Foreign object detection method and foreign object detection device

Abstract

To materialize a foreign matter detection method and a foreign matter detection device, enabling improvement of the accuracy of detecting foreign matter such as a packing material adhered to or mixed with a food piece, thereby enabling increase of the commodity value of food.SOLUTION: A foreign matter detection method is provided in which a plurality of food pieces having uneven shapes are transported while being rolled or inverted by vibration, the food pieces being transported are imaged in a preset imaging range, and foreign matter adhered to or mixed with these food pieces are detected on the basis of color information in each food piece obtained from the imaging result. Also a foreign matter detection device is provided, comprising: transport means transporting a plurality of food pieces having uneven shapes while rolling or inverting them by vibration; and imaging means imaging the food pieces being transported by the transport means in a preset imaging range, the foreign matter detection device detects foreign matter adhered to or mixed with these food pieces on the basis of color information in each food piece obtained from the result of imaging performed by the imaging means.SELECTED DRAWING: Figure 22

Description

Technical Field

[0001] The present invention relates to a method and an apparatus for detecting foreign substances attached to or mixed in food pieces.

Background Art

[0002] For example, in a food processing factory, food raw materials wrapped in a packaging material such as a vinyl sheet are carried in. This food raw material is taken out of the packaging material by manual work or a mechanical device and supplied to the processing step. However, for example, when the food raw material is frozen while being packaged, it becomes difficult to peel off the packaging material, and a part of the packaging material may remain attached to the food raw material. When the food raw material with the attached packaging material is supplied to the processing step in this way, a part of the packaging material is attached to or mixed in the processed food piece. As a result, there is a problem that the commercial value is impaired whether the food piece is used as a product as it is or the food piece is reprocessed into a product.

[0003] Also, conventionally, there is a technique of installing a metal detector in a food processing step to detect metal pieces mixed in the processed food. However, such a technique cannot detect the mixing of a packaging material such as a vinyl sheet.

[0004] Therefore, as disclosed in Patent Document 1, a technique has been tried to image food pieces on a conveyor from above or from the side by a camera installed at a fixed position and detect foreign substances attached to or mixed in the food pieces.

Prior Art Documents

Patent Documents

[0005]

Patent Document 1

Summary of the Invention

[0006] However, the technology disclosed in Patent Document 1 mentioned above only images the food piece from above or the side, and therefore cannot detect foreign objects present on the underside of the food piece, resulting in a low accuracy in detecting foreign objects. Therefore, there is a risk of overlooking food pieces that have foreign matter such as packaging materials attached to or mixed in with them, and the aforementioned problem of impaired product value cannot be resolved.

[0007] The present invention aims to realize a foreign object detection method and foreign object detection device that can improve the accuracy of detecting foreign objects such as packaging materials attached to or mixed with food pieces, thereby increasing the commercial value of food products. [Means for solving the problem]

[0008] To solve the above-mentioned problems, the present invention employs the following technical means. In other words, the invention described in claim 1 is a foreign object detection method that transports a plurality of food pieces of non-uniform shape by causing them to roll or invert by vibration, images the food pieces during transport within a set imaging range, and detects foreign objects attached to or mixed with the food pieces based on the color information in each food piece obtained from the imaging results.

[0009] The invention described in claim 2 is a foreign object detection method according to claim 1, which involves setting reference color information to serve as a standard for detecting foreign objects attached to or mixed in with the food pieces, comparing the color information in each food piece obtained from the imaging results with the reference color information, and detecting foreign objects based on the comparison results.

[0010] The invention described in claim 3 is the foreign object detection method described in claim 2, wherein the reference color information can be changed and set.

[0011] The invention described in claim 4 is a foreign object detection method according to claim 3, in which, when the color information in each food piece obtained from the imaging results contains a group of pixels having the same type of color information above a threshold, the area where this group of pixels exists is detected as a foreign object.

[0012] The invention described in claim 5 is the foreign object detection method described in claim 4, wherein the threshold value can be changed.

[0013] The invention described in claim 6 is a foreign object detection method according to claim 5, which displays an image captured within the imaging range on a screen and identifies and displays a food piece containing the part detected as a foreign object on this display screen.

[0014] The invention described in claim 7 is a foreign object detection method according to claim 6, wherein the imaging range includes one or more drop sections formed in the transport path of the food piece, and the rolling or inversion of the food piece is promoted by passing through these drop sections.

[0015] The invention described in claim 8 is a foreign object detection method according to claim 7, wherein the height difference of the drop portion is made larger than the size of the food piece.

[0016] The invention described in claim 9 is a foreign object detection method according to claim 8, wherein a plurality of food pieces having a long side and a short side are transported in a state in which the long side tends to be in an orientation substantially aligned with the transport direction, and as each food piece falls at the drop section, each food piece is dropped while changing its orientation so that its long side faces in a direction intersecting the transport direction in a plan view, and is dispersed in the width direction of the transport path.

[0017] The invention described in claim 10 is a foreign object detection method according to claim 9, wherein either the frequency or amplitude of the vibration that causes the food piece to roll or invert, or both, can be changed.

[0018] The invention according to claim 11 is the foreign object detection method according to claim 10, which automatically changes either or both of the frequency and amplitude of the vibration for rolling or inverting the food pieces according to the number of food pieces transferred per unit time or the transfer speed obtained from the imaging result.

[0019] The invention according to claim 12 is the foreign object detection method according to claim 11, which automatically stops the vibration for rolling or inverting the food pieces when foreign objects attached to or mixed in the food pieces during transfer are detected.

[0020] The invention according to claim 13 is the foreign object detection method according to any one of claims 1 to 12, which performs imaging a plurality of times while the food pieces during transfer pass through the imaging range.

[0021] The invention according to claim 14 is a foreign object detection device including a transfer means for transferring a plurality of food pieces having non-uniform shapes while rolling or inverting them by vibration, and an imaging means for imaging the food pieces during transfer by this transfer means within a set imaging range, and is configured to detect foreign objects attached to or mixed in the food pieces based on the color information in each food piece obtained from the imaging result by this imaging means.

[0022] The invention according to claim 15 is the foreign object detection device according to claim 14, which includes a reference color information setting means for setting reference color information as a reference for detecting foreign objects attached to or mixed in the food pieces, and a color information comparison means for comparing the color information in each food piece obtained by the imaging means with the reference color information, and is configured to detect foreign objects based on the comparison result by this color information comparison means.

[0023] The invention according to claim 16 is the foreign object detection device according to claim 15, which is configured to be able to change the reference color information set by the reference color information setting means.

[0024] The invention according to claim 17 is the foreign object detection device according to claim 16, which is configured to detect, as a foreign object, a part where a pixel group having the same kind of color information and having a threshold value or more of the same kind of color information is included in the color information of each food piece obtained from the imaging result by the imaging means.

[0025] The invention according to claim 18 is the foreign object detection device according to claim 17, which is configured to be able to change the threshold value.

[0026] The invention according to claim 19 is the foreign object detection device according to claim 18, which includes a screen for displaying an image captured in the imaging range, and is configured to discriminatively display a food piece including a part detected as a foreign object on this screen.

[0027] The invention according to claim 20 is the foreign object detection device according to claim 19, in which one or a plurality of drop parts for promoting the rolling or inversion of the food piece are formed in the transfer path of the food piece, and this drop part is arranged within the imaging range.

[0028] The invention according to claim 21 is the foreign object detection device according to claim 20, in which the height difference of the drop part is set to be larger than the size of the food piece.

[0029] The invention according to claim 22 is configured to transfer a plurality of food pieces having long side parts and short side parts in a state having a tendency to be in a posture in which the long side parts are substantially along the transfer direction by the transfer means, and the drop part includes a plurality of transfer surfaces having a height difference, and the edge part on the downstream side in the transfer direction of each transfer surface is bent or refracted in a plan view so as to be biased more downstream toward the central part in the width direction of the transfer path, and when each food piece falls from the edge part, each food piece is dropped while changing its posture so that the long side part faces a direction intersecting the transfer direction in a plan view and is diffused in the width direction of the transfer path. The foreign object detection device according to claim 21.

[0030] The invention described in claim 23 is a foreign object detection device according to claim 22, wherein the device is configured to change either the frequency or amplitude of the vibration that causes the food piece to roll or invert, or both.

[0031] The invention described in claim 24 is a foreign object detection device according to claim 23, wherein the device obtains the number of food pieces moved per unit time or the transfer speed from the imaging results, and automatically changes either the frequency or amplitude of the vibration that causes the food pieces to roll or invert, or both, according to this number of moves or transfer speed.

[0032] The invention described in claim 25 is a foreign object detection device according to claim 24, wherein when a foreign object attached to or mixed with a food piece is detected while it is being transported, the vibration that causes the food piece to roll or invert is automatically stopped.

[0033] The invention described in claim 26 is a foreign object detection device according to any one of claims 14 to 25, wherein the imaging means takes multiple images while the food piece being transported by the transport means passes through the imaging range. [Effects of the Invention]

[0034] According to the present invention, the accuracy of detecting foreign matter attached to or mixed in food pieces can be improved, thereby increasing the commercial value of the food product. [Brief explanation of the drawing]

[0035] [Figure 1] This is a schematic diagram of the equipment inside a meat processing plant. [Figure 2] This is a side view of the foreign object detection device. [Figure 3] This is a front view of the foreign object detection device. [Figure 4] This is a side view of the transfer device in the first embodiment. [Figure 5] This is a front view of the transfer device in the first embodiment. [Figure 6] This is a plan view of the transfer device in the first embodiment. [Figure 7]This is a side view of the transfer device in the second embodiment. [Figure 8] This is a front view of the transfer device in the second embodiment. [Figure 9] This is a plan view of the transfer device in the second embodiment. [Figure 10] This is a side view of the transfer device in the third embodiment. [Figure 11] This is a front view of the transfer device in the third embodiment. [Figure 12] This is a plan view of the transfer device in the third embodiment. [Figure 13] This is a side view of the transfer device in the fourth embodiment. [Figure 14] This is a front view of the transfer device in the fourth embodiment. [Figure 15] This is a plan view of the transfer device in the fourth embodiment. [Figure 16] This is a side view of the transfer device in the fifth embodiment. [Figure 17] This is a front view of the transfer device in the fifth embodiment. [Figure 18] This is a plan view of the transfer device in the fifth embodiment. [Figure 19] This is a block circuit diagram of a foreign object detection device. [Figure 20] This is a flowchart for detecting foreign objects. [Figure 21] This is the image displayed on the monitor. [Figure 22] This is an explanatory diagram for detecting foreign objects in food pieces. [Figure 23] This is an explanatory diagram showing the relationship between foreign objects and pixels. [Modes for carrying out the invention]

[0036] In this section, a device for detecting plastic fragments ("foreign matter" in the claim) attached to or mixed with crushed frozen meat pieces ("food pieces" in the claim) will be described in detail below as one embodiment of a foreign matter detection device. Furthermore, using the direction in which the meat piece is transported by this foreign object detection device as a reference, the upstream side in the transport direction is defined as the "rear side," and the downstream side in the transport direction is defined as the "front side." When facing downstream, the left hand side is defined as the "left side," and the right hand side is defined as the "right side" for explanation purposes.

[0037] (Equipment inside a meat processing plant) As shown in Figure 1, a flaker mixer grinder 2, a foreign object detection device 3, a conveyor 4, a vertical conveyor 5, a chopper 6, and a mincepacker 7 are arranged in series within the meat processing plant 1 to form a minced meat processing line. Furthermore, the frozen chunks of meat (small pieces of meat gathered together and frozen to form larger chunks) that are brought into the meat processing plant 1 are packaged in colored, semi-transparent plastic sheets such as blue, green, and yellow. This plastic sheet is removed manually or by machine to form chunks of meat for processing.

[0038] (Flaker mixer grinder) The flaker mixer grinder 2 loads the aforementioned frozen chunk of meat into a supply chamber containing a pusher 2A, and pushes this chunk of meat toward the rotating rotor 2B by the extension action of the pusher 2A, while crushing it into pieces with numerous blades provided on the outer circumference of the rotor 2B. Pusher 2A is driven by an air cylinder, while rotor 2B and other components are driven by electric motors. (Air cylinder and electric motors are not shown in the diagram.)

[0039] The crushed meat pieces are agitated by a rotating paddle 2C below, taken into the filling spiral 2D, and transferred into the filling box 2E. The meat pieces, transported to the front end of the filling box 2E by the filling spiral 2D, flow from the front end of the filling box 2E into the rear end of the cylinder 2F, and are then pumped forward by the transfer spiral 2G within the cylinder 2F. The meat pieces, pumped by the transfer spiral 2G, are pushed out through numerous through-holes in the plate 2H located at the front end of the cylinder 2F, and fall or flow downward through the opening of the chute 2I attached to the front end of the cylinder 2F.

[0040] At this time, the aforementioned crushed meat pieces are still frozen, so when they are pushed out through the holes in plate 2H, they do not take on the same shape, but instead exhibit non-uniform shapes such as roughly cylindrical, granular, or fragmentary. Furthermore, many of these have a shape with a short side and a long side due to extrusion through the aforementioned through-holes. Furthermore, the diameter of the through-holes in plate 2H is larger than that of the through-holes in chopper 6, which will be described later. As a result, the meat pieces pushed out through the through-holes in plate 2H are relatively large pieces (coarsely ground meat).

[0041] However, the numerous pieces of meat pushed out through the through-holes in plate 2H are supplied to the foreign object detection device 3. The configuration and operation of this foreign object detection device 3 will be described later. The numerous pieces of meat that have passed through the foreign object detection device 3 flow down to the starting point of the conveyor belt 4.

[0042] (Conveyor) The conveyor 4 has an endless conveyor belt 4A wound between rollers positioned at both the front and rear ends, and the front rollers are driven by an electric motor. (Rollers and electric motor are not shown.) Furthermore, the upper surface of the conveyor belt 4A is set to an upward-sloping position. As a result, the meat pieces that flow down from the foreign object detection device 3 to the starting end of the conveyor 4 are lifted and transported by the conveyor 4, and then supplied to the vertical conveyor 5 from the end of the conveyor.

[0043] (Vertical conveyor) The vertical conveyor 5 takes over the meat pieces supplied from the end of the conveyor 4, lifts and transfers them vertically, and supplies them to the chopper 6. This vertical conveyor 5 is equipped with a bucket-shaped storage section 5A with an open top and a cylindrical lifting and transfer section 5B.

[0044] The housing section 5A is equipped with a bottom transfer screw 5C that can be driven and rotated, and the lifting transfer section 5B is equipped with a lifting transfer screw 5D that can be driven and rotated. Both the bottom transfer spiral 5C and the lifting transfer spiral 5D are configured to be driven by electric motors (not shown). A chute 5E is provided at the upper end of the lifting and transferring section 5B to guide the lifted and transferred meat pieces downward toward the chopper 6.

[0045] (chopper) The chopper 6 receives the meat pieces (coarsely ground meat) flowing down from the chute 5E of the vertical conveyor 5 through an open section formed on its upper surface, pumps them into the cylinder 6A using a transfer spiral 6B, and pushes them out through numerous through holes in a plate 6C located at the front end of the cylinder 6A. The inner diameter of the through-hole in plate 6C of this chopper 6 is formed to be smaller than the inner diameter of the through-hole in plate 2H of the flaker mixer grinder 2 described above. This process grinds the meat pieces (coarsely ground meat) twice to produce ground meat.

[0046] (Minpacker) The mince packer 7 is a device that divides and places the minced meat, which is extruded through the through-holes in the plate 6C of the chopper 6, into individual trays and sends them to the next process (metal detector side). This mince packer 7 includes a conveyor 7A that takes over the minced meat extruded from the through-holes in the plate 6C of the chopper 6, a cutter 7B that cuts the minced meat transported by the conveyor 7A, and a tray supply unit 7C that supplies trays for serving the cut minced meat. Then, the trays into which the minced meat has been packed by the mince packer 7 are covered with plastic wrap in a later process, a label indicating the weight and other information is attached, and the trays are shipped out.

[0047] (Details of the foreign object detection device) However, as shown in Figures 2 and 3, the foreign object detection device 3 consists of a support frame 8, a transport unit 9, and an imaging unit 10. First, the support frame 8 is constructed by connecting the upper, middle, and lower ends of four vertically elongated support frame 8A with short connecting frames 8B in the front-to-back and left-to-right directions. Furthermore, support leg members 8C are attached to the lower end of each support frame 8A by screwing them in vertically.

[0048] Next, the transport unit 9 is constructed by placing and fixing a support plate 9A across the upper surfaces of the front and left and right connecting frames 8B that connect the upper and lower intermediate sections of the support column frame 8A, fixing the vibration excitation device 9B on top of this support plate 9A, and attaching a transport plate 9C to the top of this vibration excitation device 9B. The vibration device 9B comprises a base fixed on a support plate 9A, a mounting member supported at a distance above the base, a lower vibrating member fixed on the mounting member, an upper vibrating member supported at a distance above the lower vibrating member, an electromagnet, and a movable iron member.

[0049] The base and the mounted member are connected at both the front and rear ends by inclined leaf spring-shaped elastic members, and the lower vibrating member and the upper vibrating member are connected at both the front and rear ends by inclined leaf spring-shaped elastic members. Furthermore, the electromagnet is fixed to the lower vibrating member, and the movable iron member facing this electromagnet is fixed to the upper vibrating member. Additionally, a counterweight is mounted at the rear of the mounted component. The individual components of the vibration excitation device 9B described above are not shown in the illustration.

[0050] With the above configuration, when current is intermittently supplied to the electromagnet, the attractive force of the electromagnet causes the upper vibrating member, which is equipped with a movable iron material, to reciprocate diagonally in the vertical direction in a trajectory constrained by the inclined position of the plate-shaped elastic member. The amplitude of this vibration is several millimeters, and the frequency is several tens of Hz.

[0051] As a result, the transport plate 9C vibrates back and forth diagonally in an up-and-down direction, transporting the meat pieces on the transport plate 9C downstream in small increments while throwing them diagonally upward. The configuration in which the transfer plate 9C is vibrated by the vibration device 9B to transfer the meat pieces on the transfer plate 9C is referred to as the "transfer means" in the claim. An example of the transfer plate 9C will be described later.

[0052] The imaging unit 10 is configured by fixing a mounting plate 10A across the left and right front support frame 8A, fixing a support member 10B in a hanging position to the front of the central part in the left-right direction of the mounting plate 10A, and attaching a color camera (the "imaging means" in the claim) 10C facing downward to the front of the hanging end of the support member 10B. Furthermore, as shown in Figures 4 to 6, the imaging range E of the color camera 10C is set as a rectangular area with a predetermined front-to-back length L mm and a predetermined left-to-right width W mm at the front of the transport plate 9C. As shown in Figure 2, by setting the positional relationship between the flaker mixer grinder 2 and the foreign object detection device 3, the plate 2H at the front end of the cylinder 2F and the chute 2I are positioned to enter above the rear of the transfer plate 9C.

[0053] (First embodiment of the transfer plate) Figures 4 to 6 show the transfer plate 9C used in Figures 1 to 3. This transport plate 9C consists of a rectangular, approximately horizontal base plate 9CU in plan view, left and right side plates 9CK that rise from both ends of the base plate 9CU to prevent it from falling off, and a flow guide plate 9CR that has the same width as the distance between the left and right side plates 9CK and is positioned in an upward sloping position. Furthermore, the central part of the bottom plate 9CU of this transfer plate 9C is mounted on top of the vibration excitation device 9B described above.

[0054] As a result, when the vibration device 9B is activated, the transport plate 9C vibrates back and forth at a predetermined frequency and amplitude in an oblique up-and-down direction (a forward-inclined direction), and the meat pieces that flow down from the flow guide plate 9CR are transported downstream in small increments as if being thrown obliquely upward on the bottom plate 9CU. At this time, the pieces of meat on the bottom plate 9CU spread out in the left-right direction, and each piece of meat is transported while rolling or inverting. The upper surface of the bottom plate 9CU may be a smooth surface or a rough surface that facilitates transport.

[0055] A transport path for the meat pieces is formed between the left and right side plates 9CK on the upper surface of the bottom plate 9CU. The imaging range E is set to a predetermined distance behind the front end of the base plate 9CU. In addition, in the second to fifth embodiments of the transfer plate 9C described below, components common to the first embodiment are denoted by the same reference numerals in the drawings and their descriptions are omitted.

[0056] (Second embodiment of the transfer plate) As shown in Figures 7 to 9, a drop section 9CX consisting of two steps may be formed at the front of the bottom plate 9CU of the transfer plate 9C. Furthermore, the height difference between each stage in this drop section 9CX is set to be greater than the diameter of the through-hole in the plate 2H of the flaker mixer grinder 2.

[0057] This facilitates the rolling or inversion of the meat pieces as they pass through the drop section 9CX while falling, as they are being transported on the bottom plate 9CU. The imaging range E is set to a predetermined distance behind the front end of the bottom plate 9CU, and the drop section 9CX is included within this imaging range E.

[0058] (Third embodiment of the transfer plate) As shown in Figures 10 to 12, the drop section 9CX formed at the front of the bottom plate 9CU may consist of four steps. In this case as well, the height difference of each stage in the drop section 9CX is set to be greater than the diameter of the through hole in the plate 2H of the flaker mixer grinder 2.

[0059] This further promotes the rolling or inversion of the meat pieces as they pass through the drop section 9CX while falling, as they are being transported on the bottom plate 9CU. The imaging range E is set to a predetermined distance behind the front end of the bottom plate 9CU, and the drop section 9CX is included within this imaging range E.

[0060] (Fourth embodiment of the transfer plate) As shown in Figures 13 to 15, a drop section 9CX consisting of three steps may be formed at the front of the bottom plate 9CU, and an inclined surface 9CY that slopes downwards towards the front may be formed on the front side of this drop section 9CX. In this case as well, the height difference of each stage in the drop section 9CX is set to be greater than the diameter of the through hole in the plate 2H of the flaker mixer grinder 2.

[0061] As a result, when the meat pieces being transported on the bottom plate 9CU pass through the drop section 9CX while falling, their rolling or reversal is promoted, and they are smoothly handed over from the inclined surface 9CY to the starting end of the conveyor 4. The imaging range E is set to a predetermined distance behind the upper end of the inclined surface 9CY, and the drop portion 9CX is included within this imaging range E.

[0062] (Fifth embodiment of the transfer plate) As shown in Figures 16 to 18, a drop section 9CX consisting of three steps may be formed at the front of the bottom plate 9CU, and an inclined surface 9CY that slopes downwards towards the front may be formed on the front side of the drop section 9CX. This drop section 9CX is formed by providing four transport surfaces 9CU1 to 9CU4 that have a difference in height.

[0063] Then, the front edge portions (downstream edge portions in the transport direction) of each transport surface 9CU1 to 9CU4 are made to protrude so that the portion closer to the center in the width direction of the bottom plate 9CU (width direction of the transport path) is biased forward (downstream in the transport direction), and are formed by refraction on three sides in a plan view. Alternatively, it may be formed by refracting the light along two sides in a plan view, or it may be formed in an arc shape without refraction. In other words, during transport, each piece of meat tends to assume an orientation such that its long side is aligned with the transport direction (vibration direction) because the longer side of the piece has a longer contact area with the upper surface of the bottom plate 9CU.

[0064] As the meat pieces are transported in this position, they change their orientation at each front edge (downstream side in the transport direction) of each transport surface 9CU1 to 9CU4 so that the longer side of each meat piece faces a direction that intersects the transport direction in a plan view (so that it is in an orientation that follows the edge of the transport surface), and then fall onto the next transport surface. Furthermore, as this falling process is repeated, the pieces of meat spread out while rolling along the width of the transport path.

[0065] Furthermore, the imaging range E is set to a predetermined distance behind the upper end of the inclined surface 9CY, and the drop section 9CX and the four transport surfaces 9CU1 to 9CU4 are included within this imaging range E. Furthermore, the drop portion 9CX in the second to fifth embodiments described above may be formed from a single step.

[0066] (Block circuit in a foreign object detection device) As shown in Figure 19, the control device 11 of the foreign object detection device 3 includes a controller 15 which has an image processing unit 12, a vibration frequency / amplitude adjustment unit 13, and an abnormal state determination unit 14. Then, the startup signal receiver 16, the color camera 10C, the operation panel 17, the frequency adjustment dial 18, and the amplitude adjustment dial 19 are connected to the input side of this controller 15. On the other hand, the output side of the controller 15 is connected to the illumination device 20, the electromagnet coil 21 of the vibration device 9B, the monitor 22, the alarm device 23, and the stop signal transmission unit 24.

[0067] The aforementioned startup signal receiving unit 16 receives the startup signal emitted when the flake mixer grinder 2, which is located in the preceding process of the foreign object detection device 3, starts up, via a wired or wireless line. When this activation signal is received, the controller 15 automatically starts detecting foreign objects. Alternatively, instead of this activation signal receiving unit 16, a switch that allows for manual operation to start foreign object detection may be connected.

[0068] The color camera 10C has a collection of tiny square pixels, and if the length of one side of each pixel is a mm, then the number of pixels P within the imaging range E is: P = (L × W) / a 2 That is the case. This allows the size of an object to be detected from the number of pixels it occupies in the image, and also allows the position of the object within the imaging range E to be detected.

[0069] Furthermore, the RGB signals acquired from each pixel are transmitted to the controller 15, where the image processing unit 12 converts them to the HSV color space to obtain color information from the object. The control panel 17 is a touch panel, allowing users to set reference color information and threshold values. Alternatively, instead of using touch operation on this control panel 17, the system may be configured to input and set reference color information and thresholds using a display panel and a mouse or keyboard.

[0070] In other words, multiple color information sets are pre-configured in the image processing unit 12 to match the color of the plastic sheet that packaged the block of meat (blue, green, yellow, etc.), and the color information selected by the operator using the operation panel 17 is set as the reference color information. The function of setting reference color information using this operation panel 17 and image processing unit 12 is referred to as the "reference color information setting means" in the claim.

[0071] Furthermore, with respect to pixels that have the same type of color information (similar color information) as this reference color information, the operator sets the number of pixels necessary to form a pixel group of a predetermined size by operating the control panel 17, and this number of pixels is set as a threshold in the image processing unit 12. The frequency adjustment dial 18 and amplitude adjustment dial 19 adjust the power intermittently supplied to the coil 21 via the frequency / amplitude adjustment unit 13, thereby changing the attractive frequency and attractive force of the electromagnet. This allows the vibration frequency and amplitude of the transfer plate 9C to be adjusted by operating the vibration frequency adjustment dial 18 and the amplitude adjustment dial 19 according to the condition of the meat piece.

[0072] Furthermore, the illumination device 20 is integrated with the color camera 10C and illuminates the area including the imaging range E with white light. The illumination by this illumination device 20 is performed in synchronization with the imaging by the color camera 10C.

[0073] The coil 21 is a wire wound around the core of the magnetic material attached to the electromagnet described above, and a magnetic force is temporarily generated when current is passed through this coil 21. The monitor 22 is a monitoring device that displays images captured by the color camera 10C.

[0074] As shown in Figure 21, the image display area of ​​this monitor 22 has the same shape and area as the imaging area E of the color camera 10C. The alarm device 23 notifies the user of any malfunction in the control device 11, etc., using sound or light, and examples include a buzzer and a warning light. The stop signal transmission unit 24 transmits a status signal to the flaker mixer grinder 2 in the preceding process when it detects a piece of meat with foreign matter attached to or mixed in it, and the vibration device 9B automatically stops based on this, thereby stopping the transfer of the meat piece by the transfer plate 9C.

[0075] This allows the flake mixer grinder 2 to be automatically stopped, halting the supply of meat pieces to the foreign object detection device 3 and preventing meat pieces from overflowing into the foreign object detection device 3. Furthermore, the system may be configured to automatically stop the entire processing line, including the conveyor 4, vertical conveyor 5, chopper 6, and mince packer 7, upon receiving a signal from the stop signal transmission unit 24.

[0076] (Foreign object detection process) Based on the flowchart in Figure 20, the process for detecting foreign matter attached to or mixed with meat pieces will be explained. When the start signal for the flaker mixer grinder 2 is received by the start signal receiving unit 16 (STEP 1), white light is emitted from the illumination device 20 (STEP 2), and almost simultaneously, an image of the imaging range E is acquired by the color camera 10C (STEP 3).

[0077] Figure 21 shows the display image of the monitor 22 (the "screen" in the claim) based on this acquired image. This monitor 22 displays the state in which numerous pieces of meat M are being transported while spreading out, with the spacing between them increasing as they move downstream in the transport direction. Furthermore, since these meat pieces are still at a temperature of around -5°C, they are less likely to adhere to the upper surface of the bottom plate 9CU of the transfer plate 9C, and are being transferred smoothly.

[0078] Then, the RGB signals obtained from each pixel in this image are converted to the HSV color space by the image processing unit 12 (STEP 4), and the color information of the object is obtained (STEP 5). Further noise reduction is performed (STEP 6), and pixels having the same type of color information are extracted by comparing them with the reference color information selected by operating the control panel 17 (processing function of the image processing unit 12 corresponding to the "color information comparison means" in the claim).

[0079] Then, as illustrated in Figures 22 and 23, if it is determined that the color information in the meat piece M contains a group of nine pixels C (in this case, a threshold) with the same type of color information, the area where this pixel group CE exists is detected as the area where the plastic piece (foreign object) ex exists (STEP 8). Furthermore, as illustrated in Figure 22, if it is determined that the color information in the meat piece M contains two consecutive pixels C with the same type of color information, the area where this continuum of pixels CZ exists is not detected as the area where the vinyl piece ex exists, but is treated as noise and cut out.

[0080] Then, as shown in Figure 21, the meat piece M containing the area where the plastic piece (foreign object) ex was detected is identified and displayed on the display image of the monitor 22 by circling it (STEP 9). Furthermore, the meat piece M containing the detected plastic fragment (foreign object) ex may be identified and marked with a different color from the other meat pieces M. Furthermore, the foreign object detection device 3 itself is automatically stopped, and the flaker mixer grinder 2 is automatically stopped by a signal transmitted from the stop signal transmission unit 24 (STEP 10).

[0081] On the other hand, if it is determined that the color information in the meat sample M contains a group of eight or fewer pixels C having the same type of color information, the above-mentioned identification display and automatic stop will not be performed. In this case, the process returns to irradiation by the illumination device 20 (STEP 2), and the steps from image acquisition (STEP 3) to foreign object detection (STEP 8) are repeated at very short time intervals (several hundred msec intervals). As a result, the meat piece M is imaged multiple times as it rolls or flips over while passing through the imaging range E during transport, and the entire circumference or a nearly entire area of ​​the meat piece M is imaged, thus improving the detection accuracy of the plastic piece (foreign object) ex.

[0082] (Another example) The vibration frequency and amplitude of the vibrations generated by the vibration exciter 9B may be controlled as follows. In other words, the system is configured to obtain the number of transfers or transfer speed of the tissue piece M per unit time from the imaging results, and to automatically change either the frequency or amplitude of the vibration device 9B, or both, according to this number of transfers or transfer speed. In the embodiments described above, the food piece in the present invention was a meat piece M, but the invention is not limited to this and can also be applied to frozen vegetable pieces, butter pieces, cheese pieces, ice pieces, etc. [Explanation of Symbols]

[0083] 9B Vibration device (transfer means) 9C Transfer plate (transfer means) 9CX drop section 9CU1 Transfer surface 9CU2 Transfer surface 9CU3 Transfer surface 9CU4 Transfer surface 10C Color Camera (Imaging Device) 12 Image Processing Unit (Color Information Comparison Means) 17. Operation panel (reference color information setting means) M Meat piece (food piece) e.g., a piece of plastic (foreign object)

Claims

1. A foreign object detection device comprising a transport means for transporting multiple food pieces of uneven shape while causing them to roll or invert by vibration, and an imaging means for imaging the food pieces being transported by the transport means within a set imaging range, wherein foreign objects attached to or mixed with the food pieces are detected based on color information in each food piece obtained from the imaging results by the imaging means, and the device is configured such that the multiple food pieces are imaged multiple times while rolling or inverting by vibration as they pass through the imaging range.

2. A foreign object detection device according to claim 1, comprising: a reference color information setting means for setting reference color information that serves as a standard for detecting foreign objects attached to or mixed in with the food pieces; and a color information comparison means for comparing color information in each food piece obtained by the imaging means with the reference color information, wherein the foreign object is detected based on the comparison result by the color information comparison means.

3. The foreign object detection device according to claim 2, wherein the configuration allows the reference color information set by the reference color information setting means to be changed.

4. The foreign object detection device according to claim 3, wherein the device is configured to detect a region where a group of pixels having the same type of color information is present as a foreign object when the color information of each food piece obtained from the imaging results of the imaging means contains a group of pixels with a threshold or more.

5. The foreign object detection device according to claim 4, wherein the threshold value can be changed.

6. The foreign object detection device according to claim 5, further comprising a screen for displaying images captured within the aforementioned imaging range, and configured to identify and display food pieces including the parts detected as foreign objects on this screen.

7. The foreign object detection device according to claim 6, wherein one or more drop sections are formed in the transport path of the food pieces to promote rolling or inversion of the food pieces, and these drop sections are arranged within the imaging range.

8. The foreign object detection device according to claim 7, wherein the height difference of the drop section is set to be greater than the size of the food piece.

9. The foreign object detection device according to claim 8, wherein a plurality of food pieces having a long side and a short side are transported in a state in which the long side tends to be in an orientation substantially aligned with the transport direction by the transport means, the drop section includes a plurality of transport surfaces having a difference in height, and the downstream edge of each transport surface in the transport direction is formed by bending or refraction in a plan view such that the portion closer to the center in the width direction of the transport path is biased downstream, and as each food piece falls from the edge, each food piece falls while changing its orientation so that its long side faces in a direction intersecting the transport direction in a plan view, and is dispersed in the width direction of the transport path.

10. The foreign object detection device according to claim 9, wherein the device is configured to change either the frequency or amplitude of the vibration that causes the food piece to roll or invert, or both.

11. The foreign object detection device according to claim 10, wherein the device obtains the number of food pieces transferred per unit time or the transfer speed from the imaging results, and automatically changes either the frequency or amplitude of the vibration that causes the food pieces to roll or invert, or both, according to this number of transfers or transfer speed.

12. The foreign object detection device according to claim 11, wherein when a foreign object attached to or mixed with a food piece during transport is detected, the vibration that causes the food piece to roll or invert is automatically stopped.

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