JPS60165506A - Optical detecting method - Google Patents

Abstract

PURPOSE:To detect the shape, etc., of a body to be detected by a simple means securely by irradiating the body to be detected with laser light almost linearly at right angles to the relative movement and detecting its reflection or irradiation state, and detecting the shape of the body, etc., from mutual transition to a linear and a nonlinear state. CONSTITUTION:The body 2 to be detected which is wide perpendicularly to the conveyance direction is mounted on a carrying device 1, a reflecting roll 3 is fitted to the detection position for the objective body 2 so that the roll can rotate synchronizing with the conveying speed of the device 1, and the bode 2 to be detected is irradiated with the laser light LB from an irradiating device 4 almost linearly at a spread angle corresponding to the width at right angles to the conveyance direction. A photodetecting device 8 is arranged on the path of reflected light of the light LB from the roll 3, and numbers of its photodetecting elements 9 are arrayed in the axial direction; and an electrical signal having a voltage level corresponding to the quantity of reflected light of the light LB is outputted to a comparing circuit 10 and the binary-coded signal based upon a specific threshold value is supplied to an electronic controller 20 to detect an irregular part (not shown in figure), etc., of the objective body 2.

Description

DETAILED DESCRIPTION OF THE INVENTION TECHNICAL FIELD The present invention relates to an optical detection method in which an object to be detected is irradiated and detected in a substantially straight line.

BACKGROUND ART Conventionally, in the detection method of irradiating light onto an object to be detected that moves relative to a light source, it is necessary to obtain clear contrast especially for outlines or defective areas, so that the object to be detected is approximately evenly spaced.
A certain amount of light had to be emitted. For a detected object whose width in the direction perpendicular to the relative movement is long, a light source such as a long fluorescent tube whose width in the direction perpendicular to the relative movement must be at least greater than the width in the direction of relative movement of the object must be used. For objects to be detected whose directional width is greater than the width of the light source, there is a problem in that the detection accuracy deteriorates significantly. In addition, when a single high-output light source is used, the wavelength band of the emitted light is wide, so it is easily affected by ambient light, and the emitted light is easily diffused by a clamp etc. The problem was that there was a difference in contrast between the area directly under the irradiation and the edge of the area.

Can these drawbacks be avoided by correcting each electricity number 18 output from the light receiving element according to the distance from the light source to each irradiation position according to the reflection state or irradiation state from the object to be detected? There is also the problem that the cost of the device increases due to the complexity of the electrical signal correction circuit.

Purpose of the Invention In view of the above-mentioned conventional drawbacks, an object of the present invention is to provide a method for irradiating a relatively linear laser beam onto an object to be detected that moves relatively by simple means and detecting the laser beam in a reflective manner. There is a particular thing.

Not implemented Hereinafter, embodiments will be described according to the drawings.

1st Embodiment In FIG. 1, an object 2 to be detected, such as plywood or veneer veneer, whose width in the direction perpendicular to the direction of conveyance is elongated, is placed on a roller-type conveying device 1. transported to. Further, a reflection roll 3 whose axial width is at least as wide as the width of the detected object 2 in the direction perpendicular to the conveyance direction is attached to the detection position of the detected object 2 in the conveyance device 1 so as to be rotatable in synchronization with the conveyance speed of the conveyance device 1. There is. A brush C (not shown) is attached to the outer periphery of the reflecting roll 3 so as to be able to touch the entire axial length of the reflecting roll 3, if necessary, to peel off and remove dust attached to the outer periphery of the reflecting roll 3. The reflection state of the roll 3 can be kept substantially constant.

111j Above the conveying device 1 is a laser jl that irradiates the reflective roll 3 with a laser beam LB at an appropriate irradiation angle.
The lJ injection device 4 is fixedly arranged. This laser!
(The α irradiation device 4 uses an optical lens (not shown) to
A laser beam LB oscillated from an Nc laser oscillator or a semiconductor laser element, etc. is irradiated onto the detected object 2 at an opening angle corresponding to the width in the direction perpendicular to the conveyance direction, and in a state where it is converged in a substantially linear shape. . As a method of irradiating the laser beam LB in a straight line at a desired opening angle, the laser beam LB irradiated at 1.
It is also possible to carry out a method such as a method of irradiating the light onto a curved mirror to form a straight line at a desired aperture angle, or a method of transmitting the light through a cylindrical lens and irradiating the light in a straight line at a desired aperture angle.

Specific examples of these include the Luzama I Kink System (sold by Quantum Electronics Co., Ltd.);
1-Laser Markink J [sold by Nippon Kagaku Engineering Co., Ltd.] and the like are listed. This laser beam LB is a visible light whose oscillation wavelength is 780 nm or less, and its oscillation output is transmitted to each light receiving element 9, which will be described later.
It is set appropriately according to the photodetection characteristics of. Moreover, this laser beam LB is a coherent beam, and is irradiated onto the outer periphery of the reflection roll 3 with a substantially uniform beam intensity.

On the other hand, a linear light-receiving device a8 is disposed on the reflected optical path of the laser beam LB reflected in a substantially straight line from the 1+iI reflection roll 3. The light receiving device 8 is composed of, for example, a CCD type image sensor in which a large number of light receiving elements 9 are arranged in the axial direction of the reflecting roll 3. The number of arrays of the light receiving elements 9 and the pitch between the arrays are appropriately set according to the resolution. Each light-receiving element 9 receives an electric signal KS at a voltage level corresponding to the amount of reflected light of the laser beam LB, which changes due to the position, shape, defect, etc. of the detected object 2 passing through the detection position a every scanning time, to a comparison circuit 10. Output to.

The second comparator circuit 10 is configured, for example, as a floating type threshold circuit, which floats the threshold value based on the average voltage level of the nearby electrical signal KS (1 m), and also floats the threshold value based on the average voltage level of the nearby electrical signal KS. Converts to 2rm No. 16 according to KS. That is, '1' when the voltage level of the electrical signal KS is above the threshold (fJ, and conversely, when the voltage level of the electrical signal KS is below the threshold In this case, a binary signal of "o" is used.In addition, under working conditions that are susceptible to disturbance light, a filter (not shown in the figure) corresponding to the oscillation wavelength of the laser beam LB is installed for each light receiving element 9. The S/N ratio can be improved by attaching the following.

The electronic control 4Ii 20 transfers the 11'll 2 signal inputted serially every scanning time to the -H shift register 21.
After the data is stored in the shift register 21, the data is stored in the shift register 21.

For example, as shown in FIGS. 2 to 4, a position detection operation for cutting and removing an uneven portion at the rear end of the detected object 2 in the transport direction ljJ will be described.

As shown in FIG. 1, when the detected object 2 is not being conveyed to the detection position a, the laser beam LB linearly irradiated in the axial direction of the reflecting roll 3 is directed approximately linearly by the reflecting roll 3. After being reflected, the light is received by each light receiving element 9. As a result, each light-receiving element 9 outputs an electrical signal KS at a high voltage level, so that each comparator circuit 10 outputs a binary signal of "1'°," and the shift register 21
to be memorized. In this state, the electronic control device 20 determines that the detected object 2 is in a non-detection state based on the binarized signal accessed from the shift register 21.

As shown in FIG. 2, when the end side of the object to be detected 2 in the transport direction liJ is positioned at the detection position ia from the above state as the transport device 1 transports, the laser beam LB irradiated from the laser irradiation device 4 A part of the laser beam LB is absorbed by the irregular portion 2a of the end 1111 of the object to be detected 2411, and the other laser beam LB is reflected by the reflection roll 3 and received by the corresponding light receiving element 9. As a result, the state of reflection of the laser beam LB by the reflection roll 3 changes from a substantially linear state to a non-linear state, and in accordance with this non-linear state, a binary signal in which at least one signal changes to "0" is output. In this state, the electronic control device 20 detects the irregular portion 2a of the detected object 2 on the curved end side in the transport direction.

As shown in FIG. 3, when the object 2 to be detected that continues in the transport direction and the direction perpendicular to the transport is positioned at the detection position a from the above state, all of the irradiated laser beam LB is absorbed by the object 2 to be detected. , reflection to each light receiving element 9 is regulated. As a result, the electric signals KS output from all the light receiving elements 9 change to a low voltage level, and all the binary IS signals change to 0'°. In this state, the control device 20 controls the detected object 2Jtlf.
A cutting position for cutting and removing the irregular portion 2a on the i side is detected, and a cutting operation is performed by a cutting device disposed on the downstream side in the conveyance direction.

As shown in FIG. 4, when the uneven portion 2b on the rear end side of the detected object 2 is located at the detection position a from the above state, a part of the laser beam LB irradiated to the uneven portion 2b is emitted from this position. Other laser beams LB that are absorbed by the irregular portion 2b and irradiated to areas other than the irregular portion are reflected by the reflection roll 3 and received by the corresponding light receiving elements 9. As a result, the reflective roll 3
The reflection state of the laser beam LB transitions to a non-linear state,
A portion of the electrical signal KS changes from a low voltage level to a high voltage level, and the z-valued signal changes from 0'' to 1''. In this state, the control device 20 controls the rear t of the detected object 2.
Cutting position C for cutting and removing the uneven portion 2b on the 4I side
13IJ11i located on the downstream side in the transport direction.
The device performs the cutting operation.

Next, the case of detecting defects such as holes will be explained according to FIG.

...As described in 1, since the laser beam LB irradiated to the detected object 2 is absorbed in the detected state of the detected object 2, all the electricity 1B@KS output from each light receiving element 9 is at a low voltage level. . In this state, when the hole 2c formed in the detected object 2 is located at the detection position a, the laser beam LB is reflected by the reflection roll 3 through this hole 2C and is received by the corresponding light receiving element 9. . As a result, the electrical signal KS
Since a part of the voltage changes from a low voltage level to a high voltage level, a part of the binary signal changes from 0'' to 1''. In this state, the electronic control unit 20 changes from 0'' to 1''.
Counter 2
2 is incremented to detect the width of the hole 2C in the direction perpendicular to the transport direction. Also, the control device 120 initially moves from 0″ to °°1°.
The timer 23 is activated based on the binary signal changed to ', and the width in the transport direction is detected. Then, the control device M20 detects the defective hole 2C when the counted values of the counter and timer exceed preset data.

Therefore, in this embodiment, the laser beam LB is reflected onto the reflection roll 3 in a substantially straight line in the direction perpendicular to the conveyance direction, and the reflected state of the laser beam LB changes from the linear state as the detected object 2 passes through the detection position a. It can be in a non-linear state or non-straight.

In FIG. 6 of the second embodiment, the laser irradiation device 4 described above irradiates the laser beam LB in a substantially straight line in the direction perpendicular to the conveyance over the entire width of the object to be detected 2 in the direction perpendicular to the conveyance at a predetermined detection position a, and as appropriate. It is fixedly installed so that it irradiates at an irradiation angle of . Moreover, above the detection position a described in ■■, there is a camera device 3 that detects the irradiation state of the laser beam LB irradiated onto the detected object z.
o is placed. This camera device 30 includes, for example, a CCD type image sensor in which a large number of light receiving elements according to the resolution are arranged in a matrix, and a comparison circuit ( 1d1 (both not shown), and detects the irradiation state of the laser beam LB to the detected object 2.

This comparator circuit is composed of, for example, a floating threshold output circuit, which changes the threshold value according to the average value of the nearby video signals, and compares the image f with a voltage level higher than this threshold value. i! Signal "1", and low voltage level video No. 18" o
” and outputs it to the electronic control device 31.The electronic control device 31 once stores this video pattern data VD in the shift register 32, and then outputs the video pattern data VD from the shift register 32 at each scanning time. Access the pattern data VD.This electronic control device 31
compares the video pattern data VD with reference video pattern data stored in the ROM 33 in advance. This reference image pattern data is image pattern data VD obtained when the laser beam LB is irradiated onto the object 2 in a substantially straight line over the entire direction orthogonal to the conveyance direction. Then, the electronic control device 31 uses the video pattern data VD and the reference video pattern data to first detect the uneven portion on the #il side after the conveyance direction diJ of the detected object 2, as shown in FIGS. 7 to 9. A position detection method for cutting and removing will be explained.

As shown in FIG. 6, when the detection object 2 is not transported to the detection position a in the transport direction lr+1 end j,
The laser beam LB irradiated from the laser irradiation device 4 is irradiated to a location other than the detection position Ba in an appropriate state. For this reason, since the camera device 30 outputs video pattern data VD according to the background, the electronic control device 31 compares this video pattern data VD with the reference video pattern data, and since they do not match, the detected object is judged to be in a non-detection state.

Next, as shown in FIG. 7, when the uneven portion 2a on the conveyance direction 11'+J@ side of the detected object 2 is positioned at the detection position a from the above state, the laser beam LB is absorbed by the uneven portion 2a. Therefore, the irradiation state of the laser beam LB to the detected object 2 becomes discontinuous. move. Therefore, when the video pattern data VD of the laser beam LB continuously irradiated from the camera device 30 is output, the electronic control device 31 outputs the video pattern data VD and the image data written in the ROM 33! ll video pattern data. In this case, since the two data do not match, the electronic control unit fi31 determines that the cutting position is not detected.

As shown in FIG. 8, when the object 2 to be detected that continues in the transport direction and the direction perpendicular to the transport from the above state is positioned at the detection position a, the laser LB continues on the object 23 to be detected in the direction perpendicular to the transport. It is irradiated in a substantially straight line. and camera device 30
When the image pattern data VD of the laser beam LB which is irradiated onto the detected object 2 in a substantially straight line is outputted, the electronic control device 31 converts this image pattern data VD and the reference image pattern data in the same manner as in the operation described in 1111. compare. In this case, the electronic control unit #f31 detects the cutting position of the irregular portion 2a on the front end side of the object to be detected 2 in the conveyance direction when the two match, and performs cutting by the cutting device disposed on the lower side in the conveyance direction. Execute.

As shown in FIG. 9, the irregular portion 2b on the rear end side in the transport direction of the detected object 2 is positioned at the detection position a with the laser beam LB being irradiated onto the detected object 2 in a substantially straight line. At this time, the irradiation state of the laser beam LB on the detected object 2 changes from a linear state to a non-linear state.

Accordingly, when non-linear video pattern data vD is output from the camera device 30, the electronic control device fi31
Similar to the operation described above, this video pattern data VD is compared with the reference video pattern data, and since they do not match, a cutting position C is detected for cutting and removing the irregular portion 2b of the tilted rear end of the detected object 2. Then, a cutting operation is performed by a cutting device disposed on the lower side 1111 in the conveyance direction.

Next, a method for detecting holes or recesses formed in the object to be detected 2 will be explained.

When the detected object 2 with no defects passes through the detection position a, the laser beam LB is irradiated onto the detected object 2 in a substantially straight line over the entire width in the direction perpendicular to the transport direction, as described above. 1st
As shown in Figure 0, in this state, for example, the detected object 2
When the hole 2c passes through the detection position a, the detected object 2
Since the laser beam LB irradiated on the object 2 passes through the hole 2c, the state of irradiation of the laser beam LB on the detected object 2 changes from a substantially linear state to a non-linear state. As a result, when the camera device 30 outputs the video pattern data VD corresponding to the non-linear state, the electronic control device 31 outputs the video pattern data VD according to the non-linear state.
D and reference image pattern data are compared, and if the two do not match, a hole 2C formed in the object to be detected 2 is detected. At that time, the electronic control unit adjusts the
The counter 34 is incremented in accordance with the video pattern data VDI that has changed, and the width of the hole 2C in the direction perpendicular to the conveyance direction is determined. Control may be performed such that the hole 2C is detected as a defect only when the count value of this counter is greater than or equal to the data regarding the width in the transport orthogonal direction stored in the register 35 in advance.

Next, the case of detecting a recess in the detected object 2 will be described.

As shown in FIGS. 11 and 12, when the recess 2d or 6 locations 2c of the detected object 2 is transported to the detection position a, the laser beam LB irradiated onto the detected object 2 is It is in a curved state compared to the laser beam LB irradiated to the spot. This curved state deviates depending on the width, depth, or height of the recess 2d or the six recesses 2c in the direction perpendicular to the conveyance direction. As a result, the state of irradiation of the laser beam LB onto the detected object 2 changes from a linear state to a non-linear state. Then, when the video pattern data VD corresponding to the non-linear state is output from the camera device 30, the electronic control device 31 compares the transitioned video pattern data VD and the reference video pattern data in the same manner as in the operation described in 1rlJ, and compares both the video pattern data VD and the reference video pattern data. The recess 2d or 6 does not match.
Detect location 2c.

Therefore, in this embodiment, the laser beam LB is irradiated substantially linearly in the direction perpendicular to the conveyance over the entire width of the detected object 2 being conveyed, and the state of irradiation of the laser beam LB to the detected object 2 is controlled. It can be in a substantially straight line state.

In addition, in the first and second embodiments, the object to be detected 2 is transported by the transport device l.
At the same time, a fixedly attached laser irradiation device 4 is used to irradiate the moving object 2 with a laser beam LB substantially linearly in the direction perpendicular to the transport direction over the entire width of the object to be detected 2 in the direction perpendicular to the transport direction. (1) The present invention can be carried out even in a single method, in which a laser beam is irradiated onto the object to be detected in a substantially straight line while moving a laser irradiation device and a light receiving device to the object to be detected, which is fixedly arranged. obtain.

Further, the first embodiment is a method in which the laser beam LB irradiated from the laser irradiation device 4 is reflected by the reflection roll 3, and detection is performed based on the irradiation light amount of the laser beam LB that changes as the detected object 2 passes. However, in the case of an object to be detected that can reflect the irradiated laser beam, even when the object to be detected passes through the detection position, the output from each light receiving element placed on the reflected optical path of the laser beam is It can be implemented.

Furthermore, in the second embodiment, a laser beam LB is irradiated from one direction onto the object to be detected 2 being conveyed at an appropriate angle over the entire width in the direction orthogonal to the conveyance, and a camera device 30 is used to detect the object to be detected. However, the present invention is not limited to this embodiment, and as shown in FIG. 13, the laser irradiation device 40 and 41 are arranged opposite to each other, and the laser beam LB is irradiated substantially linearly in a substantially straight line in the direction orthogonal to the conveyance over the entire width of the detected object z conveyed by the laser beam #J devices 40 and 41 over the entire width thereof in the direction orthogonal to the conveyance. It is also possible to implement a configuration in which: With this configuration, for example, the concave Pfi2 of the detected object 2
When detecting d, as shown in FIG. 14, the state of irradiation of the laser beam LB to the recess 2d becomes a double irradiation state compared to the state of substantially linear irradiation to the detected object 2 without defects. Then, the electronic control device 31 can reliably determine that the heat radiation state has transitioned from a substantially linear state to a non-linear state based on this double image pattern data (D).

Further, in the second embodiment, a 4!4 configuration is adopted in which a single camera device u30 detects the irradiation state of the laser beam LB over the entire width of the object to be detected 2 in the direction perpendicular to the conveyance direction. I according to the width in the orthogonal direction! It is also possible to implement a method in which a number of light receiving devices 6 are arranged and detection is performed by each of the light receiving devices.

Effects of the Invention: As explained, the present invention uses a laser irradiation device that emits laser light in a fan-shaped LB using an optical lens or mirror as a light source, and irradiates a long object to be detected in a substantially straight line with a substantially uniform amount of light over the entire width in the direction perpendicular to the relative movement of the object, and determines the irradiation state or reflection state of the laser beam irradiated to the object to be detected.a Non-i1 from line state! This is an optical detection method that can reliably perform detection because it is in a linear state or in a non-linear state.

[Brief explanation of Fig. 101] Fig. 1 is an explanatory diagram showing the outline of the first embodiment, Figs. 2 to 5 are explanatory diagrams showing the detection operation, and Fig. 6 is an explanatory diagram showing the outline of the second embodiment. FIGS. 7 to 12 are explanatory diagrams showing the detection operation, and FIGS. 13 and 14 are explanatory diagrams showing modified embodiments of the present invention.

In the figure, 2 is an object to be detected, 4 is a laser irradiation device, 9 is a light receiving device, 30 is a camera device as a light receiving device, and LB is a laser beam.

Figure 8 Figure 11

Claims (1)

[Claims] 1. A laser irradiation device that is movable relative to the object to be detected irradiates the object to be detected with laser light in a substantially straight line in a direction orthogonal to the relative movement, and a light receiving device reflects the laser light irradiated onto the object to be detected. An optical detection method that detects a state or an irradiation state, and changes the reflection state or irradiation state of a laser beam from a substantially linear state to a non-linear state, or has non-linear characteristics.