouth surface so as to pass through the position of the marrow with the measuring element in contact with the mouth surface. A characteristic measurement method is provided.

  In order to achieve the second object, according to the third aspect of the present invention, based on the photographing means for photographing the wooden face of the raw wood, and the image of the wooden face taken by the photographing means, Detecting means for detecting the position of the medullary cord, a measuring element for measuring a predetermined characteristic of the raw wood in contact with the kerf surface, and the buttock surface passing through the position of the medulla detected by the detecting means And a moving means for moving one of the measuring element or the raw wood including the butt face in the radial direction.

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

  According to the second and third aspects of the present invention, the measurement accuracy of the characteristics of the raw wood can be improved.

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 Drawing 1 from the top. (A) is the figure which looked at the measuring apparatus of FIG. 1 from the front, (B) is a block diagram of the control unit of the measuring apparatus of FIG. (A) is a perspective view of a support unit, (B) is the II sectional view taken on the line of FIG. 4 (A). FIG. (A)-(C) are three views of a measuring element. (A) And (B) is explanatory drawing of the measurement aspect of a measuring element. (A) And (B) is a flowchart which shows the process example of a control unit. (A) And (B) is a flowchart which shows the process example of a control unit. (A) is explanatory drawing of a front end, (B) is explanatory drawing which shows the example of a detection of a medullary position. Explanatory drawing which shows the example of a detection of a medullary position. Explanatory drawing which shows the example of a detection of a medullary position.

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

<Measurement device>
A measuring apparatus A according to an embodiment of the present invention will be described with reference to FIGS. FIG. 1 is a side view of the measuring device A, FIG. 2 is a top view of the measuring device A, and FIG. 3A is a front view of the measuring device A.

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

  The measurement apparatus A includes a measurement unit 1, a photographing unit 2, an illumination unit 3, a slide unit 4, a lifting / lowering 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 that photographs the end face W0, and includes an image sensor such as a CCD sensor and an optical system such as a lens that forms a subject image on the image sensor.

  The photographing unit 2 is disposed so as to face the butt face W0 so that the butt face W0 is located within the shootable range, and is located at the center of the measurement range of the measurement unit 1 and deviated from the measurement track (measurement unit 1). In the upper center of the measurement direction). For this reason, if the wood end surface WO of the log W is arranged outside the measurement range of the photographing unit 2, it is regarded as a log W that cannot be measured (is deformed so that there is no commercial value), and measurement by the measurement unit 1 is stopped. .

  The illumination unit 3 is a unit that irradiates light to the end face W0 when the end face W0 is photographed by the photographing unit 2, and includes a light emitting element such as an LED. In the case of this embodiment, the illumination unit 3 irradiates light of a predetermined color toward the end face W0. The predetermined color is, for example, red. By photographing the end face W0 in a state where the end face W0 is irradiated with light of a predetermined color, it is possible to improve the extraction accuracy of the image of the end face 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 the slide unit 4. The slide unit 4 is moved up and down by the lifting unit 5. By raising and lowering the slide unit 4, it is possible to adjust the height of the measurement unit 1 and the photographing unit 2 with respect to the end face W0. At the time of photographing on the end face W0, the height of the slide unit 4 is adjusted so that the photographing unit 2 is positioned at a height facing the end face W0. Further, at the time of measuring the characteristics of the raw wood W, the height of the slide unit 4 is adjusted so that the measuring unit 1 is positioned at a height facing the end face W0.

  The slide unit 4 includes a support unit 41 and a support plate 42. The support unit 41 supports the measurement unit 1 in a swingable manner. In the case of this embodiment, the support unit 41 supports the measurement unit 1 so as to be swingable 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. 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 the line I-I in FIG. 4A.

  The support unit 41 includes two attachment portions 410, a support portion 411, an attachment portion 412, a hollow support portion 413, an arm portion 414, a shaft 415, and a spherical body 416. The two attachment 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 elevating unit 5 is fixed to the hole 411a. Further, the support portion 413 is fixed to one side surface of the two attachment portions 410 and the support portion 411 (the surface on the cylinder 11 side of the measurement unit 1: the right side surface in FIG. 4B).

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

  The support portion 413 has a cavity inside thereof, and has a recess 413 a that is in surface contact with the surface of the spherical body 416. The surface of the sphere 416 is supported so as to roll along the surface of the recess 413a, and the mounting portion 412 is three-dimensionally swingable (floating). For this reason, the measurement unit 1 fixed to the mounting portion 412 is also supported in a three-dimensional manner so as to be swingable. However, a buffer unit ABR, which will be described later, abuts on the measurement unit 1 and is measured by the elastic force of the elastic member 419. Since 1 is always 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 attachment 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 an axial member extending in the X direction, and the tip of the rod 417 is inserted into a hole 418b (FIG. 4B) of the bracket 418a fixed to the back of the measurement unit 1. Is done. The hole 418b is a hole having a diameter larger than that 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, the X direction). A spring receiver 417 b is fixed to the base side of the rod 417, and an elastic member 419 is provided between the spring receiver 417 b and the stopper 418. In this embodiment, the elastic member 419 is a coil spring, and the elastic member 419 is wound around the rod 417.

  The stopper 418 is brought into contact with the back portion 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) returns the measurement unit 1 to the swing center. Power). Thus, the two elastic members 419 bias the measurement unit 1 so as to maintain the measurement unit 1 at the center of swinging. The support plate 42 is a plate-like member and is fixed to the two attachment portions 410. The photographing unit 2 and the lighting unit 3 are fixed to the front surface of a support plate 42 (the surface on the side facing the log W: the right side surface in FIG. 1).

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

  A ball screw shaft 53 extending in the Z direction is disposed between the two rail members 52. The ball screw shaft 53 is supported by the main body 51 so as to be rotatable about its axis. The upper end portion 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 being driven. A ball nut unit 55 is screwed onto 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 slide unit 4, the measurement unit 1, the photographing unit 2, and the illumination unit 3 are moved up and down integrally by the rotation of the ball screw 53. In the present embodiment, a ball screw mechanism is employed as the drive mechanism of the lifting unit 5, but other drive mechanisms such as a rack and pinion mechanism, a belt transmission mechanism, or a linear motor may be used.

  The elevating unit 5 is provided on the slide table 6. The slide table 6 is a plate-like member, and a plurality of sliders 61 are provided on the lower surface thereof. The slider 61 is engaged with the rail member 81. The slider 61 can slide along the rail member 81 by the guide of the rail member 81, and the entire slide table 6 can slide 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 separated from each other in the Y direction. A 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. The base plate 8 can be moved back and forth in the X direction by driving the drive unit 7.

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

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

  The measurement unit 1 includes a cylindrical body 11 that forms the outer wall, a measuring element 12, and a moving unit 13.

  The cylindrical body 11 forms a rectangular hollow body extending in the Y direction as a whole, and is composed of four wall bodies on the upper and lower sides, and the left and right sides thereof are closed by cover members. The front wall constitutes an abutting member 11a that abuts against the butt face 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 end face 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 abutting member 11a, and moves in the Y direction with the measuring element 12 arranged inside the cylindrical body 11 exposed to the end face W0 side and the measuring element 12 exposed. Enable.

  The moving unit 13 is a mechanism for moving the measuring element 12 in the extending direction (Y direction) of the cylinder 11, and includes a motor 131, a ball screw shaft 132, a ball nut unit 133, a rail member 134, and a slider 135. With. The ball screw shaft 132 and the rail member 134 are extended in the extending direction (Y direction) of the cylindrical body 11, 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 engages with the rail member 134 and can slide on the rail member 134 by the guide of the rail member 134. The rail member 134 moves the measuring element 12 while the positional relationship between the contact surface of the contacting member 11a and the measuring element 12 in the X direction is maintained at a constant distance in the extending direction (Y direction). They are arranged in parallel as possible.

  The ball nut unit 133 is configured 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 extending direction (Y direction) of the cylindrical body 11.

  The slider 135 has a measuring element 12 fixed to the front side thereof. Therefore, when the slider 135 moves, the measuring element 12 moves together with the slider 135. Thereby, it is possible to move the measuring element 12 with respect to the log W in the radial direction of the end face W0. In the present embodiment, the moving unit 13 moves the probe 12 relative to the log W, but conversely, a configuration in which the log W is moved relative to the probe 12 can be employed. In this embodiment, a ball screw mechanism is employed as the drive mechanism of the moving unit 13, but other drive mechanisms such as a rack and pinion mechanism, a belt transmission mechanism, or a linear motor may be used. In addition, the contact surface of the contact member 11a is abutted against the butt face W, but it may be defined by at least three contact points, and may be defined by three contact members.

  In the case of this embodiment, the measuring element 12 is a contact-type sensor unit including the load cell 123 as a sensor. In addition, the sensor with which the measuring element 12 is provided may be a contact type sensor other than the load cell.

  The measuring element 12 includes a main body part 121 and a housing part 122. The main body 121 is a plate-like member.

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

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

  A pair of arm members 125 are integrally provided on the disc 124. A rigid sphere 126 is supported on the distal ends of the pair of arm members 125 via pins 125a. When the hard sphere 126 comes into contact with the butt face W0 and receives a reaction force from the butt face W0, the reaction force is transmitted to the load cell 123 through the pair of arm members 125 and the disc 124 and detected. In the natural state of the leaf spring 127, the hard sphere 126 is in a state of protruding outward (to the end face W0 side) from the opening 11b. The pin 125a is an axis extending in the Z direction, and the hard sphere 126 is supported so as to be rotatable about the pin 125a.

  With reference to FIG. 7 (A) and FIG. 7 (B), the measurement aspect of the characteristic of the raw wood W by the measuring element 12 is demonstrated. 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 end face W0 as shown in FIG. Since the measurement unit 1 is supported by the support unit 41 so as to be swingable in the Dz direction and the Dy direction, the measurement unit 1 follows the surface direction of the end face W0 by abutting the contact member 11a on the end face W0. Oscillates so that the extending direction of the measuring unit 1 (that is, the moving direction of the measuring element 12) and the surface direction of the butt face W0 are the same (or substantially the same). In this way, by bringing the contact member 11a into contact with the end face W0, the measuring element 12 can be easily moved in parallel to the surface direction of the end face W0.

  As described above, in the natural state of the leaf spring 127, the hard sphere 126 is in a state of protruding from the opening 11b toward the butt face W0, and the hard sphere 126 is brought into contact with the butt face W0 by bringing the abutment member 11a into contact with the butt face W0. Abuts on W0. The measuring element 12 is pressed to the inside of the cylinder 11 and displaced so as to be retracted to the inside of the cylinder 11 so that a load is input to the load cell 123 and the leaf spring 127 is elastically deformed. When the leaf spring 127 is elastically deformed, when the contact member 11a is separated from the end face W0 after the measurement is completed, the leaf spring 127 returns to a natural state, and the rigid ball 126 can be returned to the original position.

  As shown in FIG. 7B, the characteristic measurement is performed by sampling the detection result of the load cell 123 while moving the measuring element 12 in the radial direction (Y direction) of the butt face W0. As described above, since the hard sphere 126 is supported so as to be rotatable about the pin 125a, it rolls on the butt face W0, whereby the probe 12 moves smoothly on the butt face W0.

  When the probe 12 is moved, the load cell 123 is moved over the entire range of the mouthpiece surface W0 by moving the probe 12 over the radial direction of the mouthpiece surface W0 so that the hard sphere 126 passes through the position of the pith of the mouthpiece surface W0. The detection result is obtained. A line H in FIG. 7A indicates the position (height) of the pith.

  Here, the medulla and the like of the end face W0 will be described. FIG. 10A shows an example of the end face W0. The marrow W1 means the central part of the annual ring. There is a heartwood W2 around the marrow 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. As shown by the alternate long and short dash line in FIG. 10A, the difference in the characteristics of the core material W2 and the sapwood W3 can be clarified by measuring the characteristic distribution on the line passing through the pith W1.

  The amount of displacement of the probe 12 in the X direction is affected by the hardness of the end face W0. In the soft part, the measuring element 12 is relatively located on the side of the mouth end W0, and in the hard part, the measuring element 12 is relatively located on the slider 135 side. By converting the detection result of the load cell 123 by a predetermined conversion formula, the hardness or moisture content of the end face W0 can be calculated. In the case of this embodiment, since the characteristic is measured by bringing the probe 12 into direct contact with the butt face W0, characteristic values at a plurality of positions on the butt face W0 can be directly obtained. In particular, it is possible to obtain a distribution of characteristic values on a line that crosses the butt face 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 method measurement using a microwave or the like.

  In FIG. 7B, the entire area from one end to the other end in the radial direction of the end face W0 is the measurement range, but the measurement range is not limited thereto. For example, only the distance corresponding to the radius from the medulla W1 to one end in the radial direction of the butt face W0 may be set as the measurement range. At that time, the measurement start point may be the medulla W1 or the vicinity of the outer bark W4.

<Control unit>
A control unit for controlling the measuring apparatus 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 that interfaces an external device and the processing unit 101. The interface unit 103 includes a communication interface that performs communication with the host computer. The host computer is, for example, a computer that controls the entire manufacturing facility in which the measuring apparatus 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 various sensors such as a sensor that detects the position of the slider 4, a sensor that detects the position of the measuring element 12, and an image sensor of the photographing unit 2. An image processing processor that processes an image captured by the image sensor may be provided. Various actuators 104 include, for example, motors 54 and 131 and a cylinder 7.

<Control example>
An example of processing executed by the processing unit 101 will be described. FIG. 8A is a flowchart illustrating an example of processing executed by the processing unit 101. In S1, the position of the medulla on the end face W0 is automatically detected. Details will be described later. In S2, as described with reference to FIGS. 7A and 7B, the probe 12 is moved across the radial direction of the mouth end surface W0 so that the hard sphere 126 passes through the position of the pith of the end face W0. And measure the characteristics of the log W. Details will be described later. Thus, one unit of processing is completed.

<Detection of pith position>
An example of the process of detecting the position of the spinal cord W1 in S1 will be described. FIG. 8B is a flowchart showing an example of the processing. In S1, photographing of the end face W0 is performed. Here, first, the photographing unit 2 is moved up and down to a height facing the end face W0. The lighting unit 3 irradiates the buttock surface W0, and the photographing unit 2 shoots the buttock surface W0. An image IMO in FIG. 10B shows an example of the captured image. The image IMO includes images other than the end face W0, for example, a background or the like. Specifically, in the factory where the measuring apparatus A is installed, an image of an object existing around or behind the butt face W0 is also reflected. When photographing, the illumination unit 3 irradiates the end face W0 with a predetermined color, thereby making it easy to distinguish the image of the end face W0 from the background image. Here, the case where red light is irradiated is illustrated as an example, and description is advanced. Illumination may be other than red light, but the end face generally has a higher luminance value of R among RGB (red, green, blue), and red light irradiation 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 photographing system with the position coordinate space of the measurement unit 1. Therefore, an image IM1 (FIG. 10B) in which coordinate space conversion and image distortion are corrected is obtained. The image IM1 becomes a reference image.

  In S12, a range for extracting annual rings is set as a pre-process of the process for extracting annual rings on the end face W0 (S13). Although annual rings may be extracted over the entire end face W0, the processing time becomes longer and the processing load becomes larger. In the present embodiment, the extraction range of the annual rings is set to a certain area around the spinal cord W1 to shorten the processing time or the processing load.

  The process of S12 specifies a contour extracting step for extracting the contour of the mouth end surface W0 based on the image IM1 of the end face W0, a circle that approximates the extracted contour of the end face W0, and is concentric with the circle and has a predetermined radius. And a process of setting a circle having the extraction range. First, in order to extract an outline, as shown in FIG. 10B, the image IM1 is separated into a red component (R), a green component (G), and a blue component (B) that are components of the three primary colors of light. Since the end face W0 is illuminated in red at the time of shooting, the R image is an image having a high brightness on the end face W0. Subsequently, as shown in FIG. 10B, each separated component 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 are extracted.

  Next, the H image is binarized based on whether the red component (R) is within a predetermined value range, and the V image is binarized based on whether the lightness is within a predetermined value range. The end face W0 utilizes the fact that red is strong and the brightness is high due to illumination. Further, the logical product of the pixel values is obtained from the binarized H image and the binarized V image to generate an image IM2 in FIG. Thereby, the image IM2 in which the influence of disturbance light is reduced can be obtained.

  For the image IM2, “hole filling” is performed on the area surrounded by the pixels to generate the image IM3. In order to remove noise from the image IM3, the image IM3 is subjected to an opening process to generate an image IM4. When the image IM4 includes a plurality of images separated from each other, the largest image among them is regarded as the image of the butt face W0, and other images are deleted. Since the image IM4 includes two images (a large image b1 and a small image s1), the small image s1 is deleted. Further, convex hull processing is performed on the image of the end face W0 to generate an image IM5 in which the image of the end face W0 is close to a circle.

  In the image IM5, an image IM6 is generated by converting the image of the end face W0 into data whose outline is represented by a line. Further, a perfect circle approximate to the image IM6 is specified. Here, for example, the straight line portion is deleted from the contour line of the end face W0, and a perfect circle that approximates the maximum arc line among the remaining arc lines is specified. The image IM7 shows an example of the identified perfect circle with 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 the specified radius and the center in common 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 50% of the radius of a perfect circle, for example. In the image IM8, the extraction range of annual rings is indicated by arrows. Thus, the extraction range setting process in S12 ends.

  Returning to FIG. 8B, in S13, annual ring extraction processing is performed. First, an image obtained by cutting out the extraction range set in S12 from the reference image IM1 is generated. Furthermore, annual rings are extracted from the clipped image. An image IM9 in FIG. 12 shows an image displayed by highlighting the annual rings for an image obtained by cutting out the extraction range from the reference image IM1. It is not necessary to generate this image itself, and it is only necessary to extract annual rings. An annual ring can be identified by specifying the boundary based on the change in shading of the image. Even when the same annual ring is recognized in terms of image recognition, if the change in curvature reaches a certain level or more, it may be divided and recognized as another annual ring. In addition, an annual ring having a size smaller than a certain size may be regarded as noise and deleted.

  In S14, a virtual circle specifying process is performed. Here, first, a perfect circle that approximates each annual ring extracted in S13 is specified. An image IM10 in FIG. 12 shows an image displaying a perfect circle that approximates each annual ring. It is not necessary to generate the image itself, and it is only necessary to extract each perfect circle. Here, for example, a straight line portion is deleted from the extracted annual ring, and a perfect circle that approximates the largest arc line among the 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, the position determination process for the pith W1 is performed. Here, the position of the medulla W1 of the end face W0 is determined based on the overlapping degree between the virtual circles specified in S14. Various methods can be adopted as a method for evaluating the degree of overlap, but here, a luminance value is used. FIG. 9A is a flowchart showing a processing example of S15.

  In S21, a process of adding a luminance value is performed for a portion where the virtual circles overlap. A specific example will be described. An image IM11 in FIG. 12 shows an image in which each virtual circle is displayed as indicated by a broken line arrow. Each virtual circle is not an outline but an image of a filled circle, and the luminance values of the virtual circles are the same. For example, a circle having a radius of 20 pixels and a luminance value of 1 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 line arrow in the image IM11 has a high luminance value. That is, the portion having the high luminance value is a portion that is the center of more annual rings.

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

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

  Thus, one unit of processing is completed. In this way, in this embodiment, the detection of the position of the medulla on the mouth end surface can be automated. In the present embodiment, a circle that approximates each annual ring is specified, and a virtual circle that is concentric with this circle and has a predetermined radius is specified. The position of the medulla was determined from the degree of overlap of the virtual circles. Since the position of the medulla can be determined by fitting a circle that substantially approximates an annual ring, the position of the medulla can be detected by a relatively simple process. Further, since the position of the medulla is near the center of the annual ring, the accuracy of detection of the specified position of the medulla is improved by determining the position of the medulla based on the degree of overlap of the virtual circles. In particular, the closer to the medulla, the more likely the medulla is located in the center of the annual ring.By setting the extraction range of the annual ring to an area close to the medulla, not only the processing burden is reduced, but also the detection accuracy of the position of the medulla 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 probe 12 is adjusted. Here, the measurement unit 1 is moved up and down so that the probe 12 is positioned at the height of the medullary 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 measuring element 12 is moved by the moving unit 13 so that the position of the measuring element 12 in the Y direction matches the measurement start position on the end face W0.

  In S32, the contact member 11a is brought into contact with the end face W0. As a result, the probe 12 comes into contact with the measurement start position of the end face W0. At this time, since the measurement unit 1 is supported by the support unit 41 so as to be swingable in the Dz direction and the Dy direction, the measurement unit 1 floats along the surface direction of the butt face W0. In S33, the moving unit 13 moves the probe 12 and acquires the detection result of the load cell 123 to measure the characteristic of the butt face W0. The measuring element 12 is moved in the radial direction of the butt face W0 and passes through the position of the medulla W1 in the process of movement, and the characteristics of each part of the medulla W1, the heartwood W2, and the sapwood W3 are measured. Thus, one unit of processing is completed.

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

Claims (16)

A shooting process for shooting the cut end of the raw wood,
An extraction step of extracting a plurality of annual rings from the image of the end surface photographed in the photographing step;
Identifying a circle that approximates each annual ring extracted in the extraction step, and identifying a virtual circle that is concentric with the circle and has a predetermined radius; and
A determination step of determining the position of the medullary surface of the mouthpiece based on the degree of overlap between the virtual circles identified in the virtual circle identification step,
A detection method characterized by the above. The detection method according to claim 1,
In the photographing step, the top surface is photographed by irradiating the top surface with light of a predetermined color.
A detection method characterized by the above. The detection method according to claim 1,
A setting step for setting an extraction range for extracting annual rings in the extraction step among the mouth end surface,
The setting step includes
A contour extracting step for extracting a contour of the mouth end surface based on the image of the end surface taken in the photographing step;
Identifying a circle that approximates the extracted contour of the mouth end surface, and setting a circle having a predetermined radius concentric with the circle as the extraction range,
A detection method characterized by the above. The detection method according to claim 3,
The contour extraction step includes
Separating the image photographed in the photographing step into a red component, a green component, and a blue component that 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 by the above. The detection method according to claim 4,
The contour extracting step includes a component extracting step of extracting an image of a hue component and an image of a lightness component from the images subjected to HSV conversion in the converting step,
A detection method characterized by the above. The detection method according to claim 5, comprising:
The contour extracting step includes a step of binarizing each image extracted in the component extracting step, and extracting a contour of the mouth end based on a result of the binarizing processing.
A detection method characterized by the above. The detection method according to claim 1,
The determination step includes
An adding step of adding the luminance values of the overlapping portions between the virtual circles specified in the specifying step;
A region extraction step of extracting a region having a luminance value equal to or greater than a predetermined value after the addition in the addition step;
A detection method characterized by the above. The detection method according to claim 7, comprising:
The determination step includes
In the region extraction step, when there are a plurality of regions having a luminance value of a predetermined value or more, a selection step of selecting a maximum region,
A detection method characterized by the above. The detection method according to claim 7, comprising:
The determination step includes
Determining the centroid of the area where the luminance value is equal to or greater than a predetermined value as the position of the medullary surface of the mouth end;
A detection method characterized by the above. A method for measuring raw wood in which the position of the marrow of the mouth end surface is detected by the detection method according to claim 1,
Contacting the probe with the end of the mouth,
Moving the one of the measuring element or the raw wood over the radial direction of the mouth surface so as to pass through the position of the marrow with the measuring element in contact with the mouth surface,
A measuring method characterized by the above. Photographing means for photographing the front end of the log,
Detection means for detecting the position of the medullary surface of the mouthpiece based on the image of the mouthpiece surface photographed by the photographing means;
A measuring element that contacts the end face and measures a predetermined characteristic of the raw wood;
Moving means for moving one of the measuring element or the original wood including the mouth surface in the radial direction of the mouth surface so as to pass through the position of the marrow detected by the detecting means;
A measuring device. The measuring device according to claim 11,
The moving means is a measuring element moving mechanism that moves the measuring element in a predetermined direction;
The measuring apparatus includes a measuring unit including the measuring element and the measuring element moving mechanism,
The measurement unit is
A contact member extending in parallel with the predetermined direction and contacting the end face;
A measuring device. A measuring device according to claim 12,
The contact member is
An opening that extends parallel to the predetermined direction and exposes the probe;
An abutting surface that delimits the opening and abuts against the mouth end surface,
A measuring device. The measuring device according to claim 11,
The photographing means includes
Illuminating means for irradiating light of a predetermined color toward the mouth end surface,
A measuring device. The measuring device according to claim 13,
Further comprising support means for swingably supporting the measurement unit;
The support means includes elastic means for biasing the measurement unit so as to maintain it at the center of oscillation.
A measuring device. The measuring device according to claim 11,
The characteristic is hardness or moisture content,
A measuring device.