Video roll call imaging device and imaging method thereof

Abstract

The application discloses a kind of video roll call image acquisition equipment and its image acquisition method, it is related to roll call image acquisition technical field, including frame channel steel, cross plate is equipped in frame channel steel, the two sides of frame channel steel are equipped with a pair of fixed shaft, cross plate is connected with a pair of fixed shaft by limiting mechanism, the bottom end of fixed shaft is equipped with U-shaped plate;Two side walls of U-shaped plate are equipped with a pair of J-shaped slide plate, first connecting shaft is equipped in U-shaped plate, second connecting shaft is equipped between a pair of J-shaped slide plate, first connecting shaft is connected with second connecting shaft by jacking mechanism, the bottom surface of a pair of J-shaped slide plate is equipped with fixed plate;The bottom surface of fixed plate is equipped with electric telescopic cylinder, the telescopic rod end of electric telescopic cylinder is equipped with image acquisition device, fixed plate is connected with lifting plate by connecting rod mechanism.The application solves the problem of poor accuracy and lack of protection of video roll call image acquisition equipment, and the overall structure design is compact, not only enhances the range of roll call image acquisition, improves its accuracy, but also can further play a safety protection, avoid causing damage.

Description

Technical Field

[0001] This invention relates to the field of roll call image acquisition technology, and in particular to a video roll call image acquisition device and its acquisition method. Background Technology

[0002] With the rapid development of facial recognition technology, it has been widely applied in various industries, such as facial recognition access control systems and facial recognition visitor systems. However, the development of facial recognition in prisons is mainly focused on access control systems, failing to fully realize the potential of this technology. For example, a Chinese utility model discloses a prison facial recognition roll call device (publication number: CN209946952U), which includes a facial recognition terminal, a communication device and a data processing device connected to the facial recognition terminal, a firewall connected to the communication device, a server and a PC connected to the firewall. The facial recognition terminal captures facial information and extracts feature points. The data processing device analyzes and compares the extracted feature points, and the comparison results are sent to the server via the communication device. Officers can then view and access the comparison results stored on the server using the PC.

[0003] In prisons, roll call and personnel counting are done by officers personally. While this is manageable in smaller prisons, it significantly increases the workload for officers in larger prisons and fails to fully reflect the development of smart prisons and prison information systems. Another example is a Chinese utility model patent that discloses a prison patrol robot video monitoring device (publication number: CN215991064U). This device includes a protective device, an emergency avoidance component movable within the protective device, and an impact-resistant component fixedly installed on top of the emergency avoidance component for image acquisition. The protective device includes a base plate with a protective cover at its top center, two symmetrically fixed impact feedback structures inside the protective cover, and a window at the top of the protective cover. The emergency avoidance component includes a housing with a controller and signal receiver symmetrically arranged inside, a platform movable at the top center of the housing, and an electrically telescopic rod fixedly installed on the top of the platform. It also includes a camera body and a protective cover.

[0004] Current prison video roll call equipment has the following drawbacks: 1. It mainly observes the surroundings through video monitoring devices installed on the machine, then analyzes the data through the controller inside the machine, and then uploads it to the cloud. Its roll call range is effective, but its accuracy cannot be guaranteed; 2. When roll call is not in operation, the video roll call equipment lacks protection and is susceptible to interference and damage from external factors, which reduces its service life. Summary of the Invention

[0005] The purpose of this invention is to address the shortcomings of existing video roll call acquisition devices, such as poor accuracy and lack of protection, and to propose a video roll call acquisition device and acquisition method thereof.

[0006] To address the problems of poor accuracy and lack of protection in existing video roll call acquisition equipment, the present invention adopts the following technical solution:

[0007] A video roll call and image acquisition device includes a frame-shaped channel steel, a cross plate is provided in the middle of the frame-shaped channel steel, the four ends of the cross plate are fixedly connected to the bottom wall of the inner side wall of the frame-shaped channel steel, a pair of symmetrically distributed fixed shafts are provided on both sides of the bottom surface of the frame-shaped channel steel, the cross plate is connected to the pair of fixed shafts through a limiting mechanism, an elliptical plate is fixedly provided at the bottom end of each fixed shaft, and a U-shaped plate is fixedly provided on the bottom surface of each elliptical plate.

[0008] The U-shaped plate has a pair of J-shaped notches on both sides, and a pair of vertically sliding and engaging J-shaped sliding plates are provided inside the pair of J-shaped notches. A first connecting shaft is provided between the middle of the two sides of the U-shaped plate, and a second connecting shaft is provided between the top of the opposite surfaces of the pair of J-shaped sliding plates. The first connecting shaft is connected to the second connecting shaft through a lifting mechanism, and a fixing plate is fixed on the bottom surface of the pair of J-shaped sliding plates.

[0009] An electric telescopic cylinder with its telescopic end facing downwards is fixedly installed in the middle of the bottom surface of the fixed plate. A lifting plate is fixedly installed at the end of the telescopic rod of the electric telescopic cylinder. A fixed rod is fixedly installed in the middle of the bottom surface of the lifting plate. An image acquisition device is fixedly installed at the bottom end of the fixed rod. A pair of image acquisition probes are provided on the outer side of the image acquisition device. The fixed plate is connected to the lifting plate through a linkage mechanism.

[0010] Preferably, the frame-shaped channel steel is square and has a frame-shaped sliding groove on the bottom wall. Each fixed shaft is fitted with a concentrically fixed elliptical slider in the middle. Each elliptical slider is slidably engaged in the frame-shaped sliding groove. Support plates are fixed at the top of the four corners inside the frame-shaped channel steel. A pair of expansion bolts are inserted into the bottom surface of each support plate.

[0011] Preferably, the inner and outer walls of the frame-shaped channel steel are fixed with frame-shaped slide rails, the top end of the fixed shaft is fitted with a rotatably connected limiting pulley, the limiting pulley is rotatably engaged in the frame-shaped slide rails, and the upper middle part of the fixed shaft is fitted with a concentrically fixed anti-fall ring, the anti-fall ring is located inside the frame-shaped channel steel and is slidably connected to the inner bottom wall of the frame-shaped channel steel.

[0012] Preferably, the limiting mechanism includes a central swing arm, a first through hole is provided in the middle of the cross plate, a first motor is fixed inside the first through hole, a central swing arm is sleeved on the end of the motor shaft of the first motor, a pair of symmetrically distributed elliptical pin holes are provided on the left and right sections of the central swing arm, and the lower middle parts of a pair of fixed shafts are slidably inserted into the corresponding pair of elliptical pin holes.

[0013] Preferably, the lifting mechanism includes a first eccentric gear and a second eccentric gear. The first eccentric gear is eccentrically fixed to the middle of the first connecting shaft, and the second eccentric gear is eccentrically fixed to the middle of the second connecting shaft. The first eccentric gear and the second eccentric gear are meshed and connected.

[0014] Preferably, a pair of eccentrically fixed eccentric rollers are fitted on both sides of the first coupling shaft, and a pair of eccentrically fixed eccentric pulleys are fitted on both sides of the second coupling shaft, with the outer ring surfaces of the pair of eccentric pulleys respectively engaging with the outer ring surfaces of the pair of eccentric rollers.

[0015] Preferably, a U-shaped bracket is fixed on one side of the U-shaped plate, and a second through hole is opened in the middle of the outer side wall of the U-shaped bracket. A second motor is fixed inside the second through hole, and the end of the motor shaft of the second motor is coaxially connected to one end of the first connecting shaft.

[0016] Preferably, the linkage mechanism includes an L-shaped swing arm, and a U-shaped lug is fixedly provided in the middle of the four side walls of the fixed plate. A movably hinged connecting swing arm is provided in the opening of each U-shaped lug. A movably hinged L-shaped swing arm is provided at the bottom end of each connecting swing arm. An L-shaped connecting plate is fixedly provided in the middle of the four side walls of the lifting plate. The corner of each L-shaped swing arm is movably hinged to the top end of the corresponding L-shaped connecting plate.

[0017] Preferably, the outer side of the image sensor is provided with four circular, outwardly flared notch covers. Each notch cover has a vertically fixed bent swing arm on its outer side wall. The top end of each bent swing arm is movably hinged to the bottom end of the corresponding L-shaped swing arm. The upper middle part of each bent swing arm and the middle part of the corresponding L-shaped connecting plate are provided with a pair of movably hinged parallel swing arms. Each pair of parallel swing arms and the corresponding L-shaped swing arm are in a parallel state.

[0018] This invention also proposes an image acquisition method for a video roll call image acquisition device, comprising the following steps:

[0019] Step 1, initial state: The frame-shaped channel steel is fixed to the top wall of the prison by the expansion bolts on the support plate. The electric telescopic cylinder is activated, and the telescopic rod of the electric telescopic cylinder slowly extends, driving the lifting plate, L-shaped connecting plate, fixed rod, and image sensor to slowly descend. Through the bottom end of the connecting arm, the top part of the L-shaped arm swings inward along the middle top part of the L-shaped connecting plate. Then, through the parallel hinge action of the parallel arm and the L-shaped arm, the bending arm and the notch cover expand outward synchronously, so that the image sensor is fully exposed.

[0020] Step 2: Start the second motor. The motor shaft of the second motor drives the first coupling, the first eccentric gear, and the eccentric pulley to rotate synchronously. The first eccentric gear meshes and drives the second eccentric gear, the second coupling, and the eccentric pulley to rotate in the opposite direction. Since both the first and second eccentric gears are eccentrically set, they drive the J-shaped slide plate to slide up and down along the J-shaped notch.

[0021] Step 3: Start the first motor. The motor shaft of the first motor drives the central swing arm to rotate synchronously. The elliptical pin hole on the central swing arm forms a limiting effect with the fixed shaft, which drives the elliptical slider to slide along the frame-shaped slide groove. Simultaneously, it drives the fixed shaft, anti-fall ring, elliptical plate, U-shaped plate, fixed plate and image sensor to translate along the trajectory of the frame-shaped channel steel.

[0022] Step four: Before the roll call and image capture operation, arrange for the inmates to stand around the lower perimeter of the frame-shaped channel steel, and simultaneously start a pair of image capture devices. Under the action of the image capture devices, the inmates are captured on video through a pair of image capture probes.

[0023] Compared with the prior art, the beneficial effects of the present invention are:

[0024] 1. In this invention, through the cooperation of the limiting mechanism, the elliptical pin hole on the central swing arm and the fixed shaft form a limiting effect, driving the image acquisition device to move along the trajectory of the frame-shaped channel steel, thereby enhancing the image acquisition range of the image acquisition device; the inmates stand around the lower periphery of the frame-shaped channel steel, and under the action of the image acquisition device, a pair of image acquisition probes are used to conduct video roll call image acquisition of the inmates.

[0025] 2. In this invention, through the use of the lifting mechanism, since both the first eccentric gear and the second eccentric gear are eccentrically set, the J-shaped slide plate is driven to slide up and down along the J-shaped notch, which can drive the image acquisition device to adjust its height; when the roll call image acquisition stops, through the use of the linkage mechanism, the four notch covers can be driven to close synchronously through the combined action of each swing arm, forming an enclosure for the image acquisition device, thereby achieving effective safety protection;

[0026] In summary, this invention solves the problems of poor accuracy and lack of protection in video roll call imaging equipment. Moreover, the overall structure is compact, which not only enhances the range of roll call imaging and improves its accuracy, but also provides further safety protection to prevent damage. Attached Figure Description

[0027] The accompanying drawings, which are included to provide a further understanding of the invention and form part of this application, illustrate exemplary embodiments of the invention and, together with their description, serve to explain the invention and do not constitute an undue limitation thereof. In the drawings:

[0028] Figure 1 This is a schematic diagram of the main structure of the present invention;

[0029] Figure 2 This is a bottom-view structural diagram of the present invention;

[0030] Figure 3 This is an exploded view of the present invention;

[0031] Figure 4 This is a half-section schematic diagram of the frame-shaped channel steel and frame-shaped slide rail of the present invention;

[0032] Figure 5 This is a schematic diagram of the connection between the U-shaped plate and the fixing plate of the present invention;

[0033] Figure 6 This is a schematic diagram of the lifting mechanism structure of the present invention;

[0034] Figure 7 For the present invention Figure 6 An explosion diagram;

[0035] Figure 8 This is a schematic diagram of the linkage mechanism structure of the present invention;

[0036] Figure 9 For the present invention Figure 8 An explosion diagram;

[0037] The components in the diagram are numbered as follows: 1. Frame-shaped channel steel; 11. Frame-shaped slide rail; 12. Elliptical slider; 13. Fixed shaft; 14. Limiting pulley; 15. Anti-fall ring; 16. Elliptical plate; 17. Cross plate; 18. First motor; 19. Central swing arm; 110. Support plate; 2. U-shaped plate; 21. J-shaped sliding plate; 22. First connecting shaft; 23. First eccentric gear; 24. Eccentric chuck; 25. Second connecting shaft; 26. Second eccentric gear; 27. Eccentric pulley; 28. U-shaped bracket; 29. ​​Second motor; 3. Fixed plate; 31. Electric telescopic cylinder; 32. Lifting plate; 33. Fixed rod; 34. Image sensor; 35. Image sensor probe; 36. Connecting swing arm; 37. L-shaped connecting plate; 38. L-shaped swing arm; 39. Parallel swing arm; 310. Bending swing arm; 311. Notch cover. Detailed Implementation

[0038] The technical solutions of the present invention will be clearly and completely described below with reference to the accompanying drawings of the embodiments of the present invention. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments.

[0039] Example 1: This example provides a video roll call image acquisition device, see [link to example]. Figure 1-9Specifically, it includes a frame-shaped channel steel 1, a cross plate 17 in the middle of the frame-shaped channel steel 1, the four ends of the cross plate 17 being fixedly connected to the bottom wall of the inner side wall of the frame-shaped channel steel 1, a pair of symmetrically distributed fixed shafts 13 on both sides of the bottom surface of the frame-shaped channel steel 1, the cross plate 17 being connected to the pair of fixed shafts 13 through a limiting mechanism, an elliptical plate 16 being fixedly provided at the bottom end of each fixed shaft 13, and a U-shaped plate 2 being fixedly provided on the bottom surface of each elliptical plate 16.

[0040] The U-shaped plate 2 has a pair of J-shaped notches on both sides. Inside the pair of J-shaped notches, there is a pair of vertically sliding and engaging J-shaped slide plates 21. A first connecting shaft 22 is provided between the middle of the two sides of the U-shaped plate 2. A second connecting shaft 25 is provided between the top of the opposite surfaces of the pair of J-shaped slide plates 21. The first connecting shaft 22 is connected to the second connecting shaft 25 through a lifting mechanism. A fixing plate 3 is fixed on the bottom surface of the pair of J-shaped slide plates 21.

[0041] An electric telescopic cylinder 31 with its telescopic end facing downward is fixedly installed in the middle of the bottom surface of the fixed plate 3. A lifting plate 32 is fixedly installed at the end of the telescopic rod of the electric telescopic cylinder 31. A fixed rod 33 is fixedly installed in the middle of the bottom surface of the lifting plate 32. An image acquisition device 34 is fixedly installed at the bottom end of the fixed rod 33. A pair of image acquisition probes 35 are provided on the outer side of the image acquisition device 34. The fixed plate 3 is connected to the lifting plate 32 through a linkage mechanism.

[0042] It should be noted that in this embodiment, the frame-shaped channel steel 1 is a square frame with a frame-shaped groove on the bottom wall. Each fixed shaft 13 is fitted with a concentrically fixed elliptical slider 12 in the middle. Each elliptical slider 12 is slidably engaged in the frame-shaped groove and slides along the frame-shaped groove. Support plates 110 are fixed at the top of the four corners inside the frame-shaped channel steel 1. A pair of expansion bolts are inserted on the bottom surface of each support plate 110. The frame-shaped channel steel 1 is fixed to the top wall of the prison by the expansion bolts on the support plates 110.

[0043] Example 2: In Example 1, there was a problem that the image sensor 34 could not be moved. Therefore, based on Example 1, this example also includes:

[0044] In the specific implementation process, such as Figure 2 and Figure 4 As shown, the limiting mechanism includes a central swing arm 19. A first through hole is opened in the middle of the cross plate 17. A first motor 18 is fixed inside the first through hole. The motor shaft end of the first motor 18 is fitted with the central swing arm 19, which is centrally fixed. A pair of symmetrically distributed elliptical pin holes are opened in the left and right sections of the central swing arm 19. The lower middle parts of a pair of fixed shafts 13 are slidably inserted into the corresponding pair of elliptical pin holes. The motor shaft of the first motor 18 drives the central swing arm 19 to rotate synchronously. The elliptical pin holes on the central swing arm 19 and the fixed shafts 13 form a limiting effect, driving the elliptical slider 12 to slide along the frame-shaped groove.

[0045] A frame-shaped slide rail 11 is fixedly installed on the inner and outer walls of the frame-shaped channel steel 1. A rotatably connected limiting pulley 14 is sleeved on the top of the fixed shaft 13. The limiting pulley 14 is rotatably engaged in the frame-shaped slide rail 11. A concentrically fixed anti-fall ring 15 is sleeved on the upper middle part of the fixed shaft 13. The anti-fall ring 15 is located in the frame-shaped channel steel 1 and is slidably connected to the inner bottom wall of the frame-shaped channel steel 1. When the elliptical slider 12 slides along the frame-shaped slide groove, it drives the limiting pulley 14 to slide along the frame-shaped slide rail 11. The anti-fall ring 15 plays a protective role and increases the stability of the elliptical slider 12 sliding.

[0046] Example 3: In Example 1, there was a problem with the inconvenience of adjusting the height of the image sensor 34. Therefore, based on Example 1, this example also includes:

[0047] In the specific implementation process, such as Figure 6 and Figure 7 As shown, the lifting mechanism includes a first eccentric gear 23 and a second eccentric gear 26. The first eccentric gear 23 is eccentrically fixed to the middle of the first connecting shaft 22, and the second eccentric gear 26 is eccentrically fixed to the middle of the second connecting shaft 25. The first eccentric gear 23 and the second eccentric gear 26 are meshed together. The motor shaft of the second motor 29 drives the first connecting shaft 22, the first eccentric gear 23, and the eccentric chuck 24 to rotate synchronously. Since the first eccentric gear 23 and the second eccentric gear 26 are both eccentrically set, they drive the J-shaped slide plate 21 to slide up and down along the J-shaped notch.

[0048] A pair of eccentrically fixed eccentric rollers 24 are fitted on both sides of the first connecting shaft 22, and a pair of eccentrically fixed eccentric pulleys 27 are fitted on both sides of the second connecting shaft 25. The outer ring surfaces of the pair of eccentric pulleys 27 are respectively engaged with the outer ring surfaces of the pair of eccentrically fixed eccentric rollers 24, thereby enhancing the stability of the J-shaped skateboard 21.

[0049] A U-shaped bracket 28 is fixedly provided on one side of the U-shaped plate 2. A second through hole is provided in the middle of the outer side wall of the U-shaped bracket 28. A second motor 29 is fixedly provided inside the second through hole. The end of the motor shaft of the second motor 29 is coaxially connected to one end of the first connecting shaft 22. The motor shaft of the second motor 29 drives the first connecting shaft 22, the first eccentric gear 23, and the eccentric chuck 24 to rotate synchronously.

[0050] Example 4: In Example 1, there was a problem that the image sensor 34 lacked protection. Therefore, based on Example 1, this example also includes:

[0051] In the specific implementation process, such as Figure 8 and Figure 9As shown, the linkage mechanism includes an L-shaped swing arm 38. U-shaped lugs are fixed in the middle of the four side walls of the fixed plate 3. Each U-shaped lug has a movably hinged connecting swing arm 36 in its opening. Each connecting swing arm 36 has a movably hinged L-shaped swing arm 38 at its bottom end. L-shaped connecting plates 37 are fixed in the middle of the four side walls of the lifting plate 32. Each L-shaped swing arm 38 is movably hinged to the top end of the corresponding L-shaped connecting plate 37 at its corner. The telescopic rod of the electric telescopic cylinder 31 slowly extends, causing the lifting plate 32, L-shaped connecting plate 37, fixed rod 33, and image sensor 34 to slowly descend. The bottom end of the connecting swing arm 36 drives the top end of the L-shaped swing arm 38 to swing inward along the middle top end of the L-shaped connecting plate 37.

[0052] The outer side of the image sensor 34 is provided with four circular, outwardly flared notch covers 311. Each notch cover 311 has a vertically fixed bent swing arm 310 on its outer side wall. The top of each bent swing arm 310 is movably hinged to the bottom of the corresponding L-shaped swing arm 38. The upper middle part of each bent swing arm 310 and the middle part of the corresponding L-shaped connecting plate 37 are provided with a pair of movably hinged parallel swing arms 39. Each pair of parallel swing arms 39 and the corresponding L-shaped swing arm 38 are in a parallel state. Through the parallel hinge action of the parallel swing arms 39 and the L-shaped swing arms 38, the bent swing arms 310 and the notch covers 311 expand outward synchronously, so that the image sensor 34 is fully exposed to the outside.

[0053] Example 5: Specifically, the working principle and operation method of the present invention are as follows:

[0054] Step 1, initial state: The frame-shaped channel steel 1 is fixed to the top wall of the prison by the expansion bolts on the support plate 110. The electric telescopic cylinder 31 is activated. The telescopic rod of the electric telescopic cylinder 31 slowly extends, driving the lifting plate 32, L-shaped connecting plate 37, fixing rod 33, and image sensor 34 to slowly descend. Through the bottom end of the connecting swing arm 36, the top part of the L-shaped swing arm 38 swings inward along the middle top part of the L-shaped connecting plate 37. Then, through the parallel hinge action of the parallel swing arm 39 and the L-shaped swing arm 38, the bending swing arm 310 and the notch cover 311 expand outward synchronously, so that the image sensor 34 is fully exposed to the outside.

[0055] Step two, start the second motor 29. The motor shaft of the second motor 29 drives the first connecting shaft 22, the first eccentric gear 23, and the eccentric chuck 24 to rotate synchronously. The first eccentric gear 23 meshes with and drives the second eccentric gear 26, the second connecting shaft 25, and the eccentric pulley 27 to rotate in the opposite direction. Since the first eccentric gear 23 and the second eccentric gear 26 are both eccentrically set, they drive the J-shaped slide plate 21 to slide up and down along the J-shaped notch.

[0056] Step 3: Start the first motor 18. The motor shaft of the first motor 18 drives the central swing arm 19 to rotate synchronously. The elliptical pin hole on the central swing arm 19 forms a limiting effect with the fixed shaft 13, which drives the elliptical slider 12 to slide along the frame-shaped slide groove. Simultaneously, the fixed shaft 13, the anti-fall ring 15, the elliptical plate 16, the U-shaped plate 2, the fixed plate 3 and the image sensor 34 are translated along the trajectory of the frame-shaped channel steel 1.

[0057] Step four: Before the roll call and image collection operation, arrange for the inmates to stand around the lower perimeter of the frame-shaped channel steel 1, and simultaneously start a pair of image collectors 34. Under the action of the image collectors 34, the inmates are recorded via video roll call through a pair of image collection probes 35.

[0058] This invention solves the problems of poor accuracy and lack of protection in video roll call imaging equipment. Moreover, the overall structure is compact, which not only enhances the range of roll call imaging and improves its accuracy, but also provides further safety protection to avoid damage.

[0059] The above description is only a preferred embodiment of the present invention, but the scope of protection of the present invention is not limited thereto. Any equivalent substitutions or modifications made by those skilled in the art within the scope of the technology disclosed in the present invention, based on the technical solution and inventive concept of the present invention, should be covered within the scope of protection of the present invention.

Claims

1. A video roll call image acquisition device, comprising a frame-shaped channel steel (1), characterized in that: The frame-shaped channel steel (1) has a cross plate (17) in the middle. The four ends of the cross plate (17) are fixed to the bottom wall of the inner side wall of the frame-shaped channel steel (1). The bottom surface of the frame-shaped channel steel (1) has a pair of symmetrically distributed fixed shafts (13). The cross plate (17) is connected to the pair of fixed shafts (13) through a limiting mechanism. The bottom end of each fixed shaft (13) is fixed with an elliptical plate (16). The bottom surface of each elliptical plate (16) is fixed with a U-shaped plate (2). The U-shaped plate (2) has a pair of J-shaped notches on both sides. Inside the pair of J-shaped notches, there is a pair of vertically sliding and engaging J-shaped sliding plates (21). A first connecting shaft (22) is provided between the middle of the inner two sides of the U-shaped plate (2). A second connecting shaft (25) is provided between the top of the opposite surfaces of the pair of J-shaped sliding plates (21). The first connecting shaft (22) is connected to the second connecting shaft (25) through a lifting mechanism. A fixing plate (3) is fixed on the bottom surface of the pair of J-shaped sliding plates (21). An electric telescopic cylinder (31) with its telescopic end facing downward is fixedly installed in the middle of the bottom surface of the fixed plate (3). A lifting plate (32) is fixedly installed at the end of the telescopic rod of the electric telescopic cylinder (31). A fixed rod (33) is fixedly installed in the middle of the bottom surface of the lifting plate (32). An image acquisition device (34) is fixedly installed at the bottom end of the fixed rod (33). A pair of image acquisition probes (35) are provided on the outer side of the image acquisition device (34). The fixed plate (3) is connected to the lifting plate (32) through a linkage mechanism. The limiting mechanism includes a central swing arm (19), and a first through hole is provided in the middle of the cross plate (17). A first motor (18) is fixed inside the first through hole. The motor shaft end of the first motor (18) is fitted with a centrally fixed central swing arm (19). The left and right sections of the central swing arm (19) are provided with a pair of symmetrically distributed elliptical pin holes. The lower middle parts of a pair of fixed shafts (13) are slidably inserted into the corresponding pair of elliptical pin holes. The lifting mechanism includes a first eccentric gear (23) and a second eccentric gear (26). The first eccentric gear (23) is eccentrically fixed in the middle of the first connecting shaft (22), and the second eccentric gear (26) is eccentrically fixed in the middle of the second connecting shaft (25). The first eccentric gear (23) and the second eccentric gear (26) are meshed and connected. A pair of eccentrically fixed eccentric chucks (24) are fitted on both sides of the first connecting shaft (22), and a pair of eccentrically fixed eccentric pulleys (27) are fitted on both sides of the second connecting shaft (25). The outer ring surfaces of the pair of eccentric pulleys (27) are respectively engaged on the outer ring surfaces of the pair of eccentric chucks (24). A U-shaped bracket (28) is fixedly provided on one side of the U-shaped plate (2). A second through hole is provided in the middle of the outer side wall of the U-shaped bracket (28). A second motor (29) is fixedly provided inside the second through hole. The motor shaft end of the second motor (29) is coaxially connected to one end of the first connecting shaft (22). The linkage mechanism includes an L-shaped swing arm (38), and a U-shaped lug is fixedly provided in the middle of the four side walls of the fixed plate (3). A connecting swing arm (36) is provided in the opening of each U-shaped lug. A connecting L-shaped swing arm (38) is provided at the bottom end of each connecting swing arm (36). An L-shaped connecting plate (37) is fixedly provided in the middle of the four side walls of the lifting plate (32). The corner of each L-shaped swing arm (38) is movably hinged to the top end of the corresponding L-shaped connecting plate (37). The outer side of the image sensor (34) is provided with four circular outwardly oriented notch covers (311). Each notch cover (311) has a vertically fixed bent swing arm (310) on its outer side wall. The top of each bent swing arm (310) is movably hinged to the bottom of the corresponding L-shaped swing arm (38). The upper middle part of each bent swing arm (310) and the middle part of the corresponding L-shaped connecting plate (37) are provided with a pair of movably hinged parallel swing arms (39). Each pair of parallel swing arms (39) and the corresponding L-shaped swing arm (38) are in a parallel state.

2. The video roll call image acquisition device according to claim 1, characterized in that: The frame-shaped channel steel (1) is square and has a frame-shaped sliding groove on the bottom wall. Each fixed shaft (13) is fitted with a concentrically fixed elliptical slider (12) in the middle. Each elliptical slider (12) is slidably engaged in the frame-shaped sliding groove. Support plates (110) are fixed at the top of the four corners of the frame-shaped channel steel (1). A pair of expansion bolts are inserted on the bottom surface of each support plate (110).

3. The video roll call image acquisition device according to claim 2, characterized in that: The inner and outer walls of the frame-shaped channel steel (1) are fixed with frame-shaped slide rails (11). The top of the fixed shaft (13) is fitted with a rotatably connected limiting pulley (14). The limiting pulley (14) is rotatably engaged in the frame-shaped slide rail (11). The upper middle part of the fixed shaft (13) is fitted with a concentrically fixed anti-fall ring (15). The anti-fall ring (15) is located inside the frame-shaped channel steel (1) and is slidably connected to the inner bottom wall of the frame-shaped channel steel (1).

4. The image acquisition method of a video roll call image acquisition device according to claim 3, characterized in that, Includes the following steps: Step 1, initial state: The frame-shaped channel steel (1) is fixed to the top wall of the prison by the expansion bolts on the support plate (110). The electric telescopic cylinder (31) is started. The telescopic rod of the electric telescopic cylinder (31) slowly extends, driving the lifting plate (32), L-shaped connecting plate (37), fixing rod (33), and image sensor (34) to slowly descend. Through the bottom end of the connecting arm (36), the top part of the L-shaped arm (38) swings inward along the middle top part of the L-shaped connecting plate (37). Then, through the parallel hinge action of the parallel arm (39) and the L-shaped arm (38), the bending arm (310) and the notch cover (311) expand outward synchronously, so that the image sensor (34) is exposed to the outside. Step 2: Start the second motor (29). The motor shaft of the second motor (29) drives the first connecting shaft (22), the first eccentric gear (23), and the eccentric chuck (24) to rotate synchronously. The first eccentric gear (23) meshes and drives the second eccentric gear (26), the second connecting shaft (25), and the eccentric pulley (27) to rotate in the opposite direction. Since the first eccentric gear (23) and the second eccentric gear (26) are both eccentrically set, they drive the J-shaped slide plate (21) to slide up and down along the J-shaped notch. Step 3: Start the first motor (18). The motor shaft of the first motor (18) drives the central swing arm (19) to rotate synchronously. The elliptical pin hole on the central swing arm (19) and the fixed shaft (13) form a limiting effect, driving the elliptical slider (12) to slide along the frame-shaped slide groove. Simultaneously, the fixed shaft (13), the anti-fall ring (15), the elliptical plate (16), the U-shaped plate (2), the fixed plate (3), and the image sensor (34) are translated along the trajectory of the frame-shaped channel steel (1). Step 4: Before the roll call and image collection operation, arrange for the inmates to stand around the lower perimeter of the frame-shaped channel steel (1), and simultaneously start a pair of image collectors (34). Under the action of the image collectors (34), the inmates are recorded on video through a pair of image probes (35).

Images