Optical sorting machine

Abstract

The optical sorting machine includes: an intermittent light source that intermittently emits light toward a plurality of sorting objects being transferred; an optical sensor that detects light associated with one of the plurality of sorting objects being transferred during a plurality of intermittent light scanning periods; a determination unit that determines whether a foreign object and / or a defective product is present in the one sorting object based on a signal acquired by the optical sensor; and a light source control unit that controls the intermittent light source. The light source control unit is configured to control the intermittent light source so that when the intermittent light source is lit during at least one of the plurality of intermittent light scanning periods, there is a lighting period during which the intermittent light source is lit and a extinguishing period during which the intermittent light source is extinguished in each of the at least one intermittent light scanning period, and the lighting period starts at a time point delayed from the start of the at least one intermittent light scanning period.

Description

Technical Field

[0001] The present invention relates to an optical sorting machine. Background Art

[0002] Conventionally, there is known an optical sorting device that uses light information obtained by an optical sensor when the sorting object is irradiated with light to identify and remove foreign matter or defective products contained in the sorting object (for example, Patent Document 1 listed below).

[0003] Patent Document 1: Japanese Patent Application Laid-Open No. 2009-240876

[0004] However, there is room for improvement in this optical sorting device. For example, the optical sorting machine described in Patent Document 1 can improve the accuracy of distinguishing cracked grains of rice grains, but there is room for improvement in improving the accuracy of distinguishing other types of defective grains (e.g., white unripe grains, green unripe grains, colored grains, etc.) of brown rice or polished rice, or in improving the accuracy of distinguishing granular objects other than brown rice and polished rice (e.g., rice, other types of grains (wheat grains, etc.), beans (soybeans, chickpeas, edamame, etc.), resins (granules, etc.), rubber sheets, etc.) as the objects to be sorted. Summary of the invention

[0005] The present invention has been made to solve the above-mentioned problems, and can be implemented in the following forms, for example.

[0006] According to the first technical solution of the present invention, an optical sorting machine is provided. The optical sorting machine comprises: an intermittent light source that intermittently emits light toward a plurality of sorting objects being transferred; an optical sensor that detects light associated with one of the plurality of sorting objects being transferred during a plurality of intermittent light scanning periods; a determination unit that determines foreign matter and / or defective products for one of the sorting objects based on a signal acquired by the optical sensor; and a light source control unit that controls the intermittent light source. The light source control unit is configured to control the intermittent light source so that when the intermittent light source is illuminated during at least one of the plurality of intermittent light scanning periods, there is a lighting period during which the intermittent light source is illuminated and a extinguishing period during which the intermittent light source is extinguished in each of the at least one intermittent light scanning period, and the lighting period starts at a time point delayed from the start of the at least one intermittent light scanning period.

[0007] According to such an optical sorter, the intermittent light source is extinguished at the start time point of at least one intermittent light scanning period. Therefore, the light emitted from the intermittent light source during a certain intermittent light scanning period is not detected during the previous intermittent light scanning period. For example, assuming that there is a first intermittent light scanning period and a second intermittent light scanning period subsequent to the first intermittent light scanning period, if the intermittent light source is switched from extinguishing to lighting at the same time as the start of the second intermittent light scanning period (in other words, the end of the first intermittent light scanning period), the light emitted at the same time as the start of the second intermittent light scanning period may be mixed into the detection result of the first intermittent light scanning period as noise. According to the present technical solution, such a phenomenon does not occur, and therefore, the determination accuracy of the determination unit can be improved.

[0008] According to the second technical solution of the present invention, in the first technical solution, the light source control unit is configured to control the intermittent light source so that the lighting period ends at a time point earlier than the end of at least one intermittent light scanning period. According to such a technical solution, the intermittent light source is extinguished at the end time point of at least one intermittent light scanning period. Therefore, the light emitted from the intermittent light source during a certain intermittent light scanning period is not detected during the subsequent intermittent light scanning period. For example, assuming that there is a first intermittent light scanning period and a second intermittent light scanning period subsequent to the first intermittent light scanning period, if the intermittent light source is switched from lighting to extinguishing at the same time as the end of the first intermittent light scanning period (in other words, the beginning of the second intermittent light scanning period), the light emitted at the end of the first intermittent light scanning period may be mixed into the detection result of the second intermittent light scanning period as noise. According to the present technical solution, such a phenomenon does not occur, and therefore, the determination accuracy of the determination unit can be improved.

[0009] According to the third technical solution of the present invention, in the first or second technical solution, the intermittent light source includes: a first intermittent light source, which is arranged on the first side relative to the transfer path of the plurality of sorting objects and emits the first light; and a second intermittent light source, which is arranged on the second side opposite to the first side and emits the second light having the same wavelength as the first light. The optical sensor includes a first optical sensor arranged on the first side and a second optical sensor arranged on the second side. The plurality of intermittent light scanning periods include a first intermittent light scanning period and a second intermittent light scanning period. The light source control unit is configured to control the first intermittent light source and the second intermittent light source so that during the first intermittent light scanning period, the first intermittent light source is lit and the second intermittent light source is not lit, and during the second intermittent light scanning period, the first intermittent light source is not lit and the second intermittent light source is lit. According to such a technical solution, during the scanning period for the first intermittent light, the first optical sensor on the first side detects the reflected light (light reflected by the sorting object) based on the first light, and the second optical sensor on the second side detects the transmitted light (light transmitted through the sorting object) based on the first light. During the scanning period for the second intermittent light, the first optical sensor on the first side detects the transmitted light based on the second light, and the second optical sensor on the second side detects the reflected light based on the second light. Therefore, the determination unit can determine foreign matter and / or defective products based on the transmitted image (image represented by the transmitted light) and the reflected image (image represented by the reflected light) of both sides of the sorting object (in other words, the first side and the second side). Therefore, compared with the case based on the transmitted image and the reflected image for one side of the sorting object, the determination accuracy of the determination unit can be improved. For example, even if there is a defective part only on one side of the sorting object (in other words, one of the first side and the second side), foreign matter and / or defective products can be determined with high accuracy.

[0010] According to a fourth technical solution of the present invention, in the third technical solution, the first light and the second light are red light. According to such a technical solution, foreign matter and / or defective products can be determined with high accuracy based on the red transmitted light and reflected light. For example, when the object to be sorted is rice, white unripe grains can be distinguished with high accuracy.

[0011] According to the fifth technical solution of the present invention, in the third or fourth technical solution, the intermittent light source includes: a third intermittent light source, which is arranged on the first side and emits a third light having a wavelength different from that of the first light; and a fourth intermittent light source, which is arranged on the second side and emits a fourth light having the same wavelength as that of the third light. The light source control unit is configured to control the third intermittent light source and the fourth intermittent light source so that they are both lit during the first intermittent light scanning period and the second intermittent light scanning period. According to such a technical solution, during the first intermittent light scanning period and the second intermittent light scanning period, the first optical sensor detects the reflected light based on the third light and the transmitted light based on the fourth light together, and the second optical sensor detects the transmitted light based on the third light and the reflected light based on the fourth light together. Therefore, the determination unit can determine foreign matter and / or defective products based on the reflected and transmitted images (images represented by the light synthesized by the reflected light and the transmitted light) based on the third light and the fourth light on both sides of the sorting object. Therefore, the types of foreign matter and / or defective products that can be determined by the determination unit can be increased. Furthermore, since the third intermittent light source and the fourth intermittent light source are each turned on during the first intermittent light scanning period and the second intermittent light scanning period, the resolution of the reflection-transmission image is not reduced.

[0012] According to the sixth technical solution of the present invention, in the fifth technical solution, the third light and the fourth light both include green light and blue light. According to such a technical solution, foreign matter and / or defective products can be determined based on the green and blue reflected transmission images. For example, when the object to be sorted is rice, colored grains can be distinguished with high accuracy.

[0013] According to the seventh technical solution of the present invention, in the first or second technical solution, the intermittent light source emits invisible light having a wavelength in the invisible wavelength region as light. The optical sensor is configured as an invisible light optical sensor for detecting invisible light. The optical sorting machine also includes: a visible light source that emits visible light having a wavelength in the visible wavelength region toward a plurality of sorting objects being transferred; and a visible light optical sensor that detects visible light associated with one sorting object during a plurality of visible light scanning periods. The determination unit is configured to determine foreign matter and / or defective products based on a signal obtained by the invisible light optical sensor and a signal obtained by the visible light optical sensor. The intermittent light scanning period and the visible light scanning period are defined by time periods of different lengths. According to such a technical solution, it is possible to set scanning periods suitable for the detection of invisible light and the detection of visible light, respectively. For example, when the invisible light is near-infrared light, the optical sensor's near-infrared light receiving sensitivity is usually smaller than the visible light receiving sensitivity, and therefore, the intermittent light scanning period can be set longer than the visible light scanning period. In this way, near infrared light can be detected without reducing the resolution of the visible light optical sensor (in other words, without reducing the accuracy of determination based on visible light) and obtaining a signal intensity sufficient for determination by the determination unit.

[0014] According to the 8th technical scheme of the present invention, in the 7th technical scheme, the intermittent light scanning period is set to N times the visible light scanning period (N is an integer greater than 2). According to such a technical scheme, if the start time point of the initial intermittent light scanning period and the start time point of the initial visible light scanning period for a sorting object are set to be simultaneous, then the end time point of the last intermittent light scanning period and the end time point of the last visible light scanning period for a sorting object become simultaneous. Therefore, in the determination unit, for the same sorting object, it is possible to easily make the image based on the signal acquired by the first optical sensor correspond to the image based on the signal acquired by the second optical sensor. Therefore, the calculation processing of the determination unit can be simplified.

[0015] According to a ninth aspect of the present invention, in the seventh or eighth aspect, the invisible light is near infrared light. According to such an aspect, the near infrared light can be detected without reducing the resolution of the visible light optical sensor and obtaining a signal strength sufficient for determination by the determination unit.

[0016] According to the tenth technical solution of the present invention, in any one of the first to ninth technical solutions, the optical sensor is a CMOS sensor. The lighting period ends at the same time as the start of charge reading of the CMOS sensor, or ends at a time point later than the start of reading and earlier than the end of charge reading. According to such a technical solution, at least a part of the charge reading period is set as the extinguishing period, so that it is possible to suppress the unnecessary lighting of the intermittent light source during the charge reading period when the charge is not accumulated.

[0017] According to the 11th technical solution of the present invention, in the 1st or 2nd technical solution, the intermittent light source includes: a first intermittent light source that emits a first light having a first wavelength within a first wavelength range; and a second intermittent light source that emits a second light having a second wavelength different from the first wavelength within the first wavelength range. The optical sorter also includes an additional light source that emits a third light having a third wavelength within a second wavelength range outside the first wavelength range toward a plurality of sorting objects being transferred. The optical sensor integrally includes: a first light receiving element having a sensitivity greater than a predetermined value within the first wavelength range, a second light receiving element having a sensitivity greater than a predetermined value within the second wavelength range, and a spectrometer that splits incident light into light within the first wavelength range and light within the second wavelength range. The plurality of intermittent light scanning periods include a first intermittent light scanning period and a second intermittent light scanning period. The light source control unit is configured to control the intermittent light source and the additional light source so that during the first intermittent light scanning period, the first intermittent light source is lit, the second intermittent light source is not lit, and the additional light source is lit, and the intermittent light source and the additional light source are controlled so that during the second intermittent light scanning period, the first intermittent light source is not lit, the second intermittent light source is lit, and the additional light source is lit. According to such a technical solution, three kinds of light with different wavelengths (in other words, the first light, the second light, and the third light mentioned above) can be detected by an optical sensor. As a result, the optical sorting machine can be made low-cost. In addition, the third light is emitted during both the first intermittent light scanning period and the second intermittent light scanning period, so that sufficient detection intensity for the third light can be ensured.

[0018] According to the twelfth technical solution of the present invention, an optical sorting machine is provided. The optical sorting machine comprises: a first light source, which is a first light source that emits a first light toward a plurality of sorting objects being transferred, and is arranged on a first side relative to a transfer path of the sorting objects; a second light source, which is a second light source that emits a second light having the same wavelength as the first light toward a plurality of sorting objects being transferred, and is arranged on a second side opposite to the first side; a first optical sensor, which is arranged on the first side, and detects a first light associated with one of the plurality of sorting objects being transferred during a plurality of scans including a first scan period and a second scan period. The first light or the second light; the second optical sensor, which is arranged on the second side and detects the first light or the second light associated with a sorting object during multiple scans; the determination unit, which determines foreign matter and / or defective products for a sorting object based on the signals obtained by the first optical sensor and the second optical sensor; and the light source control unit, which controls the first light source and the second light source so that during the first scan, the first light source is lit and the second light source is not lit, and during the second scan, the first light source is not lit and the second light source is lit. According to such a technical solution, the same effect as the third technical solution can be obtained.

[0019] According to a thirteenth aspect of the present invention, in the twelfth aspect, the first light and the second light are red light. According to such an aspect, the same effect as that of the fourth aspect can be obtained.

[0020] According to the 14th technical solution of the present invention, in the 12th or 13th technical solution, the optical sorter includes: a third light source, which is arranged on the first side and emits a third light having a wavelength different from that of the first light; and a fourth light source, which is arranged on the second side and emits a fourth light having the same wavelength as the third light. The light source control unit is configured to control the third light source and the fourth light source so that they are lit during the first scanning period and the second scanning period. According to such a technical solution, the same effect as the fifth technical solution can be obtained.

[0021] According to a fifteenth aspect of the present invention, in the fourteenth aspect, the third light and the fourth light both include green light and blue light. According to such an aspect, the same effect as that of the sixth aspect can be obtained.

[0022] According to the 16th technical solution of the present invention, an optical sorting machine is provided. The optical sorting machine comprises: a first light source, which emits a first light having a wavelength in an invisible wavelength region toward a plurality of sorting objects being transferred; a second light source, which emits a second light having a wavelength in a visible wavelength region toward a plurality of sorting objects being transferred; a first optical sensor, which detects the first light associated with one of the plurality of sorting objects being transferred during a plurality of first scans; a second optical sensor, which detects the second light associated with one of the sorting objects during a plurality of second scans; and a determination unit, which determines foreign matter and / or defective products for one of the sorting objects based on a signal acquired by the first optical sensor and a signal acquired by the second optical sensor. The first scanning period and the second scanning period are respectively defined by time of different lengths. According to such a technical solution, the same effect as the seventh technical solution can be obtained.

[0023] According to a seventeenth aspect of the present invention, in the sixteenth aspect, the first scanning period is set to N times the second scanning period (N is an integer greater than or equal to 2). According to such an aspect, the same effect as that of the eighth aspect is obtained.

[0024] According to an eighteenth aspect of the present invention, in the sixteenth or seventeenth aspect, the first light is near infrared light. According to such an aspect, the same effect as that of the ninth aspect can be obtained.

[0025] According to the 19th technical solution of the present invention, an optical sorting machine is provided. The optical sorting machine comprises: a light source that intermittently emits light toward a plurality of sorting objects being transferred; a CMOS sensor that detects light associated with one of the plurality of sorting objects being transferred during multiple scans; a determination unit that determines foreign matter and / or defective products for one of the sorting objects based on a signal acquired by the CMOS sensor; and a light source control unit that controls the light source. The light source control unit is configured to control the light source so that when the light source is illuminated during at least one of the multiple scans, there is a lighting period during which the light source is illuminated and a extinguishing period during which the light source is extinguished in each of the at least one scan, and the lighting period ends simultaneously with the start of charge reading of the CMOS sensor, or ends at a time point later than the start of reading and earlier than the end of charge reading. According to such a technical solution, the same effect as the 10th technical solution can be obtained.

[0026] According to the 20th technical solution of the present invention, an optical sorting machine is provided. The optical sorting machine comprises: a first light source that intermittently emits a first light having a first wavelength within a first wavelength range toward a plurality of sorting objects being transferred; a second light source that intermittently emits a second light having a second wavelength within the first wavelength range toward a plurality of sorting objects being transferred; a third light source that emits a third light having a third wavelength within a second wavelength range outside the first wavelength range toward a plurality of sorting objects being transferred; and an optical sensor. The optical sensor integrally comprises: a first light receiving element having a sensitivity greater than or equal to a predetermined value within the first wavelength range, a second light receiving element having a sensitivity greater than or equal to a predetermined value within the second wavelength range, and a spectrometer that splits incident light into light within the first wavelength range and light within the second wavelength range. The optical sensor detects one of the first light and the second light associated with one of the plurality of sorting objects being transferred and the third light associated with one of the sorting objects during a plurality of scanning periods including a first scanning period and a second scanning period. The optical sorting machine further comprises: a determination unit, which determines foreign matter and / or defective products of a sorting object based on a signal obtained by the optical sensor; and a light source control unit, which controls the first light source, the second light source and the third light source, so that during the first scanning period, the first light source is lit, the second light source is not lit, and the third light source is lit, and during the second scanning period, the first light source is not lit, the second light source is lit, and the third light source is lit. According to such a technical solution, the same effect as the eleventh technical solution is achieved.

[0027] According to the 21st technical solution of the present invention, an optical sorting machine is provided. The optical sorting machine comprises: a first light source, which emits a first light having a first wavelength within a first wavelength range toward a plurality of sorting objects being transferred; a second light source, which emits a second light having a second wavelength within the first wavelength range toward a plurality of sorting objects being transferred; a third light source, which emits a third light having a third wavelength within a second wavelength range outside the first wavelength range toward a plurality of sorting objects being transferred; a fourth light source, which emits a fourth light having a fourth wavelength within the second wavelength range toward a plurality of sorting objects being transferred; and an optical sensor. The optical sensor integrally comprises: a first light receiving element having a sensitivity greater than a predetermined value within the first wavelength range, a second light receiving element having a sensitivity greater than a predetermined value within the second wavelength range, and a spectrometer that splits incident light into light within the first wavelength range and light within the second wavelength range. The optical sensor detects three types of light, namely, the first light, the second light, the third light, and the fourth light, associated with one of the plurality of sorting objects being transferred during a plurality of scans including the first scan and the second scan. The optical sorter further comprises: a determination unit that determines foreign matter and / or defective products for one of the sorting objects based on a signal acquired by the optical sensor; and a light source control unit that controls the first light source, the second light source, the third light source, and the fourth light source in a mode selected from the first mode and the second mode. In the first mode, during the first scan, the first light source is turned on, the second light source is not turned on, one of the third light source and the fourth light source is turned on, and the other of the third light source and the fourth light source is not turned on, and during the second scan, the first light source is not turned on, the second light source is turned on, one of the light sources is turned on, and the other of the light sources is not turned on. In the second mode, during the first scanning period, one of the first and second light sources is turned on, the other of the first and second light sources is not turned on, the third light source is turned on, and the fourth light source is not turned on. During the second scanning period, one of the first and second light sources is turned on, the other of the first and second light sources is not turned on, the third light source is not turned on, and the fourth light source is turned on. According to such a technical solution, the same effect as the eleventh technical solution is achieved. In addition, by selecting one of the first and second modes, the wavelength of the light used can be changed according to the type of the sorting object or the type of foreign matter and / or defective products to be sorted.

[0028] The various technical solutions described above can also be implemented in combination with the structures of other known optical sorting machines. For example, the first technical solution can also be combined with the structure of an existing optical sorting machine, which has: a continuous light source that continuously emits light toward a plurality of sorting objects being transferred; and an optical sensor that detects the light emitted from the continuous light source. BRIEF DESCRIPTION OF THE DRAWINGS

[0029] Figure 1 This is a schematic diagram showing a schematic configuration of an optical sorter according to a first embodiment of the present invention.

[0030] Figure 2 It is a timing chart showing the relationship between the scanning period of the optical sensor and the lighting time point of the light source.

[0031] Figure 3 This is an explanatory diagram showing the relationship between a sorting object and a scan number.

[0032] Figure 4 This is a schematic diagram showing a schematic structure of an optical sorter according to the second embodiment.

[0033] Figure 5 It is a timing chart showing the relationship between the scanning period of the optical sensor and the lighting time point of the light source.

[0034] Figure 6 This is a schematic diagram showing a schematic structure of an optical sorter according to a third embodiment.

[0035] Figure 7 It is a schematic diagram showing the schematic structure of an optical sensor.

[0036] Figure 8 This is a timing chart showing the relationship between the scanning period of the optical sensor and the lighting time point of the light source in the first mode.

[0037] Fig. 9 This is a timing chart showing the relationship between the scanning period of the optical sensor and the lighting time point of the light source in the second mode. DETAILED DESCRIPTION

[0038] A. First Implementation Method:

[0039] Figure 1 1 is a schematic diagram showing a schematic structure of an optical sorting machine (hereinafter referred to as a sorting machine) 10 as a first embodiment of the present invention. In this embodiment, the sorting machine 10 is used to sort foreign matter (such as pebbles, mud, glass pieces, etc.) and defective products (such as unripe grains, colored grains, etc.) from rice as a sorting object (hereinafter referred to as an object) 90. However, the object 90 is not limited to rice, and may be any granular object (such as grains other than rice, plastic, etc.).

[0040] like Figure 1As shown, the sorting machine 10 includes an optical detection unit 20, a storage tank 71, a feeder 72, a chute 73, a good product discharge trough 74, a defective product discharge trough 75, an ejector 76, and a control device 80. The control device 80 controls all actions of the sorting machine 10. The control device 80 also functions as a light source control unit 81 and a determination unit 82. The functions of the control device 80 can also be implemented by the CPU executing a prescribed program, or by a dedicated circuit. The light source control unit 81 and the determination unit 82 can also be implemented by an integrated device. For example, the light source control unit 81 and the determination unit 82 can also be two functions implemented by one CPU. Alternatively, the light source control unit 81 and the determination unit 82 can also be implemented as separate devices. Details of the functions of the control device 80 will be described later.

[0041] The storage tank 71 temporarily stores the object 90. The feeder 72 supplies the object 90 stored in the storage tank 71 to the chute 73. The optical detection unit 20 irradiates light to the object 90 that slides down from the chute 73, and detects the light associated with the object 90 (specifically, the transmitted light that passes through the object 90 and / or the reflected light reflected by the object 90). The output from the optical detection unit 20, that is, the analog signal representing the intensity of the detected light, is converted into a digital signal by an AC / DC converter (not shown). The digital signal is input to the control device 80. Based on the detection result of the input light (in other words, the image), the control device 80 determines whether the object 90 is a good product (in other words, a rice grain with relatively high quality), a foreign body (in other words, not a rice grain), or a defective product (in other words, a rice grain with relatively low quality) as a process of the determination unit 82. This determination is performed for each object 90.

[0042] When the object 90 is determined to be a foreign object or a defective product, the ejector 76 ejects the air 77 toward the object 90. As a result, the object 90 is blown away, deviates from the falling trajectory from the chute 73, and is introduced into the defective product discharge chute 75. On the other hand, when the object 90 is determined to be a good product, the air 77 is not ejected. Therefore, the object 90 determined to be a good product is introduced into the good product discharge chute 74 without changing the falling trajectory.

[0043] The optical detection unit 20 and the control device 80 are described in detail below. Figure 1 As shown, the optical detection unit 20 includes a first light source 30a, a second light source 30b, third light sources 40a and 50a, fourth light sources 40b and 50b, a first optical sensor 60a, and a second optical sensor 60b.

[0044] The first light source 30a emits the first light 31a toward the multiple objects 90 being transferred (in other words, falling from the chute 73). Similarly, the second light source 30b emits the second light 31b toward the multiple objects 90 being transferred. In the present embodiment, the first light 31a is red light. The second light 31b has the same wavelength as the first light 31a. In other words, the second light 31b is also red light. Therefore, the first light source 30a and the second light source 30b are also referred to as red light sources 30a, 30b. In addition, the first light 31a and the second light 31b are also referred to as red light 31a, 31b.

[0045] The third light sources 40a and 50a emit the third light 41a and 51a respectively toward the multiple objects 90 being transferred. The fourth light sources 40b and 50b emit the fourth light 41b and 51b respectively toward the multiple objects 90 being transferred. The third light 41a and 51a have wavelengths different from those of the first light 31a. In the present embodiment, the third light 41a is green light, and the third light 51a is blue light. The fourth light 41b and 51b have the same wavelengths as those of the third light 41a and 51a respectively. In other words, the fourth light 41b is green light, and the fourth light 51b is blue light. Therefore, the third light source 40a and the fourth light source 40b are also referred to as green light sources 40a and 40b. In addition, the third light 41a and the fourth light 41b are also referred to as green light 41a and 41b respectively. Similarly, the third light source 50a and the fourth light source 50b are also referred to as blue light sources 50a and 50b, and the third light 51a and the fourth light 51b are also referred to as blue light 51a and 51b.

[0046] In the present embodiment, the first light source 30a, the second light source 30b, the third light sources 40a and 50a, and the fourth light sources 40b and 50b are LEDs. Figure 1 , the number of each of the first light source 30a, the second light source 30b, the third light source 40a, 50a, and the fourth light source 40b, 50b is shown as one, but the number of at least some of these light sources may be plural.

[0047] The first optical sensor 60a and the second optical sensor 60b detect light associated with one of the multiple objects 90 being transferred. In the present embodiment, the first optical sensor 60a and the second optical sensor 60b are color CCD sensors that can detect red light, green light, and blue light separately. However, the first optical sensor 60a and the second optical sensor 60b may also be other types of color sensors such as color CMOS sensors. Furthermore, in the present embodiment, the first optical sensor 60a and the second optical sensor 60b are line sensors, but may also be surface sensors.

[0048] The first light source 30a, the third light sources 40a and 50a, and the first optical sensor 60a are arranged on one side (also referred to as the front side) with respect to the transfer path of the object 90 (in other words, the falling trajectory from the chute 73). On the other hand, the second light source 30b, the fourth light source 40b and 50b, and the second optical sensor 60b are arranged on the other side (also referred to as the rear side) with respect to the transfer path of the object 90.

[0049] The first optical sensor 60a on the front side can detect red light 31a (also called reflected red light 31a) emitted from the first light source 30a on the front side and reflected by the object 90, green light 41a (also called reflected green light 41a) emitted from the third light source 40a on the front side and reflected by the object 90, blue light 51a (also called reflected blue light 51a) emitted from the third light source 50a on the front side and reflected by the object 90, red light 31b (also called transmitted red light 31b) emitted from the second light source 30b on the rear side and transmitted through the object 90, green light 41b (also called transmitted green light 41b) emitted from the fourth light source 40b on the rear side and transmitted through the object 90, and blue light 51b (also called transmitted blue light 51b) emitted from the fourth light source 50b on the rear side and transmitted through the object 90.

[0050] The second optical sensor 60b on the rear side is capable of detecting red light 31b (also called reflected red light 31b) emitted from the second light source 30b on the rear side and reflected by the object 90, green light 41b (also called reflected green light 41b) emitted from the fourth light source 40b on the rear side and reflected by the object 90, blue light 51b (also called reflected blue light 51b) emitted from the fourth light source 50b on the rear side and reflected by the object 90, red light 31a (also called transmitted red light 31a) emitted from the first light source 30a on the front side and transmitted through the object 90, green light 41a (also called transmitted green light 41a) emitted from the third light source 40a on the front side and transmitted through the object 90, and blue light 51a (also called transmitted blue light 51a) emitted from the third light source 50a on the front side and transmitted through the object 90.

[0051] As is well known, the first optical sensor 60a and the second optical sensor 60b perform multiple scans on an object 90. In other words, the first optical sensor 60a and the second optical sensor 60b respectively detect light associated with an object 90 during multiple scans. The scanning period is the time from the start to the end of a scan. By synthesizing the images obtained by each scan, the overall image of the object 90 is obtained. In the case where the optical sensor is a CCD sensor, the "scanning period" can be defined as the time from the start of charge accumulation in the photosensitive element to the end of charge accumulation. In the case where the optical sensor is a CMOS sensor, the "scanning period" can be defined as the time from the start of charge accumulation in the photosensitive element to the output of the accumulated charge.

[0052] Such an optical detection unit 20 is controlled by a control device 80. The light source control unit 81 controls the first light source 30a, the second light source 30b, the third light sources 40a and 50a, and the fourth light sources 40b and 50b according to a predetermined rule. Figure 2 It is a timing chart showing the relationship between the scanning period of the first optical sensors 60a and 60b and the lighting timing of these light sources. Figure 2 In FIG. 1 , “R” represents the red light source 30 a or the red light source 30 b. Similarly, “G” represents the green light source 40 a or the green light source 40 b, and “B” represents the blue light source 50 a or the blue light source 50 b.

[0053] Figure 3 1 is an explanatory diagram showing the relationship between an object 90 and the scanning numbers (numbers indicating the number of scans) of the first optical sensor 60a and the second optical sensor 60b. Figure 3 As shown, in the present embodiment, image data is acquired by scanning one object 90 eight times (the number is shown to be smaller than the actual number for the sake of simplicity of description). Figure 3 The numbers 1 to 8 shown indicate the number of the scan in which the image data of the corresponding area is acquired. For example, the area labeled "1" indicates that the image data is acquired by the first scan. Figure 2 In the Scan No. Figure 3 The scan number shown corresponds to the

[0054] like Figure 2As shown, the red light source 30a on the front side is lit only for a predetermined time during the scanning period with an odd-numbered scanning number (indicated as ON in the figure), and is not lit at all during the scanning period with an even-numbered scanning number (indicated as OFF in the figure). On the other hand, the red light source 30b on the rear side is lit only for a predetermined time during the scanning period with an even-numbered scanning number, and is not lit at all during the scanning period with an odd-numbered scanning number. In this way, the red light source 30a and the red light source 30b are alternately lit in a manner in which only one of them is lit during one scanning period. In other words, the red light source 30a and the red light source 30b are lit exclusively relative to each other.

[0055] The green light source 40a and the blue light source 50a on the front side are lighted for a predetermined time during all scanning periods, and similarly, the green light source 40b and the blue light source 50b on the rear side are lighted for a predetermined time during all scanning periods.

[0056] According to such a lighting method, the first optical sensor 60a on the front side can detect the reflected red light 31a, the light synthesized by the reflected green light 41a and the transmitted green light 41b, and the light synthesized by the reflected blue light 51a and the transmitted blue light 51b, respectively, during the scanning period with an odd-numbered scanning number. In other words, a red reflected image, a green reflected transmitted image, and a blue reflected transmitted image are obtained through the first optical sensor 60a. In the present application, a reflected image refers to an image represented by only reflected light. A transmitted image refers to an image represented by only transmitted light. A reflected transmitted image refers to an image represented by light synthesized by reflected light and transmitted light.

[0057] In addition, the first optical sensor 60a on the front side detects the transmitted red light 31b, the light synthesized by the reflected green light 41a and the transmitted green light 41b, and the light synthesized by the reflected blue light 51a and the transmitted blue light 51b, respectively, during the scanning period with an even-numbered scanning number. In other words, a red transmitted image, a green reflected transmitted image, and a blue reflected transmitted image are obtained via the first optical sensor 60a.

[0058] On the other hand, the second optical sensor 60b at the rear side detects the transmitted red light 31a, the light synthesized by the reflected green light 41b and the transmitted green light 41a, and the light synthesized by the reflected blue light 51b and the transmitted blue light 51a, respectively, during the scanning period with the odd-numbered scanning number. In other words, a red transmitted image, a green reflected transmitted image, and a blue reflected transmitted image are obtained via the second optical sensor 60b.

[0059] In addition, the second optical sensor 60b at the rear side detects the reflected red light 31b, the light synthesized by the reflected green light 41b and the transmitted green light 41a, and the light synthesized by the reflected blue light 51b and the transmitted blue light 51a, respectively, during the scanning period with an even-numbered scanning number. In other words, a red reflected image, a green reflected transmitted image, and a blue reflected transmitted image are obtained via the second optical sensor 60b.

[0060] The determination unit 82 uses the red reflected image and the transmitted image, the green reflected transmitted image, and the blue reflected transmitted image thus obtained to determine whether there is foreign matter and / or defective products. Specifically, Figure 3 In the process, a front red reflection image consisting of an area marked with an odd-numbered scanning number, a front red transmission image consisting of an area marked with an even-numbered scanning number, a rear red transmission image consisting of an area marked with an odd-numbered scanning number, a rear red reflection image consisting of an area marked with an even-numbered scanning number, a front green reflection transmission image consisting of an area marked with scanning numbers 1 to 8, a front blue reflection transmission image consisting of an area marked with scanning numbers 1 to 8, a rear blue reflection transmission image consisting of an area marked with scanning numbers 1 to 8, and a rear blue reflection transmission image consisting of an area marked with scanning numbers 1 to 8 are obtained. Therefore, the determination unit 82 determines foreign matter and / or defective products by comparing all or part of these images with a predetermined threshold value. The determination method can adopt any known determination method.

[0061] According to the above-mentioned sorting machine 10, a scanning period in which only one of the red light source 30a on the front side and the red light source 30b on the rear side is lit and a scanning period in which only the other side is lit are set. Therefore, the determination unit 82 can make a determination of foreign matter and / or defective products based on the red transmission image and reflection image of the front side and the red transmission image and reflection image of the rear side. Therefore, the determination accuracy can be improved compared with the case based on the red transmission image and reflection image of either the front side or the rear side. In the case where the object 90 is rice, the red transmission image and reflection image are suitable for distinguishing white unripe grains, for example. White unripe grains are usually mostly white and turbid throughout the grain, but sometimes there are partially white and turbid parts. When the white unripe grains (in other words, the object 90) with such partially white and turbid parts fall from the chute 73, depending on the direction of the object 90, sometimes the white and turbid parts only appear in the transmission image or reflection image of either the front side or the rear side. According to the above-mentioned sorting machine 10, even in such a case, the turbid portion can be detected and it can be determined that the object 90 is a white unripe grain.

[0062] In addition, according to the sorting machine 10, it is possible to obtain green reflection transmission images of both the front side and the rear side, and blue reflection transmission images of both the front side and the rear side, so that the types of foreign matter and / or defective products that can be identified by the determination unit 82 can be increased. In the case where the object 90 is rice, the green reflection transmission image and the blue reflection transmission image are suitable for the identification of colored particles, for example. In addition, during all scanning periods, the green light source 40a and the green light source 40b are lit, so the resolution of the green reflection transmission image is not reduced. In this regard, the same is true for the blue reflection transmission image.

[0063] like Figure 2 As shown, the light source control unit 81 controls the light source so that when any one of the light sources is turned on in at least one scanning period (for example, when the front red light source 30a is turned on in a scanning period with an odd-numbered scanning number), there is an on period in which the light source is turned on and an off period in which the light source is turned off in the scanning period. Figure 2 In the example, regarding the red light source 30a on the front side, during the third scanning period, the period from the start time T0 of the scanning period to the time T1 is an off period, the period from the time T1 to the time T2 is a lighting period, and the period from the time T2 to the end time T3 of the scanning period is an off period.

[0064] Furthermore, the light source control unit 81 controls the light source so that when any light source is turned on in at least one scanning period, the lighting period starts at a time point delayed from the start of the scanning period. Figure 2 In the example, during the third scanning period, the front red light source 30a is lit in a manner that the lighting period starts at a time point (in other words, time T1) delayed from the start time T0 of the scanning period. In other words, at the start time T0 of the scanning period, the red light source 30a is extinguished. Therefore, the red light 31a emitted from the front red light source 30a during the third scanning period is not detected by the first optical sensor 60a or the second optical sensor 60b during the previous scanning period (in other words, the second scanning period). Specifically, if the front red light source 30a is lit at the start time T0 (which is also the end time of the second scanning period) during the third scanning period, the red light 31a emitted at the same time as the start of the third scanning period may be mixed as noise into the detection result detected by the first optical sensor 60a or the second optical sensor 60b during the second scanning period. On the other hand, according to the present embodiment, such a phenomenon does not occur, and therefore, the determination accuracy of the determination unit 82 can be improved. Here, the red light source 30 a on the front side is described as an example, but this point is not limited to the red light source 30 a on the front side, and is common to all light sources.

[0065] Furthermore, the light source control unit 81 controls the light source so that when any light source is turned on during at least one scanning period, the lighting period ends at a time point earlier than the end of the scanning period. Figure 2 In the example, during the third scanning period, the red light source 30a on the front side switches from lighting to extinguishing at a time T2 earlier than the end time T3 of the scanning period. Therefore, the red light 31a emitted from the red light source 30a on the front side during the third scanning period is not detected by the first optical sensor 60a or the second optical sensor 60b during the subsequent scanning period (in other words, the fourth scanning period). Therefore, the determination accuracy of the determination unit 82 can be improved. Here, the red light source 30a on the front side is used as an example for explanation, but this point is not limited to the red light source 30a on the front side, and is common to all light sources.

[0066] The above-mentioned embodiments can be modified in various ways. For example, instead of the red light sources 30a and 30b, light sources that emit light of any wavelength that does not interfere with the wavelength of light emitted from other light sources can be arranged on the front and rear sides, and lighted alternately between the front and rear sides. For example, the green light sources 40a and 40b can be alternately lit, and the blue light sources 50a and 50b can be alternately lit. In addition, in the above-mentioned examples, all light sources emit light intermittently, but the green light sources 40a, 40b and / or the blue light sources 50a and 50b can also be continuously lit during the entire scanning period. In addition, it is also possible that when the red light sources 30a and 30b are lit during at least one scanning period, they are continuously lit from the start time T0 to the end time T3 of the at least one scanning period.

[0067] B. Second Implementation Method:

[0068] The optical sorting machine (hereinafter referred to as the sorting machine) 100 according to the second embodiment of the present invention is described below. The sorting machine 100 is different from the first embodiment in that it includes an optical detection unit 120 instead of the optical detection unit 20 of the first embodiment and includes a control unit 180 instead of the control unit 80 of the first embodiment. In the following, only the differences from the first embodiment are described for the second embodiment. Figure 4 It is a schematic diagram showing a schematic structure of the sorting machine 100. Figure 4 In the diagram, the components shown in the figure are the same as those in the first embodiment ( Figure 1 ) are marked with the same reference numerals as those marked in the first embodiment. Figure 4 As shown, the optical detection unit 120 includes first light sources 130a and 130b, second light sources 140a and 140b, a first optical sensor 150a, and second optical sensors 160a and 160b.

[0069] The first light sources 130a and 130b emit the first lights 131a and 131b having wavelengths in the invisible wavelength region toward the object 90 being transported. In the present embodiment, the first lights 131a and 131b have wavelengths in the near-infrared wavelength region (e.g., 1550 nm). Therefore, the first light sources 130a and 130b are also referred to as near-infrared light sources 130a and 130b, and the first lights 131a and 131b are also referred to as near-infrared lights 131a and 131b. The second light sources 140a and 140b emit the second lights 141a and 141b having wavelengths in the visible wavelength region toward the object 90 being transported. In the present embodiment, the second lights 141a and 141b are white lights containing wavelengths of red, green, and blue. Therefore, the second light sources 140a and 140b are also referred to as visible light sources 140a and 140b, and the second light 141a and 141b are also referred to as visible light 141a and 141b. In the present embodiment, the first light sources 130a and 131b and the second light sources 140a and 140b are LEDs. Figure 4 , although the number of each of the first light source 130a, 131b and the second light source 140a, 140b is shown to be one, the number of at least a part of these light sources may be plural.

[0070] The first optical sensor 150a detects near infrared light 131a, 131b associated with one of the multiple objects 90 being transferred. Therefore, the first optical sensor 150a is also referred to as an optical sensor 150a for near infrared light. The optical sensor 150a for near infrared light is configured to detect near infrared light 131a and / or near infrared light 131b in each first scanning period of multiple first scanning periods. The second optical sensors 160a, 160b detect visible light 141a, 141b associated with one of the multiple objects 90 being transferred. Therefore, the second optical sensors 160a, 160b are also referred to as optical sensors 160a, 160b for visible light. The optical sensors 160a, 160b for visible light are configured to detect visible light 141a and / or visible light 141b in each second scanning period of multiple second scanning periods. The near-infrared optical sensor 150a is a CMOS sensor. In this embodiment, the visible light optical sensors 160a and 160b are color CCD sensors and can detect red light, green light, and blue light independently. CMOS sensors may also be used as the visible light optical sensors 160a and 160b.

[0071] The near-infrared light source 130a, the visible light source 140a, the near-infrared light optical sensor 150a, and the visible light optical sensor 160a are arranged on the front side. On the other hand, the near-infrared light source 130b, the visible light source 140b, and the visible light optical sensor 160b are arranged on the rear side. The near-infrared light optical sensor 150a on the front side can detect the near-infrared light 131a emitted from the near-infrared light source 130a on the front side and reflected by the object 90, and the near-infrared light 131b emitted from the near-infrared light source 130b on the rear side and transmitted through the object 90. The visible light optical sensor 160a on the front side can detect the visible light 141a emitted from the visible light source 140a on the front side and reflected by the object 90, and the visible light 141b emitted from the visible light source 140b on the rear side and transmitted through the object 90. The rear visible light optical sensor 160 b can detect visible light 141 a emitted from the front visible light source 140 a and transmitted through the object 90 , and visible light 141 b emitted from the rear visible light source 140 b and reflected by the object 90 .

[0072] Such an optical detection unit 120 is controlled by a control device 180. The light source control unit 181 controls the first light sources 130a and 130b and the second light sources 140a and 140b according to a predetermined rule. Figure 5 It is a timing chart showing the lighting timings of these light sources. Figure 5 In the figure, "white" indicates the visible light source 140a or the visible light source 140b, and "NIR" indicates the near infrared light source 130a or the near infrared light source 130b. "RGB scan No." indicates the scan number of the optical sensor 160a, 160b for visible light. In addition, "NIR scan No." indicates the scan number of the optical sensor 150a for near infrared light. Figure 5 In order to simplify the explanation, for one object 90, 16 scans are performed to obtain image data based on visible light 141a and 141b, and for one object 90, 4 scans are performed to obtain image data based on near-infrared light 131a and 131b. Based on this, the lighting time point of each light source is shown.

[0073] like Figure 5As shown, the first scanning period for the near-infrared optical sensor 150a and the second scanning period for the visible light optical sensors 160a and 160b are defined by different lengths of time. Therefore, the first scanning period suitable for the detection of the near-infrared light 131a and 131b and the second scanning period suitable for the detection of the visible light 141a and 141b can be set separately. In this embodiment, the first scanning period is set to a time longer than the second scanning period. Generally, the sensitivity of the near-infrared optical sensor to near-infrared light is lower than the sensitivity of the visible light optical sensor to visible light. Therefore, by setting the first scanning period to be longer than the second scanning period, the near-infrared light 131a and 131b can be detected in a manner to obtain a signal strength sufficient for the determination of the determination unit 82. In addition, the second scanning period will not be set longer due to the detection of the near-infrared light 131a and 131b, so the resolution of the visible light optical sensors 160a and 160b will not be reduced.

[0074] Furthermore, in this embodiment, the first scanning period is set to N times the second scanning period (N is an integer greater than or equal to 2). Figure 5 In the example shown, N=4. Thus, when the first scanning period is N times the second scanning period, if the time point of the start of the first scanning period for one object 90 (in other words, Figure 5 The time point at which the NIR scan No. 1 starts) and the time point at which the first second scan period starts (in other words, Figure 5 1) is set to be the same, then the end time of the last 1st scanning period for an object 90 (in other words, Figure 5 The end time of NIR scan No. 4) and the end time of the last second scan period (in other words, Figure 5 16) is simultaneous. Therefore, in the determination unit 82, with respect to the same object 90, it is possible to easily make an image based on a signal acquired by the near-infrared light optical sensor 150a correspond to an image based on a signal acquired by the visible light optical sensors 160a and 160b. Therefore, the calculation processing of the determination unit 82 can be simplified. In the present embodiment, the near-infrared light optical sensor 150a is a CMOS sensor, and the visible light optical sensors 160a and 160b are CCD sensors, but if a sensor of the same form as the near-infrared light optical sensor 150a and the visible light optical sensors 160a and 160b is used, the output time point of the signal obtained in the last scan for the same object 90 can be made the same between the near-infrared light optical sensor 150a and the visible light optical sensors 160a and 160b.

[0075] like Figure 5 As shown, the visible light source 140a on the front side and the visible light source 140b on the rear side are always lit during all scanning periods. The near-infrared light source 130a on the front side is lit only during the prescribed period in the first scanning period with an odd-numbered scanning number, and is not lit at all during the first scanning period with an even-numbered scanning number. On the other hand, the near-infrared light source 130b on the rear side is lit only for a prescribed time during the first scanning period with an even-numbered scanning number, and is not lit at all during the first scanning period with an odd-numbered scanning number. In this way, the near-infrared light sources 130a and 130b are alternately lit in a first scanning period in such a manner that only one side is lit. Therefore, through the visible light optical sensors 160a and 160b, the reflected and transmitted images of the red light, the green light, and the blue light are obtained during all second scanning periods. In addition, the near-infrared optical sensor 150a acquires a reflection image based on the near-infrared light 131a during the first scanning period with an odd-numbered scanning number, and acquires a transmission image based on the near-infrared light 131b during the first scanning period with an even-numbered scanning number. The determination unit 82 determines foreign matter and / or defective products based on the images thus acquired.

[0076] When the near-infrared light sources 130a and 130b are turned on in one first scanning period, the period from the start time T0 of the first scanning period to the time T1 is the off period, the period from the time T1 to the time T2 is the on period, and the period from the time T2 to the end time T3 of the first scanning period is the off period. This is the same as the lighting method of each light source in the first embodiment.

[0077] As is well known, a CMOS sensor sequentially performs charge accumulation and charge readout in one scanning period. As described above, the near-infrared light optical sensor 150a is a CMOS sensor. Figure 5 , the period during which the near-infrared optical sensor 150a performs charge accumulation is shown as period TE1, and the period during which the near-infrared optical sensor 150a performs charge reading is shown as period TE2. In the present embodiment, the lighting time points of the near-infrared light sources 130a and 130b are determined based on the periods TE1 and TE2 of the near-infrared optical sensor 150a. Specifically, when the near-infrared light source 130a or the near-infrared light source 130b is turned on during the prescribed first scanning period, the time point ( Figure 5The time T2 shown in the figure is set to be simultaneous with the start of the readout of the charge of the near-infrared optical sensor 150a (the start of period TE2). In other words, the near-infrared optical sensor 150a is lit only during the period TE1 that contributes to the accumulation of charge, and is extinguished during the period TE2 that does not contribute to the accumulation of charge. According to such a setting, the near-infrared light sources 130a and 130b will not be unnecessarily illuminated without contributing to the accumulation of charge. In an alternative embodiment, the time point (time T2) when switching from lighting to extinguishing can also be a time point later than the start of the readout of the charge of the near-infrared optical sensor 150a (the start of period TE2) and earlier than the end of the readout of the charge (the end of period TE2). In this way, the effect of suppressing the unnecessary lighting of the near-infrared light sources 130a and 130b is also obtained to a certain extent.

[0078] The second embodiment described above can be modified in various ways. For example, instead of the near-infrared light sources 130a, 130b and the near-infrared optical sensor 150a, a light source that emits light of any wavelength in the invisible wavelength region and an optical sensor that detects the light can be used. In addition, the visible light sources 140a, 140b can also be lit intermittently in a manner that there is a lighting period and an extinguishing period during each second scanning period. In addition, instead of the visible light sources 140a, 140b that emit white light, one or more light sources that emit light of any wavelength in the visible wavelength region can be arranged on the front side and / or the rear side. In addition, in addition to the near-infrared optical sensor 150a on the front side, a near-infrared optical sensor can also be arranged on the rear side, or instead of the near-infrared optical sensor 150a on the front side, a near-infrared optical sensor can be arranged on the rear side.

[0079] C. 3rd Implementation Method:

[0080] The optical sorting machine (hereinafter referred to as the sorting machine) 200 according to the third embodiment of the present invention is described below. The sorting machine 200 is different from the first embodiment in that it includes an optical detection unit 220 instead of the optical detection unit 20 of the first embodiment and includes a control unit 280 instead of the control unit 80 of the first embodiment. In the following, only the differences from the first embodiment are described for the third embodiment. Figure 6 It is a schematic diagram showing a schematic structure of the sorting machine 100. Figure 6 In the diagram, the components shown in the figure are the same as those in the first embodiment ( Figure 1 ) are marked with the same reference numerals as those marked in the first embodiment. Figure 6As shown, the optical detection unit 220 includes first light sources 230a and 230b, second light sources 240a and 240b, third light sources 250a and 250b, fourth light sources 260a and 260b, and optical sensors 270a and 270b.

[0081] The first light sources 230a and 230b emit first lights 231a and 231b having a first wavelength within the first wavelength range (in this embodiment, 750 nm) toward the plurality of objects 90 being transported, respectively. In this embodiment, the output peaks of the first light sources 230a and 230b are 750 nm. The second light sources 240a and 240b emit second lights 241a and 241b having a second wavelength within the first wavelength range (in this embodiment, 870 nm) toward the plurality of objects 90 being transported, respectively. In this embodiment, the output peaks of the second light sources 240a and 240b are 870 nm. The third light sources 250a and 250b emit third lights 251a and 251b having a third wavelength within the second wavelength range outside the first wavelength range (in this embodiment, 1200 nm) toward the plurality of objects 90 being transported, respectively. In the present embodiment, the output peak of the third light source 250a, 250b is 1200nm. The fourth light source 260a, 260b emits the fourth light 261a, 261b having the fourth wavelength (1550nm in the present embodiment) within the second wavelength range toward the plurality of objects 90 being transported. In the present embodiment, the output peak of the fourth light source 260a, 260b is 1550nm. In the present embodiment, the first to fourth light sources are LEDs. Figure 1 In the figure, the number of each light source is shown to be one, but the number of at least a part of these light sources may be plural.

[0082] Figure 7 2 is a schematic diagram showing the schematic structure of the optical sensors 270a and 270b. The optical sensors 270a and 270b have the same structure, so Figure 7, the components of the optical sensor 270a and the components of the optical sensor 270b are marked together. The optical sensors 270a and 270b are respectively provided with spectrometers 271a and 271b, first light receiving elements 272a and 272b, and second light receiving elements 273a and 273b. The spectrometers 271a and 271b split the incident light L0 into the light L1 in the first wavelength range (including the wavelength region of 750nm and 870nm) and the light L2 in the second wavelength range (including the wavelength region of 1200nm and 1550nm). The first light receiving elements 272a and 272b have a sensitivity greater than a prescribed value in the first wavelength range and are configured to receive the light L1. The sensitivity greater than a prescribed value here refers to a sensitivity sufficient for the determination of the determination unit 82, and is also referred to as an effective sensitivity. The second light receiving elements 273a and 273b have an effective sensitivity in the second wavelength range and are configured to receive the light L2. Therefore, for example, when the first light 231b (λP=750nm) or the second light 241b (λP=870nm) enters the spectrometer 271a, the first light 231b or the second light 241b is detected by the first light receiving element 272a. Similarly, when the third light 251b (λP=1200nm) or the fourth light 261b (λP=1550nm) enters the spectrometer 271a, the third light 251b or the fourth light 261b is detected by the second light receiving element 273a.

[0083] The first light source 230a, the second light source 240a, the third light source 250a, the fourth light source 260a and the optical sensor 270a are arranged on the front side, and the first light source 230b, the second light source 240b, the third light source 250b, the fourth light source 260b and the optical sensor 270b are arranged on the rear side. The optical sensor 270a on the front side can detect the first light 231a emitted from the first light source 230a on the front side and reflected by the object 90, the second light 241a emitted from the second light source 240a and reflected by the object 90, the third light 251a emitted from the third light source 250a and reflected by the object 90, the fourth light 261a emitted from the fourth light source 260a and reflected by the object 90, the first light 231b emitted from the first light source 230b on the rear side and passed through the object 90, the second light 241b emitted from the second light source 240b on the rear side and passed through the object 90, the third light 251b emitted from the third light source 250b on the rear side and passed through the object 90, and the fourth light 261b emitted from the fourth light source 260b on the rear side and passed through the object 90. The optical sensor 270b on the rear side is capable of detecting the first light 231a emitted from the first light source 230a on the front side and passing through the object 90, the second light 241a emitted from the second light source 240a and passing through the object 90, the third light 251a emitted from the third light source 250a and passing through the object 90, the fourth light 261a emitted from the fourth light source 260a and passing through the object 90, the first light 231b emitted from the first light source 230b on the rear side and reflected by the object 90, the second light 241b emitted from the second light source 240b on the rear side and reflected by the object 90, the third light 251b emitted from the third light source 250b on the rear side and reflected by the object 90, and the fourth light 261b emitted from the fourth light source 260b on the rear side and reflected by the object 90.

[0084] Such an optical detection unit 220 is controlled by a control device 280. The light source control unit 281 controls the first to fourth light sources according to a predetermined rule. In the present embodiment, the light source control unit 281 controls the first to fourth light sources according to the selected mode of the first mode 283 and the second mode 284. The mode is selected by the user through a user interface (not shown) provided in the sorting machine 100.

[0085] Figure 82 is a timing diagram showing the scanning period of the optical sensors 270a and 270b and the lighting time points of each light source in the first mode 283. In the first mode 283, as shown in the figure, the first light source 230a on the front side and the first light source 230b on the rear side are lit only during the scanning period with odd-numbered scanning numbers, and are not lit at all during the scanning period with even-numbered scanning numbers. The second light source 240a on the front side and the second light source 240b on the rear side are lit only during the scanning period with even-numbered scanning numbers, and are not lit at all during the scanning period with odd-numbered scanning numbers. The third light source 250a on the front side and the third light source 250b on the rear side are always lit during all scanning periods. The fourth light source 260a on the front side and the fourth light source 260b on the rear side are always off during all scanning periods.

[0086] According to the first mode 283, the optical sensors 270a and 270b obtain reflection and transmission images based on the first light 231a and 231b during the scanning period with odd scanning numbers, and obtain reflection and transmission images based on the second light 241a and 241b during the scanning period with even scanning numbers. In addition, the optical sensors 270a and 270b obtain reflection and transmission images based on the third light 251a and 251b during all scanning periods.

[0087] According to the first mode 283, by alternately lighting the first light sources 230a, 230b and the second light sources 240a, 240b that emit two wavelengths of light (first light 231a, 231b and second light 241a, 241b) within the effective sensitivity of the first light receiving elements 272a, 272b, it is possible to detect two wavelengths of light by one first light receiving element 272a, 272b. Furthermore, by lighting the third light sources 250a, 250b that emit one wavelength of light (third light 251a, 251b) within the effective sensitivity of the second light receiving elements 273a, 273b, it is possible to detect the light of the one wavelength by the second light receiving elements 273a, 273b. In other words, it is possible to detect three wavelengths of light by each of the optical sensors 270a, 270b.

[0088] Fig. 92 is a timing diagram showing the scanning period of the optical sensors 270a and 270b and the lighting time points of each light source in the second mode 284. In the second mode 284, as shown in the figure, the first light sources 230a and 230b are always lit during all scanning periods. The second light sources 240a and 240b are always extinguished during all scanning periods. The third light sources 250a and 250b are lit only during the scanning period with odd-numbered scanning numbers for a prescribed period, and are not lit at all during the scanning period with even-numbered scanning numbers. The fourth light sources 260a and 260b are lit only during the scanning period with even-numbered scanning numbers for a prescribed period, and are not lit at all during the scanning period with odd-numbered scanning numbers.

[0089] According to the second mode 284, both the optical sensors 270a and 270b obtain reflection transmission images based on the third light 251a and 251b during the scanning period with odd scanning numbers, and obtain reflection transmission images based on the fourth light 261a and 261b during the scanning period with even scanning numbers. In addition, both the optical sensors 270a and 270b obtain reflection transmission images based on the second light 241a and 241b during all scanning periods. According to the second mode 284, as in the first mode 283, the optical sensors 270a and 270b can each detect three wavelengths of light.

[0090] According to such a sorting machine 200, three wavelengths of light can be detected by one optical sensor, so the sorting machine 200 can be made low-cost. In addition, one of the three wavelengths of light is continuously emitted, so sufficient detection intensity can be ensured. In addition, by selecting one of the first mode 283 and the second mode 284, the wavelength of the light used can be changed according to the type of the object 90 or the type of foreign matter and / or defective products to be sorted.

[0091] The third embodiment described above can be modified in various ways. For example, in the first mode 283, the fourth light source 260a, 260b may be turned on instead of the third light source 250a, 250b. Similarly, in the second mode 284, the second light source 240a, 240b may be turned on instead of the first light source 230a, 230b. In addition, in the first mode 283, the third light source 250a, 250b may be turned on intermittently in a manner that there are both a lighting period and an extinguishing period during multiple scans. In this way, the resolution of the image obtained based on the third light source 250a, 250b may be greater than that of the image obtained based on other light sources. Similarly, in the second mode 284, the first light source 230a, 230b may be turned on intermittently in a manner that there are both a lighting period and an extinguishing period during multiple scans. In addition, the wavelength of light emitted from the light sources of the first to fourth wavelengths may be set arbitrarily. The light source control unit 281 may control each light source in only one of the first mode 283 and the second mode 284. In this case, the light source that is not turned on (for example, the fourth light sources 260a and 260b in the first mode 283) can be omitted.

[0092] Several embodiments of the present invention have been described above, but the embodiments of the invention described above are for easy understanding of the present invention and do not limit the present invention. The present invention can be changed and improved without departing from its main purpose, and the present invention includes its equivalents. In addition, within the scope that can solve at least part of the above-mentioned problems or within the scope of at least part of the effect, any combination or any omission of the various components described in the technical solution and the specification can be performed. For example, the above-mentioned intermittently lit light source can also be lit from the beginning of the scanning period of the optical sensor that receives the light emitted by the light source. Alternatively, as a mechanism for transferring the object 90, a conveyor can be used instead of the chute 73.

[0093] Description of Reference Numerals

[0094] 10...optical sorting machine; 20...optical detection unit; 30a...first light source (red light source); 30b...second light source (red light source); 31a...first light (red light); 31b...second light (red light); 40a...third light source (green light source); 40b...fourth light source (green light source); 41a...third light (green light); 41b...fourth light (green light); 50a...third light source (blue light source); 50b...fourth light source (blue light source); 51a...third light (blue light); 51b...fourth light (green light); light (blue light); 60a...first optical sensor; 60b...second optical sensor; 71...storage tank; 72...feeder; 73...chute; 74...good product discharge slot; 75...bad product discharge slot; 76...injector; 77...air; 80...control device; 81...light source control unit; 82...judgment unit; 90...sorting object; 100...optical sorter; 120...optical detection unit; 130a, 130b...first light source (near infrared light source); 131a, 131b...first light (near infrared light); 140a, 140b...second light source (visible light source); 141a, 141b...second light (visible light); 150a...first optical sensor (optical sensor for near infrared light); 160a, 160b...second optical sensor (optical sensor for visible light); 180...control device; 181...light source control unit; 200...optical sorting machine; 220...optical detection unit; 230a, 230b...first light source; 231a, 231b...first light; 240a, 240b... The second light source; 241a, 241b...the second light; 250a, 250b...the third light source; 251a, 251b...the third light; 260a, 260b...the fourth light source; 261a, 261b...the fourth light; 270a, 270b...the optical sensor; 271a, 271b...the spectrometer; 272a, 272b...the first light receiving element; 273a, 273b...the second light receiving element; 280...the control device; 281...the light source control unit; 283...the first mode; 284...the second mode.

Claims

1. An optical sorting machine, characterized in that: have: An intermittent light source that intermittently emits light toward a plurality of objects to be sorted being transferred; an optical sensor that detects the light associated with one of the plurality of sorting objects being transferred during a plurality of intermittent light scanning periods; a determination unit that determines whether the one of the sorting objects is a foreign object and / or a defective product based on the signal acquired by the optical sensor; as well as a light source control unit, which controls the intermittent light source, The light source control unit is configured to control the intermittent light source so that In a case where the intermittent light source is turned on during at least one of the plurality of intermittent light scanning periods, in order to prevent light emitted from the intermittent light source from being detected during a preceding intermittent light scanning period, during each of the intermittent light scanning periods of the at least one intermittent light scanning period, There is a lighting period during which the intermittent light source is lit and a extinguishing period during which the intermittent light source is extinguished, and The lighting period starts at a time point delayed from the start of the at least one intermittent light scanning period.

2. The optical sorting machine according to claim 1, characterized in that: The light source control unit is configured to control the intermittent light source so that the lighting period ends at a time point earlier than the end of the at least one intermittent light scanning period to prevent the light emitted from the intermittent light source from being detected in the next intermittent light scanning period.

3. The optical sorting machine according to claim 1 or 2, characterized in that: The intermittent light source comprises: a first intermittent light source, which is arranged on a first side relative to a transfer path of the plurality of sorting objects and emits a first light; and a second intermittent light source, which is arranged on a second side opposite to the first side and emits a second light having the same wavelength as the first light. The optical sensor includes a first optical sensor disposed on the first side and a second optical sensor disposed on the second side. The plurality of intermittent light scanning periods include a first intermittent light scanning period and a second intermittent light scanning period. The light source control unit is configured to control the first intermittent light source and the second intermittent light source so that during the scanning period of the first intermittent light, the first intermittent light source is lit and the second intermittent light source is not lit, and during the scanning period of the second intermittent light, the first intermittent light source is not lit and the second intermittent light source is lit.

4. The optical sorting machine according to claim 3, characterized in that: The first light and the second light are red light.

5. The optical sorting machine according to claim 3, characterized in that: The intermittent light source has: a third intermittent light source disposed on the first side and emitting a third light having a wavelength different from that of the first light; and a fourth intermittent light source, which is disposed on the second side and emits a fourth light having the same wavelength as the third light, The light source control section is configured to control the third intermittent light source and the fourth intermittent light source so that they are turned on during both the first intermittent light scanning period and the second intermittent light scanning period.

6. The optical sorting machine according to claim 5, characterized in that: The third light and the fourth light both include green light and blue light.

7. The optical sorting machine according to claim 1 or 2, characterized in that: The intermittent light source emits invisible light having a wavelength in the invisible wavelength region as the light, The optical sensor is configured as an invisible light optical sensor for detecting the invisible light. The optical sorting machine further comprises: a visible light source that emits visible light having a wavelength in a visible wavelength region toward the plurality of sorting objects being transferred; and a visible light optical sensor that detects the visible light associated with the one sorting object during a plurality of visible light scans, The determination unit is configured to determine the foreign matter and / or the defective product based on the signal acquired by the invisible light optical sensor and the signal acquired by the visible light optical sensor. The intermittent light scanning period and the visible light scanning period are defined by time periods of different lengths.

8. The optical sorting machine according to claim 7, characterized in that: The intermittent light scanning period is set to N times the visible light scanning period, where N is an integer greater than or equal to 2.

9. The optical sorting machine according to claim 7, characterized in that: The invisible light is near infrared light.

10. The optical sorting machine according to claim 1 or 2, characterized in that: The optical sensor is a CMOS sensor, The lighting period ends simultaneously with the start of charge reading of the CMOS sensor, or ends at a time point later than the start of the readout and earlier than the end of the charge reading.

11. The optical sorting machine according to claim 1 or 2, characterized in that: The intermittent light source comprises: a first intermittent light source that emits a first light having a first wavelength within a first wavelength range; and a second intermittent light source that emits a second light having a second wavelength within the first wavelength range that is different from the first wavelength. The optical sorter further includes an additional light source that emits a third light having a third wavelength within a second wavelength range outside the first wavelength range toward the plurality of sorting objects being transferred. The optical sensor integrally comprises: a first light receiving element having a sensitivity greater than a predetermined value in the first wavelength range, a second light receiving element having a sensitivity greater than a predetermined value in the second wavelength range, and a spectrometer for splitting incident light into light within the first wavelength range and light within the second wavelength range. The plurality of intermittent light scanning periods include a first intermittent light scanning period and a second intermittent light scanning period. The light source control unit is configured to control the intermittent light source and the additional light source so that during the first intermittent light scanning period, the first intermittent light source is lit, the second intermittent light source is not lit, and the additional light source is lit, and to control the intermittent light source and the additional light source so that during the second intermittent light scanning period, the first intermittent light source is not lit, the second intermittent light source is lit, and the additional light source is lit.

12. An optical sorting machine, characterized in that: have: a first light source that emits first light having a wavelength in an invisible wavelength region toward a plurality of objects to be sorted being transferred; a second light source that emits a second light having a wavelength in a visible wavelength region toward the plurality of sorting objects being transferred; a first optical sensor for detecting, during a plurality of first scanning periods, a first light associated with one of the plurality of separation objects being transferred; a second optical sensor for detecting a second light associated with the one sorting object during a plurality of second scanning periods; as well as a determination unit that determines whether the one sorting object is a foreign object and / or a defective product based on the signal acquired by the first optical sensor and the signal acquired by the second optical sensor, The first scanning period and the second scanning period are defined by time periods of different lengths.

13. The optical sorting machine according to claim 12, characterized in that: The first scanning period is set to be N times the second scanning period, where N is an integer greater than or equal to 2.

14. The optical sorting machine according to claim 12 or 13, characterized in that: The first light is near infrared light.

15. An optical sorting machine, characterized in that: have: a first light source that intermittently emits a first light having a first wavelength within a first wavelength range toward a plurality of objects to be sorted being transferred; a second light source that intermittently emits a second light having a second wavelength within the first wavelength range toward the plurality of objects to be sorted being transferred; a third light source that emits a third light toward the plurality of sorting objects being transferred, the third light having a third wavelength within a second wavelength range outside the first wavelength range; and Optical sensors, The optical sensor integrally comprises: a first light receiving element having a sensitivity greater than a predetermined value in the first wavelength range, a second light receiving element having a sensitivity greater than a predetermined value in the second wavelength range, and a spectrometer for splitting incident light into light within the first wavelength range and light within the second wavelength range. The optical sensor detects one of the first light and the second light associated with one of the plurality of sorting objects being transferred, and the third light associated with the one sorting object, during a plurality of scanning periods including a first scanning period and a second scanning period. The optical sorting machine further comprises: a determination unit that determines whether the one of the sorting objects is a foreign object and / or a defective product based on the signal acquired by the optical sensor; and A light source control unit controls the first light source, the second light source, and the third light source so that during the first scan, the first light source is turned on, the second light source is not turned on, and the third light source is turned on, and during the second scan, the first light source is not turned on, the second light source is turned on, and the third light source is turned on.

Images