JP2722376B2 - Apparatus for removing foreign matter in transparent bodies - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an apparatus for separating foreign matters such as stones and ceramics from a large number of transparent bodies, for example, collected glass pieces such as cullet and detecting the foreign matters.

[0002]

2. Description of the Related Art The present applicant has already proposed such an apparatus described in Japanese Patent Application Laid-Open No. 3-75545. In this conventional apparatus, an object in which a foreign substance is mixed in a transparent body is conveyed by a belt conveyor, and the object is dispersed and discharged from the belt conveyor, and is linearly scanned with a linearly polarized laser beam while being dropped. Reflected light is received by the CCD of the CCD camera (solid-state imaging device camera) via the polarizing filter, and the pixel output of the CCD camera (each C
By performing digital image processing on the output of the CD), it is determined whether the object is a transparent body or an opaque foreign matter.

[0003] That is, in the case of a transparent body, most of the laser beam is transmitted and only a small part is reflected, but the reflected light is cut off by the polarizing filter because it remains linearly polarized light. In contrast, in the case of opaque foreign matter,
Most of the light is diffusely reflected and becomes circularly polarized light, and most of the light passes through the polarizing filter and enters the CCD. Therefore, the output of the CCD is very small in the case of a transparent body, and becomes large in the case of an opaque foreign matter. Therefore, in the case of an opaque foreign substance, air is blown during falling from the conveyor to separate it from the transparent body.

[0004]

However, in the case of recovered cullet and the like, in addition to heavy opaque foreign matters such as stones and ceramics, light foreign matters such as resin films and paper labels are included. Such resin films, paper labels, etc. often float in an undetermined direction when subjected to air jetting, and if they contain a large amount of water, they remain attached to the wall surface of the foreign matter collection section, etc. If it is within the scanning range of the laser beam and within the field of view of the CCD camera, foreign substances are always present in the detection field of view, causing disturbance in detection, and erroneous detection continues. In such a state, the foreign matter removing operation is continuously performed, the amount of air for removal is reduced, and the foreign matter may not be removed.

[0005] Further, since the CCD camera condenses light in the field of view with a lens and guides the light to the CCD, the distance from the CCD camera to the object to be photographed is fixed depending on the focal depth specific to the lens used. There are restrictions that must be kept within the range. However, in the above-described apparatus proposed earlier by the present applicant, as shown in FIG. 10, a CCD camera 2 is arranged above a laser light source (laser light scanning apparatus) 1 and the light of the CCD camera 2 is Axis 3 and laser light source 1
The laser beam projection optical axis 4 is shifted up and down, and the laser beam 5 is projected from below onto the field of view of the CCD camera 2. Therefore, there are the following problems.

That is, as shown in FIG. 1, the object 7 which is discharged from the belt conveyor 6 and falls is not only the width direction of the belt conveyor 6 (scanning direction by the laser beam) but also its transport direction (light of the CCD camera 2). (Axial direction). Now, a certain object falls along a parabolic locus A, and another object falls along a parabolic locus B which is farther than the parabolic locus A when viewed from the CCD camera 2. Optical axis 3 is laser beam 5
, But there is no point on the parabolic locus B where the optical axis 3 of the CCD camera 2 intersects the laser beam 5. In this case, the object falling along the parabolic locus A is irradiated with the laser beam 5 at the point a and the reflected light enters the CCD camera 2, but the object falling along the parabolic locus B is Even if the laser beam 5 intersects the optical axis 3 of the CCD camera 2 at the point b, the laser beam 5 does not hit the object at this point b because the laser beam 5 is out of the point b.
There is no reflected light incident on the D camera 2. Therefore, when the target object falls along the parabolic locus B, the reflected light from the target object due to the laser beam scanning is not received by the CCD camera 2, and
Foreign matter cannot be detected. In addition, 8 is a transparent body collection part, and 9 is a foreign substance collection part.

SUMMARY OF THE INVENTION An object of the present invention is to easily prevent a situation in which a resin film, a paper label, or the like remains in a detection visual field and causes disturbance in detection, and that objects are scattered in a conveying direction of a conveyor. The object of the present invention is to allow a solid-state imaging device camera to receive reflected light from an object caused by laser beam scanning even when the camera falls, thereby enabling accurate detection of foreign matter.

[0008]

According to the present invention, in order to achieve the first object, as shown in FIG. 1, a laser beam from a laser beam scanning device 10 is applied to an object falling from a conveyor 14. In order to scan from obliquely above, the projection optical axis 11 of the laser beam scanning device 10 is tilted from the horizontal plane by a predetermined angle α, and the solid-state imaging device camera 12 is moved to the position where the light receiving optical axis 13 Similarly, it is inclined by a predetermined angle α so as to be located on the same inclined plane as the optical axis 11. In addition, when the roller 17 rotating at a high speed is hit by an opaque foreign matter, the roller 17 is flipped into the foreign matter collecting unit 20.
Reflection of the laser beam reflected from the roller surface near the entrance of the foreign matter collection unit 20 below the discharge drop position from the conveyor 14 and the laser beam irradiation so that the reflected light of the laser beam on the roller surface does not enter the solid-state imaging device camera 12. It is arranged at an angled position. Preferably, the roller surface is black, and the cleaning brush 18 is slidably contacted with the roller surface so that the roller surface is always automatically cleaned by the high-speed rotation of the roller 17.

[0009]

In the apparatus according to the present invention, the resin film or paper label discharged from the conveyor 14 is used for the air injection device 2.
8, falls while being brought to the foreign matter collection unit 20 while hitting the foreign matter collection unit 20, and hits the roller 17 rotating at a high speed, and the rotation causes the laser beam 16 to fly out of the scanning range of the laser beam 16 and out of the visual field of the solid-state imaging device camera 12. Be skipped. Although the roller 17 is constantly irradiated with the laser beam 16, the reflected light does not enter the solid-state imaging device camera 12, so that the roller 17 is not determined as a foreign substance.

Since the laser beam projection optical axis 11 of the laser beam scanning device 10 and the light receiving optical axis 13 of the solid state imaging device camera 12 are located on the same inclined plane, the light receiving optical axis 13 is located at a point a on the parabolic locus A. At the point b on the parabolic locus B, the laser beam projection optical axis 1
Intersect with 1. Therefore, the object falling along the parabolic locus A is irradiated with the laser beam 16 from obliquely upward and forward at the point a, and the reflected light enters the solid-state imaging device camera 12 and drops along the parabolic locus B. The object to be irradiated is irradiated with the laser beam 16 at the point b, and the reflected light similarly enters the solid-state imaging device camera 12.

The transparent object among the objects 15 discharged from the conveyor 14 falls into the transparent body collecting section 19 as it is, but the opaque foreign matter falls into the foreign matter collecting section 20 by receiving the air injection from the air injection device 28. I do. The laser beam 16 of the laser beam scanning device 10 is projected obliquely from above at a certain angle, avoiding the conveyor 14, and the light receiving optical axis 13 of the solid-state imaging device camera 12 is set at the same angle as the conveyor 1.
Even if the camera 4 is removed from the field of view of the camera, if the laser beam 16 that did not hit the falling object 15 hits another reflecting object and the reflected light enters the solid-state imaging device camera 12, the problem of erroneous detection may occur. Occurs.

However, the laser beam 16 that did not hit the falling object 15 hits the roller 17, but the laser beam reflected from the roller 15 does not enter the solid-state imaging device camera 12, so that the above-described erroneous detection may occur. No problem.
The roller 17 also has a function of blocking background light from behind.

[0013]

Embodiments of the present invention will be described below in detail with reference to the drawings. FIG. 2 shows an overall schematic configuration of the foreign matter removing apparatus according to the present invention. This foreign matter removing device includes a hopper 21, a dispersion feeder 22, a vibrator 23, a white belt conveyor 14, and a black foreign matter (stone) that does not reflect light from among objects 15 conveyed on the belt conveyor 14. Etc.), a diffused light source 24 for detecting black foreign matter, a CCD camera 25 for detecting black foreign matter, an image processing device (including a computer) 26 for detecting black foreign matter, and an opaque foreign matter that reflects light from the object 15 Laser beam scanning device 10 for detecting opaque foreign matter, CCD camera 12 for detecting opaque foreign matter, and image processing device (including computer) 27 for detecting opaque foreign matter for detecting (porcelain, etc.), and air ejecting device for blowing away foreign matter 28, and the air injection when any one of the image processing device 26 for detecting black foreign matter and the image processing device 27 for detecting opaque foreign matter is detected. A foreign matter elimination control circuit 29 for operating the device 28, a collection container 30 having a transparent body collection unit 19 and a foreign matter collection unit 20, and a roller 17 for flipping off a resin film, a paper label, or the like discharged from the belt conveyor 14. It has.

A large number of objects 15 having opaque or black foreign matter mixed in a transparent body such as a cullet are put into a hopper 21 and dispersed by a vibrator 23.
The paper is conveyed while being dispersed on the upper side, and is transferred onto the belt conveyor 14. While being conveyed on the belt conveyor 14, the CCD camera 25 captures an image from above while irradiating the diffused light from the diffused light source 24, and the black foreign matter is image-processed for black foreign matter detection because the belt conveyor 15 is white. 26.

Further, the object 15 is a belt conveyor 14.
The laser beam is conveyed by the laser beam and dispersed from the end, falls down, and is scanned in the horizontal direction by the laser beam 16 from the laser beam scanning device 10 during the fall, and the reflected light is a CCD type image of the CCD camera 12 provided with the polarizing filter. It is detected by the sensor 31.

Laser beam scanning device 10 and CCD camera 12
Are the former laser beam projecting optical axis 11 and the latter receiving optical axis 1
3 are located on the same inclined plane, and these objects 15 fall from a horizontal plane by a laser beam 16 from the laser beam scanning device 10 at a predetermined inclination angle α (for example, 45 degrees). CCD) scanning from diagonally above with the same angle and directivity angle
The camera 12 receives reflected light from the object 15 through a polarizing filter.

Then, the output from the image sensor 31 of the CCD camera 12 is analyzed by the image processing device 27 to determine whether it is a transparent body or an opaque foreign matter.
The air injection device 28 is controlled according to the result of the determination. Here, in the case of the transparent body 15a, it falls directly into the transparent body collecting section 19 of the collecting container 30, whereas in the case of the opaque foreign matter 15b, air is injected from the air injection device 28. It falls into the foreign substance collection part 15b. Similarly, the black foreign matter detected by the black foreign matter detection image processing 26 also falls into the foreign matter collection unit 15b by being jetted with air from the air injection device 28.

As shown in FIG. 3, a roller 17 for flipping a resin film, a paper label, or the like is disposed below the discharge and drop position from the belt conveyor 14 in the scanning range of the laser beam 16 irradiation. The position is also near the entrance of the foreign matter collection unit 20. The roller 17 is moved in the scanning direction of the laser beam 16 (this scanning will be described later).
The laser beam 16 scans the surface of the roller 17 parallel to its axis, but the roller 1
The position of 7 is such that the reflected light of the laser beam on the roller surface does not enter the CCD camera 12 at a reflection angle. The roller 17 is made of resin, and its surface is blackened in order to minimize the reflection of the laser beam 16.

The roller 17 is, as shown in FIG. 4, a pair of bearings 3 suspended from a frame 14a of the belt conveyor 14.
The rotation of the motor 33 is transmitted via the timing belt 34 to rotate at high speed in the direction of the arrow in FIG. A cleaning brush 18 is pressed against the surface of the roller 18 from below to prevent small cullets and the like from adhering, and the roller 18 rotating at high speed is constantly cleaned.

The resin film, paper label, and the like discharged from the belt conveyor 14 fall while receiving the air injection from the air injection device 28, and the roller 1 rotating at a high speed.
When it hits 7, it is flipped out of the scanning range of the laser beam 16 and out of the field of view of the CCD camera 12 due to its rotation, and enters the foreign matter collection unit 20.

As shown in FIG. 5, the air injection device 28 includes, for example, twenty nozzles 38 arranged in a horizontal line, and the same number of solenoid valves 39 similarly arranged in a horizontal line corresponding to the nozzles 38 in a one-to-one relationship. And one receiver tank 40 common to these solenoid valves 39 is arranged on a base 41. The entire air injection device 28 is installed diagonally on the gantry 42 as shown in FIG.
The air can be blown obliquely from above toward the opaque foreign matter 15b and the black foreign matter falling from above.

FIG. 6 shows a schematic electrical configuration of the foreign matter separating apparatus of this embodiment. The laser light scanning device 10 includes the laser light source 5
0, a rotation deflector 51 and a synchronization detector 52.
The laser beam from the laser light source 50 is reflected by the reflecting mirror 53 in FIG. 7 and further reflected by the rotating polygon mirror 54 of the rotary deflector 51 to become a laser beam 16 that scans in a horizontal straight line. The projection is repeated while monitoring the projection direction by the rotary deflector 51. The projected laser beam 16 irradiates the surface of the roller 16 rotating at high speed as described above in parallel with its axis, but is shielded by the roller 16 before the roller 16. The laser beam 16 is detected by a synchronization detector 52, and a synchronization signal is output from the synchronization detector 52 for each scan.

The image sensor 31 of the CCD camera 12 is a so-called one-dimensional image sensor in which, for example, 1024 CCDs are arranged in a horizontal line, and the output from each CCD is output from the synchronous detector 52 of the laser beam scanning device 10. The signal is taken out by the camera controller 55 for each scan in accordance with the synchronizing signal, converted into a binary electric signal by a binarizing circuit 56 based on a fixed threshold value, taken into the computer 57, and stored in the memory in the computer 57. It is memorized. The voltage output from each CCD differs depending on whether the object 15 scanned by the laser beam 16 is transparent or opaque. That is, the reflected light from the opaque foreign matter 15b is mainly circularly polarized and passes through the polarizing filter, while the reflected light from the transparent body 15a is slightly and mostly linearly polarized and is blocked by the polarizing filter. Therefore, the output voltage from each CCD is opaque foreign matter 15b.
Much higher than the case.

Such a difference can be further reduced if the same transparent body and the same opaque foreign matter are scanned a plurality of times by the laser beam scanning device 10 and AND logic is applied to the outputs of the image sensor 31 for the number of scans. growing. Therefore, in this example, every time the laser beam scanning device 10 performs the scanning twice, the outputs from the image sensor 31 for two times are binarized and then ANDed.

In the case of this example, the CCD of the image sensor 31
Is 1024, whereas the number of nozzles 38 of the air injection device 28 is 20 which is far smaller than the number of CCDs. Therefore, in this example, CC is set for one nozzle.
For example, 1024 CCDs are divided into 20 blocks by making D correspond, for example, to 51 blocks, and the 51 CCDs determine whether each block is transparent or opaque. In this case, since 51 × 20 = 1020, four of the 1024 CCDs are surplus, but the output of two CCDs at both ends of the CCD arranged in a horizontal line is handled. Not excluding these 10
The outputs of 20 CCDs are made valid.

When it is determined that an opaque foreign substance is present in a certain CCD block, not only air is ejected from one nozzle 38 corresponding to the CCD block but also two nozzles on both sides adjacent to the nozzle 38. The solenoid valve 39 is controlled by the valve controller 58 so that the air is simultaneously ejected from the nozzle 38 (the air from the adjacent nozzle 38 overlaps as described above). In the case of black foreign matter detection by the black foreign matter detection image processing device 26, air injection is performed similarly.

FIG. 7 shows the scanning of the transparent body 15a and the opaque foreign matter 15b by the laser beam from the laser beam scanning device 10, and the CCD of the image sensor 31 in the first scan.
An analog signal that continuously represents the output of the group, an analog signal that continuously represents the output of the CCD group of the image sensor 31 in the second scan, and
D-processed AND signal for the same scan line, CCD block divided into 20 as described above, transparent / opaque determination result, presence / absence of operation of 20 electromagnetic valves 39, and 20 nozzles The relationship with the presence / absence of air injection from No. 38 is shown. FIG. 8 shows an analog signal from the CCD group of the image sensor 31 in each of the first scan and the second scan, a binary signal obtained by binarizing these analog signals by the binarization circuit 56, and the binary signal. AND after
9 shows an AND signal for the same processed scanning line.

FIG. 9 shows the flow of the discriminating operation between the transparent body and the opaque foreign matter and the sorting operation performed by the computer 57. First, in the initial setting of step 101, the number of CCDs per one CCD block to be divided, that is, the number of CCDs corresponding to each nozzle 38 is set.
A unit number N of D (51 in the above example) and a reference width T to be used as a reference for determining opacity / transparency based on the width of the AND signal are set.

Thereafter, in step 102, the binarizing circuit 56
, The binary signal of the first scan is fetched and stored in the memory,
Subsequently, similarly, in step 103, the binary signals of the second scan are fetched and stored in the memory.
Is ANDed. Next, for the same scan line, the rising address and the falling address of each AND signal are detected in step 105. That is, for each AND signal, its rise and fall are represented by C
The position of the CCD in the CD group corresponding to the CCD is detected.
The position according to the CD arrangement order is stored in the memory for each AND signal.

In the next step 106, it is sequentially determined from the left AND signal that each AND signal is from which block in the divided CCD block and therefore corresponds to the nozzle 38. It is obtained by the following calculation one by one. That is, the first AND
Assuming that the rising address of the signal is D1 as shown in FIG. 8, the order X of the nozzle 38 corresponding to this AND signal is:
X = (D1 / N) +1 from D1 and the number of units N. Here, X is a positive integer. For example, assuming that N is “51” as described above using FIG. 7 as an example, D1 becomes “42”.
In the case of "0", X becomes "9", which corresponds to the ninth nozzle 38.

Next, at step 107, the width W between the rising and falling edges of the AND signal is obtained from the number of CCDs between the rising and falling addresses. That is, in FIG. 7, the rising address of the first AND signal is D1, as shown above, and the falling address is L1.
Then, the width W of the AND signal is W = (L1-D1)
Becomes

Next, at step 108, it is determined whether or not the width W of the AND signal exceeds the reference width T. If so, the process proceeds to step 109, where it is determined that the object is an opaque foreign substance. To judge that the object is transparent. For example, in FIG. 8, if (L1-D1)> T as in the first AND signal, an opaque foreign substance, and (L2-D2) as in the second AND signal.
If <T, it is a transparent body. If it is an opaque foreign matter, the process proceeds to step 111, where the valve controller 5
Under the control of 8, the three solenoid valves 39 are simultaneously operated.
That is, the three solenoid valves 39 corresponding to the X-th, (X-1) -th, and (X + 1) -th three nozzles 38 are opened, and air is simultaneously ejected from these three nozzles 38 to make the nozzle opaque. The opaque foreign matter 15b is sprayed on the foreign matter 15b, and is dropped into the foreign matter collecting section 20 in FIG. In the example of FIG. 7, since it is determined that the opaque foreign matter is present in the ninth CCD block, air is ejected not only from the ninth nozzle 38 but also from the eighth and tenth nozzles 38 adjacent to both sides thereof. I do.

In the next step 112, it is determined whether or not there is another AND signal for the same scanning line. If there is, in step 113 the rising and falling addresses of the next AND signal are read from the memory. The processing from 106 to step 112 is repeated,
In the case of the opaque foreign matter 15b, air is jetted in the same manner as above.

If there is no other AND signal for the same scanning line, it is determined in step 114 whether or not there is a command to stop laser scanning.
Returning to step 2, the same process is repeated for the next scan, and if there is a stop command, the process ends.

If the output of the image sensor 31 is binarized and the AND processing is performed for three or more scans, the accuracy of discrimination between a transparent body and an opaque foreign matter can be further improved. The image sensor 31 includes a CCD
However, the present invention is not limited to a so-called one-dimensional image sensor in which solid-state imaging devices are arranged in a horizontal line, and may be a two-dimensional image sensor in which solid-state imaging devices are arranged in a matrix.

Further, in the above example, the X-th single nozzle corresponding to the CCD block in which the opaque foreign object is detected, and the (X-1) -th and (X +
1) The air is simultaneously jetted from the third three nozzles. However, the width of the nozzle of each nozzle is reduced, and for example, air is jetted simultaneously from the (X-2) th and (X + 2) ths. The number of nozzles for air injection can be arbitrarily selected, for example, by changing the number of nozzles for air injection according to the width of the AND signal.

[0037]

The effects of the present invention will be described below separately for each claim.

<Claim 1> Since the laser beam projection optical axis of the laser beam scanning device and the light receiving optical axis of the solid-state image pickup device camera are located on the same inclined surface, the objects fall in the transport direction of the transport means and fall. Even in this case, the solid-state imaging device camera can receive the reflected light from the object by the laser light scanning, and can accurately detect the foreign matter. Since the laser light projection optical axis and the light receiving optical axis of the solid-state imaging device camera are located on the same inclined plane, the resin film or paper label released from the conveyor may be repeatedly in the visual field of the solid-state imaging device camera. When it enters, there is a risk that reflected light from it may cause disturbance in detection.However, these foreign substances can be bounced out of the scanning range of the laser beam and out of the field of view of the solid-state imaging device camera by a roller rotating at high speed. Therefore, it is possible to easily prevent a situation in which a resin film, a paper label, or the like floats in the detection visual field and causes disturbance in detection. The roller surface is constantly irradiated with the laser beam and is always within the field of view of the solid-state imaging device camera, but since the reflected light from the roller surface does not enter the solid-state imaging device camera, the roller is determined as a foreign object. Never. Since the roller is disposed near the entrance of the foreign substance collecting unit, the resin film, paper label, and the like that have been hit and hit by the high-speed rotating roller can be collected in the foreign substance collecting unit. <Claim 2> Since the roller surface is black, reflection from the surface is suppressed and disturbance light can be reduced as much as possible.

<Claim 3> Since the roller surface can be automatically cleaned by the cleaning brush with the high-speed rotation of the roller, disturbance light from the roller surface due to adhesion of foreign matter and the like can be eliminated.

[Brief description of the drawings]

FIG. 1 is a schematic configuration diagram of a foreign matter removing device according to the present invention.

FIG. 2 is a schematic configuration diagram of the entire foreign matter removing apparatus.

FIG. 3 is an enlarged view of the vicinity of the end of the belt conveyor in the above.

FIG. 4 is a cross-sectional view of a roller for flipping a resin film, a paper label, and the like discharged from a belt conveyor, and a related portion thereof.

FIG. 5 is a plan view of a belt conveyor and an air injection device.

FIG. 6 is a block diagram of an electrical schematic configuration of the foreign matter removing device according to the present invention.

FIG. 7 is a schematic diagram illustrating processing from scanning by laser light to separation by air injection in the same apparatus.

FIG. 8 is a timing chart showing a process of processing an output from an image sensor.

FIG. 9 is a flowchart showing a flow of processing in the computer.

FIG. 10 is a schematic configuration diagram of a conventional example.

[Explanation of symbols]

 REFERENCE SIGNS LIST 10 laser light scanning device 11 laser light projection optical axis 12 CCD camera 13 light receiving optical axis 14 belt conveyor 15 a transparent body 15 b opaque foreign matter 16 laser beam 17 roller 18 cleaning brush 19 transparent body collection unit 20 foreign matter collection unit 28 air injection device

Claims (3)

(57) [Claims] An object in which a foreign substance is mixed in a transparent body is conveyed by a conveyor, and the object is dispersed and discharged from the conveyor, and is scanned horizontally by a laser beam from a laser beam scanning device. The solid-state image sensor camera receives the reflected light from the camera and digitally processes the pixel output from the solid-state image sensor camera with an image processing circuit to determine whether the object is transparent or opaque. In the apparatus for removing foreign matter in a transparent body that injects air and drops to a foreign matter collection unit, the laser light from the laser light scanning device is scanned obliquely from above on an object falling from the conveyor, The projection optical axis of the scanning device is inclined from the horizontal plane by a predetermined angle α, and the solid-state image sensor camera is positioned such that its light receiving optical axis is on the same inclined plane as the projection optical axis of the laser light scanning device. So that the roller rotating at a high speed rotates the high-speed rotating roller into the foreign matter collecting section when hit by an opaque foreign matter. In the vicinity of the entrance, furthermore, in the scanning range by the laser beam irradiation, it is disposed at a position where the reflected light of the laser beam on the roller surface has a reflection angle that does not enter the solid-state imaging device camera, Foreign matter removal device. 2. The apparatus according to claim 1, wherein the surface of the roller is black. 3. The apparatus according to claim 1, further comprising a cleaning brush that slides on and cleans the surface of the roller as the roller rotates.