JP7417383B2 - Foreign object detection system - Google Patents

Description

The present invention relates to a technique for detecting foreign matter accompanying an object to be inspected.

2. Description of the Related Art Techniques for detecting objects using electromagnetic waves are known. For example, in Patent Document 1, a guidance device mounted on a flying object is equipped with both a passive system and an active system, and at a distant stage where there are no reflected waves from the target, observation is started using only the passive system, and tracking is performed. In the final stage, a technology is described in which the active system also functions to guide the projectile toward the target. Patent Document 2 describes a technique for searching underwater conditions using an active sonar having a wave transmitting/receiving function and a passive sonar having only a wave receiving function.

Japanese Patent Application Publication No. 2011-7464 Japanese Patent Application Publication No. 2005-91307

However, in the technologies described in Patent Documents 1 and 2, since the active system and the passive system are provided separately, the device becomes large and the space occupied by the device increases accordingly. .
An object of the present invention is to reduce the space occupied by a foreign object detection system and to reduce the cost of the foreign object detection system.

The present invention consists of an active system in which a light receiving part receives electromagnetic waves emitted by a light emitter and reflected by an object to be inspected, and a passive system in which a light receiving part receives electromagnetic waves emitted by the object to be inspected. A foreign object detection system that uses a common component and detects foreign objects accompanying an object to be inspected based on the light reception results of the active system and the passive system, wherein the direction of the electromagnetic waves is determined by changing the angle of the mirror. Provided is a foreign object detection system that switches between a light receiving section corresponding to the active type system and the passive type system .

Furthermore, the present invention combines an active system in which a light receiving part receives electromagnetic waves emitted by a light projecting part and reflected by an object to be inspected, and a passive system in which a light receiving part receives electromagnetic waves emitted by the object to be inspected. A foreign object detection system that shares a component of a part and detects a foreign object accompanying an object to be inspected based on the light reception results of the active system and the passive system, wherein the light projecting part emits electromagnetic waves. A foreign object detection system is provided in which a light shielding section blocks electromagnetic waves directed toward a light receiving section of the passive system when the electromagnetic waves are being emitted.

Furthermore, the present invention combines an active system in which a light receiving part receives electromagnetic waves emitted by a light projecting part and reflected by an object to be inspected, and a passive system in which a light receiving part receives electromagnetic waves emitted by the object to be inspected. A foreign object detection system that shares a component of a part and detects a foreign object accompanying an object to be inspected based on the light reception results of the active system and the passive system, the active system and the passive system Provided is a foreign object detection system that detects a foreign object by using one of the passive systems when a difference between an object to be inspected and the surroundings of the object cannot be detected using the other one .

In the foreign object detection system, the optical system of the light projector and the optical system of the light receiver in the active system may be non-coaxial .

In the foreign object detection system, it may be determined whether to use the active system or the passive system based on a comparison result between the temperature around the object to be inspected and a threshold value.

In the foreign object detection system, the shared component may include one or more of a condenser lens, a scan mirror, and a light receiving section.

According to the present invention, the space occupied by the foreign object detection system can be reduced and the cost of the foreign object detection system can be reduced.

FIG. 1 is a diagram showing an example of the configuration of a foreign object detection system 100 according to a first embodiment. FIG. 2 is a diagram illustrating the principle of detecting a foreign object using an active method. FIG. 3 is a diagram illustrating the principle of detecting a foreign object using a passive method. 1 is a diagram showing an example of the configuration of an inspection device 110. FIG. 3 is a flowchart showing a first operation example of the foreign object detection system 100. FIG. 7 is a flowchart showing a second operation example of the foreign object detection system 100. 3 is a diagram showing an example of a sensor signal acquired from the inspection device 110. FIG. 7 is a diagram showing another example of a sensor signal acquired from the inspection device 110. FIG. It is a figure showing an example of composition of inspection device 210 concerning a 2nd embodiment.

1. First Embodiment (1) Configuration FIG. 1 is a diagram showing an example of the configuration of a foreign object detection system 100 according to the first embodiment. The foreign object detection system 100 tests for the presence or absence of foreign objects accompanying an object to be inspected, such as a person or object. This inspection is a non-destructive inspection that detects foreign objects without destroying the object to be inspected. For example, the foreign object detection system 100 is used as a body scanner to detect dangerous objects carried by people in places such as airports where bringing in dangerous objects is restricted. The foreign object detection system 100 selectively uses an active method and a passive method to detect foreign objects accompanying an object to be inspected.

FIG. 2 is a diagram illustrating the principle of detecting a foreign object using the active method. In the active method, an object to be inspected is irradiated with electromagnetic waves, and the electromagnetic waves reflected by the object to be inspected are received. For example, when a person hides a hidden object 3 in clothing 2, the electromagnetic waves reflected from the human body 1 and the electromagnetic waves reflected from the hidden object 3 have different reflectances. Therefore, the hidden object 3 hidden by a person can be detected based on changes in the reflectance of electromagnetic waves.

FIG. 3 is a diagram illustrating the principle of detecting foreign objects using the passive method. In the passive method, electromagnetic waves derived from heat emitted by the object to be inspected are received. The human body 1 emits heat-derived electromagnetic waves. However, for example, when a person has a concealed object 3 hidden inside their clothes 2, the electromagnetic waves emitted from the human body 1 are blocked in the part where the hidden object 3 is located, so the electromagnetic waves are weaker than in the part without the hidden object 3. Strength decreases. Therefore, the hidden object 3 hidden by a person can be detected by changes in the intensity of electromagnetic waves.

As shown in FIG. 1, the foreign object detection system 100 includes an inspection device 110, a plurality of temperature sensors 120, and a processing device 130. The processing device 130 is connected to each of the plurality of temperature sensors 120 and the processing device 130 via communication lines.

FIG. 4 is a diagram showing an example of the configuration of the inspection device 110. The inspection device 110 has an active system and a passive system, and inspects the presence or absence of foreign matter in the inspection object 5 based on the light reception results of the active system and the passive system, respectively. The active method includes an illumination method and a narrow beam method, and the illumination method is used here. The active system and the passive system share some components. The inspection device 110 includes a light projecting module 111 and a light receiving module 112. The active system includes a light projecting module 111 and a light receiving module 112. On the other hand, the passive type system does not include the light projecting module 111 but only the light receiving module 112. That is, the active type system and the passive type system share the light receiving module 112.

The light projection module 111 irradiates the inspection object 5 with electromagnetic waves. The light projection module 111 includes a light source 113 (an example of a light projection section) and a lens 114. Light source 113 emits electromagnetic waves. As this electromagnetic wave, an electromagnetic wave having a wavelength similar to the electromagnetic wave emitted by the inspection object 5 itself is used. For example, if the inspection object 5 mainly emits electromagnetic waves in the terahertz band rather than infrared rays due to the influence of the transparency of obstacles such as clothing, electromagnetic waves in the terahertz band or a frequency band around it may be emitted from the light source 113. . The lens 114 diverges the electromagnetic waves emitted by the light source 113 so that the entire inspection target area of the inspection object 5 is irradiated, or limits the irradiation range of the electromagnetic waves. For example, if the irradiation range of electromagnetic waves is expanded too much, the irradiation intensity at one point will decrease, and there is a possibility that electromagnetic waves reflected from areas other than the object to be inspected 5 will be detected. In order to prevent this, the irradiation range of electromagnetic waves may be limited. For example, a concave lens is used for the lens 114.

The light receiving module 112 receives electromagnetic waves reflected by the object to be inspected 5 or electromagnetic waves emitted by the object to be inspected 5 itself. The light receiving module 112 includes a condensing lens 115, a scan mirror 116, an optical sensor 117 (an example of a light receiving section), an attenuator 118, and a driving section 119. In the first embodiment, the components shared by the active system and the passive system include a condenser lens 115, a scan mirror 116, and a photosensor 117.

The condenser lens 115 focuses the electromagnetic waves obtained from the inspection object 5 onto the scan mirror 116 . For example, a convex lens is used as the condensing lens 115. The electromagnetic waves that have passed through the condenser lens 115 may or may not be focused on the scan mirror 116. When the electromagnetic waves are focused on the scan mirror 116, the size of the scan mirror 116 can be reduced, for example, and the time required for inspection can be shortened. The scan mirror 116 reflects the electromagnetic waves focused by the condenser lens 115 in a direction toward the optical sensor 117. At this time, the scanning mirror 116 reflects the electromagnetic waves obtained from each part of the inspection target area in a direction toward the optical sensor 117 in a predetermined order by gradually changing the angle. For example, a MEMS (Micro Electro Mechanical Systems) mirror may be used as the scan mirror 116. The optical sensor 117 receives the electromagnetic waves reflected by the scan mirror 116 and outputs a sensor signal indicating the received electromagnetic waves. For example, the optical sensor 117 includes a light receiving element and an amplifier. The light receiving element receives electromagnetic waves and converts them into sensor signals. The amplifier amplifies the sensor signal. The sensor signal output from the optical sensor 117 is transmitted to the processing device 130 via a communication line.

The attenuator 118 is also called an attenuator and attenuates the electromagnetic waves incident on the optical sensor 117. Attenuator 118 is provided between scan mirror 116 and optical sensor 117. For example, a filter or a waveguide may be used as the attenuator 118. This filter may, for example, pass only electromagnetic waves in one direction and block electromagnetic waves in other directions.

The drive unit 119 drives the attenuator 118 to move it between the operating position shown in FIG. 4(a) and the retracted position shown in FIG. 4(b). The action position is a position through which the electromagnetic waves reflected by the scan mirror 116 pass, as shown in FIG. 4(a). When the attenuator 118 moves to the active position, the electromagnetic waves reflected by the scan mirror 116 are attenuated by the attenuator 118 and then enter the optical sensor 117 . On the other hand, the retracted position is a position where the electromagnetic waves reflected by the scan mirror 116 do not pass, as shown in FIG. 4(b). When the attenuator 118 moves to the retracted position, the electromagnetic wave reflected by the scan mirror 116 does not pass through the attenuator 118, and therefore enters the optical sensor 117 without being attenuated by the attenuator 118. For example, an actuator is used for the drive unit 119. Although FIG. 4 shows an example in which the drive unit 119 moves the attenuator 118 linearly, the method of movement is not limited to linear movement. For example, the drive unit 119 may rotate the attenuator 118.

For example, when the active method is used, the drive unit 119 moves the attenuator 118 to the operating position as shown in FIG. 4(a) in order to attenuate the electromagnetic waves incident on the optical sensor 117. This is because, in the active method, the electromagnetic waves obtained from the test object 5 are electromagnetic waves that are irradiated onto the test object 5 and reflected by the test object 5, and have a higher intensity than when the passive method is used. Therefore, if the dynamic range of the optical sensor 117 is narrow, if the electromagnetic waves are incident on the optical sensor 117 without being attenuated, the intensity of the electromagnetic waves may exceed the upper limit of the dynamic range and the optical sensor 117 may malfunction. It is.

On the other hand, when the passive method is used, the drive unit 119 uses an attenuator 118 as shown in FIG. Move to the evacuation position. This is because, in the passive method, the electromagnetic waves obtained from the test object 5 are electromagnetic waves emitted by the test object 5 itself, and have a lower intensity than when the active method is used. Therefore, if the electromagnetic waves are attenuated, it becomes difficult to recognize differences in the strength of the electromagnetic waves.

The light projecting module 111 and the light receiving module 112 are arranged non-coaxially in order to facilitate the design of the optical system. If the light projecting module 111 and the light receiving module 112 are arranged coaxially, the difficulty in designing the optical system will increase, especially when an illumination method is adopted. For example, the light projecting module 111 and the light receiving module 112 are arranged so that the optical axis L1 of the light source 113 and the lens 114 intersects with the optical axis L2 of the condensing lens 115, as shown in FIG. 4(a).

Returning to FIG. 1, the plurality of temperature sensors 120 measure the temperature around the test object 5 and output a temperature signal indicating the measured temperature. A plurality of temperature sensors 120 are installed around the inspection object 5. For example, the plurality of temperature sensors 120 may be arranged at different positions around the test object 5. Temperature signals output from the plurality of temperature sensors 120 are transmitted to the processing device 130 via a communication line.

The processing device 130 uses the sensor signal supplied from the inspection device 110 to detect foreign matter accompanying the inspection object 5. Furthermore, the processing device 130 determines whether to use an active method or a passive method to detect foreign objects, depending on the temperature supplied from the plurality of temperature sensors 120 or the sensor signal supplied from the inspection device 110. . Here, the sensor signals and temperature signals supplied from the inspection device 110 and the temperature sensor 120 may be used after being converted from analog signals to digital signals by an A/D (Analog-to-digital) converter. The processing device 130 includes, for example, a processor and a memory, and the functions of the processing device 130 are realized when the processor executes a program stored in the memory. Alternatively, the processing device 130 may include a circuit such as an ASIC (Application Specific Integrated Circuit), a PLD (Programmable Logic Device), or an FPGA (Field Programmable Gate Array), and the functions of the processing device 130 may be realized by this circuit.

(2) Operation (2-1) First operation example FIG. 5 is a flowchart showing a first operation example of the foreign object detection system 100. In the first operation example, the active method and the passive method are switched according to the temperature around the test object 5 in order to prevent the test from becoming impossible due to a change in the temperature around the test object 5. This is because, depending on the temperature around the inspection object 5, foreign objects may not be detected by one of the active and passive methods, but may be detected by the other method. For example, when the test object 5 is a person, as the temperature around the test object 5 increases, the difference between the temperature of the test object 5 and the temperature around the test object 5 generally becomes smaller. In the passive method, since the electromagnetic waves derived from heat emitted by the inspection object 5 are used, when the difference between the temperature around the inspection object 5 and the temperature of the inspection object 5 is small, the inspection object 5 The noise emitted from the surrounding area increases, making it difficult to detect foreign objects. On the other hand, in the active method, the electromagnetic waves are irradiated onto the inspection object 5 and the electromagnetic waves reflected by the inspection object 5 are used, so the difference between the temperature around the inspection object 5 and the temperature of the inspection object 5 is Foreign objects can be detected even if they are small. Furthermore, when the object to be inspected 5 is a person, when the temperature around the object to be inspected 5 becomes low, the person wears thick clothing, and therefore the obstacle covering the object to be inspected 5 becomes thicker. In the active method, electromagnetic waves are irradiated onto the inspection object 5 and the electromagnetic waves reflected from the inspection object 5 are used, so when the obstacle becomes thick, noise reflected from the surface of the obstacle mixes in and the foreign object is detected. It becomes difficult to do. On the other hand, in the passive method, since electromagnetic waves derived from heat emitted by the inspection object 5 are used, noise reflected from the surface of the obstacle is not observed, and foreign objects can be detected.

The process shown in FIG. 5 is started in response to an operation by the examiner, for example, when starting an examination. In step S11, the processing device 130 acquires a plurality of temperature signals indicating the temperature around the inspection object 5. For example, each of the plurality of temperature sensors 120 measures the temperature around the inspection object 5 at predetermined time intervals, and transmits a temperature signal indicating the measured temperature to the processing device 130. A plurality of temperature signals transmitted from a plurality of temperature sensors 120 are received by a processing device 130, and are converted from analog signals to digital signals by an A/D converter.

In step S12, the processing device 130 calculates a temperature difference by subtracting the temperature around the test object 5 from the temperature of the test object 5. The temperature of the inspection object 5 is predetermined. Here, it is assumed that the temperature of the inspection object 5 is 37 degrees. For example, the average value of the plurality of temperatures indicated by the plurality of temperature signals acquired in step S11 is used as the temperature around the inspection object 5. For example, if the temperature around the inspection object 5 is 20 degrees, the temperature difference is 37 degrees - 20 degrees = 17 degrees. On the other hand, for example, if the temperature around the inspection object 5 is 35 degrees, the temperature difference is 37 degrees - 35 degrees = 2 degrees.

In step S13, the processing device 130 determines whether the temperature difference calculated in step S12 is larger than a threshold value. This threshold value is predetermined according to the temperature resolution of the optical sensor 117. For this threshold value, for example, a value obtained by multiplying the temperature resolution of the optical sensor 117 by a constant may be used. Here, it is assumed that the threshold value is 6 degrees. For example, when the temperature difference calculated in step S12 is 17 degrees, this temperature difference is larger than the threshold of 6 degrees, so the determination in step S13 is YES. On the other hand, for example, when the temperature difference calculated in step S12 is 2 degrees, this temperature difference is less than the threshold of 6 degrees, so the determination in step S13 is NO.

If the determination in step S13 described above is YES, the process proceeds to step S14. In step S14, the processing device 130 determines to use the passive system, and causes the inspection device 110 to perform the inspection using the passive system. For example, the processing device 130 transmits a control signal to the inspection device 110 instructing switching to the passive method. Upon receiving this control signal, the inspection device 110 turns off the light source 113 so that the electromagnetic waves are not irradiated onto the inspection object 5, and moves the attenuator 118 to the retracted position using the drive unit 119. move it to Thereby, the electromagnetic waves emitted from the inspection object 5 reach the optical sensor 117 via the condenser lens 115 and the scan mirror 116, and are received by the optical sensor 117. At this time, since the attenuator 118 has moved to the retracted position, the electromagnetic wave is not attenuated by the attenuator 118 and enters the optical sensor 117. A sensor signal corresponding to the electromagnetic waves received by the optical sensor 117 is then transmitted to the processing device 130 via the communication line.

On the other hand, if the determination in step S13 described above is NO, the process proceeds to step S15. In step S15, the processing device 130 determines to use the active method, and causes the inspection device 110 to perform the inspection using the active method system. For example, the processing device 130 transmits a control signal to the inspection device 110 instructing switching to the active method. Upon receiving this control signal, the inspection device 110 turns on the light source 113 to irradiate the inspection object 5 with electromagnetic waves, and also moves the attenuator 118 to the active position using the drive section 119, as shown in FIG. 4(a). move it. As a result, the inspection object 5 is irradiated with electromagnetic waves, and the electromagnetic waves reflected by the inspection object 5 reach the optical sensor 117 via the condenser lens 115, the scan mirror 116, and the attenuator 118, and are detected by the optical sensor 117. Light is received. At this time, the electromagnetic waves are attenuated by the attenuator 118 before entering the optical sensor 117 . A sensor signal corresponding to the electromagnetic waves received by the optical sensor 117 is then transmitted to the processing device 130 via the communication line.

In step S16, the processing device 130 acquires the sensor signal. For example, a sensor signal transmitted from the inspection device 110 is received by the processing device 130, and is converted from an analog signal to a digital signal by an A/D converter. In step S17, the processing device 130 performs a process of detecting a foreign object accompanying the inspection object 5 using the sensor signal acquired in step S16. For example, when a passive method is used, if the sensor signal indicates that there is a part where the electromagnetic waves emitted from the object to be inspected 5 are blocked as shown in FIG. Detected. On the other hand, when the active method is used, if the sensor signal indicates that there are parts with different electromagnetic wave reflectances as shown in FIG. 2, a foreign object accompanying the inspection object 5 is detected.

(2-2) Second Operation Example FIG. 6 is a flowchart showing a second operation example of the foreign object detection system 100. In the second operation example, in order to prevent the inspection from becoming impossible due to changes in the inspection object 5 or the environment of the inspection object 5, the active method and the passive method are switched according to the result of the pre-inspection. This is because, depending on the object to be inspected 5 or the environment of the object to be inspected, one of the active method and the passive method may not be able to detect a foreign object, but the other method may be able to detect a foreign object.

The process shown in FIG. 6 is started in response to an operation by the examiner, for example, when starting an examination. In step S21, similarly to step S14 described above, the processing device 130 causes the inspection device 110 to perform a pre-inspection using a passive system. However, at this time, the inspection device 110 sequentially receives electromagnetic waves emitted by the inspection object 5 itself and electromagnetic waves emitted from around the inspection object 5. This means, for example, moving the test object 5 or the test device 110 to a position where the test device 110 can receive electromagnetic waves emitted from the test object 5 and a position where the test device 110 can receive electromagnetic waves emitted from around the test object 5. This may be realized by Thereby, sensor signals corresponding to the electromagnetic waves emitted from the object to be inspected 5 and the electromagnetic waves emitted from around the object to be inspected 5 are transmitted to the processing device 130 via the communication line.

In step S22, the processing device 130 acquires the sensor signal. For example, a sensor signal transmitted from the inspection device 210 is received by the processing device 130, and is converted from an analog signal to a digital signal by an A/D converter. In step S23, the processing device 130 determines whether inspection can be performed in a passive manner, depending on the difference between the object to be inspected 5 and the surroundings of the object to be inspected 5, which is indicated by the sensor signal acquired in step S22. This sensor signal may be processed in advance to smooth out variations in value using a filter.

FIG. 7 is a diagram showing an example of a sensor signal acquired from the inspection device 110. In the sensor signal S1, the peak included in the period T1 generally has a peak value P1, and the peak included in the period T2 has a peak value P2 that is generally larger than the peak value P1. This indicates that electromagnetic waves emitted from the vicinity of the inspection object 5 are received during period T1, and electromagnetic waves emitted from the inspection object 5 are received during period T2, and there is a difference in the intensity of these electromagnetic waves. . In this case, the difference between the inspection object 5 and the surroundings of the inspection object 5 is detected from the sensor signal S1. Further, only when the period T2 continues for a predetermined time or more and the difference Δ1 between the peak value P1 and the peak value P2 is equal to or more than the threshold value, the difference between the inspection object 5 and the inspection object 5 is determined from the sensor signal S1. Differences from the surroundings may be detected. This predetermined time is predetermined, for example, according to the time when it can be considered that the electromagnetic waves emitted from the inspection object 5 are received. This threshold value is predetermined, for example, according to the boundary between a difference in signal strength that allows foreign objects to be detected using the passive method and a difference in signal strength that does not allow foreign objects to be detected using the passive method. In this way, when a difference between the object to be inspected 5 and the surroundings of the object to be inspected 5 is detected from the sensor signal S1, it is determined that the inspection can be performed using the passive method.

FIG. 8 is a diagram showing another example of the sensor signal acquired from the inspection device 110. The sensor signal S2 has a peak approximately at the peak value P3 throughout the entire period. This indicates that there is substantially no difference in intensity between the electromagnetic waves emitted from the surroundings of the test object 5 and the electromagnetic waves emitted from the test object 5. In this case, the difference between the inspection object 5 and the surroundings of the inspection object 5 is not detected from the sensor signal S2. In this way, if a difference between the object to be inspected 5 and the surroundings of the object to be inspected 5 is not detected from the sensor signal S2, it is determined that inspection cannot be performed using the passive method.

If it is determined in step S23 that the passive method can be inspected, the determination in step S23 becomes YES, and the process proceeds to step S24. In step S24, similarly to step S14 described above, the processing device 130 causes the inspection device 210 to perform the inspection using the passive system. On the other hand, if it is determined in step S23 that the passive method cannot be tested, the determination in step S23 becomes NO, and the process proceeds to step S25. In step S25, similarly to step S15 described above, the processing device 130 causes the inspection device 110 to perform an inspection using the active system. The processes in steps S26 and S27 are similar to the processes in steps S16 and S17 described above, respectively. Note that in the case where the inspection using the passive system has been completed for the entire inspection target area in the pre-inspection in step S21, if the determination in step S23 is YES, the processes in steps S24 and S26 are skipped. You may proceed to step S27. In this case, in step S27, a process of detecting a foreign object using the sensor signal acquired in step S22 is performed.

According to the first embodiment, since the active system and the passive system share the condenser lens 115, the scan mirror 116, and the optical sensor 117, the active system and the passive system share these components. Compared to the case where the configurations are provided separately, the inspection device 110 is smaller, and the space occupied by the foreign object detection system 100 is reduced accordingly. Furthermore, the cost of the inspection apparatus 110 is reduced compared to the case where these configurations are provided separately for the active system and the passive system. Furthermore, according to the first operation example, since the active method and the passive method are switched depending on the temperature around the object to be inspected 5, it is possible to prevent the inspection from becoming impossible due to changes in the temperature around the object to be inspected 5. can do. Furthermore, according to the second operation example, since the active method and the passive method are switched according to the result of the pre-inspection, it is possible to prevent the inspection from becoming impossible due to a change in the test object 5 or its environment.

2. Second Embodiment A foreign object detection system 200 according to a second embodiment includes an inspection device 210 in place of the inspection device 110 included in the foreign object detection system 100 according to the first embodiment. Other configurations are similar to the foreign object detection system 100 according to the first embodiment.

FIG. 9 is a diagram showing an example of the configuration of the inspection device 210 according to the second embodiment. The inspection device 210 includes a light projecting module 211 and a light receiving module 212. The light projection module 211 includes a light source 213 and a lens 214. The light receiving module 212 includes a condensing lens 215, a scanning mirror 216, optical sensors 217A and 217B (an example of a light receiving section), and a mirror 218. In the second embodiment, components shared by the active system and the passive system include a condenser lens 215, a scan mirror 216, and a mirror 218.

The light source 213, lens 214, condensing lens 215, and scan mirror 216 are the same as the light source 113, lens 114, condensing lens 115, and scan mirror 116, respectively, according to the first embodiment. However, the scan mirror 216 reflects the electromagnetic waves focused by the condenser lens 215 in the direction toward the mirror 218 . Mirror 218 reflects the electromagnetic waves reflected by scan mirror 216 in a direction toward either optical sensor 217A or optical sensor 217B. For example, the mirror 218 switches the destination of the electromagnetic waves between the optical sensor 217A and the optical sensor 217B by changing the angle. The angular range of mirror 218 includes a first angle and a second angle. When the angle of the mirror 218 is the first angle, as shown in FIG. 9(a), the electromagnetic waves reflected by the mirror 218 head toward the optical sensor 217A. On the other hand, when the angle of the mirror 218 is the second angle, as shown in FIG. 9(b), the electromagnetic waves reflected by the mirror 218 head toward the optical sensor 217B. Both of the optical sensors 217A and 217B, similarly to the optical sensor 117 according to the first embodiment, receive electromagnetic waves reflected by the mirror 218 and output sensor signals indicating the received electromagnetic waves. However, in the active method, the optical sensor 217A is used to receive electromagnetic waves that are irradiated onto the inspection object 5 and reflected by the inspection object 5. That is, the optical sensor 217A is used in the active method, but not in the passive method. On the other hand, the optical sensor 217B is used in a passive method to receive electromagnetic waves derived from heat emitted by the inspection object 5 itself. That is, the optical sensor 217B is used in the passive method, but not in the active method.

The foreign object detection system 200 according to the second embodiment performs the same operation as the first operation example or the second operation example described in the first embodiment. However, when performing inspection using a passive system, the inspection apparatus 210 turns off the light source 213 and changes the angle of the mirror 218 to the second angle, as shown in FIG. 9(b). As a result, the electromagnetic waves emitted by the inspection object 5 reach the optical sensor 217B via the condenser lens 215, the scan mirror 216, and the mirror 218, and are received by the optical sensor 217B. On the other hand, when performing inspection using an active system, the inspection apparatus 210 turns on the light source 213 and changes the angle of the mirror 218 to the first angle, as shown in FIG. 9(a). As a result, the electromagnetic waves irradiated onto the inspection object 5 and reflected by the inspection object 5 reach the optical sensor 217A via the condenser lens 215, the scan mirror 216, and the mirror 218, and are received by the optical sensor 217A. . Furthermore, when a passive method is used, a sensor signal is acquired from the optical sensor 217B. On the other hand, when the active method is used, a sensor signal is acquired from the optical sensor 217A.

According to the second embodiment, since the active system and the passive system share the condenser lens 215, the scan mirror 216, and the mirror 218, these configurations are different between the active system and the passive system. The inspection device 210 is smaller than the case where the foreign object detection system 200 is provided separately, and the space occupied by the foreign object detection system 200 is reduced accordingly. Furthermore, the cost of the inspection device 210 is reduced compared to the case where these configurations are provided separately for the active system and the passive system.

3. Modifications The present invention is not limited to the first and second embodiments described above. The first embodiment and second embodiment described above may be modified as in the following example. Further, the following modifications may be used in combination.

(1) In the second embodiment described above, the method of realizing a configuration in which the optical sensors 217A and 217B are switched between when the active method is used and when the passive method is used is limited to the method using the mirror 218. Not done. For example, without providing the mirror 218, the direction of the electromagnetic waves reflected by the scan mirror 216 may be kept constant, and the optical sensors 217A and 217B may be moved. For example, the inspection device 210 includes a drive unit that drives optical sensors 217A and 217B. The drive unit moves one of the optical sensors 217A and 217B to an active position, and moves the other to a retreat position. The action position is a position through which the electromagnetic waves reflected by the scan mirror 216 pass. The retreat position is a position through which electromagnetic waves reflected by the scan mirror 216 do not pass.

When performing an inspection using a passive system, the inspection device 210 turns off the light source 213, uses the drive unit to move the optical sensor 217B to the active position, and moves the optical sensor 217A to the retreat position. Thereby, the electromagnetic waves emitted from the inspection object 5 are received by the optical sensor 217B. On the other hand, when performing an inspection using an active system, the inspection device 210 turns on the light source 213, uses the drive unit to move the optical sensor 217A to the active position, and moves the optical sensor 217B to the retreat position. As a result, the object to be inspected 5 is irradiated with electromagnetic waves, and the electromagnetic waves reflected by the object to be inspected 5 are received by the optical sensor 217A. According to this modification, even without using the mirror 218, the optical sensors 217A and 217B can be switched and used depending on whether the active method is used or the passive method is used.

(2) In the second embodiment described above, the method of realizing a configuration in which the optical sensors 217A and 217B are switched between when the active method is used and when the passive method is used is limited to the method using the mirror 218. Not done. For example, without providing the mirror 218, the optical sensor 217A and the optical sensor 217B are arranged adjacent to each other. Scan mirror 216 reflects electromagnetic waves toward a range that includes both optical sensor 217A and optical sensor 217B. The sensor signal output from one of the optical sensors 217A and 217B may be used, and the sensor signal output from the other may not be used.

When performing an inspection using a passive system, the inspection apparatus 210 turns off the light source 213. Thereby, the electromagnetic waves emitted from the inspection object 5 are received by both the optical sensors 217A and 217B. At this time, the processing device 130 performs a process of detecting a foreign object using the sensor signal output from the optical sensor 217B, without using the sensor signal output from the optical sensor 217A. On the other hand, when performing an inspection using an active system, the inspection apparatus 210 turns on the light source 213. As a result, the object to be inspected 5 is irradiated with electromagnetic waves, and the electromagnetic waves reflected by the object to be inspected 5 are received by both the optical sensors 217A and 217B. At this time, the processing device 130 performs a process of detecting a foreign object using the sensor signal output from the optical sensor 217A, without using the sensor signal output from the optical sensor 217B.

Further, in this modification, the inspection device 210 may include a light shielding section and a driving section. This light shielding section is provided between the scan mirror 216 and the optical sensor 217B, and blocks electromagnetic waves reflected by the scan mirror 216. The drive section drives the light shielding section to move it between the operating position and the retreat position. The action position is a position where the electromagnetic waves reflected by the scan mirror 216 in the direction toward the optical sensor 217B pass. The retreat position is a position where electromagnetic waves reflected by the scan mirror 216 toward the optical sensors 217A and 217B do not pass through. When performing an inspection using a passive system, the inspection device 210 moves the light shielding section to the retracted position using a driving section. Thereby, the electromagnetic waves emitted from the inspection object 5 are received by the optical sensor 217B. On the other hand, when performing an inspection using an active system, the inspection device 210 moves the light shielding section to the operating position using a driving section. As a result, when using the active method, electromagnetic waves are blocked by the light shielding part and do not enter the optical sensor 217B. Thereby, even when the dynamic range of the optical sensor 217B is small, failure of the optical sensor 217B can be prevented. Note that the light shielding part does not necessarily have to block all electromagnetic waves. For example, the light shielding part may attenuate electromagnetic waves. In this case, an attenuator similar to the attenuator 118 according to the first embodiment may be used as the light shielding part.

(3) In the first embodiment described above, the condenser lens 115 and the scan mirror 116 do not necessarily need to be provided. For example, when inspecting by bringing the inspection device 110 close to the inspection target 5, the optical sensor 117 can receive electromagnetic waves without providing the condenser lens 115 and the scan mirror 116. 116 may not be provided. In this case, the active system and the passive system share only the optical sensor 117. Further, in this modification, the optical sensor 117 may be moved so as to receive electromagnetic waves reflected from or emitted from each part of the inspection target area in a predetermined order. Furthermore, the optical sensor 117 may include a plurality of light receiving elements arranged in a line or matrix.

(4) In the first embodiment described above, the scan mirror 116 does not necessarily need to be provided. For example, the optical sensor 117 may be provided at a position to receive the electromagnetic waves converged by the condensing lens 115, and may receive the electromagnetic waves.

(5) In the second embodiment described above, the inspection device 210 may be provided with two mirrors 218. In this case, the two mirrors 218 are placed next to each other. Scan mirror 216 reflects electromagnetic waves to a range including two mirrors 218 . One mirror 218 reflects the electromagnetic waves reflected by the scan mirror 216 in the direction toward the optical sensor 217A. The other mirror 218 reflects the electromagnetic waves reflected by the scan mirror 216 in the direction toward the optical sensor 217B. In this case, the active system and the passive system share only the condenser lens 215 and the scan mirror 216.

(6) In the first embodiment described above, the position where the attenuator 118 is provided is not limited to between the scan mirror 116 and the optical sensor 117. For example, the attenuator 118 may be provided between the condenser lens 115 and the scan mirror 116. That is, the attenuator 118 may be provided at any position as long as it can attenuate the electromagnetic waves reflected by the inspection object 5 before being received by the optical sensor 117.

(7) In the first and second embodiments described above, the temperature of the test object 5 may be measured. In this case, a temperature sensor for measuring the temperature of the test object 5 is provided. Before inspecting the test object 5, the temperature of the test object 5 is measured by this temperature sensor. This temperature measurement may be performed every time the test object 5 changes. A temperature signal indicating the temperature measured by this temperature sensor is sent to the processing device 130.

(8) In the first operation example described above, it may be determined whether to use the active system or the passive system based on the comparison result between the temperature around the inspection object 5 and a threshold value. This threshold value is predetermined, for example, according to the boundary between the temperature at which the noise emitted from the surroundings of the inspection object 5 becomes large enough to be inspected using the passive method and the temperature at which the noise becomes large enough to be inspected using the passive method. . Here, it is assumed that the threshold value is 30 degrees. In this case, if the temperature of the inspection object 5 is 30 degrees or less, it is determined that the passive system is used. On the other hand, if the temperature of the inspection object 5 is higher than 30 degrees, it is determined that the active system is to be used.

(9) In the second operation example described above, a pre-inspection may be performed using an active system, and the system may be switched to a passive system based on a sensor signal supplied from the inspection device 110. At this time, the inspection device 110 receives the electromagnetic waves irradiated onto the inspection object 5 and reflected by the inspection object 5. The processing device 130 determines whether to use the passive method or the active method, depending on the intensity of the electromagnetic waves indicated by the sensor signal acquired from the inspection device 110. For example, if the peak value of the sensor signal is equal to or greater than the threshold value, there is a possibility that the inspection object 5 is covered with a thick obstacle. The average value of a plurality of peak values having a predetermined intensity or higher may be used as this peak value. For example, this threshold value is determined by the intensity of electromagnetic waves depending on the reflectance of an obstacle that generates noise large enough to prevent the active method from detecting a foreign object, and the reflection of an obstacle that generates noise large enough to detect a foreign object using the active method. The rate is predetermined according to the intensity of the electromagnetic wave and the boundary. In the active method, electromagnetic waves are irradiated onto the inspection object 5 and the electromagnetic waves reflected from the inspection object 5 are used, so if the obstacle becomes thick, noise reflected from the surface of the obstacle will be mixed in and the foreign object will be detected. It becomes difficult to do. On the other hand, in the passive method, since electromagnetic waves derived from heat emitted by the inspection object 5 are used, noise reflected from the surface of the obstacle is not observed, and foreign objects can be detected. Therefore, in this case, it may be decided to use a passive method. On the other hand, for example, when the peak value of the sensor signal is less than the threshold value, it is unlikely that the inspection object 5 is covered with a thick obstacle. Therefore, in this case, it may be decided to use the active method.

(10) In the second operation example described above, in the pre-inspection, the electromagnetic waves emitted from around the inspection object 5 may not be received. In this case, in the pre-inspection, electromagnetic waves mainly emitted from the inspection object 5 are received. If the difference between the maximum value and the minimum value of the sensor signal is greater than the threshold, it is determined that the passive method can be used for inspection, and if this difference is less than the threshold, it is determined that the passive method cannot be used for inspection. Good too. This threshold value may be, for example, a value obtained by multiplying the difference between the maximum value and the minimum value of the sensor signal output from the optical sensor 217B during a period in which the optical sensor 217B is not receiving electromagnetic waves by a constant.

(11) In the second operation example described above, if one of the active method and the passive method performs pre-inspection on the same inspection object 5 multiple times, and there are variations in the results, the other method method may be used.

(12) In the first and second embodiments described above, when the second operation example is performed, the plurality of temperature sensors 120 may not be provided.

(13) The entities that realize the functions of the foreign object detection systems 100 and 200 are not limited to the examples described in the above-described first and second embodiments. For example, the inspection devices 110 and 210 may have at least some of the functions of the processing device 130.

(14) The processing steps performed in the foreign object detection system 100 or 200 are not limited to the examples described in the first embodiment or the second embodiment. The steps of this process may be interchanged as long as there is no contradiction. Further, the present invention may be provided as a processing method performed in the foreign object detection system 100 or 200.

100, 200: foreign object detection system, 110, 210: inspection device, 111, 211: light projecting module, 112, 212: light receiving module, 113, 213: light source, 114, 214: lens, 115, 215: condensing lens, 116, 216: Scan mirror, 117, 217A, 217B: Optical sensor, 118: Attenuator, 119: Drive section, 218: Mirror, 120: Temperature sensor, 130: Processing device

Claims (6)

Some components are shared between an active system in which the light receiving part receives electromagnetic waves emitted by the light emitter and reflected by the object to be inspected, and a passive system in which the light receiving part receives the electromagnetic waves emitted by the object to be inspected. and a foreign object detection system that detects a foreign object accompanying the inspection object based on the light reception results of the active system and the passive system,
A foreign object detection system in which the destination of electromagnetic waves is switched between a light receiving section corresponding to each of the active system and the passive system by changing the angle of a mirror. Some components are shared between an active system in which the light receiving part receives electromagnetic waves emitted by the light emitter and reflected by the object to be inspected, and a passive system in which the light receiving part receives the electromagnetic waves emitted by the object to be inspected. and a foreign object detection system that detects a foreign object accompanying the inspection object based on the light reception results of the active system and the passive system,
A foreign object detection system, wherein when the light projecting section emits electromagnetic waves, a light shielding section blocks electromagnetic waves directed toward the light receiving section of the passive system. Some components are shared between an active system in which the light receiving part receives electromagnetic waves emitted by the light emitter and reflected by the object to be inspected, and a passive system in which the light receiving part receives the electromagnetic waves emitted by the object to be inspected. and a foreign object detection system that detects a foreign object accompanying the inspection object based on the light reception results of the active system and the passive system,
A foreign object detection system in which, when a difference between an object to be inspected and the surroundings of the object cannot be detected using one of the active system and the passive system, the other is used to detect a foreign object. In the active system, the optical system of the light projecting section and the optical system of the light receiving section are non-coaxial.
A foreign object detection system according to any one of claims 1 to 3 . The foreign object detection system according to any one of claims 1 to 4 , wherein the foreign object detection system determines whether to use the active system or the passive system based on a comparison result between the ambient temperature of the object to be inspected and a threshold value. . The foreign object detection system according to any one of claims 1 to 5, wherein the shared component includes one or more of a condenser lens, a scan mirror, and a light receiving section.

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