JP2014044070A - Food examination apparatus - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a food examination apparatus that is safe to humans present on a production line, can be handled by anyone and can discern not only the presence or absence of any foreign matter in the food examined but even its position.SOLUTION: A food examination apparatus comprises: an area light source L that irradiates a food, which is the object of examination, with first examination light having its center wavelength in a near infrared region and second examination light having another center wavelength different from the first examination light in the near infrared region; an imaging mechanism 2 that picks up images of the food with light resulting from transmission of the first examination light and the second examination light by the food and outputs a first image picked up on the basis of the first examination light and a second image picked up on the basis of the second examination light; and a differential image generator 5 that generates a differential image of the first image and the second image.

Description

  The present invention relates to a food inspection apparatus for detecting foreign substances contained in food to be inspected by non-contact and non-destructive methods.

  For example, food inspection apparatuses using X-rays are used in food factories and the like to maintain food safety. For example, Patent Document 1 and the like indicate that the presence or absence of a foreign substance contained in food is checked based on an image of the food imaged by X-rays.

  By the way, when food is inspected using X-rays, an X-ray management room or a radiologist must be stationed in order to safely handle X-rays in the production line. For this reason, when a food inspection apparatus using X-rays is introduced into the production line, a corresponding production cost is generated.

  As a food inspection apparatus in which such a problem does not occur, for example, as shown in Patent Document 2, there is an apparatus using near infrared light that has almost no adverse effect on the human body and can be handled by ordinary people.

  The food inspection apparatus using near-infrared light described in Patent Document 2 irradiates food with near-infrared light obliquely from above, and has a detection unit that provides diffuse reflected light generated in the food directly above the food. It is configured to detect. And this food inspection apparatus is comprised so that the presence or absence of the foreign material contained in food may be detected based on the spectrum of the diffuse reflection light measured in the said detection part.

  However, in the food inspection apparatus disclosed in Patent Document 2, since the inspection is performed based on the spectrum of the diffuse reflected light reflected from the near-infrared light in the food, the presence or absence of foreign matters contained in the food can be detected. It is impossible to detect where the foreign substance is present in the food.

  For this reason, for example, in order to remove a foreign substance from food, a human must carefully re-inspect the position of the foreign substance. The re-inspection work is not commensurate with the unit price of food or the manufacturing cost of food, and food that is actually judged to have foreign substances can be disposed of even if it can be reused by removing foreign substances. The food is wasted.

JP 2002-243665 A JP 2009-168748 A

  The present invention has been made in view of the above-described problems, is safe for humans on the production line, can be handled by anyone, and includes not only the presence or absence of foreign matter contained in food, but also its position. It aims at providing the food inspection device which can be grasped.

  That is, the food inspection apparatus of the present invention inspects the first inspection light having a center wavelength in the near infrared region and the second inspection light having a center wavelength different from the first inspection light in the near infrared region. The surface light source that irradiates the target food, and the first inspection light and the second inspection light are captured by the light transmitted through the food, and the first image is captured based on the first inspection light. And an image pickup mechanism that outputs a second image picked up based on the second inspection light, and a difference image generation unit that generates a difference image between the first image and the second image. .

  If it is such, since the 1st inspection light and 2nd inspection light which have the center wavelength of a near-infrared area are irradiated with respect to the foodstuff which is inspection object, a part of inspection light is applied to foodstuff and a foreign material The absorbed result can be imaged by the imaging mechanism with light transmitted through the food. In addition, since the difference image generation unit generates a difference image between the first image captured based on the first inspection light and the second image captured based on the second inspection light, the food of each central wavelength and It is possible to sharpen the difference in the absorption rate of the foreign matter, and to obtain the position of the foreign matter in the food from the difference image. Furthermore, by referring to the difference image, it is possible to know not only the presence / absence of a foreign substance but also the position of the foreign substance in the food.

  In addition, because near-infrared light is used as each inspection light, there is no need to set up a special management area for safety or to have a special qualification holder for food inspection. The cost can be reduced.

  Moreover, since the light in the near infrared region is used as the first inspection light and the second inspection light, it is possible to grasp the position of the bone in the food by sharpening the difference in the light absorption rate. There is.

  The amount of light that passes through the food to be inspected can be increased as much as possible, and the difference between the food and foreign matter in the difference image becomes clearer by making the first image and the second image to be captured brighter. In order to do so, the surface light source may be formed by a plurality of SLDs and arranged so that the optical axis of each SLD is concentrated on the food. If it is said SLD, it will be easy to increase the quantity of the light which permeate | transmits foodstuffs, since directivity is good and polarization is uniform.

  In order to increase the amount of light by concentrating the first inspection light and the second inspection light irradiated to the food, and to make it easier to clarify the difference between the food and the foreign matter by changing the transmission result due to the difference in the irradiation angle, The SLDs may be arranged in a cross shape when viewed from the food side, and the SLDs may be arranged in curved surfaces having different curvatures in each arrangement direction.

  In order to be able to capture the first image and the second image without using a complicated optical system, and to realize a food inspection apparatus with a simple configuration, the surface light source includes the first inspection light and the first inspection light. The second inspection light is configured to be alternately turned on every predetermined lighting cycle, and the imaging mechanism is configured to output the first image and the second image in synchronization with the predetermined lighting cycle. It only has to be. If it is such, it can obtain the 1st image and 2nd image from which the wavelength of the light imaged by the process of software differs, without splitting 1st inspection light and 2nd inspection light by a half mirror etc. it can.

  In order to make it difficult for the scattered light from the food to enter the imaging mechanism and to allow only the transmitted light to be incident so that a difference image easily shows a difference between the food and the foreign matter, the food and the imaging mechanism As long as the distance between the food and the surface light source is at least a predetermined multiple.

  As an example of the combination of the first inspection light and the second inspection light, the difference in absorption rate can easily appear in the transmitted light, the difference between the food and the foreign matter can be clarified, and the position of the foreign matter can be clearly grasped. The center wavelength of light is 680 nm, and the center wavelength of the second inspection light is 830 nm.

  An example of a configuration for making it easy for the imaging mechanism to capture only transmitted light that has passed through the food without adding a special configuration, and to easily show the difference between the food and the foreign object, is between the food and the imaging mechanism. In which the separation distance is set to 10 times or more the width dimension of the food.

  As a specific configuration example for making it easy to capture only transmitted light from food without increasing the separation distance between the food and the imaging mechanism, a first aperture disposed between the food and the imaging mechanism And a second aperture disposed at a position spaced apart from the first aperture by a predetermined distance between the food and the imaging mechanism.

  As another configuration example for compactly configuring the entire apparatus without increasing the separation distance between the food and the bill group mechanism, a rod for guiding light is inserted between the food and the imaging mechanism. If it is what.

  As described above, according to the present invention, light in the near-infrared region is used as inspection light, so there is almost no adverse effect on the human body, a management area is provided for safety, or a special administrator is assigned. There is no need to do. Therefore, since inspection can be performed by a general worker, cost in food inspection can be reduced. Moreover, the difference of the absorption factor with respect to the foodstuff and a foreign material of the 1st test | inspection light and 2nd test | inspection light from which a center wavelength differs can be caught by imaging transmitted light. Furthermore, the position of the foreign matter in the food can be grasped by sharpening the difference in the absorption rate of the food and foreign matter appearing in the first image and the second image by the difference image generation unit.

The external view of the food inspection apparatus which concerns on one Embodiment of this invention. The top view shown about arrangement | positioning of SLD in the embodiment. The side view shown about attachment of SLD in the embodiment. The functional block diagram of the food inspection apparatus in the embodiment.

  An embodiment of the present invention will be described with reference to the drawings.

  The food inspection apparatus 100 according to the present embodiment is used, for example, in a food factory or the like to check whether or not foreign matter is contained in food. Here, the foreign matter is attached to food, or it is derived from food such as bone fragments contained in the meat part that is an edible part when it is targeted for hair or metal pieces contained in the food. In some cases, these substances are targeted.

  As shown in the perspective view of FIG. 1, the food inspection apparatus 100 has a substantially rectangular parallelepiped shape, and has a food placement portion 4 on which food is placed on an upper surface, and the food placement portion 4 from the inside. A light source unit L for irradiating near-infrared light with respect to the food placing part 4 so as to be movable in the vertical direction with respect to the food placing part 4. The imaging mechanism 2 that captures an image with L light, the imaging position changing mechanism 3 that changes the imaging position by moving the imaging mechanism 2 in the vertical direction, the software function of each unit, and the imaging mechanism 2 A difference image generation unit 5 that generates a difference image from a captured image, and a computer C that functions as a foreign object detection unit 6 that detects a foreign object based on the difference image generated by the difference image generation unit 5 It is. That is, the food inspection apparatus 100 of the present embodiment does not use light such as X-rays but uses near infrared light, and therefore does not require a special management area or a dedicated manager. It is. Here, near infrared light refers to light having a wavelength in the range of 750 nm to 1400 nm, for example.

  Each part will be described in detail.

  The light source unit L is formed with a passage window for allowing light to pass through the upper surface of a substantially rectangular parallelepiped casing, and the outer surface of the passage window is used as the food placing portion 4. Inside the housing is housed a surface light source L provided with a number of SLDs 11 on a mounting plate having two substantially semi-cylindrical cross sections crossing each other as shown in FIGS. Further, the light source unit L includes a light source control unit 13 that controls lighting of each SLD 11 described later.

  The surface light source L has a first inspection light having a central wavelength in the near-infrared region and a food that is an inspection target for a second inspection light having a central wavelength different from the first inspection light in the near-infrared region. Is irradiated.

  More specifically, the surface light source L is composed of two types of SLDs 11, a first SLD 11 that emits first inspection light and a second SLD 11 that emits second inspection light, and adjacent SLDs 11 are of different types. It arrange | positions so that it may become SLD11. In the present embodiment, the first SLD 11 that outputs the first inspection light outputs near-infrared light having a center wavelength of 680 nm, and the second SLD 11 that outputs the second inspection light has near-infrared light having the center wavelength of 830 nm. It outputs light.

  Details of the arrangement of each SLD 11 will be described with reference to FIGS.

  As shown in FIG. 2, the plurality of SLDs 11 are arranged in a cross shape when viewed from the food side, and the SLDs 11 are arranged on a mounting plate 12 having curved surfaces with different curvatures in each arrangement direction. . More specifically, the curvature of the curved surface in which the SLD 11 is arranged in the horizontal direction in FIG. 2 is configured to be larger than the curvature of the curved surface in which the SLD 11 is arranged in the vertical direction.

  Further, as shown in FIG. 3, the optical axes of the respective SLDs 11 are arranged so as to concentrate on the central part of the food placing unit 4, that is, on the placed food.

  The light source control unit 13 realizes its function by executing a program stored in the memory in the above-described computer C provided with a memory, a CPU, an A / D, a D / A converter, and the like. As shown in the functional block diagram of FIG. 4, the SLD 11 that irradiates the first inspection light and the SLD 11 that irradiates the second inspection light are alternately turned on at predetermined intervals. The timing at which each inspection light is irradiated is used for image output in the imaging mechanism 2 described later.

  The image pickup mechanism 2 picks up an image with light transmitted through the food out of the near-infrared light irradiated to the food from the surface mouth source. More specifically, the imaging mechanism 2 images the food by the light transmitted through the food by the first inspection light and the second inspection light, and the first image captured based on the first inspection light. And the 2nd image imaged based on the said 2nd test | inspection light is output so that it may output.

  More specifically, as shown in FIG. 4, the imaging mechanism 2 includes a camera 21 provided to face the food placing unit 4, and a first image and an image captured by the camera 21. It is comprised from the captured image output part 22 which outputs a 2nd image.

  The vertical position of the camera 21 is appropriately set by the imaging position changing mechanism 3 so that the distance from the food is 10 times or more the width of the food. By doing in this way, the amount of light that directly enters the camera 21 without passing through the food out of the near-infrared light emitted from the surface light source L is reduced, and a captured image of only substantially transmitted light is obtained. Can do. With such a captured image, the brightness of the background can be reduced, and amplification or the like can be performed to easily increase the difference in brightness between the food and the foreign object.

  The captured image output unit 22 realizes its function by executing a program stored in the memory of the computer C. The captured image output unit 22 receives the first inspection light and the second inspection light from the light source control unit. Obtaining the irradiation timing, providing information about which inspection light is used to capture the currently captured image based on the irradiation timing, and outputting the first image and the second image It is.

  The difference image generation unit 5 shown in FIG. 4 outputs a difference image based on the brightness difference between the first image and the second image. For example, in the present embodiment, the transmittance of the first inspection light and the second inspection light is almost the same for the edible portion of the food, so that the edible portion is output with almost no brightness in the difference image. The On the other hand, since the brightness of the first inspection light and the second inspection light is large in the foreign matter portion, the foreign matter portion is output as, for example, a bright portion in the difference image.

  The foreign object detector 6 shown in FIG. 4 detects the presence or absence of a foreign object based on the difference image. Here, the foreign matter detection unit 6 is configured to determine that there is a foreign matter at the position of the difference image if there is a portion whose brightness is a predetermined value or more. That is, the foreign matter detection unit 6 is configured to determine not only whether there is a foreign matter in the food but also where the foreign matter is. Therefore, for example, when bone fragments are mixed in an edible portion such as meat, the bone fragments can be removed and reprocessed.

  As described above, according to the food inspection apparatus 100 of the present embodiment, since light in the near infrared region is used as inspection light, there is almost no adverse effect on the human body, and a management area is provided for safety, There is no need to have a special administrator. Therefore, since inspection can be performed by a general worker, cost in food inspection can be reduced.

  Moreover, the difference in the absorptivity in the foodstuffs and foreign substances of the 1st test | inspection light and 2nd test | inspection light from which a center wavelength differs can be utilized by imaging transmitted light. More specifically, the difference image generation unit 5 can sharpen the difference in the absorption rate of the food and foreign matter appearing in the first image and the second image, thereby capturing the position of the foreign matter in the food.

  Furthermore, since the position of the foreign substance in the food can be grasped, the foreign substance can be removed in some cases and used for reprocessing, and the food waste rate can be reduced.

  Other embodiments will be described.

  In the imaging mechanism, as another aspect for increasing the detection accuracy of the foreign matter so that a captured image captured only with the transmitted light that has passed through the food is output, between the food and the imaging mechanism. It may further include a first diaphragm arranged and a second diaphragm arranged at a predetermined distance from the first diaphragm between the food and the imaging mechanism.

  As another embodiment for imaging food only with transmitted light, a rod in which light is guided is inserted between the food and the imaging mechanism. In the above embodiment, the SLD is used. However, other semiconductor light emitting elements may be used. In short, any light source capable of irradiating predetermined near infrared light may be used.

  In addition, various modifications and combinations of embodiments may be performed without departing from the spirit of the present invention.

DESCRIPTION OF SYMBOLS 100 ... Food inspection apparatus 1 ... Light source unit 11 ... SLD
DESCRIPTION OF SYMBOLS 12 ... Mounting plate 2 ... Imaging mechanism 21 ... Camera 22 ... Captured image output part 3 ... Imaging position change mechanism 4 ... Food placing part 5 ... Difference image generation part 6 ... Foreign object detection part L ... Surface light source

Claims (8)

A surface light source that irradiates a food to be inspected with a first inspection light having a center wavelength in the near infrared region and a second inspection light having a center wavelength different from the first inspection light in the near infrared region; ,
The first inspection light and the second inspection light are imaged based on the first image captured based on the first inspection light and the second inspection light. An imaging mechanism for outputting a second image;
A food inspection apparatus comprising: a difference image generation unit configured to generate a difference image between the first image and the second image. The surface light source is formed by a plurality of SLDs;
The food inspection apparatus according to claim 1, wherein the optical axis of each SLD is arranged so as to concentrate on the food. The plurality of SLDs are arranged in a cross shape when viewed from the food side,
The food inspection apparatus according to claim 2, wherein the SLD is disposed on curved surfaces having different curvatures in each arrangement direction. The surface light source is configured to alternately light the first inspection light and the second inspection light at predetermined lighting periods;
The food inspection apparatus according to any one of claims 1 to 3, wherein the imaging mechanism is configured to output the first image and the second image in synchronization with the predetermined lighting period. The food inspection apparatus according to any one of claims 1 to 4, wherein a center wavelength of the first inspection light is 680 nm, and a center wavelength of the second inspection light is 830 nm.   The food inspection apparatus according to claim 1, wherein a separation distance between the food and the imaging mechanism is set to be 10 times or more a width dimension of the food. A first aperture disposed between the food and the imaging mechanism;
The food inspection apparatus according to claim 1, further comprising a second aperture disposed at a position spaced apart from the first aperture by a predetermined distance between the food and the imaging mechanism.   The food inspection apparatus according to claim 1, wherein a rod for guiding light is inserted between the food and the imaging mechanism.