A new color sorter based on white light Michelson interference

Abstract

The present invention relates to a new type of color sorter based on white light Michelson interference, comprising a feeding mechanism, a color sorter body and a material distribution hopper connected in sequence, and a control system. The color sorter body comprises a shell, and a first optical system and a spray valve arranged in the shell, characterized in that the first optical system comprises a first image sensor, and a first light source, a first lens, a first semi-transparent and semi-reflective mirror, a first plane lens and a first plane reflector arranged in sequence, and the feeding mechanism, the first image sensor, the first light source and the spray valve are all connected to the control system. Compared with the prior art, the present invention adopts white light Michelson interference technology, changes the previous method of directly imaging by reflected light in the color sorter, improves the measurement accuracy of the color sorter, and provides a new solution for the development of the color sorter in the direction of higher accuracy and wider application fields.

Description

Technical Field

[0001] The invention relates to a color sorter, in particular to a novel color sorter based on white light Michelson interference. Background Art

[0002] Color sorters are devices that automatically sort out particles of different colors from granular materials using photoelectric detection technology based on differences in the optical properties of the materials. Currently, color sorters are used in the fields of bulk materials or packaging industrial products, and food quality inspection and grading.

[0003] For example, Chinese patent CN107790405A discloses a color sorter and its spray valve assembly, the spray valve assembly includes: a valve body, a connecting pipe, a mounting plate and a material retaining member, the valve body is provided with an air outlet; the connecting pipe is connected to the valve body and communicated with the air outlet; the valve body is arranged on the mounting plate, and the valve body is provided with a avoidance port for avoiding the air outlet; the material retaining member is arranged on the mounting plate and is located above the air outlet to define a material retaining space at the air outlet, and at least a portion of the edge of the upper surface of the material retaining member is formed as a material guide surface extending downward and outward. However, the above-mentioned color sorters are all based on visual image sensing or infrared technology, and the impurities that can be measured and sorted are all within the size range visible to the human eye, and the measurement accuracy is not high enough. At present, the application of color sorters in some industries has put forward higher requirements for the sorting accuracy of color sorters. Summary of the invention

[0004] The purpose of the present invention is to provide a new color sorter based on white light Michelson interferometry in order to overcome the defects of the above-mentioned prior art. By combining white light interferometry technology with color sorting technology, precise measurement and sorting at the micron level can be achieved, which greatly improves the sorting accuracy of the color sorter. The color sorter can be applied to a wider range of industries, providing an effective method and approach for the further development of the color sorter.

[0005] The purpose of the present invention can be achieved by the following technical solutions:

[0006] A novel color sorter based on white light Michelson interference comprises a feeding mechanism, a color sorter body and a material hopper connected in sequence, and a control system. The color sorter body comprises a shell, a first optical system arranged in the shell, and a spray valve. The first optical system comprises a first image sensor, and a first light source, a first lens, a first semi-transparent and semi-reflective mirror, a first plane lens and a first plane reflector arranged in sequence. The first image sensor, the feeding mechanism, the spray valve and the first light source are all connected to the control system. The first light source is a white light LED. The light emitted by the first light source is converged by the first lens and irradiated to the first semi-transparent and semi-reflective mirror to be divided into two beams of light with nearly equal amplitudes, namely, transmitted light and reflected light.

[0007] The light transmitted through the first semi-transparent and semi-reflective mirror is projected by the first plane lens and irradiated onto the first plane reflector. Then, it is reflected back to the first semi-transparent and semi-reflective mirror in the opposite direction of the incident direction and then reflected for the second time to obtain a reference beam.

[0008] After the light reflected by the first semi-transparent and semi-reflective mirror is irradiated on the material, it is reflected back to the first semi-transparent and semi-reflective mirror through the surface of the material, and transmission occurs to obtain a measuring beam.

[0009] The measuring light beam and the reference light beam interfere with each other after passing through the first semi-transparent and semi-reflective mirror, generating light and dark interference fringes, which are received by the first image sensor (507) and transmitted to the control system (601) for image algorithm analysis to judge the quality of the material, and then control the switch of the spray valve (701) to select the material.

[0010] The first semi-transparent and semi-reflective mirror is installed at a 45-degree angle to the incident light, and the transmission and reflection ratio is 50 / 50.

[0011] The first plane lens is arranged parallel to the first semi-transparent and semi-reflective mirror, and has the same refractive index and thickness as the first semi-transparent and semi-reflective mirror.

[0012] The first image sensor is a high-speed linear array color or black-and-white image sensor.

[0013] The first image sensor is arranged above the first semi-transparent and semi-reflective mirror.

[0014] The color sorter body further comprises a second optical system which is symmetrically arranged with the first optical system, and the first optical system and the second optical system are respectively located on both sides of the material entry path.

[0015] The feeding mechanism comprises a vibrating feeding system, a feeding port and a conveyor belt which are arranged in sequence. The feeding port is at one end of the conveyor belt, and the other end of the conveyor belt is connected to the shell. The vibrating feeding system is located at the feeding port.

[0016] The first optical system also includes an adjusting mechanism for adjusting the distance between the first plane reflector and the first semi-transparent semi-reflective mirror, and the adjusting mechanism is connected to the control system.

[0017] Compared with the prior art, the present invention has the following beneficial effects: the white light Michelson interference technology is adopted, which changes the previous method of directly imaging by reflected light in the color sorter, greatly improves the measurement accuracy of the color sorter, and provides a new solution for the development of the color sorter towards higher accuracy and wider application fields. BRIEF DESCRIPTION OF THE DRAWINGS

[0018] Figure 1 It is a structural schematic diagram of the present invention;

[0019] Among them: 101, shell, 201, vibration feeding system, 301, feed port, 401, conveyor belt, 501, first light source, 502, second light source, 503, first lens, 504, second lens, 505, first plane reflector, 506, second plane reflector, 507, first image sensor, 508, second image sensor, 509, first semi-transparent and semi-reflective mirror, 510, second semi-transparent and semi-reflective mirror, 511, first plane lens, 512, second plane lens, 601, control system, 701, spray valve, 801, distribution hopper. DETAILED DESCRIPTION

[0020] The present invention is described in detail below in conjunction with the accompanying drawings and specific embodiments. This embodiment is implemented based on the technical solution of the present invention, and provides a detailed implementation method and specific operation process, but the protection scope of the present invention is not limited to the following embodiments.

[0021] Optical interferometry refers to the method of generating interference fringes by superimposing a beam of light reflected, refracted or diffracted by an object with another beam of light reflected from the surface of a reference mirror. Optical interferometry is used for precision measurement in many fields, such as fiber optic sensing, microscopic contour restoration, surface contour measurement lamps, etc.

[0022] When using optical interference technology for measurement, interference fringes are the carrier of measurement information. By analyzing the interference fringes, information related to the measured surface structure contained in the fringes can be obtained. White light interferometry is also called low coherence technology. In white light interferometry, all colors of light in the spectrum of the light source participate in interference, and the interference intensity distribution of each color of light is superimposed on the interference image finally formed.

[0023] The present invention combines white light interference technology with color sorting technology, which can achieve micron-level precision measurement and sorting, greatly improving the sorting accuracy of the color sorter. The color sorter can be applied to a wider range of industries, providing an effective method and approach for the further development of the color sorter.

[0024] A new type of color sorter based on white light Michelson interference, such as Figure 1As shown, it includes a feeding mechanism, a color sorter body and a material dividing hopper 801 connected in sequence, and a control system 601. The color sorter body includes a shell 101, and a first optical system, a second optical system and a spray valve 701 arranged in the shell. The first optical system includes a first image sensor 507, and a first light source 501, a first lens 503, a first semi-transparent mirror 509, a first plane lens 511 and a first plane reflector 505 arranged in sequence. The first image sensor 507, the feeding mechanism, the spray valve 701 and the first light source 501 are all connected to the control system 601. The first light source 501 is a white light LED. The light emitted by the first light source 501 is converged by the first lens 503 and irradiated to the first semi-transparent mirror 509, and is divided into two beams of light with nearly equal amplitude, the transmitted light and the reflected light.

[0025] The light transmitted through the first semi-transparent and semi-reflective mirror 509 is irradiated onto the first plane reflector 505 through the first plane lens 511, and then reflected back to the first semi-transparent and semi-reflective mirror 509 in the opposite direction of the incident direction, and then reflected for the second time to obtain a reference beam.

[0026] After the light reflected by the first semi-transparent and semi-reflective mirror 509 is irradiated onto the material, it is reflected back to the first semi-transparent and semi-reflective mirror 509 through the surface of the material, and is transmitted to obtain a measuring beam.

[0027] The measuring beam and the reference beam interfere with each other after passing through the first semi-transparent and semi-reflective mirror 509 , generating interference fringes of alternating light and dark, which are received by the first image sensor 507 and transmitted to the control system 601 .

[0028] The first semi-transparent and semi-reflective mirror 509 is installed at a 45 degree angle to the incident light, and the transmission and reflection ratio is 50 / 50.

[0029] A first plane lens 511 for compensating the light path is provided between the first semi-transparent mirror 509 and the first plane reflector 505 . The first plane lens 511 is arranged parallel to the first semi-transparent mirror 509 , and has the same refractive index and thickness as the first semi-transparent mirror 509 .

[0030] The first image sensor 507 is a high-speed linear array color or black-and-white image sensor.

[0031] The first image sensor 507 is disposed above the first semi-transparent mirror 509 .

[0032] The color sorter body also includes a second optical system symmetrically arranged with the first optical system, and the first optical system and the second optical system are respectively located on both sides of the material falling point.

[0033] The second optical system includes a second image sensor 508, and a second light source 502, a second lens 504, a second semi-transparent mirror 510, a second plane lens 512 and a second plane reflector 506 which are arranged in sequence. The second image sensor 508 and the second light source 502 are both connected to the control system 601. The second light source 502 is a white light LED. The light emitted by the second light source 502 is converged by the second lens 504 and irradiated to the second semi-transparent mirror 510, and is divided into two beams of light with nearly equal amplitude, namely, transmitted light and reflected light. The light transmitted by the second semi-transparent mirror 510 passes through the second plane lens 512 and irradiates the second plane reflector 506. After being reflected back to the second semi-transparent mirror 510 against the incident direction, a second reflection occurs to obtain a reference beam; after the light reflected by the second semi-transparent mirror 510 is irradiated on the material, it is reflected back to the second semi-transparent mirror 510 through the surface of the material and transmitted to obtain a measuring beam; the measuring beam and the reference beam interfere with each other after passing through the second semi-transparent mirror 510, generating interference fringes of light and dark, which are received by the second image sensor 508 and transmitted to the control system 601, and image algorithm analysis is performed together with the image simultaneously received by the first image sensor 507 to judge the quality of the material, and then the switch of the spray valve 701 is controlled to select the material.

[0034] A second plane lens 512 for compensating the light path is disposed between the second semi-transparent mirror 510 and the second plane reflector 506 . The second plane lens 512 is disposed parallel to the second semi-transparent mirror 510 , and has the same refractive index and thickness as the second semi-transparent mirror 510 .

[0035] The thickness, coating thickness, coating material, installation angle, transmittance and reflectivity of the second semi-transparent mirror 510 and the first semi-transparent mirror 509 are all the same. The second image sensor 508 and the first image sensor 507 are completely the same. The second plane lens 512 and the first plane lens 511 are used as compensation plates in Michelson interference, and their thickness is the same as that of the second semi-transparent mirror 510 and the first semi-transparent mirror 509. The first light source 501 and the second light source 502 are the same white light LED lamps, and their brightness, color temperature, wavelength and light wave transmission direction are all the same. The first lens 503 and the second lens 504 are both convex lenses, which are used to converge the white light emitted by the LED, and their thickness, refractive index and curvature are all the same. The first plane reflector 505 and the second plane reflector 506 are all the same in material, thickness and reflectivity, and are used as compensation plates for Michaelson interference. The imaging is adjusted by adjusting them to the first semi-transparent mirror 509 and the second semi-transparent mirror 510.

[0036] The feeding mechanism includes a vibrating feeding system 201, a feeding port 301, and a conveyor belt 401, which are arranged in sequence. The feeding port 301 is at one end of the conveyor belt 401, and the other end of the conveyor belt 401 is connected to the housing 101. The vibrating feeding system 201 is located at the feeding port 301. The conveyor belt 401 is a high-speed conveyor belt, and its speed can be adjusted by the control system 601. The dividing hopper 801 consists of a finished product trough and a defective product trough.

[0037] The first optical system further includes an adjusting mechanism for adjusting the distance between the first plane reflecting mirror 505 and the first semi-transparent mirror 509 , and the adjusting mechanism is connected to the control system 601 .

[0038] The material enters from the vibrating feeding system 201, reaches the conveyor belt 401 through the feed port 301, and is fed into the optical path system at a uniform speed. The optical path system of the present invention uses a white light LED as the incident light source, which is respectively irradiated onto the semi-transparent and semi-reflective mirrors through the convergence of the lens, and is divided into two beams of light with nearly equal amplitudes, namely, the transmission light and the reflection light. After the transmitted light is irradiated onto the plane mirror, it is reflected back to the surface of the semi-transparent and semi-reflective mirror in the opposite direction of the incident direction, and is reflected again, which is the reference beam; the reflected light is irradiated onto the material and is also reflected back to the semi-transparent and semi-reflective mirror on the surface of the material, which is the measurement beam. A plane mirror parallel to the semi-transparent and semi-reflective mirror and having the same thickness and refractive index is added between the plane reflector and the semi-transparent and semi-reflective mirror to compensate for the optical path difference caused by the different number of times the measurement beam and the reference beam pass through the semi-transparent and semi-reflective mirror. After the measurement beam and the reference beam pass through the semi-transparent and semi-reflective mirror for the second time, interference occurs, generating interference fringes of light and dark, which are received by the image sensor and transmitted to the control system 601, and image algorithm analysis is performed to judge the quality of the material, and then the switch of the spray valve is controlled to select the material. Since the generation of interference fringes depends on the multiple relationship between the optical path difference between the reference light and the measurement light and the wavelength, the optical path difference between the reference light and the measurement light can be adjusted by horizontally adjusting the positions of the two plane mirrors, thereby controlling the interference fringes state.

Claims

1. A novel color sorter based on white light Michelson interference, comprising a feeding mechanism, a color sorter body and a material distribution hopper (801) connected in sequence, and a control system (601); the color sorter body comprises a housing (101), and a first optical system, a second optical system and a spray valve (701) arranged in the housing, characterized in that: The first optical system comprises a first image sensor (507), and a first light source (501), a first lens (503), a first semi-transparent mirror (509), a first plane lens (511) and a first plane reflector (505) which are arranged in sequence. The first image sensor (507), the feeding mechanism, the spray valve (701) and the first light source (501) are all connected to the control system (601). The first light source (501) is a white light LED. The light emitted by the first light source (501) is converged by a first lens (503) and irradiated onto a first semi-transparent and semi-reflective mirror (509), where it is divided into two beams of light, one with nearly equal amplitude, one with transmission and one with reflection. The light transmitted through the first semi-transparent and semi-reflective mirror (509) is projected by the first plane lens (511) and then irradiated onto the first plane reflective mirror (505). The light is then reflected back to the first semi-transparent and semi-reflective mirror (509) in the opposite direction of the incident direction and then reflected a second time to obtain a reference beam. After the light reflected by the first semi-transparent and semi-reflective mirror (509) is irradiated onto the material, it is reflected back to the first semi-transparent and semi-reflective mirror (509) via the surface of the material, and is transmitted to obtain a measuring light beam. The measuring light beam and the reference light beam interfere with each other after passing through the first semi-transparent and semi-reflective mirror (509), generating light and dark interference fringes, which are received by the first image sensor (507) and transmitted to the control system (601) for image algorithm analysis to judge the quality of the material, and then control the opening and closing of the spray valve (701) to select the material.

2. A novel color sorter based on white light Michelson interference according to claim 1, characterized in that: The first semi-transparent and semi-reflective mirror (509) is installed at an angle of 45 degrees to the incident light, and the transmission and reflection ratio is 50 / 50.

3. A novel color sorter based on white light Michelson interference according to claim 1, characterized in that: The first plane lens (511) is arranged parallel to the first semi-transparent and semi-reflective mirror (509), and has the same refractive index and thickness as the first semi-transparent and semi-reflective mirror (509).

4. A novel color sorter based on white light Michelson interference according to claim 1, characterized in that: The first image sensor (507) is a high-speed linear array color or black-and-white image sensor.

5. The novel color sorter based on white light Michelson interference according to claim 1 is characterized in that: The first image sensor (507) is arranged above the first semi-transparent and semi-reflective mirror (509).

6. A novel color sorter based on white light Michelson interference according to any one of claims 1 to 5, characterized in that: The color sorter body also includes a second optical system symmetrically arranged with the first optical system, and the first optical system and the second optical system are respectively located on both sides of the material falling point.

7. The novel color sorter based on white light Michelson interference according to claim 1 is characterized in that: The feeding mechanism comprises a vibrating feeding system (201), a feeding port (301), and a conveyor belt (401) which are arranged in sequence, wherein the feeding port (301) is at one end of the conveyor belt (401), and the other end of the conveyor belt (401) is connected to the housing (101), and the vibrating feeding system (201) is located at the feeding port (301).

8. The novel color sorter based on white light Michelson interference according to claim 1 is characterized in that: The first optical system also includes an adjustment mechanism for adjusting the distance between the first plane reflector (505) and the first semi-transparent semi-reflective mirror (509), and the adjustment mechanism is connected to the control system (601).

9. The Michelson interference color sorter based on white light interference according to claim 1, characterized in that The material distribution hopper (801) consists of a finished product trough and a defective product trough.

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