Optical sorting machine

Abstract

The optical sorting machine includes: a first light source arranged on the first side; a second light source arranged on the second side; an optical sensor configured to detect light during a plurality of scanning periods including a first scanning period and a second scanning period; a determination unit configured to determine foreign matter and / or defective products; and a light source control unit. The light source control unit is configured to control the first light source and the second light source in a manner of lighting up in a first lighting mode during a first scanning period, the first lighting mode being a lighting mode arbitrarily selected from a lighting mode in which the first light source and the second light source are lit, a lighting mode in which only one of the first light source and the second light source is lit, and a lighting mode in which only the other of the first light source and the second light source is lit; and the light source control unit is configured to control the first light source and the second light source in a manner of lighting up in a second lighting mode during a second scanning period, the second lighting mode being a lighting mode arbitrarily selected except the first lighting mode.

Description

Technical Field

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

[0002] In the past, an optical sorting machine is known, in which a red light source emitting red light is arranged on one side of a transfer path of a sorting object, and optical sensors are arranged on both sides of the transfer path (for example, Patent Document 1 described below). According to this optical sorting machine, the red light reflected by the sorting object is detected by the optical sensor on one side, and the red light transmitted through the sorting object is detected by the optical sensor on the other side. In the optical sorting machine described in Patent Document 1, whether the sorting object, i.e., rice grains, is a white unripe grain is determined based on the detection results of the red reflected light and the transmitted light.

[0003] Patent Document 1: Japanese Patent Application Laid-Open No. 2010-42326

[0004] However, there is still room for improving the discrimination accuracy of existing optical sorting machines. For example, according to the optical sorting machine described in Patent Document 1, the judgment of white unripe grains is based on the red reflection image (the image represented by the reflected red light) and the red transmission image (the image represented by the transmitted red light), but the red reflection image (the image represented by the light synthesized by the reflected red light and the transmitted red light) is not obtained, so the types of defective products that can be distinguished are limited. Therefore, it is required to increase the types of images that can be obtained, so as to improve the discrimination accuracy of defective products and / or foreign matter. This situation is not limited to red light, and is applicable to the case of using light with any wavelength. In addition, this situation is not limited to the case of sorting rice grains, and is applicable to the case of sorting any granular objects. Summary of the invention

[0005] The present invention has been made to solve the above-mentioned problems, and can be achieved, for example, by the following technical solutions.

[0006] According to a first technical solution of the present invention, an optical sorting machine is provided. The optical sorting machine comprises: a first light source configured to emit a first light toward a plurality of sorting objects being transferred, and arranged on a first side relative to a transfer path of the plurality of sorting objects; a second light source configured to emit a second light having the same wavelength as the first light toward the plurality of sorting objects being transferred, and arranged on a second side opposite to the first side; an optical sensor configured to be arranged on at least one of the first side and the second side, and configured to detect light associated with one of the plurality of sorting objects being transferred during a plurality of scanning periods including a first scanning period and a second scanning period; a determination unit configured to perform a determination on a foreign body and / or a defective product for one of the sorting objects based on a signal obtained by the optical sensor; and a light source control unit configured to control the first light source and the second light source. The light source control unit is configured to control the first light source and the second light source in a manner of lighting up in a first lighting mode during a first scan, and the first lighting mode is a lighting mode arbitrarily selected from a lighting mode in which the first light source and the second light source are lit, a lighting mode in which only one of the first light source and the second light source is lit, and a lighting mode in which only the other of the first light source and the second light source is lit; and the light source control unit is configured to control the first light source and the second light source in a manner of lighting up in a second lighting mode during a second scan, and the second lighting mode is a lighting mode other than the first lighting mode arbitrarily selected from a lighting mode in which the first light source and the second light source are lit, a lighting mode in which only one of the first light source and the second light source is lit, and a lighting mode in which only the other of the first light source and the second light source is lit.

[0007] According to the optical sorter, the types of images that can be obtained can be increased according to the selection of the first lighting mode and the second lighting mode, and as a result, the accuracy of distinguishing defective products and / or foreign matter can be improved. The above-mentioned "multiple scanning periods including the first scanning period and the second scanning period" refers to both the case where the "multiple scanning periods" are composed of only the "first scanning period" and the "second scanning period" and the case where the "multiple scanning periods" are composed of the "first scanning period", the "second scanning period" and any other scanning period. That is, on the basis of setting the first scanning period and the second scanning period, it is not excluded that other scanning periods are also set.

[0008] According to the second technical solution of the present invention, in the first technical solution, the first light and the second light are red light. The optical sensor comprises: a first optical sensor, which is arranged on the first side; and a second optical sensor, which is arranged on the second side. In the first lighting mode, the first light source and the second light source are lit, and in the second lighting mode, only the first light source of the first light source and the second light source is lit.

[0009] According to the technical solution, during the first scan, the first optical sensor on the first side detects the reflected light (light reflected by the sorting object) based on the red light emitted from the first light source on the first side, and the transmitted light (light transmitted through the sorting object) based on the red light emitted from the second light source on the second side, and the second optical sensor on the second side detects the transmitted light based on the red light emitted from the first light source on the first side, and the reflected light based on the red light emitted from the second light source on the second side. In addition, during the second scan, the first optical sensor on the first side detects only the reflected light based on the red light emitted from the first light source on the first side, and the second optical sensor on the second side detects only the transmitted light based on the red light emitted from the first light source on the first side. That is, for red light, the determination unit can use the reflected image (image represented by the reflected light), the transmitted image (image represented by the transmitted light), and the reflected transmitted image (image represented by the light synthesized by the reflected light and the transmitted light) to determine foreign matter and / or defective products. Therefore, compared with the existing optical sorter that only uses the reflected image and the transmitted image for red light, the types of defective products that can be identified can be increased. For example, when the objects to be sorted are rice grains, green and unripe grains can be distinguished using a reflection transmission image for red light.

[0010] According to the third technical solution of the present invention, in the second technical solution, the light source control unit is configured to control the first light source and the second light source in the following manner, that is, during the first scan period, there are lighting periods and extinguishing periods for the first light source and the second light source respectively, and during the second scan period, there are lighting periods and extinguishing periods for the first light source. According to this technical solution, compared with the case where the first light source and the second light source are continuously lit during the entire first scan period, and compared with the case where the first light source is continuously lit during the entire second scan period, power consumption can be reduced. In addition, due to the shortening of the lighting time, the temperature rise of the first light source and the second light source can be suppressed, and thus the characteristic changes of the first light source and the second light source caused by the temperature rise (more specifically, the changes in the wavelength region of the emitted light) can be suppressed. Therefore, the judgment of foreign matter and / or defective products can be performed more stably.

[0011] According to a fourth technical solution of the present invention, in the third technical solution, the light source control unit is configured to control the first light source and the second light source in the following manner, that is, during the first scanning period, the lighting period for each of the first light source and the second light source starts at a time point delayed from the start of the first scanning period, and during the second scanning period, the lighting period for the first light source starts at a time point delayed from the start of the second scanning period. According to this technical solution, at the time point when the first scanning period starts, the first light source and the second light source are extinguished. In addition, at the time point when the second scanning period starts, the first light source is extinguished. Therefore, the light emitted from the first light source and / or the second light source during the Nth scanning period (N is an integer greater than or equal to 2) will not be detected during the N-1th scanning period. For example, if the first light source and the second light source are switched from extinguishing to lighting simultaneously with the start of the Nth scanning period (assuming that this corresponds to the first scanning period) (in other words, the end of the N-1th scanning period), the light emitted from the first light source and the second light source simultaneously with the start of the Nth scanning period may be mixed into the detection result of the N-1th scanning period as noise. However, according to the present technical solution, such a phenomenon does not occur, and thus the determination accuracy of the determination unit can be improved.

[0012] The above-mentioned technical solutions can also be implemented in combination with the structures of other known optical sorting machines. For example, the optical sorting machine in any of the second to fourth technical solutions can also have at least one light source that emits light other than red (for example, green light and / or blue light) on the first side and / or the second side. In this case, the first optical sensor and the second optical sensor can also detect green light and / or blue light in addition to detecting red light.

[0013] According to the fifth technical solution of the present invention, in the first technical solution, the optical sensor is configured to detect two kinds of light, i.e., reflected light, light transmitted through the sorting object, i.e., transmitted light, and light synthesized from the reflected light and the transmitted light, i.e., reflected transmitted light, based on the first lighting mode and the second lighting mode. The determination unit is configured to determine foreign matter and / or defective products based on two images corresponding to the two kinds of light detected by the optical sensor, i.e., the image represented by the reflected light, i.e., the reflected image, the image represented by the transmitted light, i.e., the transmitted image, and the image represented by the reflected transmitted light, i.e., the reflected transmitted image, and the remaining image obtained by calculating the detection results of the two kinds of light.

[0014] According to the technical solution, two images among the reflected image, the transmitted image and the reflected transmitted image can be directly obtained by the optical sensor, and the remaining image can be obtained by calculation. Therefore, the determination unit can make a high-precision determination of foreign matter and / or defective products based on the three images (i.e., the reflected image, the transmitted image and the reflected transmitted image). For example, the types of images that can be used increase, so the types of foreign matter and / or defective products increase. And the remaining image is obtained by calculation (in other words, a scanning period for obtaining the remaining image is not set in addition to the first scanning period and the second scanning period), so the resolution of the two images will not decrease due to the acquisition of the remaining image. Therefore, the discrimination accuracy based on the two images will not decrease due to the acquisition of the remaining image.

[0015] According to the sixth technical solution of the present invention, in the fifth technical solution, in the first lighting mode, the first light source and the second light source are lit. In the second lighting mode, only the first light source of the first light source and the second light source is lit. The optical sensor has a first optical sensor arranged on the first side. The first optical sensor is configured to detect the reflected transmitted light based on the first lighting mode during the first scanning period, and to detect the reflected light based on the second lighting mode during the second scanning period. The determination unit is configured to perform a determination of foreign matter and / or defective products based on at least a reflected transmitted image and a reflected image corresponding to the reflected transmitted light and the reflected light detected by the first optical sensor, and a transmitted image obtained by subtracting the detection result of the reflected light from the detection result of the reflected transmitted light. According to this technical solution, the determination unit can use the transmitted image obtained by calculation in addition to the reflected transmitted image and the reflected image directly obtained by the first optical sensor, thereby improving the recognition accuracy.

[0016] According to the seventh technical solution of the present invention, in the fifth or sixth technical solution, in the first lighting mode, the first light source and the second light source are lit. In the second lighting mode, only the first light source of the first light source and the second light source is lit. The optical sensor includes a second optical sensor arranged on the second side. The second optical sensor is configured to detect the reflected and transmitted light based on the first lighting mode during the first scanning period, and detect the transmitted light based on the second lighting mode during the second scanning period. The determination unit is configured to perform a determination of foreign matter and / or defective products based on at least a reflected and transmitted image and a transmitted image corresponding to the reflected and transmitted light detected by the second optical sensor, and a reflected image obtained by subtracting the detection result of the transmitted light from the detection result of the reflected and transmitted light. According to this technical solution, the determination unit can use the reflected image obtained by calculation in addition to the reflected and transmitted image and the transmitted image directly obtained by the second optical sensor, so that the recognition accuracy is improved. In particular, in the technical solution formed by combining the sixth technical solution and the seventh technical solution, the recognition unit can use: the reflected and transmitted image, the transmitted image, and the reflected image obtained on the first side, and the reflected and transmitted image, the transmitted image, and the reflected image obtained on the second side. Due to the different orientations of the sorting objects when irradiated with the first light and the second light, the characteristics of foreign matter and / or defective products are sometimes only visible in one of the images obtained on the first side and the image obtained on the second side. Since the combined technical solution can use the three images obtained on both sides, the identification accuracy is particularly excellent.

[0017] According to the eighth technical scheme of the present invention, in the fifth technical scheme, in the first lighting mode, only the first light source of the first light source and the second light source is lit. In the second lighting mode, only the second light source of the first light source and the second light source is lit. The optical sensor has a first optical sensor arranged on the first side. The first optical sensor is configured to detect reflected light based on the first lighting mode during the first scanning period, and to detect transmitted light based on the second lighting mode during the second scanning period. The determination unit is configured to perform a determination of foreign matter and / or defective products based on at least a reflected image and a transmitted image corresponding to the reflected light and the transmitted light detected by the first optical sensor, and a reflected transmitted image obtained by adding the detection result of the reflected light and the detection result of the transmitted light. According to this technical scheme, the determination unit can use the reflected transmitted image obtained by calculation in addition to the reflected image and the transmitted image directly obtained by the first optical sensor, so that the recognition accuracy is improved.

[0018] According to a ninth technical solution of the present invention, in the eighth technical solution, the optical sensor includes a second optical sensor disposed on the second side. The second optical sensor is configured to detect the transmitted light based on the first lighting pattern during the first scanning period, and to detect the reflected light based on the second lighting pattern during the second scanning period. The determination unit is configured to determine foreign matter and / or defective products based on at least a transmitted image and a reflected image corresponding to the transmitted light and the reflected light detected by the second optical sensor, and a reflected transmitted image obtained by adding the detection result of the transmitted light and the detection result of the reflected light. According to this technical solution, the determination unit can use the reflected transmitted image obtained by calculation in addition to the transmitted image and the reflected image directly obtained by the second optical sensor, so that the recognition accuracy is improved. In addition, the recognition unit can use: the reflected transmitted image, the transmitted image, and the reflected image obtained on the first side; and the reflected transmitted image, the transmitted image, and the reflected image obtained on the second side. Therefore, as with the technical solution formed by combining the sixth technical solution and the seventh technical solution, the recognition accuracy is particularly excellent.

[0019] According to the tenth technical solution of the present invention, in any one of the fifth to ninth technical solutions, the first light and the second light are red light. According to this technical solution, the determination unit can determine various foreign matter and / or defective products. For example, when the sorting object is rice grains, white unripe grains can be determined based on the reflection image and the transmission image, and green unripe grains can be determined based on the reflection transmission image.

[0020] The above-mentioned technical solutions can also be implemented in combination with the structures of other known optical sorting machines. For example, the optical sorting machine can also include an additional light source other than the first light source and the second light source (for example, a light source that emits light having a wavelength different from that of the first light and the second light). In this case, the optical sorting machine can also include an additional optical sensor for detecting light emitted from the additional light source, or the optical sensor in any of the first to tenth technical solutions can also detect light emitted from the additional light source. BRIEF DESCRIPTION OF THE DRAWINGS

[0021] Figure 1 It is a schematic diagram showing a schematic structure of an optical sorter according to the first embodiment of the present invention.

[0022] 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.

[0023] Figure 3 This is an explanatory diagram showing the relationship between one sorting object and a scan number.

[0024] Figure 41 is a timing chart showing the relationship between the scanning period of the optical sensor and the lighting timing of the light source according to the second embodiment.

[0025] Figure 5 1 is a timing chart showing the relationship between the scanning period of the optical sensor and the lighting timing of the light source according to the third embodiment.

[0026] Figure 6 It is a graph showing the spectral reflectance distribution for brown rice.

[0027] Figure 7 It is a graph showing the spectral reflectance distribution of coffee beans.

[0028] Figure 8 1 is a timing chart showing the relationship between the scanning period of the optical sensor and the lighting timing of the light source according to the fourth embodiment.

[0029] Fig. 9 1 is a timing chart showing the relationship between the scanning period of the optical sensor and the lighting timing of the light source according to the fifth embodiment. DETAILED DESCRIPTION

[0030] A. First embodiment

[0031] Figure 1 1 is a schematic diagram showing the schematic structure of an optical sorting machine (hereinafter referred to as the sorting machine) 10 as the 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 grains (more specifically, brown rice or polished rice) as the sorting object (hereinafter referred to as the object) 90. However, the object 90 is not limited to brown rice or polished rice, and can also be any granular object. For example, the object 90 can also be rice, wheat grains, beans (soybeans, chickpeas, edamame, etc.), resin (granules, etc.), rubber sheets, etc.

[0032] like Figure 1As shown, the sorting machine 10 includes: an optical detection unit 20; a storage box 71; a feeder 72; a chute 73; a qualified product discharge slot 74; a defective product discharge slot 75; an injector 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 may 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 may also be implemented by an integrated single device. For example, the light source control unit 81 and the determination unit 82 may also be two functions implemented by one CPU. Alternatively, the light source control unit 81 and the determination unit 82 may also be implemented by separate devices, respectively. Details of the functions of the control device 80 will be described later.

[0033] The storage box 71 temporarily stores the object 90. The feeder 72 supplies the object 90 stored in the storage box 71 to the chute 73. The optical detection unit 20 irradiates light to the object 90 sliding down from the chute 73, and detects the light associated with the object 90 (specifically, the transmitted light that has passed through the object 90 and / or the reflected light that has been 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 (in other words, the grayscale value corresponding to the analog signal) is input to the control device 80. As a process of the determination unit 82, the control device 80 determines whether the object 90 is a qualified product (i.e., a rice grain with relatively high quality), a foreign body (i.e., not a rice grain), or a defective product (i.e., a rice grain with relatively low quality) based on the detection result (i.e., image) of the input light. This determination is performed for each object 90.

[0034] When the object 90 is determined to be a foreign object or a defective product, the ejector 76 ejects air 77 toward the object 90. As a result, the object 90 is blown away, deviates from the falling track from the chute 73, and is guided to 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 does not change the falling track and is guided to the good product discharge chute 74.

[0035] 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: red light sources 30a, 30b; green light sources 40a, 40b; blue light sources 50a, 50b; and optical sensors 60a, 60b.

[0036] The red light source 30a emits red light 31a toward the multiple objects 90 being transported (i.e., falling from the chute 73). Similarly, the red light source 30b emits red light 31b (in other words, light having the same wavelength as the red light 31a) toward the multiple objects 90 being transported. The green light source 40a emits green light 41a toward the multiple objects 90 being transported. Similarly, the green light source 40b emits green light 41b toward the multiple objects 90 being transported. The blue light source 50a emits blue light 51a toward the multiple objects 90 being transported. The blue light source 50b emits blue light 51b toward the multiple objects 90 being transported.

[0037] In this embodiment, the red light sources 30a, 30b, the green light sources 40a, 40b, and the blue light sources 50a, 50b are LEDs. Figure 1 In the figure, the number of these light sources is respectively represented as one, but the number of at least a part of these light sources may also be multiple.

[0038] The optical sensors 60a and 60b detect light associated with one of the multiple objects 90 being transferred. In the present embodiment, the optical sensors 60a and 60b are color CCD sensors, which can detect red light, green light, and blue light separately. However, the optical sensors 60a and 60b may also be color sensors of other forms such as color CMOS sensors. Furthermore, the optical sensors 60a and 60b are line sensors in the present embodiment, but may also be area sensors.

[0039] The red light source 30a, the green light source 40a, the blue light source 50a, and the 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 path from the chute 73). On the other hand, the red light source 30b, the green light source 40b, the blue light source 50b, and the 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.

[0040] The optical sensor 60a on the front side is capable of detecting: red light 31a emitted from the red light source 30a on the front side and reflected by the object 90 (also called reflected red light 31a); green light 41a emitted from the green light source 40a on the front side and reflected by the object 90 (also called reflected green light 41a); blue light 51a emitted from the blue light source 50a on the front side and reflected by the object 90 (also called reflected blue light 51a); red light 31b emitted from the red light source 30b on the rear side and passed through the object 90 (also called transmitted red light 31b); green light 41b emitted from the green light source 40b on the rear side and passed through the object 90 (also called transmitted green light 41b); blue light 51b emitted from the blue light source 50b on the rear side and passed through the object 90 (also called transmitted blue light 51b).

[0041] The optical sensor 60b on the rear side is capable of detecting: red light 31b emitted from the red light source 30b on the rear side and reflected by the object 90 (also called reflected red light 31b); green light 41b emitted from the green light source 40b on the rear side and reflected by the object 90 (also called reflected green light 41b); blue light 51b emitted from the blue light source 50b on the rear side and reflected by the object 90 (also called reflected blue light 51b); red light 31a emitted from the red light source 30a on the front side and passed through the object 90 (also called transmitted red light 31a); green light 41a emitted from the green light source 40a on the front side and passed through the object 90 (also called transmitted green light 41a); blue light 51a emitted from the blue light source 50a on the front side and passed through the object 90 (also called transmitted blue light 51a).

[0042] As is well known, the optical sensors 60a, 60b scan an object 90 multiple times. In other words, the optical sensors 60a, 60b detect light associated with an object 90 in each of the multiple scanning periods. The scanning period is the time from the start to the end of a scan. By synthesizing the images obtained in each scan, an overall image of the object 90 can be 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.

[0043] The optical detection unit 20 is controlled by a control device 80. The light source control unit 81 controls the red light sources 30a, 30b, the green light sources 40a, 40b, and the blue light sources 50a, 50b according to a predetermined rule. Figure 260a and 60b are timing diagrams showing the relationship between the scanning period of the optical sensors 60a and 60b and the lighting time of these light sources. Figure 2 In the graph, "R" stands for red, "G" stands for green, and "B" stands for blue.

[0044] Figure 3 1 is an explanatory diagram showing the relationship between an object 90 and the scanning number (a number indicating the number of scanning) of the optical sensors 60a and 60b. Figure 3 As shown, in the present embodiment, one object 90 is scanned eight times (the number is shown to be smaller than the actual number for simplicity of description) to acquire image data. Figure 3 The numbers 1 to 8 shown represent the codes of the scans for obtaining the image data of the corresponding area. For example, the area marked with "1" indicates that the image data is obtained by the first scan. Figure 2 In the Scan No. Figure 3 The scan numbers shown correspond.

[0045] like Figure 2 As shown in the figure, the red light source 30a on the front side is lit for a predetermined time (indicated as ON in the figure) in each of all the scanning periods. On the other hand, the red light source 30b on the rear side is lit for a predetermined time only in the scanning period with an odd-numbered scanning number, and is not lit at all in the scanning period with an even-numbered scanning number. In this way, the red light sources 30a and 30b are lit in such a manner that there are scanning periods in which both are lit and scanning periods in which only one (in this embodiment, only the front side) is lit.

[0046] The front green light source 40a and the blue light source 50a are turned on for a predetermined time in each of all scanning periods. Similarly, the rear green light source 40b and the blue light source 50b are turned on for a predetermined time in each of all scanning periods.

[0047] By lighting in this way, the optical sensor 60a on the front side detects separately during the scan with an odd scan number: the light synthesized by the reflected red light 31a and 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. In other words, the optical sensor 60a obtains a red reflected transmission image, a green reflected transmission image, and a blue reflected transmission image. In the present application, a reflected image refers to an image represented only by reflected light. A transmitted image refers to an image represented only by transmitted light. A reflected transmission image refers to an image represented by the light synthesized by reflected light and transmitted light.

[0048] In addition, the optical sensor 60a on the front side detects separately during the scanning period with an even-numbered scanning number: the light synthesized by the reflected red light 31a, 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. In other words, the optical sensor 60a obtains a red reflected image, a green reflected transmitted image, and a blue reflected transmitted image.

[0049] On the other hand, the optical sensor 60b on the rear side detects the light synthesized by the transmitted red light 31a and the reflected red light 31b, the light synthesized by the transmitted green light 41a and the reflected green light 41b, and the light synthesized by the transmitted blue light 51a and the reflected blue light 51b during the scanning period with an odd-numbered scanning number. In other words, the optical sensor 60b obtains a red reflected transmission image, a green reflected transmission image, and a blue reflected transmission image.

[0050] In addition, the optical sensor 60b at the rear side detects separately during the scanning period with an even-numbered scanning number: the transmitted red light 31a, the light synthesized by the transmitted green light 41a and the reflected green light 41b, and the light synthesized by the transmitted blue light 51a and the reflected blue light 51b. In other words, the optical sensor 60b obtains a red transmitted image, a green reflected transmitted image, and a blue reflected transmitted image.

[0051] In summary, as a red image, four images are obtained, namely, the front side reflection and transmission image (in Figure 3 The image consists of the area marked with odd scan numbers in Figure 3 The image is composed of the area marked with an even-numbered scan number in the image), and the reflected transmission image on the rear side (in the image Figure 3 The image consists of the area marked with odd scan numbers in Figure 3 In addition, as a green image, a reflection transmission image of the front side and a reflection transmission image of the rear side are obtained. In addition, as a blue image, a reflection transmission image of the front side and a reflection transmission image of the rear side are obtained. The green image and the blue image are respectively Figure 3 The area structure in which the scan numbers 1 to 8 are marked.

[0052] The determination unit 82 uses the red reflected image, the transmission image and the reflected transmission image, the green reflected transmission image, and the blue reflected transmission image thus obtained to determine foreign matter and / or defective products. Figure 3The front red reflection transmission image consisting of the area marked with odd scanning numbers (in other words, the red reflection transmission image obtained by the optical sensor 60a) and the rear red reflection transmission image consisting of the area marked with odd scanning numbers (in other words, the red reflection transmission image obtained by the optical sensor 60b) are used to determine whether the object 90 is a green unripe grain.

[0053] In addition, based on Figure 3 The rear red transmission image consisting of the area marked with an even-numbered scanning number is used to determine whether the object 90 is a white unripe grain. The front red reflection image consisting of the area marked with an even-numbered scanning number is not used in this embodiment, but both the rear red transmission image and the front red reflection image can also be used to distinguish white unripe grains.

[0054] In addition, based on the front green reflection transmission image composed of the area marked with scan numbers 1 to 8, the front blue reflection transmission image composed of the area marked with scan numbers 1 to 8, the rear blue reflection transmission image composed of the area marked with scan numbers 1 to 8, and the rear blue reflection transmission image composed of the area marked with scan numbers 1 to 8, it is determined whether the object 90 is a colored particle. Usually, these determinations are performed by comparing the grayscale value of the image data with a predetermined threshold value. For example, in the case where the object 90 is a green unripe particle, the grayscale value of the red transmission image becomes smaller than that of the object 90 is a qualified product. By utilizing this point, when the grayscale value of the red transmission image is below the threshold, it can be determined that the object 90 is a green unripe particle. However, the determination method of the determination unit 82 can adopt any known determination method. It is also possible to replace the above-mentioned determination of unqualified products with the determination of foreign matter, or to perform the above-mentioned determination of unqualified products and determination of foreign matter.

[0055] like Figure 2 As shown, when the light source control unit 81 turns on any one of the light sources (for example, when the rear red light source 30b is turned on during a scan period with an odd-numbered scan number), the light source is controlled so that there is an on period during which the light source is turned on and an off period during which the light source is turned off. Figure 2 In the example, regarding the red light source 30a on the front side, the period from the start time T0 to the time T1 of the scanning period in the third scanning period is the extinguishing period, the period from the time T1 to the time T2 is the lighting period, and the period from the time T2 to the end time T3 of the scanning period is the extinguishing period. According to such a lighting method, compared with the case where the light source is lit during the entire scanning period, power consumption can be reduced. In addition, the temperature rise of the light source can be suppressed, so the wavelength region of the light emitted from the light source can be suppressed from changing with the temperature rise.

[0056] Furthermore, when lighting any one of the light sources, the light source control unit 81 controls the light source so that the lighting period starts at a time point delayed from the start of the scanning period. Figure 2 In the example of , during the third scanning period, the front red light source 30a is lit in such a manner that the lighting period starts at a time point (i.e., 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 will not be detected by the optical sensor 60a or the optical sensor 60b during the previous scanning period (i.e., the second scanning period). Specifically, assuming that 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 simultaneously with the start of the third scanning period may be mixed as noise into the detection result of the optical sensor 60a or the optical sensor 60b during the second scanning period. According to the present embodiment, such a phenomenon does not occur, so 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.

[0057] According to the above-mentioned sorting machine 10, there are set: a scanning period in which both the red light source 30a on the front side and the red light source 30b on the rear side are lit, and a scanning period in which only one of them is lit. Therefore, the determination unit 82 can distinguish white unripe grains based on the red reflection image (or the reflection image and the transmission image), and can distinguish green unripe grains based on the red reflection transmission image. Therefore, compared with the existing optical sorting machine that uses red light to distinguish only white unripe grains as described in Patent Document 1, the types of defective products that can be distinguished based on red light can be increased (in the above example, green unripe grains). As a result, the overall recognition accuracy can be improved.

[0058] In addition, the green light sources 40a and 40b are all lit during the entire scanning period, so the resolution of the green reflection transmission image obtained by the optical sensors 60a and 60b will not decrease. This is also true for the blue reflection transmission image. On the other hand, due to the above-mentioned lighting method of the red light sources 30a and 30b, the red reflection transmission image, red transmission image and red reflection image obtained by the optical sensors 60a and 60b have a half resolution compared to the green reflection transmission image and the blue reflection transmission image. However, the green unripe grains distinguished based on the red reflection transmission image and the white unripe grains distinguished based on the red transmission image are generally mostly discolored as a whole grain or a large part of the grain. Therefore, the discrimination accuracy will not be greatly reduced due to the half resolution.

[0059] The above embodiment can be modified in various ways. For example, when the red light sources 30a and 30b are turned on during at least one scanning period, they can also be turned on continuously from the start time T0 to the end time T3 of the at least one scanning period. In addition, the green light sources 40a and 40b and the blue light sources 50a and 50b can also be turned on continuously during all scanning periods. Figure 2 The lighting method of the red light sources 30a and 30b shown in the figure adopts the following lighting method, that is, during the scanning period with an odd-numbered scanning number, the front red light source 30a and the rear red light source 30b are lit, and during the scanning period with an even-numbered scanning number, the red light source 30a is not lit and the red light source 30b is lit. Alternatively, the following lighting method may be adopted, that is, during the scanning period with an odd-numbered scanning number, the red light source 30a is lit and the red light source 30b is not lit, and during the scanning period with an even-numbered scanning number, the red light source 30a and the red light source 30b are lit. Alternatively, the following lighting method may be adopted, that is, during the scanning period with an odd-numbered scanning number, the red light source 30a is not lit and the red light source 30b is lit, and during the scanning period with an even-numbered scanning number, the red light source 30a and the red light source 30b are lit.

[0060] B. Second Implementation

[0061] The second embodiment of the present invention is described below. The second embodiment is different from the first embodiment in the lighting method of each light source, and the other points are the same as the first embodiment. The second embodiment is described below only for the points that are different from the first embodiment. Figure 4 : is a timing chart showing the relationship between the scanning period of the optical sensors 60a and 60b and the lighting time point of each light source according to the second embodiment. Figure 4 In the example shown, the lighting pattern can be roughly divided into a scanning period with a scanning number of 3N-2 (N is a natural number), a scanning period with a scanning number of 3N-1, and a scanning period with a scanning number of 3N. That is, in the second embodiment, three lighting patterns are repeated.

[0062] During the scan with a scan number of 3N-2, the same lighting method as during the scan with an odd-numbered scan number in the first embodiment is adopted. During the scan with a scan number of 3N-1, the same lighting method as during the scan with an even-numbered scan number in the first embodiment is adopted. During the scan with a scan number of 3N, the red light source 30a on the front side is not lit, and the red light source 30b on the rear side is lit. That is, during the scan with a scan number of 3N-1 and during the scan with a scan number of 3N, the lit red light source alternates between the front side and the rear side. Thus, during the scan with a scan number of 3N, a red transmission image is obtained by the optical sensor 60a, and a red reflection image is obtained by the optical sensor 60b. Figure 4 In the example shown, the scan numbers are displayed up to 8 in accordance with the first embodiment, but the scan numbers may be set in multiples of 3.

[0063] According to the second embodiment, a front red transmission image, a front red reflection image, a rear red transmission image, and a rear red reflection image can be obtained. This embodiment is effective when it is desired to improve the accuracy of determination based on the red transmission image and / or the red reflection image by using both the front and rear images.

[0064] The second embodiment described above can be modified in various ways. Figure 4 In the case where the lighting mode of each light source during the scan period with scan number 1 is set to A, the lighting mode of each light source during the scan period with scan number 2 is set to B, and the lighting mode of each light source during the scan period with scan number 3 is set to C, Figure 4 In the figure, an example is shown in which A, B, and C are repeated in this order, but the order of appearance of each mode can be set arbitrarily in 6 orders (specifically, A, B, C; A, C, B; B, A, C; B, C, A; C, A, B; C, B, A).

[0065] C. Third Implementation

[0066] The third embodiment of the present invention is described below. The lighting method of each light source in the third embodiment is different from that in the first and second embodiments, and the other points are the same as those in the first and second embodiments. In the following, only the points that are different from the first and second embodiments are described for the third embodiment. Figure 5 : is a timing chart showing the relationship between the scanning period of the optical sensors 60a and 60b and the lighting time point of each light source according to the third embodiment. Figure 5In the example shown, the lighting pattern is roughly divided into a scanning period with a scanning number of 4M-3 (M is a natural number), a scanning period with a scanning number of 4M-2, a scanning period with a scanning number of 4M-1, and a scanning period with a scanning number of 4M. That is, in the third embodiment, four lighting patterns are repeated.

[0067] During the scan period with the scan number 4M-3, the same lighting method as that during the scan period with the scan number 3N-2 in the second embodiment is adopted. During the scan period with the scan number 4M-2, the same lighting method as that during the scan period with the scan number 3N-1 in the second embodiment is adopted. During the scan period with the scan number 4M-1, the same lighting method as that during the scan period with the scan number 4M-3 in the third embodiment is adopted. During the scan period with the scan number 4M, the same lighting method as that during the scan period with the scan number 3N in the second embodiment is adopted. That is, in the third embodiment, the type of image obtained is the same as that in the second embodiment, but the resolution of the front red reflection transmission image and the rear red reflection transmission image is doubled compared to the second embodiment. This embodiment is effective when it is desired to ensure a certain degree of resolution of the red reflection transmission image.

[0068] The third embodiment described above can be modified in various ways. For example, similarly to the contents described above with respect to the modification of the second embodiment, Figure 5 The lighting patterns shown can be set in any order of appearance.

[0069] D. Fourth Implementation

[0070] Hereinafter, regarding the fourth embodiment of the present invention, only the points different from the first embodiment will be described. Figure 8 1 is a timing chart showing the relationship between the scanning period of the optical sensors 60a and 60b and the lighting time of each light source according to the fourth embodiment. Figure 8 As shown, the lighting method of each light source is Figure 2 The lighting method of the first embodiment shown is the same.

[0071] In this embodiment, the determination unit 82 uses the green images of the front and rear sides and the blue images of the front and rear sides to determine foreign matter and / or defective products. For example, when the object 90 is brown rice, these green images and blue images can be used to determine whether the object 90 is, for example, stink bug, spotted rice, unripe rice, or dead rice.

[0072] Furthermore, in addition to using the above-mentioned four red images directly obtained by the optical sensors 60a and 60b, the determination unit 82 also uses the red image obtained by calculation to determine foreign matter and / or defective products. Specifically, with respect to the red image on the front side, the grayscale value of the transmission image is calculated by subtracting the grayscale value of the reflection image from the grayscale value of the reflection transmission image. This calculation is performed between corresponding pixels. In addition, the reflection transmission image is obtained during a scan with an odd-numbered scan number, and the transmission image is obtained during a scan with an even-numbered scan number, so the calculation (here, a subtraction operation) is performed between the images obtained during two adjacent scans. Therefore, the obtained image is processed as an image obtained during the two adjacent scans. For example, by performing a subtraction operation between the reflection transmission image obtained during the scan of No. 1 and the reflection image obtained during the scan of No. 2, the image obtained during the scan of No. 1 is obtained. Figure 3 The areas marked with "1" and the areas marked with "2" are the transmitted images. Similarly, regarding the red image on the rear side, the grayscale value of the reflected image is calculated by subtracting the grayscale value of the transmitted image from the grayscale value of the reflected transmitted image. Regarding the red image, the determination unit 82 uses the transmitted image of the front side and the reflected image of the rear side obtained by such calculation, in addition to the above-mentioned four red images directly obtained by the optical sensors 60a and 60b, to determine foreign matter and / or defective products. Figure 8 In FIG. 1 , images directly acquired by the optical sensors 60 a and 60 b and images acquired by calculation according to the above-mentioned method are shown at a glance for each scanning period.

[0073] For example, when the object 90 is brown rice, the reflected and transmitted images of the front and rear sides can be used to determine whether the object 90 is green immature rice. In addition, based on the reflected and transmitted images of the front side and the reflected and transmitted images of the rear side, it can be determined whether the object 90 is white immature rice. Not limited to the above example, foreign matter and / or defective products can also be determined by comprehensively evaluating the red image and other color images (green image and / or blue image).

[0074] According to the above-mentioned sorting machine 10, regarding the red image, the determination unit 82 can use the images obtained by calculation (the transmission image of the front side and the reflection image of the rear side) in addition to the images directly obtained by the optical sensors 60a and 60b (the reflected transmission images of the front and rear sides, the reflected image of the front side, and the transmission image of the rear side) to determine foreign matter and / or defective products. That is, for both the front side and the rear side, three types of images (reflected transmission image, transmission image, and reflection image) can be used to determine foreign matter and / or defective products. Therefore, compared with the case of using only one of the reflected transmission image, the transmission image, and the reflection image, the discrimination accuracy can be improved. For example, if the case of determining white unripe grains is considered, the transmission image obtained for the white unripe grains has a relatively small grayscale value (dark grayscale value), so the white unripe grains can also be determined using only the transmission image. However, when irradiating light to a plurality of overlapping objects 90, even if the plurality of objects 90 are qualified products, a transmission image with a relatively small grayscale value is obtained, so the qualified products may be judged as white unripe grains. On the other hand, the reflection image obtained for the white unripe grains has a relatively large grayscale value (bright grayscale value), and when irradiating light to a plurality of overlapping objects 90, a transmission image with a relatively small grayscale value is obtained, so if both the transmission image and the reflection image are used (that is, if it is determined whether both the threshold conditions set for the reflection image and the threshold conditions set for the transmission image are satisfied), the white unripe grains can be judged with high accuracy.

[0075] Furthermore, the transmission image on the front side and the reflection image on the rear side are obtained by calculation. In other words, Figure 8 Since the scanning period of the lighting pattern in which the red light sources 30a and 30b are lit is not set additionally to the lighting pattern shown, the resolution of the image directly obtained by the optical sensors 60a and 60b is not reduced due to the acquisition of the front transmission image and the rear reflection image.

[0076] Furthermore, in this optical sorting machine, depending on the orientation of the object 90 when irradiated with light, there is a situation where the characteristics of foreign matter and / or defective products appear only in one of the images obtained on the front side and the images obtained on the rear side. However, according to the sorting machine 10, reflected and transmitted images, transmitted images, and reflected images are obtained on both the front and rear sides, so even in such a situation, a higher recognition accuracy can be obtained.

[0077] The above-mentioned embodiment can be modified in various ways. For example, Figure 8The lighting pattern of the red light source 30a and the red light source 30b shown in the figure is adopted, and during the scanning with odd-numbered scanning numbers, the lighting pattern in which the red light source 30a on the front side and the red light source 30b on the rear side are lit, and during the scanning with even-numbered scanning numbers, the lighting pattern in which the red light source 30a is not lit and the red light source 30b is lit is adopted. Alternatively, the lighting pattern in which the red light source 30a is lit and the red light source 30b is not lit may be adopted during the scanning with odd-numbered scanning numbers, and the lighting pattern in which the red light source 30a and the red light source 30b are lit may be adopted during the scanning with even-numbered scanning numbers. Alternatively, the lighting pattern in which the red light source 30a is not lit and the red light source 30b is lit may be adopted during the scanning with odd-numbered scanning numbers, and the lighting pattern in which the red light source 30a and the red light source 30b are lit may be adopted during the scanning with even-numbered scanning numbers. In any of these cases, a reflected image or a transmitted image that is not directly acquired by the optical sensors 60 a and 60 b can be acquired through calculation and used in the determination of the determination unit 82 .

[0078] E. Fifth Implementation

[0079] The fifth embodiment of the present invention is described below. The lighting mode of the red light sources 30a and 30b in the fifth embodiment is different from that in the fourth embodiment. In addition, due to this difference, the reflected and transmitted images, the transmitted images, and the reflected images are obtained by a method different from that in the fourth embodiment. In the following, only the differences from the fourth embodiment are described for the fifth embodiment. Fig. 9 1 is a timing chart showing the relationship between the scanning period of the optical sensors 60a and 60b and the lighting timing of each light source according to the fifth embodiment.

[0080] like Fig. 9 As shown, the red light source 30a on the front side is lit for a predetermined time only during the scanning period with an odd-numbered scanning number, and is not lit at all during the scanning period with an even-numbered scanning number. On the other hand, the red light source 30b on the rear side is lit for a predetermined time only 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 sources 30a and 30b are lit in such a manner that there are scanning periods in which only one of the red light sources 30a and 30b is lit, and scanning periods in which only the other is lit.

[0081] According to such a lighting method, regarding red light, the optical sensor 60a on the front side detects the reflected red light 31a during the scanning period with an odd-numbered scanning number, and detects the transmitted red light 31b during the scanning period with an even-numbered scanning number. In other words, the optical sensor 60a obtains a red reflected image and a red transmitted image. In addition, regarding red light, the optical sensor 60b on the rear side detects the transmitted red light 31a during the scanning period with an odd-numbered scanning number, and detects the reflected red light 31b during the scanning period with an even-numbered scanning number. In other words, the optical sensor 60b obtains a red transmitted image and a red reflected image.

[0082] Moreover, regarding the red image on the front side, the grayscale value of the reflected and transmitted image is calculated by adding the grayscale value of the reflected image and the grayscale value of the transmitted image. This operation is performed between corresponding pixels. In addition, the reflected image is obtained during a scan with an odd scan number, and the transmitted image is obtained during a scan with an even scan number, so this operation (here, the addition operation) is performed between the images obtained during two adjacent scans. Therefore, the obtained image is processed as an image obtained during the two adjacent scans. For example, by performing an addition operation between the reflected image obtained during the scan No. 1 and the transmitted image obtained during the scan No. 2, the image obtained during the scan No. 1 is obtained. Figure 3 The reflected and transmitted images of the area marked with "1" and the area marked with "2" in the figure. Similarly, for the red image on the rear side, the grayscale value of the reflected and transmitted image is calculated by adding the grayscale value of the transmitted image and the grayscale value of the reflected image. Fig. 9 In FIG. 1 , the reflection image and the transmission image directly obtained by the optical sensors 60 a and 60 b and the reflection transmission image obtained by calculation according to the above-mentioned method are shown at a glance in each scanning period.

[0083] Regarding the red image, in addition to using the reflected image and transmitted image of the front side and the transmitted image and reflected image of the rear side directly obtained through the optical sensors 60a and 60b, the judgment unit 82 also uses the reflected and transmitted images of the front and rear sides obtained by calculation as described above to judge foreign matter and / or defective products.

[0084] In the fifth embodiment, the determination unit 82 can also use three images (reflection transmission image, transmission image, and reflection image) for both the front side and the rear side to determine foreign matter and / or defective products, as in the fourth embodiment. Therefore, the same effect as in the fourth embodiment is obtained.

[0085] The fifth embodiment described above can be modified in various ways. For example, Fig. 9The lighting pattern of the red light source 30a and the red light source 30b shown in FIG. 1 is used, and the lighting pattern of the front red light source 30a not lighting and the rear red light source 30b lighting is used during the scanning period with an odd number of scanning numbers, and the lighting pattern of the red light source 30a lighting and the red light source 30b not lighting is used during the scanning period with an even number of scanning numbers. In this case, the reflection transmission image not directly obtained by the optical sensors 60a and 60b can also be obtained by calculation and used in the determination of the determination unit 82.

[0086] Several embodiments of the present invention have been described above, but the embodiments of the invention described above are intended to facilitate the 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 its equivalents are included in the present invention. In addition, the various structural elements described in the technical solution and the specification can be arbitrarily combined or omitted within the scope of at least a part of the above-mentioned problems or at least a part of the effects. For example, Figure 2 , 4 The lighting modes shown in 5 are merely examples. For the first to third embodiments, as long as there are scanning periods in which both the front red light source 30a and the rear red light source 30b are lit and scanning periods in which only one of them is lit, it is possible to transform into a scanning period including any other lighting mode. Moreover, in the modified forms of the first to third embodiments, as long as there are scanning periods in which both the front red light source 30a and the rear red light source 30b are lit and scanning periods in which only one of them is lit, the occurrence frequency of each of the plurality of lighting modes can be arbitrarily set according to the resolution required for each image obtained. For example, in the first embodiment, the number of scanning periods in which both the front red light source 30a and the rear red light source 30b are lit may be greater than the number of scanning periods in which only one of them is lit, or vice versa. Furthermore, as a mechanism for transferring the object 90, a conveyor may be used instead of the chute 73. Furthermore, a red reflection image and / or a transmission image and a red reflection transmission image may be used to distinguish any foreign matter and / or defective products of any granular material. For example, when the object 90 is coffee beans, yellow beans that are defective may be identified based on the red reflection image.

[0087] Furthermore, the wavelengths of the red lights 31a and 31b emitted by the red light sources 30a and 30b can be appropriately set based on the type of the object 90 and the type of foreign matter and / or defective product to be identified. For example, when the object 90 is brown rice, Figure 6In the spectral reflectance distribution for brown rice shown in FIG. 1 , if light sources emitting red light 31a and 31b having peak wavelengths of 645 nm or more and 675 nm or less are used as red light sources 30a and 30b, green and unripe grains can be distinguished with high accuracy based on the obtained red reflection image. Alternatively, in the case where the object 90 is coffee beans, Figure 7 As shown in the spectral reflectance distribution for coffee beans, if light sources emitting red light 31a, 31b having a peak wavelength of not less than 665nm and not more than 695nm are used as red light sources 30a, 30b, extremely light yellow grains, light yellow grains, and dark yellow grains can be distinguished with high accuracy based on the obtained red reflection image.

[0088] Furthermore, the red light sources 30a and 30b are not limited to LEDs, and any type of light source can be used. For example, the red light sources 30a and 30b can also be CCFLs (cold cathode fluorescent lamps). In this case, a CCFL having an appropriate peak wavelength (for example, if the object 90 is coffee beans, a peak wavelength of 665 nm or more and 695 nm or less) can be selected according to the type of the object 90 and the type of foreign matter and / or defective products to be identified.

[0089] Furthermore, the red light source 30a and the red light source 30b are Figure 8 or Fig. 9 In the lighting mode shown in FIG. 1 , when lighting is performed in at least one scanning period, the at least one scanning period may be illuminated from the start time T0 to the end time T3 (see FIG. 1 ). Figure 8 ) are continuously lit. In addition, the green light source 40a, the green light source 40b, the blue light source 50a and the blue light source 50b may also be continuously lit during the entire scanning period.

[0090] and, Figure 8 as well as Fig. 9 The lighting method shown is only an example, and the fourth and fifth embodiments can be modified to include additional Figure 8 or Fig. 9 The scanning period of any other lighting mode not shown in the figure can be set. Furthermore, the frequency of occurrence of each of the plurality of lighting modes can be set arbitrarily according to the resolution required for each image obtained. For example, in the fourth embodiment, the number of scanning periods in which both the front red light source 30a and the rear red light source 30b are lit can be greater than the number of scanning periods in which only one of them is lit, or vice versa.

[0091] Furthermore, in the fourth and fifth embodiments, one of the optical sensors 60a and 60b may be omitted. In addition, as a mechanism for transferring the object 90, a conveyor may be used instead of the chute 73. In addition, instead of performing the above-mentioned operation (subtraction or addition) on the digital grayscale value, the above-mentioned operation may be performed on the analog signal. In addition, for use by the determination unit 82, instead of the red image, the above-mentioned operation (subtraction or addition) may be performed on an image obtained based on light of any wavelength (for example, green light or blue light, or invisible light). In addition, it is not limited to rice grains, and any foreign matter and / or defective products of any granular material may be identified.

[0092] The red light source 30a can be understood as an example of the “first light source” of the present invention or can be understood as an example of the “second light source” of the present invention. Similarly, the red light source 30b can be understood as an example of the “second light source” of the present invention or can be understood as an example of the “first light source”. Furthermore, the optical sensor 60a can be understood as an example of the “first optical sensor” of the present invention or can be understood as an example of the “second optical sensor” of the present invention. Similarly, the optical sensor 60b can be understood as an example of the “second optical sensor” of the present invention or can be understood as an example of the “first optical sensor” of the present invention. Furthermore, Figure 8 or Fig. 9 The illustrated scanning period with an odd scanning number can be understood as an example of the "first scanning period" of the present invention or can be understood as an example of the "second scanning period" of the present invention. Figure 8 or Fig. 9 The illustrated scanning period having an even-numbered scanning number can be understood as an example of the “second scanning period” of the present invention or can be understood as an example of the “first scanning period” of the present invention.

[0093] Description of Reference Numerals

[0094] 10...optical sorting machine; 20...optical detection unit; 30a, 30b...red light source; 31a, 31b...red light (reflects red light, transmits red light); 40a, 40b...green light source; 41a, 41b...green light (reflects green light, transmits green light); 50a, 50b...blue light source; 51a, 51b...blue light (reflects blue light, transmits blue light); 60a, 60b...optical sensor; 71...storage box; 72...feeder; 73...chute; 74...qualified product discharge slot; 75...defective product discharge slot; 76...injector; 77...air; 80...control device; 81...light source control unit; 82...judgment unit; 90...sorting object.

Claims

1. An optical sorting machine, characterized in that: have A first light source configured to emit first light toward a plurality of objects to be sorted being transferred, and arranged on a first side of a transfer path of the plurality of objects to be sorted; A second light source is configured to emit a second light having the same wavelength as the first light toward the plurality of objects to be sorted being transferred, and is disposed on a second side opposite to the first side; an optical sensor disposed on at least one of the first side and the second side, configured to detect light associated with one of the plurality of sorting objects being transferred during a plurality of scanning periods including a first scanning period and a second scanning period; a determination unit configured to determine whether the one of the sorting objects is a foreign object and / or a defective product based on the signal obtained by the optical sensor; as well as a light source control unit configured to control the first light source and the second light source, The light source control unit is configured to control the first light source and the second light source in a manner of lighting in a first lighting mode during the first scan, wherein the first lighting mode is a lighting mode arbitrarily selected from a lighting mode in which the first light source and the second light source are lit, a lighting mode in which only one of the first light source and the second light source is lit, and a lighting mode in which only the other of the first light source and the second light source is lit; and The light source control unit is configured to control the first light source and the second light source in a manner of lighting up in a second lighting mode during the second scanning period, wherein the second lighting mode is a lighting mode other than the first lighting mode selected arbitrarily from the lighting mode in which the first light source and the second light source are lit, the lighting mode in which only one of the first light source and the second light source is lit, and the lighting mode in which only the other of the first light source and the second light source is lit, The first light and the second light are red light, The optical sensor comprises: a first optical sensor, arranged on the first side; and a second optical sensor, disposed on the second side, In the first lighting mode, the first light source and the second light source are lit, and in the second lighting mode, only the first light source of the first light source and the second light source is lit, The determination unit is configured to determine foreign matter and / or defective products based on the reflected and transmitted images associated with the red light respectively obtained by the first optical sensor and the second optical sensor during the first scan, the reflected image associated with the red light obtained by the first optical sensor during the second scan, and the transmitted image associated with the red light obtained by the second optical sensor during the second scan.

2. An optical sorting machine, characterized in that: have A first light source configured to emit first light toward a plurality of objects to be sorted being transferred, and arranged on a first side of a transfer path of the plurality of objects to be sorted; A second light source is configured to emit a second light having the same wavelength as the first light toward the plurality of objects to be sorted being transferred, and is disposed on a second side opposite to the first side; an optical sensor disposed on at least one of the first side and the second side, configured to detect light associated with one of the plurality of sorting objects being transferred during a plurality of scanning periods including a first scanning period and a second scanning period; a determination unit configured to determine whether the one of the sorting objects is a foreign object and / or a defective product based on the signal obtained by the optical sensor; as well as a light source control unit configured to control the first light source and the second light source, The light source control unit is configured to control the first light source and the second light source in a manner of lighting in a first lighting mode during the first scan, wherein the first lighting mode is a lighting mode arbitrarily selected from a lighting mode in which the first light source and the second light source are lit, a lighting mode in which only one of the first light source and the second light source is lit, and a lighting mode in which only the other of the first light source and the second light source is lit; and The light source control unit is configured to control the first light source and the second light source in a manner of lighting up in a second lighting mode during the second scanning period, wherein the second lighting mode is a lighting mode other than the first lighting mode selected arbitrarily from the lighting mode in which the first light source and the second light source are lit, the lighting mode in which only one of the first light source and the second light source is lit, and the lighting mode in which only the other of the first light source and the second light source is lit, The first light and the second light are red light, The optical sensor comprises: a first optical sensor, arranged on the first side; and a second optical sensor, disposed on the second side, In the first lighting mode, the first light source and the second light source are lit, and in the second lighting mode, only the first light source of the first light source and the second light source is lit, The light source control unit is configured to control the first light source and the second light source in such a manner that during the first scanning period, there are lighting periods and off periods for the first light source and the second light source respectively, and during the second scanning period, there are the lighting periods and off periods for the first light source respectively.

3. The optical sorting machine according to claim 2, characterized in that: The light source control unit is configured to control the first light source and the second light source in the following manner, that is, during the first scanning period, the lighting period for each of the first light source and the second light source starts at a time point delayed than the start of the first scanning period, and during the second scanning period, the lighting period for the first light source starts at a time point delayed than the start of the second scanning period.

4. An optical sorting machine, characterized in that: have A first light source configured to emit first light toward a plurality of objects to be sorted being transferred, and arranged on a first side of a transfer path of the plurality of objects to be sorted; A second light source is configured to emit a second light having the same wavelength as the first light toward the plurality of objects to be sorted being transferred, and is disposed on a second side opposite to the first side; an optical sensor disposed on at least one of the first side and the second side, configured to detect light associated with one of the plurality of sorting objects being transferred during a plurality of scanning periods including a first scanning period and a second scanning period; a determination unit configured to determine whether the one of the sorting objects is a foreign object and / or a defective product based on the signal obtained by the optical sensor; as well as a light source control unit configured to control the first light source and the second light source, The light source control unit is configured to control the first light source and the second light source in a manner of lighting in a first lighting mode during the first scan, wherein the first lighting mode is a lighting mode arbitrarily selected from a lighting mode in which the first light source and the second light source are lit, a lighting mode in which only one of the first light source and the second light source is lit, and a lighting mode in which only the other of the first light source and the second light source is lit; and The light source control unit is configured to control the first light source and the second light source in a manner of lighting up in a second lighting mode during the second scanning period, wherein the second lighting mode is a lighting mode other than the first lighting mode selected arbitrarily from the lighting mode in which the first light source and the second light source are lit, the lighting mode in which only one of the first light source and the second light source is lit, and the lighting mode in which only the other of the first light source and the second light source is lit, The optical sensor is configured to detect two types of light, namely, reflected light, transmitted light, and reflected transmitted light, based on the first lighting mode and the second lighting mode, wherein the reflected light is light reflected by the sorting object, the transmitted light is light transmitted through the sorting object, and the reflected transmitted light is light synthesized from the reflected light and the transmitted light. The determination unit is configured to determine the foreign matter and / or the defective product based on a reflected image, a transmitted image, two images in the reflected transmitted image corresponding to the two types of light detected by the optical sensor, and a remaining image obtained by calculating the detection results of the two types of light, wherein the reflected image is an image represented by the reflected light, the transmitted image is an image represented by the transmitted light, and the reflected transmitted image is an image represented by the reflected transmitted light.

5. The optical sorting machine according to claim 4, characterized in that: In the first lighting mode, the first light source and the second light source are lit, In the second lighting mode, only the first light source of the first light source and the second light source is lit. The optical sensor includes a first optical sensor disposed on the first side, The first optical sensor is configured to detect the reflected transmitted light based on the first lighting pattern during the first scanning period, and detect the reflected light based on the second lighting pattern during the second scanning period. The determination unit is configured to determine the foreign matter and / or the defective product based at least on the reflected transmission image and the reflected image corresponding to the reflected transmitted light and the reflected light detected by the first optical sensor, and the transmission image obtained by subtracting the detection result of the reflected light from the detection result of the reflected transmitted light.

6. The optical sorting machine according to claim 4 or 5, characterized in that: In the first lighting mode, the first light source and the second light source are lit, In the second lighting mode, only the first light source of the first light source and the second light source is lit. The optical sensor includes a second optical sensor disposed on the second side, The second optical sensor is configured to detect the reflected transmitted light based on the first lighting pattern during the first scanning period, and detect the transmitted light based on the second lighting pattern during the second scanning period. The determination unit is configured to determine the foreign matter and / or defective product based at least on the reflected transmitted light and the transmitted light corresponding to the reflected transmitted light and the transmitted light detected by the second optical sensor, and the reflected image obtained by subtracting the detection result of the transmitted light from the detection result of the reflected transmitted light.

7. The optical sorting machine according to claim 4, characterized in that: In the first lighting mode, only the first light source of the first light source and the second light source is lit. In the second lighting mode, only the second light source of the first light source and the second light source is lit. The optical sensor includes a first optical sensor disposed on the first side, The first optical sensor is configured to detect the reflected light based on the first lighting pattern during the first scanning period, and to detect the transmitted light based on the second lighting pattern during the second scanning period. The determination unit is configured to determine the foreign matter and / or defective product based at least on the reflected image and the transmitted image corresponding to the reflected light and the transmitted light detected by the first optical sensor, and the reflected transmitted image obtained by adding the detection result of the reflected light and the detection result of the transmitted light.

8. The optical sorting machine according to claim 7, characterized in that: The optical sensor includes a second optical sensor disposed on the second side, The second optical sensor is configured to detect the transmitted light based on the first lighting pattern during the first scanning period, and detect the reflected light based on the second lighting pattern during the second scanning period. The determination unit is configured to determine the foreign matter and / or defective product based at least on the transmitted image and the reflected image corresponding to the transmitted light and the reflected light detected by the second optical sensor, and the reflected transmitted image obtained by adding the detection result of the transmitted light and the detection result of the reflected light.

9. The optical sorting machine according to any one of claims 4, 5, 7 and 8, characterized in that: The first light and the second light are red light.

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