Foreign matter detector

Abstract

The utility model provides a foreign matter detection machine which comprises a machine body with a channel, a detection light emission source installed in the machine body and a photosensitive plate sensor installed in the machine body, a first channel edge and a second channel edge of the channel extend in the left-right direction, and the first channel edge and the second channel edge are distributed at intervals in the up-down direction. The second channel edge is located between the first channel edge and the detection light emitting source in the vertical direction, all detection light rays emitted by the detection light emitting source are distributed in a fan shape and can cover the second channel edge, and the light sensing plate sensor is arranged at the position corresponding to the first channel edge. And the photosensitive plate sensor is also arranged on the side edge of the first channel along the left-right direction. The foreign matter detector solves the problem of detection dead angles, particularly solves the problem that the detection dead angles easily occur at the position, closer to the detection light emission source, of the channel, and improves the detection accuracy.

Description

Technical Field

[0001] The present invention relates to a foreign object detector, and particularly to a foreign object detector with higher detection accuracy. Background Art

[0002] In X-ray detection equipment, detection dead angles are likely to occur when the channel is closer to the detection light emission source, which is mainly related to the following factors:

[0003] Geometric distribution of light: The rays emitted by the X-ray emission source may be too concentrated near the source, resulting in the edge part of the ray beam not being fully covered at the near-source end of the channel, forming a dead angle;

[0004] Sensor layout limitation: If the layout of the sensors or detectors is not optimized around the emission source, they may not be able to capture all the rays in the area near the emission source, resulting in a detection blind area;

[0005] Ray scattering and attenuation: When X-rays penetrate materials, scattering and attenuation will occur. If the channel material or design causes a large amount of scattering or attenuation of the rays before reaching the detection area, it may result in a weak ray intensity at the near-source end, affecting the detection effect;

[0006] Device structure design: The physical structure design of the detection device, such as the shape and size of the channel, and the relative position to the X-ray source, may limit the effective coverage range of the rays;

[0007] Characteristics of the X-ray source: Some X-ray sources may have problems with uneven intensity during emission, resulting in uneven distribution of the rays in the channel;

[0008] Response characteristics of the detector: If the detector responds inconsistently to rays of different angles or intensities, it may result in a weak signal received in some areas, forming a dead angle;

[0009] Occlusion and reflection: Components or structures inside the channel may occlude or reflect the rays, affecting the uniform distribution of the rays in the channel;

[0010] Software and image processing algorithms: If the image reconstruction and processing algorithms fail to correctly handle the distribution characteristics of the rays, it may result in dead angles on the image;

[0011] It can be seen that: The geometric distribution of light, sensor layout limitation, ray scattering and attenuation, and uneven reception by the sensor will all cause the risk of dead angle missed detection, involving many factors and complex problem elimination;

[0012] For food X-ray machines, zero tolerance is required for missed detections and their blind spots, that is, missed detections and blind spots are not allowed. The food X-ray machine uses an X-ray emission source to emit X-rays into the device's channel, and a photosensitive plate sensor is provided at a position corresponding exactly to one side of the channel. During the process of the food under test passing through the channel, the X-rays will pass through the food and irradiate onto the induction plate sensor. According to the detection light conditions sensed by the photosensitive plate sensor, it is determined whether there are metal foreign objects in the food. However, existing food X-ray machines often have detection blind spots. In particular, detection blind spots are likely to occur at the end of the channel near the X-ray emission source, resulting in parts of the food at this position not being detectable, and thus it is difficult to accurately measure whether there are metal foreign objects in all parts of the food, leading to relatively low detection accuracy.

[0013] The main purpose of a food X-ray machine is to detect whether there are metal foreign objects in the food. Due to the existence of irradiation detection blind spots, food that may contain metal foreign objects may be missed. Its detection accuracy and requirements are as follows: that is, as long as the metal foreign object can be detected by normal human diet and poses a potential hazard to the human body, it must be detected. Metal foreign objects are not allowed to exist in food. Therefore, in the face of this technical requirement, the existence of blind spots, such as metal particles of 0.5 - 1 mm, may lead to the risk of missed detections. Moreover, generally, the resolution of X-ray equipment used for food detection is usually required to be below 0.1 mm to ensure that tiny metal foreign objects can be detected; the detection sensitivity is required to be able to detect at least below 0.5 mm.

[0014] Therefore, for the detection of foreign objects in products, how to overcome the risk of missed detections due to blind spots and achieve zero missed detections is an urgent problem to be solved. Summary of the Invention

[0015] In view of the above-mentioned disadvantages of the prior art, the technical problem to be solved by the present invention is to provide a foreign object detector that can improve detection accuracy, and how to solve the problem of detection blind spots that are likely to occur at one end of the channel of the existing food X-ray machine near the detection light emission source, where the images overlap, the accuracy is poor, and there is a risk of missed detections.

[0016] To achieve the above object, the present invention provides a foreign object detector, including a machine body with a channel, a detection light emission source installed in the machine body, and a photosensitive plate sensor installed in the machine body. The first channel side and the second channel side of the channel both extend in the left-right direction, and the first channel side and the second channel side are spaced apart in the up-down direction. The second channel side is located between the first channel side and the detection light emission source in the up-down direction. All the detection light rays emitted by the detection light emission source are distributed in a fan shape, and all the detection light rays emitted by the detection light emission source can cover the second channel side. A photosensitive plate sensor is provided corresponding to the first channel side, and a photosensitive plate sensor is also provided at the side of the first channel side along the left-right direction.

[0017] Further, all the light-sensitive plate sensors are sequentially distributed in the left-right direction.

[0018] Further, all the light-sensitive plate sensors are distributed in an arc shape.

[0019] Further, all the light-sensitive plate sensors are distributed in an arc shape with the light emission center of the detection light emission source as the center of the circle.

[0020] Further, the light-sensitive plate sensors are provided on both the left and right sides of the first channel side.

[0021] Further, a plurality of light-sensitive plate sensors located at the side of the first channel side are sequentially distributed in the up-down direction.

[0022] Further, the third channel side and the fourth channel side of the channel both extend in the up-down direction, and the third channel side and the fourth channel side of the channel are spaced apart in the left-right direction. A plurality of light-sensitive plate sensors located at the side of the first channel side correspond to the third channel side.

[0023] Further, a plurality of light-sensitive plate sensors corresponding to the first channel side are sequentially distributed in the left-right direction, and all the light-sensitive plate sensors are distributed in an L shape.

[0024] Further, the detection light emission source and the fourth channel side are located on the same side of the center line of the channel.

[0025] Further, the detection light emission source is an X-ray emission source.

[0026] Further, for cooperating with the arc-shaped detection channel, at least a part of the light-sensitive plate sensors are distributed in an arc shape, and with the light emission center of the detection light emission source as the center of the circle, so that the detection light passes through the object to be measured and irradiates on the light-sensitive plate sensors, and the detection image is not deformed.

[0027] As described above, the foreign object detector involved in the present invention has the following beneficial effects:

[0028] 1. The working principle of this foreign object detector is as follows: The object to be detected passes through the channel. During this process, the detection light emission source emits detection light distributed in a fan shape towards the channel. The detection light passes through the object to be detected and irradiates on the photosensitive plate sensor. By combining the situation of the detection light sensed by the photosensitive plate sensor, it is measured whether there is a foreign object in the object to be detected. At the same time, all the detection light emitted by the detection light emission source can cover the second channel side. The detection light emitted by the detection light emission source is distributed in a fan shape, that is, the radiation area of the detection light gradually becomes larger, and the detection light will cover the entire channel. Photosensitive plate sensors are provided at the position corresponding to the first channel side and on the side of the first channel side. This distribution form of photosensitive plate sensors can sense the detection light covering the entire channel, so as to realize the detection of the entire channel area, thus solving the problem of detection dead angles, especially solving the problem of detection dead angles that are likely to occur at the place closer to the detection light emission source in the channel, and improving the detection accuracy.

[0029] 2. This application eliminates the detection dead angle of the foreign object detector and improves the detection accuracy; the detection light that fully covers the detection channel and the layout of the photosensitive plate sensors suitable for the food detection channel improve the detection accuracy and eliminate the detection dead angle; it improves the high efficiency and high accuracy of the detection process.

[0030] 3. Compared with the prior art, this application has a reasonable layout of the detection channel and its supporting photosensitive plate sensors, which eliminates the overlap of irradiated objects, so that only the image of one object to be detected is received each time for photosensing, with high accuracy, no missed detection and no overlapping detection; and it is equipped with a fan-shaped distributed irradiation source, so that the intensity of the detection light is consistent, eliminating the error of the irradiation source, thereby improving the detection accuracy and resolution.

[0031] 4. This application arranges the irradiation source, the detection channel and the supporting photosensitive plate sensors, so that the radiation area is larger at the top and smaller at the bottom, and further ensures that the detection light will cover the first channel side and the entire channel; then when the bottom surface of the object to be detected in the channel is fully illuminated by the detection light, the part above the bottom surface of the object to be detected will also be irradiated, and a conventional rectangular object to be detected will be completely covered, realizing dead-angle-free detection of the object to be detected.

[0032] 5. This application uses the arc-arranged photosensitive plate sensors to eliminate the light difference of the irradiation source, ensure that the detection image is not deformed, realize the quality of dead-angle-free detection, and improve the detection accuracy.

[0033] 6. This application can sense the detection light covering the entire channel through the photosensitive plate sensor, so as to realize the detection of the entire channel area, thus solving the problem of detection dead angles, especially solving the problem of detection dead angles that are likely to occur at the place closer to the detection light emission source in the channel.

[0034] 7. A plurality of photosensitive plate sensors corresponding to the first channel side of the present application are sequentially distributed in the left-right direction, and all the photosensitive plate sensors are distributed in an L shape. In this distribution form, while being able to sense the detection light covering the entire channel, the overall structure is simple and the occupied space is small.

[0035] 8. For the foreign object detector of the present application, in the face of the requirement that the resolution of the X-ray device for food detection is usually required to be below 0.1 mm, it overcomes the defect of missed detection in the small-size dead corner. That is, by adopting the arc arrangement or L-shaped arrangement of the present application, or a combination of the two, the risk of missed detection of small sizes can be overcome to ensure that tiny metal foreign objects can be detected. Brief Description of the Drawings

[0036] Figure 1 It is a schematic structural diagram of the foreign object detector in the first embodiment of the present invention.

[0037] Figure 2 It is a schematic structural diagram of the foreign object detector in the second embodiment of the present invention.

[0038] Figure 3 It is a schematic structural diagram of the foreign object detector in the third embodiment of the present invention.

[0039] Explanation of Component Labels

[0040] 1. Machine body

[0041] 11. Channel

[0042] 111. First channel side

[0043] 112. Second channel side

[0044] 113. Third channel side

[0045] 114. Fourth channel side

[0046] 115. Center line

[0047] 2. Detection light emission source

[0048] 21. Detection light

[0049] 22. Light emission center

[0050] 3. Photosensitive plate sensor. Detailed Embodiment

[0051] The following specific embodiments illustrate the implementation manners of the present invention. Those skilled in the art can easily understand other advantages and effects of the present invention from the content disclosed in this specification.

[0052] It should be noted that the structures, proportions, sizes, etc. shown in the attached drawings of this specification are only used to cooperate with the content disclosed in the specification for those familiar with this technology to understand and read, and are not used to limit the conditions for the implementation of the present invention. Therefore, they do not have technical substantive significance. Any modification of the structure, change of the proportional relationship, or adjustment of the size, without affecting the effects that the present invention can produce and the purposes that can be achieved, should still fall within the scope covered by the technical content disclosed in the present invention. At the same time, terms such as "upper", "lower", "left", "right", "middle", and "one" cited in this specification are only for the convenience of description and are not used to limit the scope of implementation of the present invention. The change or adjustment of their relative relationships, without substantial change in the technical content, should also be regarded as the scope of implementation of the present invention.

[0053] Embodiment 1

[0054] As Figure 1 shown, this embodiment provides a foreign object detector, which includes a body 1 with a channel 11, a detection light emission source 2 installed in the body 1, and a photosensitive plate sensor 3 installed in the body 1. The first channel side 111 and the second channel side 112 of the channel 11 both extend in the left - right direction, and the first channel side 111 and the second channel side 112 are spaced apart in the up - down direction. The second channel side 112 is located between the first channel side 111 and the detection light emission source 2 in the up - down direction, that is, the second channel side 112 is closer to the detection light emission source 2. All the detection light rays 21 emitted by the detection light emission source 2 are fan - shapedly distributed, and all the detection light rays 21 emitted by the detection light emission source 2 can cover the second channel side 112. A photosensitive plate sensor 3 is provided corresponding to the first channel side 111, and a photosensitive plate sensor 3 is also provided at the side of the first channel side 111 in the left - right direction. The working principle of this foreign object detector is as follows: The object to be detected passes through the channel 11. During this process, the detection light emission source 2 emits fan - shapedly distributed detection light rays 21 into the channel 11. The detection light rays 21 pass through the object to be detected and irradiate on the photosensitive plate sensor 3. By combining the situation where the photosensitive plate sensor 3 senses the detection light rays 21, it is measured whether there are foreign objects in the object to be detected. At the same time, all the detection light rays 21 emitted by the detection light emission source 2 can cover the second channel side 112. The detection light rays 21 emitted by the detection light emission source 2 are fan - shapedly distributed, that is, the radiation area of the detection light rays 21 gradually becomes larger, and the detection light rays 21 will cover the entire channel 11. A photosensitive plate sensor 3 is provided corresponding to the first channel side 111 and at the side of the first channel side 111. This distribution form of the photosensitive plate sensor 3 can sense the detection light rays 21 covering the entire channel 11, so as to realize the detection of the entire channel 11 area, thus solving the problem of detection dead - angles, especially solving the problem that detection dead - angles are likely to occur at the place where the channel 11 is closer to the detection light emission source 2, and improving the detection accuracy;

[0055] All the detection light rays emitted by the detection light source are fan-shaped and can cover the second channel side, which means that the light rays of the detection light source are designed to be fan-shaped, so that the coverage range of the light rays gradually expands and can effectively cover the entire channel area, especially the second channel side near the light source;

[0056] The technical problem addressed: Solved the problem of detection dead angles that are prone to occur at the ends of the traditional X-ray machine channel, especially on the side close to the light emission source; The technical effect: Through the fan-shaped distributed light rays, it ensures the full coverage of the channel edge and the entire channel area, avoids the generation of dead angles, and thus improves the detection accuracy.

[0057] As Figure 1 shown, in this embodiment, the cross-section of the channel 11 is rectangular. The detection light source 2 is an X-ray source, and this detection light source 2 emits X-rays. In this embodiment, the foreign object detector can be specifically applied to detect whether there are metal foreign objects in food, etc. In this embodiment, the foreign object detector is specifically a food X-ray machine.

[0058] As Figure 1 shown, in this embodiment, a plurality of light-sensitive plate sensors 3 located on the side of the first channel side 111 are distributed in sequence in the up-down direction. The third channel side 113 and the fourth channel side 114 of the channel 11 both extend in the up-down direction, and the third channel side 113 and the fourth channel side 114 of the channel 11 are spaced apart in the left-right direction. A plurality of light-sensitive plate sensors 3 located on the side of the first channel side 111 correspond to the third channel side 113. The detection light rays 21 exceeding the first channel side 111 will pass through the third channel side 113, and this part of the light rays will irradiate onto the light-sensitive plate sensors 3 corresponding to the third channel side 113, that is, the light-sensitive plate sensors 3 corresponding to the third channel side 113 will sense the detection light rays 21 exceeding the first channel side 111. At the same time, the detection light rays 21 covering the first channel side 111 will be sensed by the light-sensitive plate sensors 3 corresponding to the first channel side 111. The detection light source 2 and the fourth channel side 114 are on the same side of the center line 115 of the channel 11, that is, the detection light source 2 is located on the side of the center line 115 of the channel 11 that is biased towards the fourth channel side 114. The detection light rays 21 emitted by the detection light source 2 will cover the second channel side 112 and the entire channel 11, and are emitted from the first channel side 111 and the third channel side 113, and then are respectively sensed by the light-sensitive plate sensors 3 corresponding to the first channel side 111 and the light-sensitive plate sensors 3 corresponding to the third channel side 113. In this embodiment, a plurality of light-sensitive plate sensors 3 corresponding to the first channel side 111 are distributed in sequence in the left-right direction, and all the light-sensitive plate sensors 3 are L-shaped distributed. This distribution form, while meeting the requirement of being able to sense the detection light rays 21 covering the entire channel 11, has a simple overall structure and occupies less space;

[0059] The L-shaped sensor distribution pattern enables the sensors to cover the bottom and side of the channel simultaneously, increasing the coverage of the detection area; effectively avoiding the problem that the traditional single-plane photosensitive plate cannot fully sense light at the corners;

[0060] Through the L-shaped layout, the coverage range and photosensitive effect of the sensors are effectively improved, reducing the detection blind spots caused by the special shape or position of the object.

[0061] In addition, as Figure 1 shown, in this embodiment, the detection light emission source 2 is specifically located below the channel 11. In this embodiment, the second channel side 112 is located below, the first channel side 111 is located above, the third channel side 113 is located on the left, and the fourth channel side 114 is located on the right. In this embodiment, the detection light emission source 2 is a bottom-illumination design.

[0062] In this embodiment, the irradiation range of all the detection light rays 21 emitted by the detection light emission source 2 covers the entire channel 11. At the same time, the photosensitive plate sensor 3 can sense the detection light rays 21 covering the entire channel 11, thereby meeting the detection requirement for the entire range of the channel 11, avoiding the occurrence of detection dead angles, and improving the detection accuracy.

[0063] In this embodiment, the channel 11 can specifically adopt a larger-diameter design to meet the detection of larger measured objects. In this embodiment, the photosensitive plate sensor 3 is a photosensitive film that can sense X-rays.

[0064] Embodiment Two

[0065] As Figure 2 shown, on the basis of the above Embodiment One, in this embodiment, the position of the detection light emission source 2 is adjusted to above the channel 11. In this embodiment, the second channel side 112 is located above, the first channel side 111 is located below, the third channel side 113 is located on the left, and the fourth channel side 114 is located on the right. That is, in this embodiment, the detection light emission source 2 adopts a top-illumination design.

[0066] Embodiment Three

[0067] As Figure 3 shown, on the basis of the above Embodiment One, all the photosensitive plate sensors 3 are sequentially distributed in the left-right direction. And all the photosensitive plate sensors 3 are distributed in an arc shape. Specifically, all the photosensitive plate sensors 3 are distributed in an arc shape with the light emission center 22 of the detection light emission source 2 as the center of the circle. And photosensitive plate sensors 3 are provided on both the left and right sides of the first channel side 111.

[0068] The arc-shaped distribution and layout of the photosensitive plate sensors in this application are to eliminate detection dead angles and improve detection accuracy.

[0069] In this embodiment, the photosensitive plate sensors 3 distributed in such a form can also ensure that all the photosensitive plate sensors 3 can sense the detection light 21 covering the entire channel 11, meeting the requirement of dead - angle - free detection. Moreover, the arc - arranged photosensitive plate sensors 3 can ensure that the detected image is not distorted, which is more conducive to achieving the quality of dead - angle - free detection and improving the detection accuracy.

[0070] In this embodiment, the light - emitting center 22 of the detection light source 2 is located on the center line 115 of the channel 11. The distance between the light - emitting center 22 of the detection light source 2 and the photosensitive plate sensor 3 can be designed according to the actual situation to ensure that all the detection light 21 emitted by the detection light source 2 can cover the second channel side 112. In this embodiment, the radiation area of the detection light 21 is larger at the top and smaller at the bottom, thus ensuring that the detection light 21 will cover the first channel side 111 and the entire channel 11. When the bottom surface of the object to be detected in the channel 11 is completely illuminated by the detection light 21, the part above the bottom surface of the object to be detected will also be irradiated, and a conventional rectangular object to be detected will be completely covered, realizing dead - angle - free detection of the object to be detected and improving the detection accuracy.

[0071] Embodiment Four

[0072] The foreign - object detector of the present application is not limited to having only one detection light source and one channel. In an integrated device with multiple detection light sources and multiple channels, they can co - exist. For example, by combining multiple technical solutions of arc - shaped distribution and L - shaped distribution, that is, the combination of devices, to achieve high - efficiency foreign - object detection with shared device space and multiple detection channels.

[0073] Embodiment Five

[0074] The limitation of the light - plate sensor of the present application is based on the matching of the detection channel. If the number of channels is increased, the light - plate sensor can be added according to whether there is a detection requirement for this channel.

[0075] The foreign - object detector can adopt the form of a single emission source + multiple channels, that is, arranging more detection channels in the area that can be irradiated by a single emission source, namely, realizing the arc - shaped and L - shaped arrangement methods.

[0076] Embodiment Six

[0077] A foreign object detector, comprising a body 1 with a channel 11, a detection light emission source 2 installed in the body 1, and a photosensitive plate sensor 3 installed in the body 1. The first channel side 111 and the second channel side 112 of the channel 11 both extend in the left-right direction, and the first channel side 111 and the second channel side 112 are spaced apart in the up-down direction. The second channel side 112 is located between the first channel side 111 and the detection light emission source 2 in the up-down direction. All the detection light rays 21 emitted by the detection light emission source 2 are fan-shapedly distributed, and all the detection light rays 21 emitted by the detection light emission source 2 can cover the second channel side 112. A photosensitive plate sensor is provided at the position corresponding to the first channel side 111 for receiving the detection light rays 21 covering the second channel side 112. A plurality of photosensitive plate sensors 3 located at the side of the first channel side 111 in the left-right direction are sequentially distributed in the up-down direction to eliminate the detection dead angle near the detection light emission source of the channel, so that the detection light rays pass through the object to be detected and irradiate on the photosensitive plate sensor, and the detection image is not deformed;

[0078] The first channel side and the second channel side are spaced apart in the up-down direction, and the second channel side is located between the detection light emission source and the first channel side: so that the light rays emitted by the light source can preferentially cover the second channel side and then pass through the first channel side at intervals to ensure that the light rays fully cover both sides of the channel;

[0079] Further preventing the detection blind area caused by the light rays being blocked by an object or unevenly distributed;

[0080] Ensuring that the light rays are uniform and unmissed when penetrating the object to be detected, and further improving the comprehensiveness and accuracy of the detection.

[0081] Embodiment Seven

[0082] A foreign object detector, for cooperating with an arc-shaped detection channel, at least a part of the photosensitive plate sensors 3 are arc-shapedly distributed, and with the light emission center 22 of the detection light emission source 2 as the center of the circle, so that the detection light rays pass through the object to be detected and irradiate on the photosensitive plate sensors 3, and the detection image is not deformed.

[0083] In summary, the present invention effectively overcomes various disadvantages in the prior art and has high industrial utilization value;

[0084] To improve the detection accuracy of the foreign object detector, especially to solve the problem of the detection dead angle that easily appears at one end of the channel of the existing food X-ray machine close to the detection light emission source, and because the traditional L-shaped detection space is adopted, the technical defect of image overlap in the current detection is very obvious;

[0085] The present invention eliminates the detection dead angle of the foreign object detector and improves the detection accuracy; the specific technical effects include achieving a detection light that covers comprehensively, an optimized layout of the photosensitive plate sensors, especially an arc-shaped layout, which is combined with a fan-shaped X-ray irradiation, and the photosensitive plate sensors distributed around the light source, improving the coverage range of the irradiation, and improving and enhancing the accuracy of the irradiation, and improving the high efficiency and high accuracy of the detection process.

[0086] In the process of detecting by the existing food X-ray machine, due to the limitations of the light distribution of the light emission source and the layout of the photosensitive plate sensors, it is easy to form a detection dead angle at the end of the channel on the side close to the light source, resulting in the food part in this area not being effectively detected, affecting the comprehensiveness and accuracy of the detection; the present invention adopts a fan-shaped distributed detection light and reasonably arranges the photosensitive plate sensors, especially in the areas close to the light source and the edge of the channel, ensuring that the light can cover the entire detection channel and be fully received by the photosensitive plate, eliminating the detection dead angle; increasing the distribution forms of the photosensitive plate sensors, such as L-shaped and arc-shaped layouts, enabling them to sense light from multiple angles and in multiple directions, improving the detection accuracy.

[0087] The above embodiments are only illustrative of the principles and effects of the present invention, and are not used to limit the present invention. Any person familiar with this technology can modify or change the above embodiments without departing from the spirit and scope of the present invention. Therefore, all equivalent modifications or changes made by those with ordinary knowledge in the technical field without departing from the spirit and technical idea disclosed by the present invention should still be covered by the claims of the present invention.

Claims

1. A foreign object detector, characterized in that, It includes a body (1) with a channel (11), a detection light emission source (2) installed in the body (1), and a photosensitive plate sensor (3) installed in the body (1). The first channel side (111) and the second channel side (112) of the channel (11) both extend in the left - right direction, and the first channel side (111) and the second channel side (112) are spaced apart in the up - down direction. The second channel side (112) is located between the first channel side (111) and the detection light emission source (2) in the up - down direction. All the detection light rays (21) emitted by the detection light emission source (2) are fan - shapedly distributed, and all the detection light rays (21) emitted by the detection light emission source (2) can cover the second channel side (112). A photosensitive plate sensor is provided corresponding to the first channel side (111) for receiving the detection light rays (21) covering the second channel side (112). A plurality of photosensitive plate sensors (3) located at the side edges of the first channel side (111) in the left - right direction are sequentially distributed in the up - down direction, for eliminating the detection dead angle near the detection light emission source of the channel, enabling the detection light rays to pass through the object to be measured and irradiate on the photosensitive plate sensor, and the detection image is not deformed.

2. The foreign object detector according to claim 1, wherein All the photosensitive plate sensors (3) are sequentially distributed in the left - right direction.

3. The foreign object detector according to claim 1 or 2, characterized in that All the photosensitive plate sensors (3) are arc - shapedly distributed.

4. The foreign object detector according to claim 3, wherein All the photosensitive plate sensors (3) are arc - shapedly distributed with the light emission center (22) of the detection light emission source (2) as the center of the circle.

5. The foreign object detector according to claim 1 or 2, characterized in that, The photosensitive plate sensors (3) are provided on both the left and right side edges of the first channel side (111).

6. The foreign object detector according to claim 1, wherein, A plurality of photosensitive plate sensors (3) located at the side of the first channel side (111) are sequentially distributed in the up - down direction.

7. The foreign object detector according to claim 6, characterized in that The third channel side (113) and the fourth channel side (114) of the channel (11) both extend in the up - down direction, and the third channel side (113) and the fourth channel side (114) of the channel (11) are spaced apart in the left - right direction. A plurality of photosensitive plate sensors (3) located at the side of the first channel side (111) correspond to the third channel side (113).

8. The foreign object detector according to claim 7, wherein A plurality of photosensitive plate sensors (3) corresponding to the first channel side (111) are sequentially distributed in the left - right direction, and all the photosensitive plate sensors (3) are L - shapedly distributed.

9. The foreign object detector according to claim 8, wherein, The detection light emission source (2) and the fourth channel side (114) are located on the same side of the center line (115) of the channel (11); the detection light emission source (2) is an X - ray emission source.

10. The foreign object detector according to claim 1, wherein, At least a part of the photosensitive plate sensors (3) are arc - shapedly distributed and with the light emission center (22) of the detection light emission source (2) as the center of the circle, enabling the detection light rays to pass through the object to be measured and irradiate on the photosensitive plate sensor (3), and the detection image is not deformed.

Images