JP2018141736A - X-ray inspection device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide an X-ray inspection device that inspects presence or absence of foreign matters getting mixed in with an inspected object, and can measure a mass of the inspected object with high accuracy.SOLUTION: An X-ray inspection device 1 comprises: an X-ray inspection unit 10 that irradiates an inspected object in transit with an X-ray, and detects the X-ray transmitting the inspected object to output detection information; a transmission image data generation unit 21 that generates transmission image data on the X-ray of a plurality of different energy areas, respectively; a determination unit 23 that conducts differential processing between at least two transmission image data, and determines presence or absence of a foreign matter getting mixed in with the inspected object, using the transmission image data having the differential processing conducted; and a mass measurement unit 24 that measures mass of the inspected object on the basis of second transmission image data serving as the transmission image data on the X-ray of a second energy area higher in an energy than the X-ray of a first energy area.SELECTED DRAWING: Figure 1

Description

  The present invention relates to a technique for detecting foreign matter in an inspection object using X-rays and measuring the mass of the inspection object.

  In factories that manufacture foods and the like, X-ray inspection devices are used to check whether foreign substances such as metals and plastics are mixed in the products. Such an X-ray inspection apparatus emits X-rays to a passage of an inspection object conveyed in a predetermined direction by a conveyor or the like, and detects X-rays transmitted through the inspection object by an X-ray detection unit. A transmission image is generated from the signal, and the presence or absence of a foreign object is determined using the transmission image.

  Furthermore, in order to improve the foreign matter detection accuracy, two pieces of transmission image data having different X-ray energies are acquired, and processing such as subtraction (difference processing of image data) on the two pieces of transmission image data is performed. An X-ray inspection apparatus that employs a method (dual energy method or multi-energy method) for improving the detection accuracy of the above has also been proposed.

  There is also an X-ray inspection apparatus that has a function of measuring the mass of an object to be inspected in addition to inspecting the presence or absence of foreign matter (see Patent Document 1). Such an X-ray inspection apparatus measures the mass of an object to be inspected by performing arithmetic processing using a mass attenuation coefficient indicating a rate of attenuation of X-rays transmitted through a substance and density data of a transmission image.

Japanese Patent Laid-Open No. 2006-300888

  The above-described mass attenuation coefficient varies depending on the energy of X-rays and is affected by the difference in material quality. Here, in an X-ray inspection apparatus for inspecting the presence or absence of foreign matter, a transmission image including low-energy X-rays in which the difference in mass attenuation coefficient due to the material becomes significant so that the object can be easily distinguished from the foreign matter. Data may be preferred.

  On the other hand, when the mass of an object to be inspected is measured using transmission image data including low-energy X-rays, the actual mass attenuation coefficient is affected by variations in the material of the object to be inspected, thereby reducing the accuracy of mass measurement. There was something to do. In particular, when a substance to be inspected is a substance in which different substances are mixed and the ratio varies from individual to individual, such as cookies with chocolate chips, the accuracy of mass measurement has been reduced.

  An object of the present invention is to provide an X-ray inspection apparatus that solves the above-described problems, inspects for the presence or absence of foreign matter mixed in an inspection object, and can measure the mass of the inspection object with high accuracy.

In order to achieve the object, an X-ray inspection apparatus according to claim 1 of the present invention includes:
An X-ray inspection unit 10 that irradiates an object under inspection with X-rays, detects X-rays transmitted through the object under inspection, and outputs detection information;
Using the detection information, X-rays in a plurality of different energy regions including X-rays in a first energy region and X-rays in a second energy region having higher energy than the X-rays in the first energy region A transmission image data generation unit 21 for generating transmission image data of
A determination unit that performs a difference process between at least two pieces of the transmission image data among the plurality of the transmission image data, and determines the presence or absence of foreign matter mixed in the inspection object using the difference-processed transmission image data 23,
And a mass measuring unit 24 that measures the mass of the inspection object based on second transmission image data that is X-ray transmission image data of the second energy region.

The X-ray inspection apparatus according to claim 2 of the present invention is the X-ray inspection apparatus according to claim 1,
The X-ray in the second energy region has an X-ray energy of 50 keV or more.

The X-ray inspection apparatus according to claim 3 of the present invention is the X-ray inspection apparatus according to claim 1 or 2,
The mass measuring unit identifies an imaging region of the inspection object in the transmission image of the second transmission image data, and sets density data in pixel units of the second transmission image data for all pixels in the imaging region. The sum is calculated, and the mass of the object to be inspected is calculated using the sum and the mass attenuation coefficient corresponding to the X-rays in the second energy region.

The X-ray inspection apparatus according to claim 4 of the present invention is the X-ray inspection apparatus according to claims 1 to 3,
The X-ray inspection unit is an X-ray generation unit 11 and a photon detection type that outputs a pulse signal having a peak value corresponding to the energy of the photon every time an X-ray photon transmitted through the inspection object is input. An X-ray detector 12;
The transmission image data generation unit determines which one of the plurality of different energy regions the peak value of the pulse signal falls in, and uses the cumulative result obtained by accumulating the number of pulse signal inputs for each energy region. X-ray transmission image data of different energy regions is generated.

The X-ray inspection apparatus according to claim 5 of the present invention is the X-ray inspection apparatus according to claims 1 to 3,
The X-ray inspection unit transmits the X-ray generation unit 11, the first X-ray detection unit 12a that detects X-rays in the first energy region that has passed through the inspection object, and the inspection object. And a second X-ray detector 12b for detecting X-rays in the second energy region.

The X-ray inspection apparatus according to claim 6 of the present invention is the X-ray inspection apparatus according to claims 1 to 3,
The X-ray inspection unit includes a first X-ray generation unit 11a that emits X-rays in the first energy region, and a second X-ray generation unit 11b that emits X-rays in the second energy region; From the first X-ray detector 12a that detects X-rays from the first X-ray generator that has passed through the inspection object, and from the second X-ray generator that has passed through the inspection object And a second X-ray detector 12b for detecting X-rays.

  The present invention generates X-ray transmission image data of a plurality of different energy regions, performs a difference process between the plurality of transmission image data, and uses the difference-processed transmission image data to inspect an object to be inspected. The mass of the object to be inspected is measured using the X-ray transmission image data in the high energy region among the plurality of generated transmission image data. For this reason, even if it is a to-be-inspected object which is not uniform, the influence of a mass attenuation coefficient can be reduced and the accuracy of the mass measurement of a to-be-inspected object can be improved.

It is a block diagram of embodiment of this invention. It is a figure which shows the relationship between X-ray energy and a mass attenuation coefficient. It is a figure which shows the detailed structure of an X-ray inspection part and a transmission image data generation part. It is a figure which shows the relationship between the pulse signal output from a sensor, and an area | region. It is a figure which shows another example of an X-ray inspection part. It is a figure which shows another example of an X-ray inspection part.

  Hereinafter, embodiments of the present invention will be described with reference to the drawings. FIG. 1 shows the overall configuration of an X-ray inspection apparatus 1 to which the present invention is applied.

  The X-ray inspection apparatus 1 includes a transport unit 2, an X-ray inspection unit 10, a processing unit 20, and a display unit 30.

  The transport unit 2 is for transporting the inspection object Z in a predetermined direction (the direction of the arrow Y in the figure, hereinafter referred to as the transport direction). Generally, the inspection object Z is fixed like a conveyor. A device that transports horizontally at a speed is used, but it is not always necessary to use a transport device that has a power source. Instead, it uses a method of sliding on the ramp using the weight of the object to be inspected or a method of dropping from above. There may be.

  The X-ray inspection unit 10 includes an X-ray generation unit 11 and an X-ray detection unit 12.

  The X-ray generation unit 11 emits X-rays to a conveyance path along which the inspection object Z is conveyed in a predetermined direction by the conveyance unit 2. In this embodiment, X-rays are emitted from above the inspection object Z conveyed by the conveyance unit 2, but the X-ray emission direction is not limited to this, and the side direction of the inspection object Z from the side. The light may be emitted from the lower side or may be emitted from the lower side upward.

  Examples of the X-ray source of the X-ray generator 11 include a hot cathode X-ray tube that accelerates electrons emitted from an overheated filament and collides with an anode target to emit X-rays, and a lattice-controlled hot cathode. An X-ray tube is used.

  The X-ray detection unit 12 has a plurality of sensors that receive X-rays and convert them into electric signals, and thereby has a function of detecting X-rays and outputting the detection information as electric signals. The plurality of sensors are positions that receive X-rays emitted from the X-ray generation unit 11 and transmitted through the inspection object Z, and are spaced in a direction perpendicular to the conveyance direction of the inspection object Z (width direction of the conveyance path). It is lined up in a row with almost no.

  Actually, the X-ray detection unit 12 is configured by a single line sensor in which a plurality of sensors are integrally connected, and is disposed on the lower surface side of the transport path of the transport unit 2. Here, for example, assuming that the width of the sensor is 1 mm, the gap between the sensors is negligibly small with respect to the width, and the width of the transport path for transporting the inspection object Z is 200 mm, a line having approximately 200 sensors. A sensor may be used.

  The X-ray detection unit 12 can output detection information in each of the plurality of energy regions with respect to X-rays in a plurality of different energy regions. Details of this configuration will be described later.

  The processing unit 20 includes a transmission image data generation unit 21, a transmission image data storage unit 22, a determination unit 23, and a mass measurement unit 24. The processing unit 20 is realized by a combination of hardware (not shown) such as a CPU (Central Processing Unit) and RAM (Random Access Memory) and a program executed by the CPU. Alternatively, the processing unit 20 may be configured by hardware such as an FPGA (Field Programmable Gate Array) or a DSP (Digital Signal Processor).

  The transmission image data generation unit 21 is an electrical signal output from each of the plurality of sensors of the X-ray detection unit 12 while the inspection object Z passes between the X-ray generation unit 11 and the X-ray detection unit 12. Detection information) is divided into scan times, and predetermined signal processing is performed, and information on a two-dimensional position determined by the conveyance direction of the inspection object Z and the alignment direction of the sensors and the signal processing result for each position are inspected. Transmission image data of the object Z is generated.

  In response to the X-ray detection unit 12 outputting detection information in each of the plurality of energy regions, the transmission image data generation unit 21 transmits the transmission image of the inspection object Z corresponding to each of the plurality of energy regions. Generate data.

  Specifically, the X-ray detection unit 12 outputs detection information in a certain energy region (first energy region), and the transmission image data generation unit 21 transmits transmission image data (first data based on this detection information). Transmission image data: A) of FIG. 1 is generated. The first energy region is, for example, an energy region in which X-ray energy is 20 keV to 40 keV. In addition, the X-ray detection unit 12 outputs detection information in an energy region (second energy region) different from the first energy region, and the transmission image data generation unit 21 transmits transmission image data ( Second transmission image data: B) in FIG. 1 is generated. This second energy region is, for example, an energy region in which X-ray energy is 50 keV to 70 keV.

  That is, the X-ray energy has a relationship of “first energy region” <“second energy region”. In the above-described example, the first energy region is set to 20 keV to 40 keV, the second energy region is set to 50 keV to 70 keV, and the two energy regions are separated from each other. However, the present invention is not limited to this. . The relationship between these two energy regions may be any of separation, adjacent, and partial overlap, and it is only necessary that the median value of each energy region satisfies the above-described magnitude relationship. Further, the number of energy regions is not limited to two, and may be three or more energy regions having different medians.

  The transmission image data storage unit 22 stores transmission image data generated by the transmission image data generation unit 21 corresponding to each of the plurality of energy regions.

  The determination unit 23 receives at least two pieces of transmission image data among a plurality of pieces of transmission image data stored in the transmission image data storage unit 22 and performs a difference process (energy subtraction process) between these pieces of transmission image data. Based on the result of the difference processing, the presence or absence of foreign matter in the inspection object Z is determined. By this difference processing, transparent image data in which foreign matter is emphasized is obtained, so that the determination accuracy can be improved. This determination result (a signal indicating the presence or absence of foreign matter) is sent to a subsequent sorting device (not shown), and the inspection object Z determined to have foreign matter is excluded from the non-defective product path.

  The mass measurement unit 24 receives the transmission image data stored in the transmission image data storage unit 22 and measures the mass of the inspection object Z by performing a predetermined calculation on the transmission image data. Here, the transmission image data received from the transmission image data storage unit 22 by the mass measurement unit 24 corresponds to the second energy region described above among the transmission image data generated corresponding to each of the plurality of energy regions. This is transmission image data (second transmission image data). Details of the mass measuring unit 24 will be described later.

The display unit 30 includes a display device such as an LCD (Liquid Crystal Display). The display unit 30 receives the determination result from the determination unit 23, the measurement result from the mass measurement unit, and the transmission image data from the transmission image data storage unit 22 or the determination unit 23, and displays these pieces of information that can be easily viewed by the inspector. Display in format.

Here, the interaction between the X-ray and the workpiece W will be described. When X-rays pass through the inspection object Z, the X-rays are attenuated by interaction (absorption, scattering, etc.) with the inspection object Z. The ratio of the attenuation is represented by the linear attenuation coefficient mu, called the result of the linear attenuation coefficient mu divided by the density ρ of the object Z to the mass attenuation coefficient mu _m. Unit of mass attenuation coefficient mu _m is a [cm ² / g] or [pixel / g] (the case of the reference pixel (pixel) for image processing).

Figure 2 is a graph for different elements, showing the relationship between the X-ray energy and mass attenuation coefficient mu _m. As shown in this graph, the X-ray energy is low, the difference between the mass attenuation coefficient mu _m by elemental increases. On the other hand, as the X-ray energy increases, the smaller the difference between the mass attenuation coefficient mu _m by elemental and X-ray energy is approximately equal to or greater than 50 keV, the smaller the difference between the mass attenuation coefficient mu _m by elemental is negligible. This is because, as the X-ray energy increases, Compton scattering among the above-described interactions becomes dominant, and the difference between the elements decreases.

Next, mass measurement by the mass measurement unit 24 will be described. When the position of an arbitrary pixel on the transmission image is represented by (i, j), the number of photons of X-rays incident on the inspection object Z is represented by I ₀ (i, j) and the number of photons after transmission is represented by this pixel. If I (i, j) and the mass of the object to be inspected Z are x (i, j), the relationship between the number of photons is expressed by the formula [Equation 1].

By transforming [Equation 1], Equation [Equation 2] for obtaining the mass x (i, j) in pixel units is obtained. Here, log (I ₀ (i, j) / I (i, j)) in [Expression 2] corresponds to density data in the transmission image data.

  Therefore, when the imaging area of the inspection object Z in the transmission image is T, the total mass W of the inspection object Z is the sum of the mass x (i, j) in pixel units for all the pixels in the imaging area T. And expressed by the mathematical formula [Equation 3].

Incidentally, if the inspection object Z is composed of a plurality of materials (elements), the mass attenuation coefficient mu _m is the product of the mass attenuation coefficient of a certain element mu _m and the proportion of that element, all elements contained This is the sum of the values. When the linear attenuation coefficient is μ, the element density is ρ, the element type is k, and the elemental content of the element k is w _k , the mass attenuation coefficient μ _m is expressed by Equation [Equation 4].

Here, (μ / ρ) _k in [Expression 4] can be approximated as shown in Expression [Expression 5] if the energy of X-rays is sufficiently high. Here, τ is an attenuation coefficient due to the photoelectric effect, σ _c is a scattering coefficient due to the Compton effect, σ _T is a scattering coefficient due to Thomson scattering, and κ is an attenuation coefficient due to electron pair generation. As X-ray energy increases, τ and σ _T decrease faster than σ _c . Moreover, since electron pair generation does not occur below 1.02 MeV, κ can be ignored. Thus, when the X-ray energy increases, Compton scattering becomes dominant, and the element type k can be ignored. Therefore, the approximate expression of [Equation 5] can be used.

Therefore, the mass attenuation coefficient mu _m, as shown in Equation [6] can be represented by a constant C.

Assuming that the reciprocal of the constant C is C ′, the total mass W of the inspected object Z can be expressed as the following [Equation 7] by modifying [Equation 3]. As described above, log (I ₀ (i, j) /
I (i, j)) corresponds to density data in the transmission image data. Thereby, the total mass W of the inspection object Z can be said to be the product of the sum of the density data in pixel units for all the pixels in the imaging region T and the constant C ′. From another point of view, the sum of the density data in pixel units for all the pixels in the imaging region T is a relative mass that relatively indicates the mass of the inspection object Z, and the constant C ′ It can also be called the conversion value converted into mass.

That is, the mass measuring unit 24 measures the total mass W of the inspection object Z by performing the calculation described below according to [Equation 7]. First, the mass measurement unit 24 receives transmission image data (second transmission image data) corresponding to the second energy region from the transmission image data storage unit 22, and obtains an imaging region T of the inspection object Z in the transmission image. Identify. Then, the density data for each pixel of the transmission image data is summed with all the pixels in the imaging region T. Then, the mass measuring unit 24 includes a total sum value, by taking the product of the value of the constant C 'is the reciprocal of the second mass attenuation coefficients corresponding to X-ray energy region mu _m, the object to be inspected The total mass W of Z is calculated.

  The constant C ′ is stored in advance in the mass measuring unit 24. A plurality of constants C ′ corresponding to the different energy regions are stored, and the mass measuring unit 24 selects and uses the constant C ′ corresponding to the transmission image data received from the transmission image data storage unit 22. It may be. As described above, the mass measuring unit 24 can measure the total mass W of the inspection object Z with high accuracy while being configured to perform simple calculations.

Next, details of the configuration of the X-ray inspection unit 10 will be described. FIG. 3 shows an example of the X-ray inspection unit 10 when a photon detection type sensor is used as the sensor of the X-ray detection unit 12 and the transmission image data generation unit 21 corresponding to the photon detection type sensor. The transmission image data generation unit 21 includes A / D conversion units 41 _{1 to} 41 _N , peak value detection units 42 _{1 to} 42 _N , region determination units 43 ₁ to 43 _N , region-specific accumulation units 44 _{1 to} 44 _N , transmission An image data output unit 45 is provided. FIG. 3 is a view of the transport unit 2 and the X-ray inspection unit 10 as viewed from the direction of the arrow Y in FIG.

X-ray detector 12, every time the photons of X-rays transmitted through the inspected object Z is input, photon detection type sensor 13 ₁ which outputs a pulse signal of a peak value corresponding to the energy of the photon as detection information to 13 _N to the conveying width direction is configured using N line sensors arranged, the number of pulses each sensor outputs per unit time would represent a density of the transmitted image.

The sensors 13 _{1 to} 13 _N output one pulse signal having a peak value corresponding to the energy of the photon with respect to the input of one photon. Since the X-ray generator 11 emits X-rays in which X-ray photons having different energies are mixed, as shown in FIG. 4, pulse signals P ₁ , P ₂ , P ₃ , Variations occur in the crest values H ₁ , H ₂ , H ₃ ,.

The peak value H ₁ , H ₂ , H ₃ ,... Of the pulse signal output from one sensor within the scan time is an area in which the entire output range of the peak value is divided into a plurality of M (M = 4 in FIG. 4) in advance. If _{one of} R _{1 to} R _M is determined and the number of pulse signal inputs within the scan time is accumulated for each region, a plurality of transmissions having different X-ray transmission energy ranges for the part corresponding to the scan time Image data can be generated.

In order to generate a plurality of transmission image data having different X-ray transmission energy ranges, the transmission image data generation unit 21 outputs the output signals of the sensors 13 _{1 to} 13 _N to the A / D conversion units 41 _{1 to} 41, respectively. _N is converted into a digital data string and input to the peak value detectors 42 _{1 to} 42 _N.

Each of the peak value detectors 42 _{1 to} 42 _N is for detecting the peak value of the pulse signal from the input data string. For example, the differential value ( The zero cross timing when the signal slope) changes from a positive value greater than or equal to a predetermined value to a negative value less than or equal to the predetermined value is detected, and the data value at the zero cross timing is detected as the peak value of the pulse signal. ₁ to 43 Output to _N.

The region determination units 43 ₁ to 43 _N include boundary value regions L _{1 to} L _M−1 that divide the output range of the peak values into a plurality of M regions R _{1 to} R _M , and peak value detection units 42 _{1 to} 42. _The peak value detected at _N is compared to determine which area the peak value falls in, and an area identification signal representing the area where the peak value enters is output to the accumulation units 44 _{1 to} 44 _N by area.

Each of the accumulation units 44 _{1 to} 44 _N receives the area identification signals output from the area determination units 43 ₁ to 43 _N within the scan time, and accumulates the number of input area identification signals indicating the same area. The cumulative number for each region within the scan time is obtained and sequentially output. The cumulative number of region identification signals is the cumulative number of pulse signals having the same region where the peak value is entered among the pulse signals output from one sensor within the scan time.

The transmission image data output unit 45 converts the cumulative number of region identification signals output from the region-by-region accumulation units 44 _{1 to} 44 _{N for} each scan time into data arranged in parallel and in time series. Output as transmission image data for the inspection object for each region.

  The method of dividing the peak value region is arbitrary, and as one example, the maximum value of the energy of X-ray photons emitted from the X-ray generator 11 (in the case of an X-ray tube, What is necessary is just to equally divide into the some between the peak value of the pulse signal which a sensor outputs with respect to a theoretical value (theoretical value which depends on an acceleration voltage), and a predetermined reference value (for example, 0). In addition, the number of areas is arbitrary with two or more, and transmission image data is first generated for many areas, and transmission image data suitable for foreign object detection and mass measurement is selected from these transmission image data. And may be used.

Specifically, for example, assuming that the initial number of regions is 10, transmission image data is generated in each region, and the first region counted from the higher energy is assigned to the region R ₁ described above. the region assigned to the region R ₂ of the above, ... so on, finally region selectively assigned from the initial region, or using transparent image data of the allocated space. Further, the transmission image data of the first and second regions counted from the higher energy are synthesized, and this is used as the transmission image data of the region R ₁ described above, and the transmission image data of the third and fourth regions is used. synthesized and, this as a transmission image data in the above described region R _2, the transmitted image data of the initial plurality of areas combined with the transmitted image data of the final one area and so ... was their synthesis Transmission image data may be used.

  In the above specific example, transmission image data is generated for the initial number of areas, and areas are assigned and transmission image data is synthesized in accordance with the optimal combination of transmission image data for foreign object detection. However, if the optimal combination of transmission image data for foreign object detection and mass measurement is known for the object to be inspected, it is only necessary to generate transmission image data for the allocated area, and a plurality of transmission image data Instead of combining, the cumulative number of area identification signals of a plurality of areas may be added to generate one transmission image data. Thereby, the storage area of the transparent image data storage unit 22 can be saved.

The above-mentioned regions _R 1 to R _M can be referred to as the energy range of different X-ray. That is, by using the photon detection type sensor, X-ray transmission image data of a plurality of different energy regions including the first transmission image data and the second transmission image data described above can be obtained. For example, the transmission image data in the region R ₄ is set as the first transmission image data, and the transmission image data in the region R ₂ having higher X-ray energy than the region R ₄ is set as the second transmission image data. The mass measuring unit 24 performs processing.

  As described above, in the configuration using the photon detection type sensor and the transmission image data generation unit corresponding thereto, it is possible to easily acquire the transmission image data of X-rays in a desired energy region. That is, X-ray transmission image data in the energy region suitable for foreign matter detection and X-ray transmission image data in the energy region suitable for mass measurement can be acquired, respectively. Therefore, X-rays having both functions of foreign matter detection and mass measurement Suitable for inspection equipment.

  The X-ray inspection unit 10 is not limited to the above-described configuration. FIG. 5 shows an example of the X-ray inspection unit 10 having another configuration. The X-ray inspection unit 10 in FIG. 5 includes an X-ray generation unit 11 and two X-ray detection units 12a and 12b. 5 and 1, the X-ray generator 11 has the same configuration.

  The X-ray detectors 12a and 12b are configured using a scintillator photosensor that generates visible light by incident X-rays, receives the generated visible light by a photosensor, and converts it into an electrical signal. One of the X-ray detectors 12a and 12b outputs detection information in the first energy region, and the other outputs detection information in the second energy region. The difference in the characteristics of the X-ray detection units 12a and 12b can be realized by using sensors having different characteristics or using X-ray filters having different characteristics. In FIG. 5, the X-ray detectors 12a and 12b are arranged side by side. However, the present invention is not limited to this, and the X-ray detectors 12a and 12b may be arranged in an overlapping manner, or a two-dimensional sensor like a TDI (Time Delay Integration) type detector. The detectors arranged in the above may be arranged alternately for each predetermined pixel.

  Then, the transmission image data generation unit 21 individually receives detection information from the X-ray detection units 12a and 12b, and generates first transmission image data and second transmission image data, respectively. In this example, since the X-ray detection units 12a and 12b are scintillator photosensors, the configuration of the transmission image data generation unit 21 is different from the example using the photon detection sensor described above. In this example, the transmission image data generation unit 21 generates transmission image data in which the value obtained by integrating the detection information with the scan time is the density data of each pixel.

  FIG. 6 shows an example of the X-ray inspection unit 10 having still another configuration. The X-ray inspection unit 10 in FIG. 6 includes two X-ray generation units 11a and 11b and two X-ray detection units 12a and 12b.

  One of the X-ray generators 11a and 11b emits X-rays in the first energy region, and the other emits X-rays in the second energy region. The X-ray detection units 12a and 12b are configured using scintillator photosensors. The X-ray detection unit 12a receives X-rays from the X-ray generation unit 11a and outputs detection information, and the X-ray detection unit 12b. Receives X-rays from the X-ray generator 11b and outputs detection information. As a result, one of the X-ray detection units 12a and 12b outputs detection information in the first energy region, and the other outputs detection information in the second energy region.

  In this example, since the X-ray generation units 11a and 11b emit X-rays in different energy regions, the X-ray detection units 12a and 12b can have the same characteristics. Then, the transmission image data generation unit 21 individually receives detection information from the X-ray detection units 12a and 12b, and generates first transmission image data and second transmission image data, respectively.

  As described above, the X-ray inspection apparatus of the present invention is useful when performing foreign matter contamination inspection and mass measurement on an object to be inspected such as food and medicine.

DESCRIPTION OF SYMBOLS 1 ... X-ray inspection apparatus, 2 ... Conveyance part, 10 ... X-ray inspection part, 11 ... X-ray generation part, 12 ... X-ray detection part, 20 ... Processing part, 21 ... Transmission image data Generation unit, 22 ... Transmission image data storage unit, 23 ... Determination unit, 24 ... Mass measurement unit, 30 ... Display unit, 13 _{1 to} 13 _N ... Sensor, 41 _{1 to} 41 _N ... A / D Conversion unit, 42 _{1 to} 42 _N ... Peak value detection unit, 43 ₁ to 43 _N ... Area determination unit, 44 _{1 to} 44 _N ... Region accumulation unit, 45.

Claims (6)

An X-ray inspection unit (10) for irradiating the object under inspection with X-rays, detecting X-rays transmitted through the object to be detected, and outputting detection information;
Using the detection information, X-rays in a plurality of different energy regions including X-rays in a first energy region and X-rays in a second energy region having higher energy than the X-rays in the first energy region A transmission image data generation unit (21) for generating transmission image data of
A determination unit that performs a difference process between at least two pieces of the transmission image data among the plurality of the transmission image data, and determines the presence or absence of foreign matter mixed in the inspection object using the difference-processed transmission image data (23) and
A mass measuring unit (24) for measuring the mass of the object to be inspected based on second transmission image data that is X-ray transmission image data of the second energy region. X-ray inspection apparatus (1).   The X-ray inspection apparatus according to claim 1, wherein the X-ray in the second energy region has an X-ray energy of 50 keV or more.   The mass measuring unit identifies an imaging region of the inspection object in the transmission image of the second transmission image data, and sets density data in pixel units of the second transmission image data for all pixels in the imaging region. 3. The mass of the object to be inspected is calculated using a summation and a summed value and a mass attenuation coefficient corresponding to an X-ray of the second energy region. X-ray inspection equipment. The X-ray inspection unit and an X-ray generation unit (11) and photon detection that outputs a pulse signal having a peak value corresponding to the energy of the photon every time an X-ray photon transmitted through the inspection object is input. A mold X-ray detector (12),
The transmission image data generation unit determines which one of the plurality of different energy regions the peak value of the pulse signal falls in, and uses the cumulative result obtained by accumulating the number of pulse signal inputs for each energy region. The X-ray inspection apparatus according to claim 1, wherein X-ray transmission image data of different energy regions is generated.   The X-ray inspection unit includes an X-ray generation unit (11), a first X-ray detection unit (12a) that detects X-rays in the first energy region that has passed through the inspection object, and the inspection target 4. The X-ray inspection apparatus according to claim 1, further comprising: a second X-ray detection unit that detects X-rays in the second energy region that has passed through an object. 5.   The X-ray inspection unit includes a first X-ray generation unit (11a) that irradiates X-rays in the first energy region, and a second X-ray generation unit that irradiates X-rays in the second energy region. (11b), a first X-ray detector (12a) for detecting X-rays from the first X-ray generator that has passed through the inspection object, and the second X-ray detection part (12a) that has passed through the inspection object The X-ray inspection apparatus according to claim 1, further comprising a second X-ray detection unit (12 b) that detects X-rays from the X-ray generation unit.