JP4249201B2 - Foreign object detection device - Google Patents

Description

  The present invention relates to a foreign object detection device that detects foreign objects such as metal and bone contained in an object to be inspected such as food, and more particularly to an object to be inspected that satisfies a predetermined reference value by using the second reference value. The present invention relates to a foreign object detection device that determines whether there is a possibility that a foreign object is included and warns the user.

Conventionally, as such a foreign matter detection device, there are an X-ray foreign matter detection device and a metal detector.
The X-ray foreign object detection device irradiates X-rays on various types of inspection objects (raw meat, fish, processed foods, medicines, etc.) that are sequentially transported on the transport line, and the amount of transmitted X-rays. This is a device that detects whether or not a foreign object such as metal, glass, stone, or bone is mixed in the inspection object.
The metal detector generates an alternating magnetic field in the transfer line, and passes through the alternating magnetic field through each type of test object (raw meat, fish, processed food, medicine, etc.) and detects when the magnetic field is passed. It is a device that detects whether or not metal is mixed from the output.
In any of these X-ray foreign matter detection devices and metal detectors, reference values for determining the presence or absence of foreign matter, such as foreign matter detection reference values and determination target values, are set in advance and detected by each device. The detected value is compared with the reference value to determine the presence or absence of foreign matter.
In the case of a determination method using such a reference value, there is a risk of erroneous determination depending on how the reference value is set, and an improvement in determination accuracy is required.

  In the X-ray foreign object detection device, in order to improve the determination accuracy, an area is specified for the inspection object, a foreign object detection reference value is set for each specified area, and foreign object contamination determination is performed for each area based on the foreign object detection reference value. A proposal has been made to realize foreign object detection with high sensitivity individually (see Patent Document 1).

  Further, in the metal detector, the influence value storage means for sequentially storing the influence value indicating the degree of influence of the inspection object itself on the magnetic field, and the influence value stored in the influence value storage means, depending on the inspection object. And a control means for variably controlling a detection condition or a determination reference value for detecting a change in the magnetic field, and changing the determination reference value for the inspected object based on the influence value to the magnetic field by the inspected object itself A proposal has been made to prevent erroneous determination due to fluctuations in the influence level of noise and fluctuations in noise level (see Patent Document 2).

JP 2004-28768 A JP 2000-314776 A

  However, in the case of the X-ray foreign matter detection apparatus as described in Patent Document 1, a foreign matter detection reference value is set for each designated region in the inspection object, and foreign matter contamination based on the foreign matter detection reference value is set for each region. A determination is made, and a single reference value is used as a determination reference in each region. When the reference value is single, if the reference value is too large than the detected value of the contaminated foreign matter, the object to be inspected with foreign matter may be judged as a non-defective product. If it is too small, even a non-foreign material may be determined to be a foreign material. Therefore, depending on how the reference value is set, there is a problem that detection accuracy is lowered and erroneous determination is caused.

  On the other hand, in the case of a metal detector as described in Patent Document 2, the degree of influence of the inspection object itself on the magnetic field is detected, and the determination reference value is changed based on the influence value indicating the degree of influence. However, there is a single reference value for determination, and similarly to the problem of the X-ray foreign matter detection apparatus as described in Patent Document 1, depending on how the reference value is changed, detection accuracy is reduced and erroneous determination is caused. There is a problem.

  Therefore, the present invention provides a reference value corresponding to the type and characteristics of food and the like, and a highly accurate reference value to be updated based on a reaction value related to a reaction signal output in response to a foreign substance mixed in food or the like. It is an object of the present invention to provide a foreign object detection device that can detect the presence or absence of foreign substances mixed in food or the like with high accuracy and does not cause erroneous determination.

In the foreign matter detection apparatus according to claim 1 of the present invention, in order to achieve the above-mentioned object, a sensor that outputs a reaction signal in response to foreign matter mixed in an object to be transported on the transport path, and the reaction In the foreign matter detection apparatus having the first determination means for comparing the reaction value based on the signal and the first reference value K1 to determine the presence or absence of the foreign matter, the first determination means among the reaction values indicates that there is a foreign matter. A second reference value setting means for setting the second reference value K2 in a range in which it is not determined that there is a foreign substance based on the first reference value K1 , based on the peak value of the response value of the non-defective product, and the second reference value Second determination means for comparing the second reference value K2 with the peak value of the reaction value related to the reaction signal output from the sensor and determining the presence or absence of foreign matter after K2 is set; , said first-size Wherein not determined object to be inspected and there foreign matter, and the inspection object in said second determination means when it is determined that there is a possibility of containing foreign matter, it contains foreign matter said the object to be inspected in the unit And warning means for warning that there is a possibility.
With this configuration, the first determination means compares the reaction value relating to the reaction signal output from the sensor with the first reference value K1 to determine the presence or absence of foreign matter, and inspects non-defective products that have not been determined to have foreign matter. The second reference value K2 is set based on the reaction value of the object, and after the second reference value K2 is set by the second determination means, the reaction value related to the reaction signal output from the sensor and the second reference value K2 Are compared to determine the possibility of containing foreign matter. When it is determined by the second determination means that there is a possibility of containing foreign matter, a warning is given that there is a possibility that foreign matter is contained in the inspection object.

In the foreign matter detection apparatus according to claim 2 of the present invention, the second reference value setting means is configured to output a second value based on an average value m and a standard deviation value σ of the reaction values obtained from a predetermined number of the non-defective products. configured to update the reference value K _2.
With this configuration, the second reference value K ₂ is set based on the average value m of the reaction values and the standard deviation value σ, and the second reference value K ₂ is updated according to the type and characteristics of the food, so that the accuracy is improved. Rise. In the present invention, the average value represents an arithmetic average value (arithmetic average value).

In the foreign matter detecting apparatus according to claim 3 of the present invention, the first determining means, the second reference value K ₂ is in the range of the first reference value the good is not determined that there is foreign matter by K ₁ to have a first reference value updating means for updating the first reference value K ₁ so that the value in the range of the first reference value K ₁ and the second reference value K ₂ when it is set to Composed.
With this configuration, when the first reference value K ₁ so that the value in the range between the and the first reference value K ₁ second reference value K ₂ are updated, from the first reference value K ₁ before update also the first reference value K ₁ of the updated approaches the second reference value K _2, the more the first reference value K ₁ accurate, first a determination is made.

In the foreign matter detecting apparatus according to claim 4 of the present invention, the first determining means, the range of the second reference value the non-defective K ₂ is not determined that there is foreign material by the first reference value K ₁ set, and when the average value m of the reaction value of the good is varied in a direction toward the first reference value K _1, the average value of said first reference value K ₁ wherein the reaction value of the good It is comprised so that it may have the 1st reference value update means updated so that it may keep away from m.
With this configuration, the average value m of the reaction value of non-defective, when fluctuation in a direction toward the first reference value K _1, despite a good, reaction value exceeds the first reference value K ₁ for things, when the first reference value K ₁ is updated away from the average value m of the reaction value of non-defective, the updated, be as reactive value of non-defective does not exceed the first reference value K ₁ it can.

In the foreign matter detecting apparatus according to claim 5 of the present invention, the first reference value updating means, the first reference value updating invalid setting which can be set so as to disable updating of the first reference value K ₁ Configured to have means.
With this configuration, the first reference value updating means, in the update of the first reference value K ₁ is set to be invalid, the first reference value K ₁ is updated fixed constant value without, the The presence / absence of foreign matter is determined by one determination means.

In the foreign matter detection apparatus according to claim 6 of the present invention, the warning means is at least one of display output means for outputting characters or images, data output means for outputting data to the outside, and audio output means for outputting sound. It is comprised so that it may have.
With this configuration, the inspector can recognize a warning from the display by characters or images, from the output data and voice.

In the foreign object detection apparatus according to claim 7 of the present invention, the first determination means counts the number of determinations performed or the determination period for determining the presence or absence of foreign objects with respect to the inspection object, and sets a predetermined value. Count arrival signal output means for outputting a count arrival signal when the count has been reached, and the second determination means stops judging whether or not there is a possibility of containing foreign matter when receiving the count arrival signal. Composed.
With this configuration, for example, based on a plurality of reaction values such as the type and characteristics of the inspected object, until the variation in the maximum and minimum values of the reaction values obtained from the plurality of inspected objects is reduced and the reaction value is stabilized. The number of determination executions and the determination execution period are set in advance, and when the count by the first determination unit reaches the set number of determinations and determination execution period, a count arrival signal is output from the first determination unit, and the second determination When the means receives the output count arrival signal, the determination by the second determination means is stopped.

In the foreign matter detecting apparatus according to claim 1, to the non-defective it is not determined that there foreign matter, further, compares the reaction value of the good, and a second reference value K _2, which is set based on the reaction value Therefore, it is possible to determine whether or not there is a possibility that foreign matter is contained in the inspected object, and there is a possibility that foreign matter is included in the inspected item for a non-defective product that is determined to be possible Can warn the inspector. The inspector who has received the warning can recognize that the object to be inspected may contain foreign objects, can take measures such as re-inspection, and conduct a more accurate inspection. There is an effect that can.

In the foreign matter detecting apparatus according to claim 2, since the second reference value K ₂ is updated to a more accurate value based on the average value m and the standard deviation value σ of the reaction value of non-defective predetermined number, There is an effect that it is possible to perform a high-accuracy inspection according to the type and characteristics of food.

In the foreign matter detecting apparatus according to claim 3, the first reference value K ₁ is, because it is updated to a more accurate value, the effect of higher accuracy the first determination is made.

In the foreign matter detecting apparatus according to claim 4, despite a good, about what reaction value exceeds the first reference value K _1, the average value m of the first reference value K ₁ is the reaction value of good because it is updated away from the updated can react values of non-defective can not exceed a first reference value K _1, to prevent erroneous determination that a highly accurate inspection effect There is.

In the foreign matter detection apparatus according to claim 5, the inspector is, for example, the first standard for the case where the range of the maximum value and the minimum value of the reaction values obtained from a plurality of inspected objects is small and the reaction value is stable. by disabling the updating of the value K _1, at a fixed constant value, we are possible to execute the first determination means. In the case of a such a reaction value has stabilized, the first reference value K ₁ can disable the update, it is possible to eliminate the process of updating the first reference value K ₁ speeded up examination effective.

  In the foreign matter detection apparatus according to claim 6, the inspector can recognize the possibility of containing foreign matter among those determined to be non-defective, and can take measures such as re-examination, There is an effect of preventing erroneous determination.

  In the foreign matter detection apparatus according to claim 7, when the variation of the maximum value and the minimum value of the reaction values obtained from a plurality of inspected objects becomes small and the reaction value becomes stable, the determination of the second determination means is stopped. This has the effect of speeding up the inspection process.

Hereinafter, an embodiment of an article inspection apparatus according to the present invention will be described with reference to the drawings.
FIGS. 1-10 is a figure which shows embodiment of the article inspection apparatus concerning this invention, and has shown the example which applied this invention to the X-ray foreign material detection apparatus.

As shown in FIGS. 1 and 2, the X-ray foreign object detection device 1 includes a transport unit 2, an X-ray generation unit 3, an X-ray detection unit 4 as a sensor, a light projecting / receiving unit 5, and a display output unit. The display unit 6, the operation unit 7, and the processing unit 8.
The X-ray foreign object detection device 1 is installed in a part of a transport line that transports a package 10 as an object to be inspected, and is mixed with metal, glass, stone, It detects the presence or absence of foreign matter such as bone.

The transport unit 2 includes four pulleys 2a, 2b, 2c, and 2d and an endless transport belt 2e that is wound around these pulleys. The transport unit 2 is configured to transport various packages 10 such as packed raw meat, fish, processed food, and medicine, and the X-rays generated by the X-ray generation unit 3 are transported to the package 10 being transported. Therefore, the transport unit 2 and the X-ray generation unit 3 are arranged so as to be exposed vertically.
The transport unit 2 is configured to transport the package 10 at a constant transport speed set in advance by driving of a drive motor M connected to the pulley 2a.

The X-ray generation unit 3 is disposed above the transport unit 2 at a predetermined height and is opposed to the X-ray detection unit 4 provided below the transport belt 2e.
For example, the X-ray generation unit 3 includes a cylindrical X-ray tube provided in a metal box, which is immersed in edge oil, and irradiates the anode target with an electron beam from the cathode of the X-ray tube. A line is generated. The X-ray tube is provided in the width direction whose longitudinal direction is orthogonal to the transport direction of the package 10. The X-ray generated by the X-ray tube is directed to the lower X-ray detection unit 4 by a slit (not shown) formed on the bottom surface of the box along the longitudinal direction of the X-ray tube, and has a width orthogonal to the conveyance direction. The screen is exposed in the form of a substantially triangular screen.

The X-ray detection unit 4 detects the transmission amount of X-rays that are exposed to and transmitted through the package 10. For the X-ray detection unit 4, for example, an array line sensor including a plurality of photodiodes arranged in a line and a scintillator provided on the photodiode is used. For example, 640 photodiodes are arranged with a pitch of 0.4 mm in the line direction (Y direction). The scintillator absorbs X-ray energy and emits fluorescence.
In the X-ray detection unit 4, X-rays are emitted from the X-ray generation unit 3 to the package 10, and X-rays transmitted through the package 10 are received by a scintillator and converted into light. Further, the light converted by the scintillator is received by a photodiode disposed under the scintillator. Each photodiode converts received light into an electrical signal and outputs it as X-ray intensity data 11a. The X-ray intensity data 11a is stored in the data memory 11 as X-ray intensity data 11a after A / D conversion by an A / D converter (not shown).

The X-ray intensity data 11a is used as data displayed on the display unit 6 as an X-ray transmission image or an X-ray absorption image.
Specifically, the X-ray transmission data of the package 10 is converted into a digital image by a line sensor such as a photodiode of the X-ray detection unit 4 and sampled in the transport direction at a sampling pitch substantially equal to the sampling pitch on one line. It may be displayed on the display unit 6 as an X-ray transmission image. In addition, when the X-ray absorption rate of the package 10 is α and the thickness of the package 10 is t, the intensity S ′ after the X-ray of the intensity S is transmitted through the package 10 is theoretically S ′ = S · exp ( −α · t), so if the logarithm of both sides is taken and transformed, α · t = log (S) −log (S ′) can be written, and the X-ray transmission image corresponds to the two-dimensional distribution of S ′. If the logarithm is transformed, it can be converted into an X-ray absorption image showing a two-dimensional distribution of the absorption amount α · t by the package 10. Thus, you may display on the display part 6 as an X-ray absorption image.

  The light projecting / receiving unit 5 includes a pair of light projecting units 5 a and a light receiving unit 5 b, and is disposed on the carry-in side of the transport unit 2. The light projecting unit 5a is located on one side of the transport belt 2e, the light receiving unit 5b is located on the other side of the transport belt 2e, and the light receiving unit 5b is moved when the package 10 passes between the light projecting unit 5a and the light receiving unit 5b. It is designed to be shielded from light.

The display unit 6 is connected to the bus 9 and has, for example, a display device such as a liquid crystal display shown in FIG. 3, and an X-ray fluoroscopic display 6b displayed based on the X-ray intensity data 11a, and FIGS. There is a possibility that a first reference value K ₁ , a second reference value K ₂ calculated from the coefficient k, the average value m, and the standard deviation value σ shown in FIG. For example, characters such as “OK”, “NG”, “good”, and “possibility of contamination” are displayed.

The operation unit 7 is connected to the bus 9. As shown in FIG. 3, the switch 7c for selecting the change mode the first reference value K ₁ is updated from time to time, the switch 7d for selecting the fixed mode to the first reference value K ₁ is fixed, stops the second determination A switch 7e for selecting the cancel mode, a switch 7b for selecting the reference value setting mode, and a switch 7a for selecting the foreign object detection mode are provided, and the mode can be executed by pressing each mode switch. It is like that. That is, the first determination means, the first reference value fluctuation means, the second determination means, and the warning means in the foreign object detection apparatus according to the present invention are executed by the operation unit 7, the CPU 19, and the mode execution program 12c. It is configured as follows.

When fluctuation mode by pressing the switch 7c is selected, the second reference value K ₂ is in the range of non-defective is not determined that there is foreign material by the first reference value K _1, i.e., the minimum rate to the first reference value when it is set in the range of the closed interval formed by the K _1, the first reference value K ₁ so that the value in the range of the first reference value K ₁ and the second reference value K ₂ is at any time It has been updated.
In the range of good here, when the reaction value is a value representing the absorption of X-rays absorbed in the object to be inspected, and minimum first reference value K ₁ and reaction value can take means for the reaction value when there is a value representing the transparency which has passed through the object to be inspected, means between the maximum reaction value can take a first reference value K _1.

The operation unit 7 is provided with a cross key 7i so that the cursor 7j displayed on the display unit 6 can be moved on the screen. In addition, a designation button 7h is provided at the center of the cross key 7i, and when the designation button 7h is pressed, a point designated by the cursor 7j can be designated. The cursor 7j can be moved by a mouse (not shown) connected to the operation unit 7. Using this cursor 7j, for example, by dragging moved up and down to pick up and move the cursor 7j on the first reference value K ₁ of the reference line displayed in Figure 7, a first reference value K ₁ manually It can be changed.

Further, the operation unit 7 is provided with a numeric keypad 7g, and a number input by the numeric keypad 7g is displayed on a numeric display unit 6a composed of a three-digit day-shaped segment as a part of the display unit. It has become so. For example, the coefficient k and the first reference value K ₁ shown in FIG. 7 can be input from the numeric keypad 7 g and can be displayed on the display unit 6.
In addition, the operation unit 7 is provided with an enter key 7f, and the setting is completed by pressing the key when making a final decision.

The processing unit 8 includes a recording medium such as a hard disk, and includes a data memory 11, a program storage unit 12, an X-ray generation unit drive circuit 16 that drives the X-ray generation unit 3, and an X-ray detection unit that drives the X-ray detection unit 4. The driving circuit 17 includes a motor driving circuit 18 that drives the motor M, a CPU 19 that controls each unit, and a bus 9 that connects them.
The program storage unit 12, a reference value setting program 12a for setting a first reference value _{K 1} and the second reference value _{K 2,} foreign object detection program 12b, mode execution program 12c, a first determination program 12d, the second judging program 12e The warning program 12f and the like are stored.

The data memory 11 is a readable / writable semiconductor memory such as a RAM, and the data memory 11 carries at least 640 pieces of X-ray intensity data 11a per line (Y direction). A predetermined number of lines (for example, 480 lines) corresponding to the length in the direction X is stored. Further, the data memory 11, the first reference value K ₁ and the second reference value K _2, which is set by the reference value setting program 12a is adapted to be stored in the storage area as the setting data 11b.

  The X-ray generation unit drive circuit 16 applies a predetermined power to the X-ray detection unit 4 in response to an inspection start command from the CPU 19 so that the X-ray generation unit 3 constantly emits X-rays. X-rays emitted from the ray generator 3 are input to the X-ray detector 4.

  The X-ray detector drive circuit 17 is configured to always turn on the X-ray generator 3 in response to an inspection start command from the CPU 19 and input X-rays emitted from the X-ray generator 3.

  The motor drive circuit 18 drives the motor M by supplying predetermined power to the motor M in response to a drive start command from the CPU 19.

  The CPU 19 is a processor that controls the entire X-ray foreign object detection apparatus 1. The CPU 19 controls the X-ray generation unit drive circuit 16, the X-ray detection unit drive circuit 17, the motor drive circuit 18, and the X from the data memory 11. Reading of the line intensity data 11a and the like, execution of the reference value setting program 12a stored in the program storage unit 12 and other various programs, transfer of other data, various calculations, temporary storage of data, and the like are performed. Yes.

Next, execution processing in the X-ray foreign matter detection apparatus according to the present invention will be described with reference to the flowcharts of FIGS.
First, the inspector places the packed package 10 such as cheese on the conveyor belt 2e shown in FIG. 1, and prepares for foreign object detection or reference value setting.
If the first reference value K ₁ and the second reference value K ₂ is set, select the foreign object detection mode by the switch 7a pressed Gaité X line shown in FIG. 3, the first reference value K ₁ or the second If the reference value K ₂ is not set, the examiner selects a reference value setting mode switch 7b by pressing down (S10). When either the reference value setting mode or the foreign object detection mode is selected, the CPU 19 recognizes the selected mode (S12). When the CPU 19 recognizes the reference value setting mode, the mode execution program 12c in the program storage unit 12 reads the reference value setting program 12a and starts execution of the reference value setting mode (S14), and after (A). The process is made. CPU19 is, recognizes the foreign object detection mode, the mode execution program 12c in the program storage unit 12, whether the first reference value K ₁ is set or a determination is made (S16). If the first reference value K ₁ is judged not to be set, the reference value setting program 12a is executed in the reference value setting mode is started by read (S14), a first reference value K ₁ is set If it is determined, the reference value setting program 12a is read out, the foreign object detection mode is started (S18), and the processing after (B) is performed.

  Hereinafter, the execution process of each program in the reference value setting mode (A) and the foreign object detection mode (B) will be specifically described.

The reference first reference value by value setting program 12a K ₁ and the second reference value K ₂ processing procedure for initializing (A) will be described with reference to the flowchart of FIG.

  When the reference value setting program 12a starts executing (S14), the CPU 19 outputs a drive command to the X-ray generator drive circuit 16, the X-ray detector drive circuit 17, and the motor drive circuit 18. The motor M is rotationally driven by the output drive command, and the transport unit 2 starts transporting the package 10 (S20). Next, X-rays are emitted from the X-ray generator 3 (S22).

The X-ray generation unit 3 and the X-ray detection unit 4 are always in an ON state, and the X-ray is exposed from the X-ray generation unit 3 to the X-ray detection unit 4 in a substantially triangular screen shape. (S22). When the package 10 passes through the X-ray screen, in the X-ray detection unit 4, transmitted X-rays transmitted through the package 10 are input to a scintillator provided in the X-ray detection unit 4. When the X-ray is input to the scintillator, it is converted into an electric signal by a photodiode provided in the X-ray detector 4. Based on this electrical signal, the average density of the package 10 is calculated, and the first reference value K is automatically calculated from the inspection conditions and the average density based on the characteristics of the product and package already set and stored in the data memory 11. ₁ is calculated (S24).
Further, in the same manner as the processing from step S28 of the article sensing to set the second reference value K ₂ below to step S40 to store the second reference value K _2, X-ray intensity data set 11a obtained by the article sensing the by image processing (S32) may calculate the first reference value K _1.

Next, select whether or not to set the second reference value _{K 2} (S26). The second reference value determining whether or not to set the K ₂ performs varieties of the package 10, the package 10 characteristics, the accumulated data and experience with reference to set predetermined conditions and the like as a reference. If you choose not to set the second reference value K _2, and stores the first reference value K ₁ calculated in step S24 as setting data 11b in the data memory 11 (S46), reference value setting program 12a ended. If you choose to set the second reference value K _2, X-rays which are exposure to the package 10 are converted into light by the scintillator in X-ray detection unit 4, electricity from light by the photodiodes of the X-ray detector 4 It is converted into a signal and stored in the data memory 11 as X-ray intensity data 11a (S30). The X-ray intensity data 11a is converted from an analog signal to a digital signal by an A / D converter (not shown), and further converted to luminance information of 256 gradations from 0 to 255 so as to emphasize a portion corresponding to a foreign object. Filter processing is performed, and image processing is performed so as to obtain a value corresponding to the density (S32).

Next, the number of packages 10 that have been transported and exposed to X-rays is counted by the count arrival signal output means (S36). It is determined whether or not the counted number has reached the predetermined number (S38). If it is determined that the predetermined number has not been reached, the transmitted X-rays that have been exposed to the X-rays and transmitted through the package 10 are determined. Is detected by the X-ray detector 4 (S28), and the process is repeated until step S38. If it is determined that has reached the predetermined number, the second reference value K ₂ calculated are stored in the data memory 11 (S40). Counted as the predetermined number of packages 10 to be counted by the arrival signal output means is determined in accordance with the type and characteristics of the package 10 can be increased more as the second reference value K ₂ accuracy. However, since the efficiency of the reference value setting decreases as the predetermined number increases, at most 1,000 is preferable, 100 to 5 is more preferable, and 20 to 10 is particularly preferable.

When calculating the second reference value K ₂ (S34), for example, reaction with an article detected by exposure to X-ray detector 4 to the X-ray is made in the package 10, a reaction value regarding the outputted response signal, determining Assuming that the average value of the reaction values 10a to be m is m, the standard deviation value of the reaction values 10a is σ, and an arbitrary coefficient is k, an equation represented by K ₂ = m + kσ may be used.
The coefficient k is a coefficient for determining an effective deviation value from the average value m, and is represented by k = (K ₂ −m) / σ. For example, 2 to 5 is preferable, and 3 to 4 is more preferable. Coefficient k by pressing Gaité confirm the entered enter key 7f numbers from the numeric keypad 7g of the operation unit 7, is used to calculate a second reference value K _2. The coefficient k may be stored in advance in the data memory 11 based on the product type, package characteristics, accumulated data, experience value, etc., and automatically read out and used in the calculation. The standard deviation value σ is expressed by the following equation (1).

式（１）中、ｎは自然数、ｘは検出された個々の反応値１０ａを表す。
具体的に選択された値は、図７〜図１０に示すように、表示部６に表示されたグラフの画面に表示するようにしてもよい。

In formula (1), n represents a natural number, and x represents each detected reaction value 10a.
The specifically selected value may be displayed on the screen of the graph displayed on the display unit 6 as shown in FIGS.

Specifically, when the coefficient k is 3, the second reference value K ₂ becomes K ₂ = m + 3σ from the following equation, K ₂ = m + kσ, and as shown in FIG. 7, from the first reference value K ₁ Is also a value obtained by adding 3σ to the average value represented by m, and satisfying the following equation, K ₁ > K ₂ (= m + 3σ). Second reference value K ₂ is based on the standard deviation sigma of the average value m and reaction value 10a of the reaction value 10a of each package 10, along with the variations of m and sigma, shown in FIGS. 8 to 10 Fluctuates as represented by the curve. That, or greater average value m, the maximum value and the greater the variation in the minimum standard deviation of the reaction value 10a sigma may become large varies so as to increase the second reference value K ₂ is also.

When the coefficient k to a small value, as shown in FIG. 7, k? Is reduced, the second reference value K ₂ will be close to the average value m. When the coefficient k to a value larger, so that the second reference value K ₂ approaches the first reference value K _1. Specifically, the coefficient k is determined in the range of 2 to 5 depending on the type and characteristics of the package 10. In the middle of the processing procedure in the foreign object detection mode, it is possible to temporarily stop and change the coefficient k to a value different from the executed value. In this case, a numerical value is input from the numeric keypad 7g of the operation unit 7, and the enter key 7f is pressed to set.
When the coefficient k is input, it is set second reference value K ₂ is stored as setting data 11b in the data memory 11 (S40), is the image processing, as shown in FIG. 7, the second reference value K ₂ Is displayed on the display unit 6 by a one-dot chain line.
Incidentally, the second reference value K ₂ shown in FIGS. 7 to 10 may not be displayed on the display unit 6 for speeding up the detection process, it may be omitted the step of graphical representation.

Next, it is judged whether or not to update the first reference value _{K 1} calculated in step S24 (S42). If it is determined not to update the first reference value K _1, and stores the first reference value K ₁ calculated in step S24 in the data memory 11 (S46) the reference value setting program 12a ended. If it is determined to update the first reference value _{K 1,} and updates the first reference value _{K 1} calculated in step S24 (S44), and stored in the data memory 11 (S46) the reference value setting program 12a ended.

Determining whether to update the first reference value K ₁ performs varieties of the package 10, the package 10 characteristics, the accumulated data and experience with reference to set predetermined conditions and the like as a reference. Depending on the type and characteristics of the package 10, to improve the first reference value accuracy K _1, as shown in FIG. 9, it may be updated values for lowering the first reference value K _1. In particular, for those reactions value 10a of the package 10 is stable, even if narrowed with the first reference value K ₁ the width of the second reference value K ₂ to b from a, there is no possibility of an erroneous determination, In addition, there is less possibility that foreign matter is contained but there are fewer warnings, the detection accuracy is improved, and speeding up of the inspection is promoted.

Further, as shown in FIG. 10, for those average value m of the reaction value 10a of the package 10 is gradually changed in a direction becomes high, also be updated values in upward direction increases the first reference value K ₁ it can. The value updated in the upward direction, it is possible to secure a width b that approximates the first reference value K ₁ and the width a of the second reference value K _2. That is, it is possible to secure an area for determining the possibility of containing foreign matter, effectively execute the second determination, and obtain a more accurate detection result.

When the first reference value K ₁ is set, the first reference value K ₁ is the image processing, as shown in FIG. 7, the horizontal line indicated by the first reference value K ₁ as the dashed-dotted line is displayed. This display, in the middle of the mountain, is where the reaction value 10a is partially projecting, higher concentration than the first reference value K ₁ is ascertained visually. If you do not update the first reference value K _1, as shown in FIG. 8, a first reference value K ₁ is displayed as a horizontal line of constant value that does not change vertically.
When updating the first reference value K _1, as shown in FIGS. 9 and 10, the first reference value K ₁ is displayed as a curve which varies up and down over time.
The graph of the first reference value K ₁ and reaction value 10a shown in FIGS. 7 to 10 may not be displayed on the display unit 6 for rapid inspection process, graphical representation of the step may be omitted .

Next, the set with the first reference value K ₁ and the second reference value K _2, to detect the presence or absence of a foreign matter content of the package 10, the foreign matter detection processing procedure by determining foreign object detection program 12b acceptability of the test ( B) will be described with reference to the chart of FIG.

First, a package 10 of the same type as the package 10 used in the reference value setting is placed on the transport belt 2e. Then, when the examiner presses the switch 7a of the foreign object detection mode of the operation unit 7 (S10), the mode execution program 12c in the program storage section 12 is read out foreign object detection program 12b is a first reference value K ₁ There determination of whether it is set is made (S16), if the first reference value K ₁ is judged not to be set, the reference value setting program 12a is the execution reference value setting mode is started read (S14), if the first reference value K ₁ is determined to be set, the reference value setting program 12a is executed in the foreign matter detection is started by read (S18), (B) the following foreign object detection Processing is done.

  When the foreign object detection is started, a drive command is output from the CPU 19 to the X-ray generation unit drive circuit 16, the X-ray detection unit drive circuit 17, and the motor drive circuit 18. As a result, the motor M is driven to rotate, and the transport unit 2 starts transporting the package 10 (S100), the X-ray generation unit 3 and the X-ray detection unit 4 are always in the ON state, and the X-rays are transferred to the package 10. It is exposed (S102).

  When the package 10 is transported and passes between the light projecting unit 5a and the light receiving unit 5b, the emitted light from the light projecting unit 5a is blocked. Thereby, it can be detected that the package 10 passes. When the package 10 passes through the X-ray screen exposed to the substantially triangular screen shape from the X-ray generation unit 3 a few seconds after the light receiving unit 5a detects the light shielding, the X-ray detection unit 4 The transmitted X-ray transmitted through the package 10 is input to the scintillator. Next, it is converted into an electric signal by the photodiode of the X-ray detector 4, and is output to the data memory 11 and stored as X-ray intensity data 11a (S104).

  The X-ray intensity data 11a stored in the data memory 11 is converted into luminance information of, for example, 256 gradations as preprocessing, and then image processing for generating X-ray image data of the package 10 is performed by a feature extraction filter. (S108). Further, as shown in FIG. 7, the horizontal axis represents time, the vertical axis represents density of 256 gradations, and graph data, fluoroscopic image data, etc. are generated that show the change in the reaction value 10a in the package 10 as a curve. Display processing is performed. The data generated by the display process is displayed on the display unit 6 as an X-ray fluoroscopic display 6b of the package 10 as shown in FIG. Moreover, as shown in FIG. 7, it displays on the number display part 6a of the display part 6 as a graph which consists of a curve. In FIG. 7, the three peak portions represented by the curves represent the three packages 10, respectively. The concavo-convex curve in each mountain represents the concentration of X-rays absorbed in the portion of the package 10 where X-rays are transmitted, and the convex portion is the concentration in one line (absorption amount of X-rays). Represents the peak value. Of the three peaks in the middle, the reaction value 10a partially protrudes, indicating that the concentration peak value is partially high.

  On the other hand, instead of the two-dimensional graph of density and time in FIG. 7, a three-dimensional solid graph is used in which the vertical axis represents density, the horizontal axis represents time, and the depth direction axis represents the length direction of one line. By displaying the package 10 in three dimensions, the peak position of the concentration based on the reaction value 10a of the package 10 can be displayed in three dimensions. Note that these display processes may be omitted for speeding up the detection process.

Next, the maximum value of the reaction value 10a for each X-ray exposure detected from the package 10, that is, the X-ray intensity data 11a stored in the data memory 11 is subjected to image processing, and image data after image processing is performed. by comparing the first reference value K ₁ executes the first determination determines the presence or absence of foreign matter content (S110). By comparison, the image processed image data, when was larger than the first reference value K _1, the portion of the value is determined as a foreign substance, is treated as failed inspection (S114). Further, when the foreign object detection process is continued, steps S104 to S144 are repeatedly performed. When the foreign object detection process is not continued, the foreign object detection program 12b is terminated.

Then, there is no value greater than the first reference value K ₁ in the first determination, the package 10 of the foreign matter is determined not, the implementation of the second determination of whether to determine the likelihood of foreign matter containing Is selected (S120). Whether or not the second determination can be performed may be selected in advance before the foreign object detection program 12b is executed (S18). Even if the execution of the second determination is selected in advance, the second determination stop mode switch 7e shown in FIG. 3 is depressed during the foreign object detection process to stop the execution of the second determination program 12e. The execution of the second determination can be stopped and the speed of the foreign object detection process can be promoted.

  In addition, the number of determination executions or the determination execution period for determining the presence or absence of foreign matter in the package 10 is counted and set to output a count arrival signal when reaching a preset value, and the output count arrival is reached. Based on the signal, the second determination program 12e may be executed, and when the count arrival signal is received, the second determination for determining the presence or absence of foreign matter may be automatically stopped. For example, based on a plurality of reaction values 10a such as the type and characteristics of the package 10, the number of determination executions and the determination execution period until the range of the plurality of reaction values 10a detected in the package 10 is reduced and the reaction value 10a is stabilized. Is set in advance, and when the set number of determinations or determination period is reached, the foreign object detection process can be made more efficient by stopping the second determination.

When the execution of the second determination is selected, the count arrival signal output means indicates how many packages 10 have been detected from the first package 10 that has started conveyance (S100) to the package 10 that is currently detected. And a count arrival signal is output (S122). When the count arrival signal is output, it is determined whether or not the number of packages 10 reaches a predetermined number based on the count arrival signal (S124). If the number is less than the predetermined number, the X-ray intensity stored in the data memory 11 is determined. the image data of the data 11a and the image processing and the second reference value _{K 2} is the comparison processing (S130). If it has reached the predetermined number, a new value by reviewing the second reference value K _2, calculated on the basis of the reaction value 10a of a predetermined number, updating (S126). And the second reference value K ₂ and clears the count when it is updated (S128) to prepare for the next count.

The reason why the number of packages 10 reaches a predetermined number is to update the second reference value K ₂ to a more accurate value. That is, since the second reference value K _2, which is calculated based on the reaction value 10a, the average value m of the reaction value 10, the coefficient k and the standard deviation sigma, Update to obtain a more accurate value, given It is because the reaction value 10a more than a number is required. The predetermined number is appropriately selected depending on the product type, package characteristics, accumulated data, experience value, and the like. For example, 5,000 to 50 are preferable, and 1,000 to 100 are more preferable.

Then, when the count is cleared, the image data of the X-ray intensity data 11a stored in the data memory 11 and the image processing and the second reference value K ₂ is the comparison processing (S130). The image data of the X-ray intensity data 11a and image processing, when not larger than the second reference value K _2, the inspection pass process is performed (S134), a value larger than the second reference value K ₂ If this happens, the warning program 12f is executed via the CPU 19 to warn that there is a possibility that foreign matter is contained in the package 10 (S136).

This warning is further displayed based on, for example, the reaction value 10a of the package 10 and the image processed image data, and is displayed on the number display unit 6a of the display unit 6 as shown in FIG. Three Yamanouchi shown in FIG. 7, the projecting portions of the central portion in the left side of the mountain, shows a value greater than the second reference value K _2, by displaying in such a graph, the possibility of foreign matter containing It can be visually recognized that there is. In addition, this warning may be displayed on the numeric display 6a as “the package 10 may contain foreign substances”, and data that is digitized as data output means or a voice device (not shown) as voice output means. ). For the package 10 thus warned, as shown in FIG. 6, the reexamination may be started from step S100 by changing the posture of the package 10 on the transport belt 2e by the same foreign object detection device. The foreign matter detection apparatus may be used to re-inspect by a different inspection method.

If any of the steps S134 and S136 is completed, whether or not to disable the update of the first reference value _{K 1} it is determined (S138). If it is determined not to invalidate the update, the update is performed first reference value K ₁ (S142). If it is determined that the update is invalid, it is determined whether or not the foreign object detection program 12b is to be ended. If not, the package 10 is further transported, and steps S104 to S144 are executed. Decision whether to invalidate the update of the first reference value K ₁ is breed, characteristics of the package, is carried out on the basis of such stored data and experience. When the foreign object detection processing for all the packages 10 is performed, the foreign object detection program 12b ends.

As described above, in the foreign matter detection apparatus according to the present invention, (1) by the execution of the foreign matter detection program 12b, X-rays are exposed to the package 10 transported by the transport unit 2, and the X-ray detection unit 4 It reacts foreign matter mixed in the package 10 is reacted signal output, the first reference value K ₁ and the first determination program set by the maximum value and the reference value setting program 12a in the reaction value 10a obtained from the response signal In comparison with the execution of 12d, the presence / absence of a foreign substance is determined, and an acceptable product and an unacceptable product are selected. Furthermore, the package 10 that have not been rejected by the execution of the first determination program 12d, a second reference value K ₂ is to be updated on the basis of the reaction value 10a of the reaction value 10a Toko by execution of the second judging program 12e It is compared and it is determined whether or not there is a possibility of containing foreign matter. If it is determined that there is a possibility that the package 10 contains foreign matter, the warning program 12f is executed, and the display unit 6 displays that the package 10 may contain foreign matter. From this display, the inspector can recognize that there is a possibility that foreign matter is mixed in the package 10, and can detect the presence or absence of foreign matter again with a foreign matter detection device or the like, and the presence or absence of foreign matter with higher accuracy. Can be detected.

In the foreign matter detection device according to the present invention, (2) by the execution of the reference value setting program 12a, the second reference value K ₂ is the average value m of the reaction value 10a, and the standard deviation value σ of the reaction value 10a, the coefficient k Thus, the calculation process is performed so as to satisfy K ₂ = m + kσ and is updated as needed, so that the accuracy of the second reference value K ₂ is further increased.

Foreign matter detection device according to the present invention, (3) by the execution of the first determination program 12d, when the second reference value K ₂ is set in the range of non-defective it is not determined that there is foreign material by the first determination the first reference value K ₁ is updated to a value within the range of the first reference value K ₁ and the second reference value K _2. Reaction value 10a by the first judgment is determined that the first reference value K ₁ is smaller than even the package 10 it is determined that the foreign object without, by the execution of the second judging program 12e, reaction value 10a and the second reference in a second determination is compared with the value K ₂ is the reaction value 10a is determined to be greater than the second reference value K _2, it is determined that the possibility of foreign matter content there for package 10, more accurate detection results obtained It is done.

In the foreign matter detection device according to the present invention, (4) by executing a first determination program 12d, the second reference value K ₂ is in the range of reaction value 10a of good it is not determined that there foreign matter by the first reference value K ₁ is set to, and when the average value m of the reaction value 10a of the defective varies toward the first reference value K _1, such that the first reference value K ₁ moves away from the average value m of the reaction value 10a of the defective Updated. Specifically, by execution of the change mode of the reference value, when the average value m of the reaction value 10a is increased, because it is updated to the first reference value K ₁ is increased, it does not contain foreign matter reaction value 10a itself of the package 10 increases, even if the average value m of the plurality of reaction value 10a becomes large, since the first reference value K ₁ is increased, first reference value before the reaction value 10a updates K ₁ Even if it becomes larger, it is not determined that there is a foreign object, and erroneous determination is prevented.

In the foreign matter detection device according to the present invention can be set (5) by executing the standard setting program 12a, so that updates the first reference value K ₁ is invalid. Specifically, the first reference value K _1, and pressing one of the switches 7c of switch 7d or fluctuation mode of the fixed mode can be selected, the examiner, for example, was detected in the package 10 multiple ranges is smaller reaction value 10a of the reaction value 10a is fixed to the first reference value K ₁ is about what is stable, the plurality of detected range is larger reaction value 10a of the reaction value 10a of the package 10 is stabilized for those not is corresponds to the reaction value 10a, the first reference value K ₁ may be updated from time to time.

  In the foreign object detection apparatus according to the present invention, (6) by executing the warning program 12f, characters or images are output to the display unit 6, data is output to the outside, and sound is output. The warning can be recognized from the display by the image, the output data and the voice, and the package 10 related to the warning can be reinspected.

  In the foreign object detection apparatus according to the present invention, (7) a value set in advance by counting the number of determination executions or the determination execution period for determining whether or not the package 10 contains foreign objects by executing the foreign object detection program 12b. The count arrival signal can be set to be output when the count reaches, and the second determination program 12e is executed based on the output count arrival signal. The second determination for determining the presence or absence can be canceled. For example, based on a plurality of detection data such as the type and characteristics of the package 10, the number of determinations and the determination execution period until the range of the plurality of reaction values 10a detected from the package 10 becomes smaller and the reaction value 10a becomes stable are determined. When the preset number of determinations or determination execution period is reached, the second determination can be stopped to increase the efficiency of the inspection process.

  As described above, the present invention uses a reference value corresponding to the type and characteristics of food and the like, and a highly accurate reference value that varies based on the reaction value, to determine the presence or absence of foreign matter mixed in food or the like. If it is a foreign object detection device that has the effect of being able to detect with high accuracy and determines the presence or absence of a foreign object using a set reference value, not only an X-ray foreign object detection device but also a magnetic field It is also useful for metal detectors that detect metal mixed in objects and other foreign matter detection devices.

It is a perspective view which shows the structure of one Embodiment of the foreign material detection apparatus concerning this invention. It is a block diagram which shows the structure of one Embodiment of the foreign material detection apparatus concerning this invention. It is a top view which shows the operation part of one Embodiment of the foreign material detection apparatus concerning this invention. It is a flowchart which shows the mode selection execution process of one Embodiment of the foreign material detection apparatus concerning this invention. It is a flowchart which shows the reference value setting process sequence of the foreign material detection of one Embodiment of the foreign material detection apparatus concerning this invention. It is a flowchart which shows the foreign material detection processing procedure of one Embodiment of the foreign material detection apparatus concerning this invention. It is a graph which shows the specific example of the determination by the reaction value and reference value of one Embodiment of the foreign material detection apparatus concerning this invention. It is a graph which shows the specific example of the reaction value of one Embodiment of the foreign material detection apparatus concerning this invention, and a reference value. It is a graph which shows the specific example of the determination by the reaction value and reference value of one Embodiment of the foreign material detection apparatus concerning this invention. It is a graph which shows the specific example of the determination by the reaction value and reference value of one Embodiment of the foreign material detection apparatus concerning this invention.

Explanation of symbols

1 X-ray foreign matter detection device (foreign matter detection device)
2 Transport unit 2a, 2b, 2c, 2d Pulley 2e Transport belt 3 X-ray generation unit 4 X-ray detection unit (sensor)
5 Light Emitting / Receiving Unit 5a Light Emitting Unit 5b Light Receiving Unit 6 Display Unit (Display Output Means)
6a Numerical display section 6b X-ray fluoroscopic display 7 Operation section 7a, 7b, 7c, 7d, 7e Switch 7f Enter key 7g Numeric keypad 7h Designated button 7i Cross key 7j Cursor 8 Processing section 9 Bus 10 Package (inspection object)
10a Reaction value 11 Data memory 11a X-ray intensity data 11b Setting data 12 Program storage unit 12a Reference value setting program 12b Foreign matter detection program 12c Mode execution program 12d First determination program 12e Second determination program 12f Warning program 16 X-ray generation unit drive Circuit 17 X-ray detector drive circuit 18 Motor drive circuit 19 CPU

Claims (7)

A sensor that outputs a reaction signal in response to a foreign substance mixed in the object to be inspected on the conveyance path and compares the reaction value based on the reaction signal with the first reference value K1 to determine the presence or absence of the foreign substance. In the foreign object detection device having the first determination means to
Among the reaction values, the second reference value K2 based on the peak value of the reaction value of the non- defective product that has not been determined to be foreign by the first determination means is a range in which it is not determined that there is foreign by the first reference value K1. a second reference value setting means for setting a,
After the second reference value K2 is set, the peak value of the reaction value related to the reaction signal output from the sensor is compared with the second reference value K2 to determine whether or not there is a possibility of containing foreign matter. A second determination means;
When the first determination means does not determine that the inspection object is foreign and the second determination means determines that the inspection object may contain a foreign object, the foreign object is present in the inspection object. Warning means to warn of possible inclusion,
A foreign matter detection apparatus comprising:   The second reference value setting means updates the second reference value K2 based on an average value m of the reaction values obtained from a predetermined number of the non-defective products and a standard deviation value σ. The foreign matter detection device described in 1.   The first determination means sets the first reference value K1 and the first reference value K2 when the second reference value K2 is set within the range of the non-defective product that is not determined to have foreign matter by the first reference value K1. The foreign matter detection device according to claim 1, further comprising a first reference value update unit configured to update the first reference value K1 so as to be a value within a range of two reference values K2.   In the first determination means, the second reference value K2 is set within the range of the non-defective product that is not determined to be foreign by the first reference value K1, and the average value m of the reaction values of the non-defective product is When it fluctuates in the direction approaching the first reference value K1, it has first reference value update means for updating the first reference value K1 so as to be away from the average value m of the response values of the good products. The foreign object detection device according to claim 1 or 2.   The first reference value update means includes first reference value update invalid setting means that can be set so as to invalidate the update of the first reference value K1. The foreign matter detection device described in 1.   6. The warning means includes at least one of a display output means for outputting characters or images, a data output means for outputting data to the outside, and an audio output means for outputting sound. The foreign matter detection device according to any one of the above. The count arrival signal that outputs the count arrival signal when the first determination means counts the number of determinations performed or the determination period for determining whether or not there is a foreign object on the inspection object and reaches a preset value. Comprising output means,
The said 2nd determination means stops the determination of the presence or absence of a foreign material containing, when receiving the said count arrival signal, The any one of Claims 1-6 characterized by the above-mentioned. Foreign object detection device.

Images