JP2008215862A - Foreign matter removing apparatus - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a foreign matter removing apparatus for calculating the brightnesses of the respective visible light regions and a near infrared light regions of aggregate and another foreign matter and comparing the respective brightness increase ratios or brightness differences to detect and remove the foreign matter other than the aggregate. <P>SOLUTION: The foreign matter removing apparatus is constituted of at least an illumination means for illuminating a fed material to be sorted, a photographing means for photographing the illuminated material to be sorted, an image processing means for calculating the brightness increase ratios or brightness differences of the respective visible light region brightnesses and near infrared light region brightnesses of the aggregate and foreign matter in the material to be sorted on the basis of the photographed image, a detection means for issuing the removal signal of the foreign matter in a case that the brightness increase ratios or brightness differences become a reference value and a removal means for removing the foreign matter becoming the reference value or more in the brightness increase ratios or the bright differences according the removal signal. <P>COPYRIGHT: (C)2008,JPO&INPIT

Description

  The present invention relates to a foreign matter detection apparatus that automatically detects and removes foreign matter such as wood waste, iron waste, and resin waste from concrete aggregates such as mined limestone, crushed stone, crushed sand, and concrete waste.

Aggregates occupy about 70% of the concrete volume, and the properties of the aggregates greatly affect the physical properties of the concrete. That is, the aggregate plays a role such as densifying the concrete structure and suppressing heat of hydration.
For this reason, to make good-quality concrete, use high-quality aggregate that is hard, physically and chemically stable, has appropriate particle size and particle shape, and does not contain harmful amounts of impurities and salt. There is a need to.

The quality of crushed stone for concrete and crushed sand is stipulated in JIS A 5005, and should not contain harmful amounts of dust, mud, organic impurities and the like.
Moreover, the performance rate (particle shape determination performance rate) is defined as 55% or more for crushed stone and 53% or more for crushed sand.
The larger the record rate, the more appropriate the particle shape and particle size, and the better the aggregate. The larger the performance rate, the smaller the unit water volume of concrete for obtaining the same slump.

The river gravel and river sand that have been used in the past are prohibited from being collected, and crushed stone and sea sand have been used instead. However, sea sand causes salt damage, and therefore, the use of crushed stone and concrete waste is increasing. In particular, aggregates from scrap concrete are made from conventional river gravel, and can be used as high-quality aggregates. Also, they are desired to be used from the effective use of resources, and are defined as JIS A 5021. It was.

Thus, if the crushed stone for concrete and the crushed sand contain foreign matters such as dust, mud, wood waste, iron waste, glass waste, plastic waste, etc., the performance of the concrete is seriously affected.
Therefore, it is necessary to remove the aforementioned foreign substances from the crushed stone for concrete and crushed sand.
In particular, in recent years, there has been a growing need for recovering aggregates from concrete waste generated by building demolition due to depletion of natural aggregates and environmental problems. Since this concrete scrap contains various building materials, it is particularly important to remove foreign substances in the production of crushed stone and crushed sand for concrete.

  Conventionally, crushed stone and crushed sand for concrete have been crushed by sieving the crushed stone produced by crushing raw stone or concrete waste material into a predetermined size with a crusher or the like, and then foreign materials have been removed manually. However, this method using a sieve cannot be removed depending on the size of foreign matter, and it is not always sufficient for humans because of the heavy burden in terms of time and cost.

As a subsequent technology, a dust removal machine has been developed that separates and removes only foreign matters that are lighter than water and float on water using buoyancy against water. Furthermore, as a technology that can remove even lighter substances that are lighter than gravel but sink into water, a technology that settles in the classification water tank, expels the light substances out of the gravel layer by jet water flow, overflows with water, and removes light substances It is disclosed (see Patent Document 1).
Moreover, after removing irons with a magnetic separator, the technique which removes foreign materials, such as a wood chip, is disclosed using a two-stage vibration sieve and a wind-power selection means together (patent document 2).
Furthermore, as a method for removing foreign matter having a small specific gravity difference, a technique relating to a specific gravity sorting device that sorts aggregate raw materials by a settling speed difference due to a specific gravity difference in a water tank having a plate having a large number of through holes is disclosed ( (See Patent Document 3).
Furthermore, as a method of separating materials with almost the same specific gravity difference, such as aggregate and glass, the glass of low strength than aggregate is pulverized by the method of colliding the aggregate and glass particles in construction composite waste. By doing so, a method of separating the aggregate and the glass is disclosed (Patent Document 4).
JP 08-155330 A JP 09-192608 A Japanese Patent Laid-Open No. 2000-070553 JP 2004-344868 A

However, all of these technologies are based on the presence or absence of magnetism of the material to be sorted and the difference in specific gravity, and the separation method also uses wind, water flow, settling speed, and strength differences, and in terms of certainty. I have to say that it is insufficient. In addition, the sorting device needs to be changed or improved depending on the type and size of the foreign matter. Furthermore, it is difficult to store quality data at the time of sorting from the viewpoint of quality control.

  As a result of diligent research, the present inventors have focused on the property of reflectance depending on the wavelength of light of the material to be sorted, and reflected the visible light and near infrared light of each material to be sorted. Since it was found that the difference in rate was different and quality data at the time of sorting could be easily stored, the foreign matter removing apparatus of the present invention was completed.

  That is, the brightness of each visible light and near-infrared light of aggregates and other foreign materials is calculated from materials to be sorted that are transported at 100 m / min to 300 m / min by a transport means such as a belt conveyor. Then, it aims at providing the foreign material removal apparatus which detects and removes foreign materials other than an aggregate by comparing each brightness | luminance difference or a brightness | luminance increase rate.

  Further, a conveying means for conveying the material to be sorted, an illuminating means for illuminating the material to be sorted, a photographing means for photographing the illuminated material to be sorted, and a material in the material to be sorted based on the photographed image An image processing means for calculating a luminance increase rate or a luminance difference between the aggregate and the foreign material, a detection means for outputting a foreign material removal signal when the luminance increase rate or the luminance difference exceeds a predetermined reference value, and a removal signal It is an object of the present invention to provide a foreign matter removing apparatus comprising a removing means for removing foreign matter.

  As a result of intensive studies to solve the above-mentioned problems, the present inventor has found that the luminance increase rate or the luminance difference is greatly different between the aggregate and the foreign material, and has completed the present invention.

That is, the present invention is a foreign matter removing apparatus characterized in that foreign matter is detected and removed by comparing the luminance increase rates of the visible light region luminance and the near infrared light region luminance of the aggregate and the foreign material, respectively ( Claim 1).
Next, the present invention provides at least illumination means for illuminating the material to be sorted, imaging means for photographing the illuminated material to be sorted, and aggregate in the material to be sorted based on the photographed image. Image processing means for calculating the luminance increase rate of each visible light region luminance and near-infrared light region luminance of the foreign material, and detection means for outputting a foreign material removal signal when the luminance increase rate exceeds a reference value; A foreign matter removing apparatus comprising: a removing means for removing foreign matter having a luminance increase rate equal to or greater than a reference value in accordance with the removal signal (claim 2).
Further, the present invention detects and removes foreign matter by comparing the average luminance increase rate between the average luminance in the visible light region and the average luminance in the near-infrared light region of the aggregate and the foreign material, respectively. It is a removal apparatus (Claim 3).
Next, the present invention provides at least illumination means for illuminating the material to be sorted, imaging means for photographing the illuminated material to be sorted, and aggregate in the material to be sorted based on the photographed image. Image processing means for calculating an average luminance increase rate between the average luminance in the visible light region and the average luminance in the near-infrared light region of the foreign material, and removal of the foreign material when the average luminance increase rate exceeds a reference value A foreign matter removing apparatus comprising: a detecting means for outputting a signal; and a removing means for removing a foreign matter having a luminance increase rate equal to or higher than a reference value in accordance with the removal signal (claim 4).
Furthermore, the present invention is a foreign matter removing apparatus characterized in that foreign matter is detected and removed by comparing the luminance increase rates of the brightness at 420 nm and the brightness at 860 nm of the aggregate and the foreign matter, respectively. .
Next, the present invention provides at least illumination means for illuminating the material to be sorted, imaging means for photographing the illuminated material to be sorted, and aggregate in the material to be sorted based on the photographed image. Image processing means for calculating a luminance increase rate between the luminance at 420 nm and the luminance at 860 nm of each foreign substance, detection means for outputting a foreign substance removal signal when the luminance increase ratio exceeds a reference value, and the removal signal In accordance with the present invention, the foreign matter removing apparatus is characterized by comprising a removing means for removing the foreign matter having a luminance increase rate equal to or higher than a reference value (claim 6).
Furthermore, the present invention is a foreign matter removing apparatus characterized in that foreign matter is detected and removed by comparing the luminance difference between the visible light luminance and the near infrared light luminance of each of the aggregate and the foreign matter. Item 7).
Next, the present invention provides at least illumination means for illuminating the material to be sorted, imaging means for photographing the illuminated material to be sorted, and aggregate in the material to be sorted based on the photographed image. Image processing means for calculating the luminance difference between the visible light luminance and the near-infrared light luminance of each foreign substance, a detection means for outputting a foreign substance removal signal when the luminance difference exceeds a reference value, A foreign matter removing apparatus comprising a removing means for removing foreign matter having a luminance difference equal to or greater than a reference value in accordance with a removal signal (claim 8).
Furthermore, the present invention detects and removes foreign matter by comparing the average luminance difference between the average luminance in the visible light region and the average luminance in the near-infrared light region of the aggregate and the foreign matter, respectively. (Claim 9).
Next, the present invention provides at least illumination means for illuminating the material to be sorted, imaging means for photographing the illuminated material to be sorted, and aggregate in the material to be sorted based on the photographed image. An image processing means for calculating an average luminance difference between the average luminance in the visible light region and the average luminance in the near-infrared light region of each foreign material, and a foreign material removal signal when the average luminance difference exceeds a reference value. A foreign matter removing apparatus comprising: a detecting means for outputting; and a removing means for removing foreign matter having an average luminance difference equal to or greater than a reference value in accordance with the removal signal (claim 10).
Furthermore, the present invention is a foreign matter removing apparatus characterized in that foreign matter is detected and removed by comparing the brightness difference between the brightness at 420 nm and the brightness at 860 nm of the aggregate and the foreign matter, respectively.
Next, the present invention provides at least illumination means for illuminating the material to be sorted, imaging means for photographing the illuminated material to be sorted, and aggregate in the material to be sorted based on the photographed image. Image processing means for calculating the brightness difference between the brightness at 420 nm and the brightness at 860 nm for each foreign substance, detection means for outputting a foreign substance removal signal when the brightness difference exceeds a reference value, and brightness according to the removal signal A foreign matter removing apparatus comprising a removing means for removing foreign matter having a difference equal to or greater than a reference value (claim 12).
In the present invention, the removing means is any one of a discharge damper device, a dropout conveyor device, an extrusion device, a scraping device, a compressed air injection device, and a pickup device. The foreign matter removing device according to any one of 2, 4, 6, 6, 8, and 12 (claim 13).

  The foreign substances used in the present invention include biogenic materials such as wood fragments, plant roots, bones, bird carcasses, and animal carcasses mixed in concrete aggregates such as crushed stone and crushed sand for concrete, iron scraps and aluminum scraps. Metal materials for civil engineering and construction such as, synthetic organic materials such as rubber scraps, plastic scraps and vinyl scraps, natural inorganic substances that are not suitable for aggregates such as clay and mud, artificial inorganics for civil engineering such as brick scraps and gypsum board scraps Material.

The aggregate used in the present invention refers to an aggregate for concrete, specifically, a recycled aggregate from crushed stone, crushed sand, limestone aggregate, and concrete waste.
The material to be selected used in the present invention is a material in which the above-mentioned concrete aggregate and foreign matter are mixed.

The foreign matter removing apparatus according to the present invention compares the difference in luminance or the rate of increase in luminance between aggregate and foreign matter in the material to be sorted, so that, for example, the specific gravity difference is the same regardless of the nature and material of the foreign matter. However, it is possible to accurately detect and remove natural inorganic substances and artificial inorganic materials for civil engineering.
In addition, the existing equipment can be simply added to the existing aggregate manufacturing apparatus or aggregate shipping facility by adding a foreign substance removing apparatus comprising the illumination means, imaging means, image processing means, detection means, and removal means of the present invention. It can be used effectively, and even if the type of foreign matter changes, there is no need to add any mechanical changes or improvements to any existing aggregate production equipment, shipping facility, or foreign matter removal device of the present invention, making it extremely efficient and economical. Is.
Furthermore, since the image processing data at the time of detecting a foreign object is electromagnetic recording data, the data storage is extremely easy and the quality control of the aggregate is extremely excellent.

The present invention will be described below.
As the conveying means for the material to be selected used in the present invention, any one of belt conveyors, chain conveyors, and roller conveyors can be appropriately selected and used.

The light source of the illumination means used in the present invention can be arbitrarily selected from incandescent lamps such as incandescent bulbs and halogen bulbs, mercury lamps, sodium lamps, xenon lamps, metal halide lamps and other discharge lamps, and xenon flashes. A light bulb is preferred.
Further, a highly efficient reflective bulb (ref lamp), a beam lamp, and a dichroic mirror that cuts heat rays are preferable, in which the inner surface of the glass sphere is an aluminum reflector having a high reflectance.
In addition, since the brightness of the foreign object cannot be measured accurately if a shadow of the aggregate is formed on the foreign object, a plurality of illumination means are used so that the aggregate cannot be shadowed on the surface of the foreign object. It is preferable to irradiate the upper material to be sorted with light.
In addition, it irradiates over the whole width direction of a conveyance means.

In the present invention, two CCD monochrome cameras can be used as photographing means.
Use only one camera with an IR filter. As a result, an image based on the reflected light in the near-infrared light region can be captured with one camera, and an image based on the reflected light in the visible light region can be captured with the camera equipped with the other IR filter.
The two CCD monochrome cameras are installed so that each can view the entire area in the width direction of the conveying means.
The two CCD monochrome cameras are preferably installed near the center in the width direction of the conveying means so that the central axis of light incident on each camera is vertical.

Further, only one camera may be used with a cold mirror. As a result, an image based on reflected light in the visible light region can be captured with one camera, and an image based on reflected light in the infrared region can be captured with the other camera equipped with a cold mirror.
As another method, an IR transmission filter, a band pass filter, a dichroic mirror, a dichroic filter, prism spectroscopy, or the like may be used. Thereby, an image based on the reflected light in the near-infrared light region and an image based on the reflected light in the visible light region can be respectively taken.

The image processing means used in the present invention irradiates the material to be sorted conveyed by the conveying means with the illumination means, visualizes the reflected luminance of the irradiated material to be sorted with a CCD camera, and analyzes the image in the material to be sorted by image analysis. For the aggregate and the foreign material, the luminance increase rate or the luminance difference between each visible light and near infrared light is calculated and compared.
The present image processing means includes a histogram processing hardware for performing high-speed image processing and a plurality of hardware look-up tables capable of luminance conversion.

Next, the luminance used in the present invention is calculated in the region of 420 nm to 960 nm.
The wavelength in the visible light region may be in the range of 420 nm to 550 nm, and the 420 nm band is particularly preferable. The wavelength in the near infrared light region may be in the range of 700 nm to 960 nm, and the 860 nm band is particularly preferable.
The luminance increase rate or the luminance difference in the present invention may be an average of the luminances of a plurality of wavelengths in the visible light region and the near-infrared light region, or may be calculated as the luminance of only a specific wavelength. .

In the image processing used in the present invention, first, in order to delete the luminance of the conveying means based on other than the material to be sorted from the luminance distribution detected by the CCD monochrome camera, a histogram processing is performed to set the material judgment threshold value. decide. An LUT (look-up table) is created so that the luminance lower than this threshold is 0, and luminance conversion is performed again to obtain an image in which only the material to be sorted is extracted.

Next, from this image, the visible average luminance value in the visible light region (or the luminance value in the specific wavelength band) and the near infrared average luminance value in the near infrared region (or the luminance value in the specific wavelength band) are obtained, and further from this An average luminance increase rate (or luminance increase rate in a specific wavelength band) is obtained.

As another method, from the above-mentioned image, the visible average luminance value in the visible light region (or luminance value in a specific wavelength band) and the near-infrared average luminance value in the near infrared region (or luminance value in a specific wavelength band) are used. Further, an average luminance difference (or a luminance difference in a specific wavelength band) may be obtained from this.

Specifically,
For example, in the case of the luminance increase rate Y (%),
Y (%) = {(760 nm luminance + 780 nm luminance + 860 nm luminance) / 3− (420 nm luminance + 500 nm luminance + 600 nm luminance) / 3} / {(420 nm luminance + 500 nm luminance + 600 nm luminance) / 3} × 100
Alternatively, Y (%) = (860 nm luminance−420 nm luminance) / 420 nm luminance × 100.
In the case of the luminance difference Y,
Y = {(760 nm luminance + 780 nm luminance + 860 nm luminance) / 3− (420 nm luminance + 500 nm luminance + 600 nm luminance) / 3
Alternatively, Y = 860 nm luminance−420 nm luminance.

Since the difference in brightness of limestone aggregates, aggregates such as crushed stone and crushed sand is small, and the difference in brightness of foreign materials such as biogenic materials and metal materials for civil engineering and construction is large, the aggregate or foreign material depends on the brightness increase rate or brightness difference Can be identified.

The detection means used in the present invention has a luminance increase rate (or luminance difference) of a certain value or more because the luminance increase rate (or luminance difference) of the aggregate is different from the luminance increase rate (or luminance difference) of the foreign matter. In this case, the material to be sorted can be determined as a foreign substance, and a removal signal can be transmitted to remove the foreign substance.
That is, if this constant value is set in advance as a reference value for each type of foreign matter, a portion exceeding this reference value can be detected as a foreign matter, and a portion exceeding this reference value can be detected from an image comparing luminance values. By obtaining a binary image extracted in white, the position information of the foreign matter can also be detected.

  As another method, binary processing is performed in which a portion different from the surrounding luminance increase rate (or luminance difference) is image-processed from an image of the material to be sorted, and the different portion is extracted white from an image comparing the luminance values. By obtaining an image, this different part can be detected as a foreign object.

Since the detection means used in the present invention also detects the position information of the foreign matter from the binary image described above, the position information can be transmitted to the removal means, and the foreign matter can be accurately removed by the removal means.

In the present invention, image processing by the image processing means, detection of foreign matter by the detection means, and position information of the foreign matter are processed by a computer.
Further, various data such as a photographed image photographed by the photographing means, a binary image processed by image processing, luminance, luminance increase rate, luminance difference, and the like may be displayed on the monitor.
These various data are stored in a computer or other electromagnetic recording medium together with data necessary for quality control such as detection date and time and shipping destination data.

The removing means used in the present invention is selected from one of a damper device, a dropout conveyor device, an extrusion device, a scraping device, a compressed air injection device, and a pickup device.
These removing means are provided downstream from the position of the conveying means where the photographing means is arranged.

A case where the removing means is a damper device will be described.
When the brightness increase rate (or brightness difference) between the aggregate and the foreign material measured and calculated by the captured image is different or exceeds the reference value, a removal signal is transmitted from the detection means to the removal means, When the foreign matter causing the removal signal is conveyed to the damper device, the damper driving device is driven to rotate the wing and feed the foreign matter into the foreign matter collection line or the foreign matter collection box.
Note that the material to be sorted (that is, only the aggregate) when the removal signal is not transmitted passes through the damper device that is not rotated, and is transported as it is by the transporting means, and the aggregate silo and the aggregate yard. Or sent to the shipping facility.

Next, the case where the removing means is a dropout conveyor will be described.
When the brightness increase rate (or brightness difference) between the aggregate and the foreign material measured and calculated by the captured image is different or exceeds the reference value, a removal signal is transmitted from the detection means to the removal means, When the foreign matter causing the removal signal is conveyed onto the drop conveyor, the dropout conveyor drive device is driven and the dropout conveyor is rotated to move the foreign matter to the foreign matter collection line or foreign matter collection box. Send it in.
When the removal signal is not transmitted, the material to be sorted (that is, only the aggregate) passes through the non-rotating dropout conveyor and is transported by the transport means as it is. It is sent to the yard or shipping facility.

Next, the case where the removing means is an extrusion apparatus will be described.
An air cylinder or a hydraulic cylinder is provided on the side of the conveying means so as to extend and contract on the conveying means in a direction perpendicular to the conveying direction, and a rectangular plate for extruding foreign matter is attached to the tip of the cylinder. ing. The plate is installed in such a state that foreign matter on the conveying means can be pushed out from the conveying means and removed by extension of the cylinder.
When the luminance increase rate (or luminance difference) between the aggregate and the foreign material measured / calculated by the photographed image is different or exceeds the reference value, a removal signal is transmitted from the detection means to the removal means, When the foreign matter that caused the removal signal to be sent is transported onto the transport means on which the removal means is installed, the cylinder is extended to extrude the foreign matter from the transport means, and the foreign matter provided beside the transport means Send it to the recovery line or foreign material recovery box. Then, the cylinder extended to extrude the foreign object immediately contracts and returns to its original state.
It should be noted that the material to be sorted (that is, only the aggregate) when the removal signal is not transmitted is not pushed out by the removing means but is conveyed by the conveying means as it is, and the aggregate silo, the aggregate yard, or the shipping facility. Is sent to.

Next, the case where the removing means is a scraping device will be described.
One or a plurality of scraping device fixing shafts each having a scraping device attached to the tip thereof are connected to a rotating shaft provided above the conveying means. The rotating shaft is provided so as to rotate in the width direction of the conveying means. The scraping device scrapes out the foreign matter on the transport means and removes it from the transport device by the rotation of the rotating shaft.
That is, when the luminance increase rate (or luminance difference) between the aggregate and the foreign material measured / calculated differs depending on the photographed image, or when it exceeds the reference value, a removal signal is sent from the detection means to the removal means When the foreign matter causing the removal signal is conveyed below the rotary shaft, the rotary shaft rotates, and the scraping device scrapes out the foreign matter from above the transport means, to the side of the transport means. It feeds into the provided foreign material recovery line and foreign material recovery box.
Note that the material to be sorted (that is, only the aggregate) when the removal signal is not transmitted is not scraped off by the removing means, but is transported by the transporting means as it is, and the aggregate silo, the aggregate yard, or the shipping facility. Is sent to.

Next, the case where a removal means is a compressed air injection apparatus is demonstrated.
A compressed air ejection nozzle is provided on the side of the conveying means so that the compressed air is ejected in a direction perpendicular to the conveying direction. The nozzle for jetting compressed air is connected to a compressor, a high-pressure air cylinder, and the like. The open / close valve of the compressed air ejection nozzle opens and closes depending on the presence or absence of a removal signal.
When the foreign matter is conveyed in front of the compressed air ejection nozzle, the on / off valve is opened by the removal signal, and the compressed air is ejected from the compressed air ejection nozzle to transmit the removal signal. The causing foreign matter is jetted, extruded or blown off from the conveying means, and sent to a foreign matter collection line or a foreign matter collection box provided beside the conveying means.
In addition, the material to be sorted when the removal signal is not transmitted (that is, only the aggregate) is conveyed by the conveying means as it is without being ejected / extruded or blown by the removing means, and the aggregate silo, aggregate yard, Or it is sent to the shipping facility.

Next, the case where the removing means is a pickup device will be described.
The pick-up device is composed of a claw for scooping or holding a foreign object and a flexible foldable arm for fixing and rotating the claw, and scoops up the foreign substance that caused the removal signal to be transmitted, or It is held and rotated on a foreign substance collection line or a foreign substance collection box provided on the side of the conveying means to drop the foreign substance onto the foreign substance collection line or the foreign substance collection box.

  Next, although an example of the Example of this invention is demonstrated in detail, this invention is not restrict | limited at all to these.

[Example 1]
A material to be sorted made of crushed limestone of 25 to 80 mm mixed with a piece of wood having a diameter of 10 mm and a length of 50 mm or more was conveyed by a belt conveyor at 135 m / min.
Then, the material to be sorted on the belt conveyor was illuminated with a ref lamp, and the material to be sorted was photographed with two CCD monochrome cameras interlocked with the lighting of the ref lamp.
Of the two CCD monochrome cameras, one is for visible light region photography with an IR filter and the other is for near infrared region photography.

The image photographed with the computer was image-analyzed, and the luminance increase rate of the 420 nm band and the 860 nm band of the limestone aggregate and the wood piece was calculated.

The measurement results of the luminance increase rate of limestone aggregate and wood pieces are shown below.

As shown in Table 1 above, the luminance increase rate of the limestone aggregate was 4.42 to 21.24%, while the luminance increase rate of the wood pieces was 59.65 to 76.38%.
Therefore, since the luminance increase rates of the limestone aggregate and the piece of wood are greatly different, it was possible to easily detect the piece of wood mixed in the limestone aggregate.

Next, based on the above measurement result, when the luminance increase rate is> 50.0%, when this piece of wood enters the dropout conveyor, a removal signal is transmitted so as to rotate the dropout conveyor. When programmed to do so, the dropout conveyor rotated and this piece of wood was dropped into a foreign material recovery box below the dropout conveyor.
After that, the dropout conveyor returns to the initial state (horizontal state where it does not rotate) and continues to convey the limestone aggregate from which no foreign matter is detected to the belt conveyor that follows the dropout conveyor. Continued to send.

[Example 2]
A material to be sorted made of crushed limestone of 25 to 80 mm mixed with a piece of wood having a diameter of 10 mm and a length of 50 mm or more was conveyed by a belt conveyor at 135 m / min.
Then, the material to be sorted on the belt conveyor was illuminated with a ref lamp, and the material to be sorted was photographed with two CCD monochrome cameras interlocked with the lighting of the ref lamp.
Of the two CCD monochrome cameras, one is for photographing in the visible light region, and the other is for photographing in the near infrared region equipped with a cold mirror.

The image taken by the computer was analyzed, and the average luminance difference between the limestone aggregate and the piece of wood was calculated.

The measurement results of the average luminance difference between the limestone aggregate and the piece of wood are shown below.

As shown in Table 2 above, the average luminance difference, which is the difference between the near-infrared light region average luminance 137.1 and the visible light region average luminance 146.2 of the limestone aggregate, was −8.
On the other hand, the average luminance difference, which is the difference between the near-infrared light region average luminance of 75.5 and the visible light region average luminance of 50.8, was 24.7.
Therefore, the average luminance difference, which is the difference between the near-infrared light region average luminance and the visible light region average luminance, is greatly different between limestone and wood pieces, so that the wood pieces mixed in the limestone aggregate can be easily detected.

Next, since the average brightness difference of the limestone aggregate was -8, when the average brightness difference of the piece of wood was> 0, when this piece of wood entered the dropout conveyor, the dropout conveyor was rotated. When programmed to send a removal signal, the dropout conveyor turned and dropped this piece of wood in a foreign material recovery box below the dropout conveyor.
After that, the dropout conveyor returns to the initial state (horizontal state where it does not rotate) and continues to convey the limestone aggregate from which no foreign matter is detected to the belt conveyor that follows the dropout conveyor. Continued to send.

In the above-described embodiment, the luminance increase rate or the average luminance difference of the limestone aggregate is referred to, and the reference value of the luminance increase rate or the luminance difference of the piece of wood to be removed (luminance increase rate> 50.0%, average luminance difference) > 0), but the following method may be used.
For example, by the above-described method, a plurality of images of aggregates that do not include foreign matters are processed in advance, and the luminance increase rate (or luminance difference) of the aggregates obtained by image processing is obtained. Even if it is programmed so that the percentage of increase in luminance (or luminance difference) is set as a reference value for removing foreign matter, in anticipation of safety so as not to remove the aggregate to be originally selected. good.
In this way, once the material to be sorted is started to be transported, no manpower is required until all the materials to be sorted are transported.

As another method, binary processing is performed in which a portion different from the surrounding luminance increase rate (or luminance difference) is image-processed from an image of the material to be sorted, and the different portion is extracted white from an image comparing the luminance values. This different part may be detected as a foreign object by obtaining an image.

Further, as another method, the foreign matter may be removed manually before being photographed only for a short period of time when a plurality of images immediately after being transported are processed.

As described above, according to the present invention, it is easy to compare the luminance increase rate (or luminance difference), which is the difference between the near-infrared light region luminance and the visible light region luminance, regardless of the material of the foreign matter. In addition, it can be instantly determined whether or not it is a foreign object.
In addition, if there is a computer in which illumination means, photographing means, and removal means are installed in a part of a belt conveyor of an existing aggregate manufacturing apparatus or aggregate shipping apparatus and a program for image processing means / detection means is incorporated, the present invention Can be easily implemented.
If the removing means is a dropout conveyor, it is only necessary to replace it with a part of an existing belt conveyor. If the removing means is a compressed air injection device, the existing belt conveyor can be left as it is, and a nozzle for jetting compressed air can be installed on the side of the belt conveyor, which is extremely economical.
Furthermore, since the foreign matter is automatically detected by comparing the brightness increase rate (or brightness difference) with the surroundings even if the type of the foreign matter changes, it is not necessary to add any improvement or change to the apparatus itself.
Further, since image processing data at the time of foreign matter selection can be stored electromagnetically, the quality control of the aggregate is extremely excellent.

It is a principal part schematic diagram which shows an example at the time of imaging | photography of the to-be-sorted material in the foreign material detection apparatus concerning this invention. It is a graph which shows the brightness according to wavelength about each of a piece of wood and limestone. It is a graph which shows the luminance increase rate according to wavelength about each of a wood piece and limestone. A in the figure indicates the luminance increase rate (860 nm-420 nm) of limestone. B in the figure represents the luminance increase rate (860 nm-420 nm) of the piece of wood. It is the image which image | photographed the to-be-sorted material by infrared light 860nm. It is the image which image | photographed the to-be-sorted material with visible light 420nm. It is the image which compared the luminance value obtained from the picked-up image (FIG. 4) of infrared light 860 nm, and the luminance value obtained from the picked-up image of visible light 420 nm (FIG. 5). FIG. 7 is a binary image obtained by extracting a foreign object (wood piece) from the image of FIG. 6 in white.

Explanation of symbols

1: Ref lamp 2: CCD monochrome camera 3: CCD monochrome camera 4: IR filter 5: Belt conveyor 6: Aggregate 7: Foreign object 8: Computer

Claims (13)

A foreign matter removing apparatus that detects and removes foreign matter by comparing the luminance increase rates of the visible light region luminance and the near infrared light region luminance of each of the aggregate and the foreign material. At least lighting means for illuminating the material to be sorted, imaging means for photographing the illuminated material to be sorted, and visible light regions of the aggregate and foreign matter in the material to be sorted based on the photographed image Image processing means for calculating a luminance increase rate between the luminance and the near-infrared light region luminance, a detection means for outputting a foreign substance removal signal when the luminance increase rate exceeds a reference value, and a luminance increase according to the removal signal A foreign matter removing apparatus comprising a removing means for removing foreign matter having a rate equal to or higher than a reference value. A foreign matter removing apparatus that detects and removes foreign matters by comparing the average luminance increase rates of the average luminance in the visible light region and the average luminance in the near infrared light region of each of the aggregate and the foreign matter. At least lighting means for illuminating the material to be sorted, imaging means for photographing the illuminated material to be sorted, and visible light regions of the aggregate and foreign matter in the material to be sorted based on the photographed image Image processing means for calculating an average brightness increase rate between the average brightness in the near-infrared light region and an average brightness in the near-infrared light region, and a detection means for outputting a foreign matter removal signal when the average brightness increase rate is equal to or greater than a reference value; A foreign matter removing apparatus comprising: a removing means for removing foreign matter having a luminance increase rate equal to or greater than a reference value in accordance with the removal signal. A foreign matter removing apparatus that detects and removes foreign matter by comparing the luminance increase rates of the brightness at 420 nm and the brightness at 860 nm of the aggregate and the foreign matter, respectively. At least illumination means for illuminating the material to be sorted, photographing means for photographing the illuminated material to be sorted, and brightness of each of the aggregate and foreign matter in the material to be sorted based on the photographed image at 420 nm And an image processing means for calculating a luminance increase rate with the luminance at 860 nm, a detection means for outputting a foreign substance removal signal when the luminance increase rate is equal to or higher than a reference value, and a luminance increase rate according to the removal signal as a reference value A foreign matter removing apparatus comprising a removing means for removing the foreign matter as described above. A foreign matter removing apparatus that detects and removes a foreign matter by comparing a luminance difference between a visible light region luminance and a near-infrared light region luminance of each of the aggregate and the foreign matter. At least lighting means for illuminating the material to be sorted, imaging means for photographing the illuminated material to be sorted, and visible light regions of the aggregate and foreign matter in the material to be sorted based on the photographed image An image processing means for calculating a brightness difference between brightness and near-infrared light brightness; a detecting means for outputting a foreign substance removal signal when the brightness difference exceeds a reference value; and a brightness difference based on the removal signal as a reference A foreign matter removing apparatus comprising a removing means for removing foreign matter having a value equal to or greater than the value. A foreign matter removing apparatus that detects and removes foreign matter by comparing an average luminance difference between an average luminance in a visible light region and an average luminance in a near infrared light region of each of an aggregate and a foreign matter. At least lighting means for illuminating the material to be sorted, imaging means for photographing the illuminated material to be sorted, and visible light regions of the aggregate and foreign matter in the material to be sorted based on the photographed image Image processing means for calculating the average brightness difference between the average brightness in the near-infrared light region and the average brightness in the near-infrared light region, detection means for outputting a foreign substance removal signal when the average brightness difference exceeds a reference value, and the removal A foreign matter removing apparatus comprising: removing means for removing foreign matter having an average luminance difference equal to or greater than a reference value according to a signal. A foreign matter removing apparatus that detects and removes foreign matter by comparing the luminance difference between the brightness at 420 nm and the brightness at 860 nm of the aggregate and the foreign matter, respectively. At least illumination means for illuminating the material to be sorted, photographing means for photographing the illuminated material to be sorted, and brightness of each of the aggregate and foreign matter in the material to be sorted based on the photographed image at 420 nm Image processing means for calculating the brightness difference between the brightness at 860 nm and the brightness at 860 nm, detection means for outputting a foreign substance removal signal when the brightness difference is greater than or equal to a reference value, and the brightness difference is greater than or equal to the reference value according to the removal signal A foreign matter removing apparatus comprising a removing means for removing foreign matter. The removal means is any one of a discharge damper device, a dropout conveyor device, an extrusion device, a scraping device, a compressed air injection device, and a pickup device. The foreign matter removing apparatus according to any one of claims 6, 8, 10, and 12.