JPH10267854A - Multilayer reflecting background for optical selector - Google Patents

Abstract

PROBLEM TO BE SOLVED: To improve matching performance of a background by layering a first layer reacting to a reflecting light at a short wavelength region and a second layer reacting to a reflecting light which penetrates the first layer and is reflected at the second layer at a long wavelength spectral region. SOLUTION: A background 40 detects a light from a light source 38 first. The light becomes a reflecting light from the background 40 as shown by optical paths 44, 46 when no object interrupts the light. The background 40 comprises a first layer reacting to the reflecting light at a short wavelength region and a second layer reacting to the reflecting light which passes the first layer and is reflected at the second layer at a long wavelength spectral region. Moreover, the background 40 matches a dichroic band or a permissible reflectance characteristic of an object 42 at each spectral region. Therefore, a detector 48 and an electric circuit 50 connected to the detector operate to monitor a good object.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a background of an optical sorter that matches an object to be sorted by a sorter in at least two wavelength ranges. One wavelength region of the two is usually represented by colors in the visible light spectrum, and the other wavelength region is usually represented by colors in the infrared light spectrum.

[0002]

BACKGROUND OF THE INVENTION A typical sorter of the type to which the present invention is applied is a high-speed sorter typically used in the food and other industries to sort products as objects. For example, in order to separate "bad" beans from standard beans by such a sorter, individual edible beans are allowed to flow naturally over channels or shoots provided at steep angles. "Bad" here
The term applies to beans that deviate from a predetermined acceptable "hue" in one or more light emission bands, which in some cases may be outside the visible color spectrum. In the simplest case, objects are sorted in a single spectrum based on shade or color shade variations, including black or white shades or gray shades. Such a sorting method is commonly referred to as monochromatic sorting, since only a single light emission spectrum is monitored.
In more complex optical color sorters, the flow of the object is sorted based on whether the object reflects an unacceptable amount of radiation in one of the two light emission bands. Such a sorting method is generally called two-color sorting. Obviously, more than two light emission bands can be used if desired.

[0003] Optical sorters such as those described above employ a sensor that includes a photoelectric detector such as one or more photodiodes. The photoelectric detector is provided at a position where the flow of the irradiated object can be monitored through the light passage window. The object stream passes through the light sensor and a background with a color or darkness that matches the standard color or shaded object stream, resulting in the color or shading of the object. The result is that a detection event occurs only when there is a change. The object should be such that it produces a standard reflection from the standard in one or more of the areas of light emission being monitored and a non-standard reflection from the reject in the same area of light emission. Is irradiated with light from one or more light sources.

[0004] The color sorter also includes an ejector mechanism located downstream from the location of the one or more sensors, the ejector mechanism being activated by an electrical signal generated upon detection of the sensor. An electrical signal is generated when a defective or defective object is detected, and the ejector is activated when the defective object and the ejector mechanism are just in line. Therefore, there is a very small delay time between the detection of a defective object and its removal. A typical ejector mechanism is usually an air ejector.

As described above, the flow of an object must match the normal product to be detected at the wavelength or wavelength band observed by the sensor.
It flows in front of a background having a color or shade that has a very large effect on the overall operation. This is usually achieved by carefully painting the background, drying the background, and actually running the sorter, or by separately analyzing whether the background color or shade is appropriate. Is done. In order to perform two-color selection, the background must be within the range where the reflectance characteristics are acceptable in two bands, especially if one of these bands is in the visible spectrum. In the case of the infrared spectrum, it is virtually impossible to speak with simple measurements. A lot of time is spent for such a method, and such a trial and error approach can still result in a match that is still as accurate as the preferred acceptable radiation area achievable by the invention described below. You can't. That is, in both the infrared spectrum and the visible light spectrum, the reflectance of the paint rarely matches the object in such a spectrum. This is because of the difference between the nature of the object and the nature of the background ground, usually a metal.

[0006] The texture of the underlayer of a typical object surface is important with respect to how light in the infrared spectral region acts or reflects, while the condition of the object surface is determined by the visible light spectral region. Is important as to how the light is reflected. Attempts to treat only the background surface with a mixture of shades, for example, do not take into account how the material under the background or the substrate reflects light in the infrared spectral region. . William C. Long (Will
iam C.I. The technique of illuminating the background with different colors, such as the technique disclosed in US Pat. No. 5,265,732 issued Nov. 30, 1993 by Long) to the state of the material under the reflective surface. Is not disclosed or mentioned.

[0007]

SUMMARY OF THE INVENTION Accordingly, a feature of the present invention is that a first layer that responds to reflected light in the short wavelength region, and a reflected light that passes through the first layer and is reflected from the second layer in the long wavelength spectral region. It is an object of the present invention to provide an improved background for a sorter, comprising a layer with a reacting second layer.

Another feature of the present invention is that the first layer reacts to reflected light in the visible light spectrum region and the reflected light passing through the first layer and reflected from the second layer in the non-visible light spectrum region. With a second layer that reacts in a layered manner,
It is to provide an improved background for the sorter.

Still another feature of the present invention is that the first layer is a plastic laminate, a thin film, or a transparent tape, and the second layer is made of a material different from the first layer, such as a wood / adhesive substrate. One object is to provide an improved layered background of the type described above for a sorter.

[0010]

SUMMARY OF THE INVENTION An improved background according to the present invention works in conjunction with an electro-optic monitoring device of a sorter for sorting small rejects in a stream of objects. Usually, such an apparatus, in which an improved background is used, is the flow of an object passing therethrough with light in a given visible spectral region and light in a given non-visible infrared spectral region. To irradiate
A two-color sorter having at least one monitoring device positioned relative to a channel through which an object flows. The light source is usually associated with a filter for producing the desired dichroic light emission, which is related to the already known reflection properties of the object to be sorted. That is,
Normal or acceptable objects are known to reflect above their respective trip levels (thresholds) in any of the aforementioned predetermined spectral regions. However, unacceptable objects (defectives) do not reflect beyond at least one of these trip levels, based on which rejection signals for defective objects are generated. become. Such operation of the sorter is well known in the art.

The background is important because it has been selected to match the acceptable object in any of the two-color spectral regions. Therefore,
When no objects are flowing, or when there is an interval between objects, no rejection signal is generated.

The background is created by selecting a substrate material and color that reflects light of a long wavelength among the dichroic waves used. The substrate may be wood or plastic and may have an adhesive surface for providing there a surface layer selected to reflect short wavelength light of the dichroic wave used. Preferably, the shorter wavelengths are in the visible spectrum, and the longer wavelengths are in the non-visible infrared spectrum.
The surface layer may be selectively coated in a predetermined appropriate color or tone, or may be a thin film or a thin transparent tape. It has been found that this type of background more naturally matches the colors of the two operating areas of the two-color sorter than those of the prior art. This means
Some other technical explanations could be given, as long wavelength light passes through the surface layer and has a texture similar to the surface texture of the sorter object for reflection purposes. It can be said that one reason is that the light is reflected from the lower layer or the substrate layer provided with the above.

If a plurality of monitors are employed to view the sorting object at different angles, it is clear that each optical monitoring device can have one or more backgrounds having substantially the same structure. It is. If necessary, three or more spectral regions can be employed.

[0014]

BRIEF DESCRIPTION OF THE DRAWINGS FIG.
The details of the present invention will be described. First, FIG. 1 shows a high-speed sorter for separating a non-standard object from a passing flow or downstream of an object to be sorted. Generally, the sorter 10 includes one or more channels, chutes or inclined gutters 12 provided at a steep angle, typically greater than or equal to 45 °, and preferably about 80 °, which is substantially vertical. The channel is supported at a predetermined position by the machine casing 14, and the object to be sorted is gravity-fed to the top position of the channel by the hopper 16 attached to the same machine casing. The sorting object is supplied from the hopper 16 to the channel 12 via the divided vibration feeder 18. Sorters used in commercial practice typically have two or more channels and are designed to operate simultaneously on objects flowing down each channel 12, For simplicity, the device 10 will be described as having only a single channel 12.

The objects to be separated or sorted by the sorter 10 are small and other objects such as edible beans. It will be appreciated that edible beans are individually identifiable by color in one or more spectral bands. The supply of the object from the hopper via the vibrating feeder and the flow down on the channel are all due to gravity. The flow of the object is slower than the free fall speed solely due to the bending of the path of the object and friction due to the surface. However, as is well known in the art, objects move at high speed and in large quantities.

An optical observer or sensor 20, described in more detail below, is located at the bottom of the channel. Since the object flow passes in front of the sensor, all non-standard or defective products are detected or detected here. It will be appreciated that such detection or detection requires that rejects be distinguished or identified from both the standard object and the background. Typically, for example, a defective food bean has a darker or darker brightness than a standard product or a product within an allowable range, compared with a predetermined allowable range of darkness, lightness or hue. The detection is based on whether the color is lighter, brighter, or of a different color or hue. This detection can be performed in a single spectral region in the case of single color detection, two separate spectral regions in the case of two-color detection, and in a large number of spectral regions in the case of multi-color detection. It will be appreciated that "spectral region" may be the entire region or a partial region in the visible light spectrum, and may be the entire region or a partial region in the non-visible spectral region. For example, detection in the infrared region is commonly performed. When a defective object or defective product is detected, an electric signal is generated, and based on the electric signal, the ejector mechanism is activated and the defective product is eliminated.

The ejector 36 or the object separator provided adjacent to the lower side of the optical detection means 20 is activated by the activation electric signal described above, and removes an undesired defective product from the flow of the object. Generates a blast to eliminate. The ejector can be a mechanical ejector if necessary. When the activation signal is generated, typically, the electromagnetic solenoid valve is operated so as to emit or output a gust against the flow of the object in order to eliminate defective products in a timely manner. The delay time from the detection time to the activation of the solenoid valve is very short, and the timing is such that the defective product just detected can be suitably eliminated. Achieved by methods well known in the art. The defective products eliminated by this processing are stored in the defective product storage unit 28.
And is entrusted to the subsequent processing. Objects that are not rejected will proceed further to the channel extension 30 and will be collected and packaged as good quality products that have successfully passed a predetermined reference value without being rejected.
Both the control of the flow of the object and the sensitivity of the sensor are controlled by a control system, as is well known in the prior art.

Referring to FIG. 2, the components of the monitoring or optical sensor and the associated sorter are shown as viewed from above. The sensor means 20 generally has a ring-like structure provided with a central opening 32. The stream of objects to be separated or sorted as described above passes through the openings at the "window" location or plane. This is the electro-optic monitoring device for the sorter. The optics or monitoring mechanism is well known and generally comprises three equally spaced peripheral sensors 37, each comprising a photocell or photodiode. It is a thing. At least three lamps 38 are on one plane, with individual lamps for each sensor. Each lamp 38 emits a beam against a corresponding background 40, the light reflected from the background,
The reflected light from the object flowing between the background and the photoelectric cell sensor is detected by the sensor.
The reason for using the three sensors is to ensure the detection accuracy of a defective product that can be detected from only one direction and can be detected without necessarily further detecting from another direction. Each of the monitoring means comprising a combination of the photoelectric cell sensor 37 and the background 40 is illustrated as having only one lamp 38. In an actual sorter, a plurality of lamps 38 are commonly used to uniformly irradiate an object,
In order to illuminate the background uniformly, the same number or even additional lamps are usually used.

Referring to FIG. 3, there is shown a schematic side view of an object 42 passing near the light source or lamp 38. The reflection of the light from the light source 38 is due to the light paths 44 and 46 when there is no object blocking the light from the light source 38.
Are reflections from the background 40 as indicated by. Since the background matches the reflectance characteristics of the acceptable object in each of the two color bands or spectral regions, the detector 48 and its associated electrical circuit 50 monitor the good object as if it were a good object. Works as you do. This means that no rejection signal is generated. Detector 48 typically includes a photodiode or similar sensor and a beam splitter and / or filter device for separating the received light into a desired spectral region. The electronic circuit suitably comprises an amplifier and a level detector, which produce an appropriate ejector activation signal with an appropriate delay time to eliminate detected rejects. All of the above are well known in the prior art and do not require further elaboration here.

The background 40 has two layers:
It first receives light from the light source 38 and first has a first or front layer 52 that is matched to respond to shorter wavelengths of the spectral region used to screen the object. . Typically, this short wavelength light is in the visible light spectral region centered on a frequency known to be capable of producing a reflection response that can be readily determined from light from a good product. For example, in the case of edible beans, the wavelength region range in the visible light spectrum known to be capable of sorting operation is from 400 nm to 500 nm. As another example, in the case of sunflower seeds, the wavelength range in the visible light spectrum known to be sortable is from 600 nm to 700 nm. Layer 5
2 may be a simple application of a matching paint to the substrate layer 54, or a thin film adhered to an upper layered substrate such as Formica (trade name). Good.

The light having a long wavelength from the light source is usually light in the infrared spectrum region, and does not react.
Pass 2 However, the substrate or second layer 54 located below layer 52 is selected to reflect in response to light of a second frequency or spectral band so that the object operates to be sorted. I have. For example, in the case of edible beans, the region of the infrared spectrum known to produce a favorable response is from 1500 nm to 160 nm.
Up to 0 nm. This response was found to be caused by a combination of wood and adhesive used for the substrate of the overlying material, such as formica. For sunflower seeds, the infrared region of the spectrum known to produce a favorable response is from 1500 nm to 1600 nm.
This response was found to be caused by the painted metal and the adhesive used to attach the first layer to the second layer. The technical explanation is too simple, but a number of experiments have proven to give the above results.

[0022]

Since the substrate layer is protected by the uppermost layer or the first layer, its performance does not significantly degrade during use except for aging. That is, dust accumulation is usually not a problem. In many cases, the first spectral region has a wider bandwidth than the second spectral region, and can withstand dust accumulation. Not only can it be better, it can also alleviate various problems related to the maintenance and control of the entire sorter compared to those that occurred when using a conventional background. .

While the general embodiments have been shown and described with reference to several alternative configurations, it will be apparent that many alternative embodiments are possible by those skilled in the art and the invention is not limited to these embodiments. It should be understood that the present invention is not limited to the embodiments.

[Brief description of the drawings]

FIG. 1 is a side view of an electro-optical separator equipped with at least one background according to the present invention.

FIG. 2 is a top view of an optical monitoring device of the electro-optical sorter as shown in FIG.

FIG. 3 is a simplified schematic diagram illustrating the use of a background according to the present invention.

FIG. 4 is a cross-sectional view of a background according to the present invention, illustrating a laminar or laminar structure.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 10 Sorting machine 12 Channel 14 Machine frame 16 Hopper 18 Split vibration feeder 20 Optical sensor means 28 Defective product accumulation part 30 Channel extension part 32 Center opening part 36 Ejector 37 Sensor 38 Lamp 40 Background 42 Object 44 Path 46 Path 48 Detector 50 Electronic Circuit 52 First Layer 54 Second Layer

 ──────────────────────────────────────────────────の Continued on front page (72) Inventor Calvin G. Gray, United States, 77027 Texas, Houston, Las Palmas 3315

Claims (10)

[Claims] 1. A flow of an object passing through an electro-optic monitoring device, selected from a group of objects of each group having different wavelength selection requirements, to a normal object having a predetermined allowable color range and reflectance range. A two-color sorter for color-sorting an object and a defective object having a color or reflectance outside the allowable color range and the reflectance range, wherein the sorter has a short wavelength region and a long wavelength region. A background for the electro-optic monitoring device, having the same acceptable color and reflectivity as within the range of acceptable colors and reflectivity for the normal object; and Lamp means for irradiating light in the short wavelength region and the long wavelength region, and as the flow of the object passes near the monitoring device, the amount of reflected light in the short wavelength region band; Reflections in the zone The first and second optical sensors for detecting the light quantity, respectively, and connected to each of the optical sensors, connected to the respective predetermined minimum reference level, of the short wavelength region band and the long wavelength region band A comparator for determining whether or not the amount of light exceeds each of the predetermined minimum reference levels; and in each of the short wavelength region band and the long wavelength region band, one of the predetermined minimum reference levels. An object separator for separating an object reflecting light below the level from the flow of the object, wherein the background reacts to the reflected light in the short wavelength band. A first layer that does not react with light in the long wavelength region band and allows light in the long wavelength region band to pass therethrough, located behind the first layer, reflected light A two-layer sorter comprising: 2. The two-color sorter according to claim 1, wherein said short wavelength band is a visible light spectrum and said long wavelength band is an infrared spectrum. 3. The two-color sorter according to claim 2, wherein the first layer is a thin film, and the second layer is made of a different material from the first layer. 4. The two-color sorter of claim 2, wherein the first layer is a plastic laminate and the second layer is a wood / adhesive substrate. 5. The background of claim 2, wherein said second layer is a painted substrate and said first layer is a thin transparent tape affixed to a surface of said second layer. Two color sorter. 6. A background for an optical sorter matched to an object to be sorted in at least a short wavelength band and a long wavelength band, wherein the background is responsive to reflected light in the short wavelength band. And a first layer that does not react with light in the long wavelength region band and allows light in the long wavelength region band to pass therethrough; located behind the first layer, the long wavelength region A second layer responsive to the reflected light of the band. 7. The background according to claim 6, wherein the short wavelength band is a visible light spectrum and the long wavelength band is an infrared spectrum. 8. The background according to claim 7, wherein said first layer is a thin film, and said second layer is made of a different material from said first layer. 9. The background according to claim 7, wherein said first layer is a plastic laminate and said second layer is a wood / adhesive substrate. 10. The background of claim 7, wherein said second layer is a painted substrate and said first layer is a thin transparent tape affixed to a surface of said second layer. Background to feature.