A small animal gait analysis device and method based on a circular runway

Abstract

This invention relates to a small animal gait analysis device and method based on a circular track. The device includes a circular track, a rotation drive module, a semi-enclosed restraint module, an imaging module, and a gait analysis module. The circular track is used for experimental animals to run on. The rotation drive module drives a rotating shaft to rotate, thereby rotating the circular track. The semi-enclosed restraint module confines the experimental animal to a specific imaging area at the bottom of the circular track. The imaging module captures a dynamic optical image sequence formed by the contact between the animal's feet and the track as it runs. The gait analysis module processes the dynamic optical image sequence acquired by the imaging module and performs gait analysis. Compared with existing technologies, this invention can induce experimental animals to run continuously, improving the initiative and spatial accuracy of gait data acquisition, as well as the accuracy of gait parameter analysis.

Description

Technical Field

[0001] This invention relates to the field of animal behavior research, and in particular to a device and method for analyzing the gait of small animals based on a circular track. Background Technology

[0002] While existing small animal gait analysis systems (such as CatWalk XT) can provide precise plantar pressure distribution and gait parameters, their core drawback is their extreme reliance on the animal's voluntary walking behavior. When faced with pain models (such as neuropathic pain and arthritis models) or animals with motor dysfunction (such as spinal cord injury and stroke models), animals often refuse to move or exhibit highly unstable gaits due to pain, fear, or impaired motor ability. This not only results in a very short effective data acquisition window and low experimental success rates, but may also introduce behavioral confusion between "unwillingness to move" and "inability to move" due to prolonged animal stillness, affecting the accurate assessment of gait abnormalities caused by the disease or injury itself, ultimately leading to long experimental cycles and low data collection efficiency.

[0003] While treadmills or rotating wheels can force animals to move, and these devices address the data volume issue by passively or inducing continuous movement, their biggest bottleneck lies in the opaque nature of the track. The opaque running belt or pedals prevent researchers from directly observing and recording the contact between the animal's feet and the track from below. Therefore, these systems typically only capture approximate body posture, limb swing amplitude, and movement trajectory from the side or above, failing to acquire high spatiotemporal resolution images of foot contact, precise footprint morphology, dynamic changes in the center of pressure, and instantaneous changes in the contact area—crucial biomechanical information. This limits the comprehensive observation and quantitative analysis of subtle gait anomalies (such as slight changes in foot strike angle or uneven pressure distribution at a single point).

[0004] For example, patent application CN119055230A discloses a gait and force acquisition device for experimental animals. This device collects mechanical parameters using an array of pressure sensors and lateral two-dimensional force sensors pre-installed beneath a running track, and uses an automatic stimulation device to encourage animal movement. This system aims to address the problem of animals spontaneously ceasing movement during experiments due to pathological conditions (such as pain or fear). However, its automatic stimulation and dispersal mechanism is unreliable in generating effective and stable gait data when dealing with animal models that are completely unable or extremely averse to walking due to severe pain or severe motor dysfunction. Furthermore, the system uses an array of pressure sensors placed under a thin cover plate to collect plantar pressure distribution during walking, but it cannot simultaneously acquire high spatiotemporal resolution plantar contact optical images and complete footprint morphology information. Therefore, it has limitations in capturing subtle gait anomalies that rely on fine visual observation, such as foot landing angle and individual toe posture changes. Summary of the Invention

[0005] The purpose of this invention is to overcome the shortcomings of the prior art by providing a small animal gait analysis device and method based on a circular track, which can induce experimental animals to run continuously, improve the initiative and spatial accuracy of gait data acquisition, and the accuracy of gait parameter analysis.

[0006] The objective of this invention can be achieved through the following technical solutions: A small animal gait analysis device based on a circular track includes a circular track, a rotation drive module, a semi-enclosed limiting module, an imaging module, and a gait analysis module. The circular track is used for experimental animals to run on. One side of the circular track is fixedly connected to a rotating shaft by multiple connecting rods. A conductive slip ring is fitted on the rotating shaft. An LED light strip is provided on the edge of the circular track connected to the rotating shaft. The conductive slip ring is used to continuously transmit external electrical energy to the LED light strip that rotates with the circular track when the circular track rotates. The rotation drive module is used to drive the rotating shaft to rotate, thereby realizing the rotation of the circular track; The semi-enclosed limiting module is used to confine the experimental animal to a specific imaging area at the bottom of the circular track. The imaging module is used to capture a sequence of dynamic optical images formed when the soles of the feet of the experimental animals come into contact with the track as they run on the circular track. The gait analysis module is used to process the dynamic optical image sequence acquired by the imaging module and perform gait analysis.

[0007] Furthermore, the circular track is made of transparent acrylic.

[0008] Furthermore, the conductive slip ring includes a rotor and a stator. The rotor is interference-fitted to the shaft, the stator is fixedly connected to the triangular bracket, the rotor is connected to the LED light strip via a wire, and the stator is connected to an external power source via a wire.

[0009] Furthermore, the wires connecting the rotor and the LED light strip are arranged along the connecting rod.

[0010] Furthermore, the rotation drive module is located on one side of the triangular bracket and includes a motor, a drive wheel, and a driven wheel. The drive wheel is located on the output shaft of the motor, and the driven wheel is located on the rotating shaft. The drive wheel and the driven wheel are connected by a belt drive.

[0011] Furthermore, the semi-enclosed limiting module includes side baffles and end baffles. The side baffles are used to prevent experimental animals from jumping out from the sides of the circular track and are fixed to both sides of a specific imaging area of ​​the circular track by trapezoidal brackets. The end baffles are used to restrict the range of activity of experimental animals within a specific imaging area of ​​the circular track and are fixed to both ends of the specific imaging area of ​​the circular track by trapezoidal brackets.

[0012] Furthermore, the imaging module includes a high-speed camera and a background plate, the background plate being used to provide contour contrast for the high-speed camera, the high-speed camera being mounted on a base, and the background plate being fixed to the top of a trapezoidal bracket.

[0013] Furthermore, the optical axis of the high-speed camera lens is on the same straight line as the center point of the specific imaging area of ​​the circular track and the center point of the background plate, and the surface of the background plate is set parallel to the imaging plane of the high-speed camera.

[0014] According to another aspect of the present invention, a method for analyzing the gait of small animals using the small animal gait analysis device based on a circular track as described above is provided, comprising the following steps: The experimental animals were placed in a specific imaging area of ​​the circular track, and the semi-enclosed limiting module was in place to prevent the experimental animals from escaping. The rotation drive module is activated to drive the circular track to rotate at a set speed, maintaining the experimental animals in a spontaneous running motion on the circular track in the opposite direction of the track's rotation. During the running of the experimental animals, the LED light strip is continuously powered through the conductive slip ring, and the imaging module is activated at the same time to capture a dynamic optical image sequence formed when the soles of the experimental animals' feet come into contact with the circular track. The dynamic optical image sequence is preprocessed by the gait analysis module to identify the spatiotemporal changes of each foot contact area and calculate gait parameters.

[0015] Furthermore, the image preprocessing includes denoising, contrast enhancement, background subtraction, and distortion elimination. The distortion elimination is based on the curvature parameters of the circular track and the calibration parameters of the imaging module to perform geometric distortion correction on the acquired dynamic optical image sequence, so as to eliminate image distortion caused by the track curvature and shooting angle.

[0016] Compared with the prior art, the present invention has the following beneficial effects: 1. This invention overcomes the limitations of traditional voluntary walking systems, which rely on the animal's subjective will, leading to difficulties in data collection, and the lack of transparency in forced movement equipment, which prevents direct observation of plantar contact dynamics. It adopts an integrated structure consisting of a circular track driven by a rotation drive module, an LED light strip powered by a conductive slip ring, a high-speed camera below, and a semi-enclosed limiting module. It solves the problems of experimental failure and parameter loss caused by the animal's unwillingness to move and the inability to obtain high-resolution plantar biomechanical images in pain or motor dysfunction models. It improves the initiative, standardization, and observation capability of gait data collection.

[0017] 2. This invention overcomes the limitations of existing technologies, such as measurement errors caused by image geometric distortion and the inability to automatically and quantitatively extract multidimensional fine gait parameters from images, by introducing an image distortion elimination step based on track curvature and camera calibration parameters, and by using image processing and computer vision algorithms to identify, track, and calculate foot regions in the corrected dynamic image sequence. It also solves the problem of spatial distortion in the original images obtained from curved tracks, and improves the spatial accuracy of gait parameter extraction and the accuracy of gait parameter analysis. Attached Figure Description

[0018] Figure 1 This is a schematic diagram of the structure of a small animal gait analysis device based on a circular track proposed in this invention; Figure 2 This is a schematic diagram showing the connection between the conductive slip ring, the rotating shaft, and the triangular support. Figure 3 This is a schematic diagram of the rotary drive module. Figure 4 This is a schematic diagram showing the connection between the conductive slip ring and the LED light strip; Figure 5 This is a flowchart illustrating a small animal gait analysis method based on a circular track proposed in this invention.

[0019] Legend: 1. Circular track; 2. Connecting rod; 3. Rotating shaft; 4. Conductive slip ring; 401. Rotor; 402. Stator; 5. Triangular bracket; 6. LED light strip; 7. Motor; 8. Drive wheel; 9. Driven wheel; 10. Belt; 11. Side baffle; 12. End baffle; 13. Trapezoidal bracket; 14. High-speed camera; 15. Background plate; 16. Base. Detailed Implementation

[0020] The present invention will now be described in detail with reference to the accompanying drawings and specific embodiments. These embodiments are based on the technical solution of the present invention and provide detailed implementation methods and specific operating procedures. However, the scope of protection of the present invention is not limited to the following embodiments.

[0021] Example 1 This embodiment provides a small animal gait analysis device based on a circular track, including a circular track 1, a rotation drive module, a semi-enclosed limiting module, an imaging module, and a gait analysis module.

[0022] The circular running track 1 is used for laboratory animals to run on, such as Figure 1 As shown, one side of the circular track 1 is fixedly connected to the rotating shaft 3 by multiple connecting rods 2. A conductive slip ring 4 is fitted on the rotating shaft 3. An LED light strip 6 is provided on the edge of the circular track 1 connected to the rotating shaft 3. The light strip rotates synchronously with the circular track 1. The material of the circular track 1 is transparent acrylic. The light from the LED light strip 6 shines into the interior of the circular track 1.

[0023] When the rotary drive module drives the rotating shaft 3 and the ring track 1 fixedly connected to it to rotate together, the conductive slip ring 4 can maintain a stable electrical connection between the rotating interfaces, and continuously transmit electrical energy from the external power source to the rotating LED light strip 6.

[0024] like Figure 2 As shown, the conductive slip ring 4 is the core component for achieving dynamic power supply. Internally, it includes a rotor 401 and a stator 402. The rotor 401 is interference-fitted with the rotating shaft 3, allowing it to rotate synchronously with the rotating shaft 3 and the annular track 1. The stator 402 is fixedly connected to the triangular bracket 5 and does not rotate with the rotating shaft. Figure 3 As shown, the rotor 401 is connected to the LED light strip 6 via wires, and the stator 402 is connected to an external power supply via wires. The wires connecting the rotor 401 and the LED light strip 6 are arranged along the connecting rod 2. The wires leading from the rotor 401 to the LED light strip 6 are laid and fixed along one of the connecting rods 2 to form a neat and reliable wiring path.

[0025] This structural design ensures that when the rotating shaft 3 drives the circular track 1 to rotate, the rotor 401 rotates accordingly, while the stator 402 remains stationary. External electrical energy is input through the stator 402, transmitted to the rotating rotor 401 via the sliding contact points inside the slip ring, and then continuously and stably supplied to the synchronously rotating LED light strip 6 through the wires arranged along the connecting rod 2, thereby achieving uninterrupted power supply and lighting during rotation.

[0026] The rotation drive module is used to drive the rotating shaft 3 to rotate, thereby realizing the rotation of the circular track 1. For example... Figure 4 As shown, the rotary drive module is located on one side of the triangular bracket 5, including a motor 7, a drive wheel 8 and a driven wheel 9. The drive wheel 8 is located on the output shaft of the motor 7, and the driven wheel 9 is located on the rotating shaft 3. The drive wheel 8 and the driven wheel 9 are connected by a belt 10.

[0027] When motor 7 starts, its output shaft drives the driving wheel 8 to rotate. The driving wheel 8 transmits power to the driven wheel 9 via belt 10, thereby driving the rotating shaft 3, which is coaxial with the driven wheel 9, to rotate. This belt drive method can effectively transmit power and can also play a role in buffering, shock absorption, and speed regulation, making the rotation of the circular track 1 more stable and controllable, so as to meet the requirements of different experiments for the movement speed of animals.

[0028] The semi-enclosed restraint module is used to confine experimental animals to a specific imaging area at the bottom of the circular track 1. The semi-enclosed restraint module includes side baffles 11 and end baffles 12. The side baffles 11 are used to prevent experimental animals from jumping out from the sides of the circular track 1 and are fixed to both sides of the specific imaging area of ​​the circular track 1 by trapezoidal brackets 13. The end baffles 12 are used to restrict the range of movement of experimental animals to the specific imaging area of ​​the circular track 1 and are fixed to both ends of the specific imaging area of ​​the circular track 1 by trapezoidal brackets 13. Together with the side baffles 11 on both sides, they form a semi-enclosed running zone.

[0029] The imaging module is used to capture a sequence of dynamic optical images formed by the contact between the soles of the feet and the track when experimental animals run on the circular track 1. The imaging module includes a high-speed camera 14 and a background plate 15. The background plate 15 provides a uniform, high-contrast background for the high-speed camera 14, thereby highlighting the movement contours of the animal's feet. The high-speed camera 14 is mounted on a base 16, and the background plate 15 is fixed to the top of a trapezoidal support 13. The optical axis of the lens of the high-speed camera 14 is aligned with the center point of a specific imaging area of ​​the circular track 1 and the center point of the background plate 15. The surface of the background plate 15 is parallel to the imaging plane of the high-speed camera 14.

[0030] When the experimental animal's paw rests on the inner surface of the transparent acrylic circular track 1, the contact point undergoes slight deformation due to pressure, scattering light from the LED light strip 6. This scattered light transmits downwards, passes through the track material, and enters the lens of the high-speed camera 14 located below the track. The background plate 15 provides stable background contrast, enabling clear recording of dynamic details of the foot contact area, such as the distribution of pressure points and instantaneous changes in contact area, thereby outputting a continuous high-frame-rate image sequence to support subsequent quantitative analysis.

[0031] The gait analysis module processes the dynamic optical image sequences acquired by the imaging module and performs gait analysis. First, the input image sequences are preprocessed. Then, through target tracking and feature point recognition algorithms, the spatial position, contact area morphology, and temporal changes of each foot are located and tracked in consecutive frames. Based on this high spatiotemporal resolution data, several key gait parameters are calculated, such as gait cycle, cadence, stride length, duration and ratio of the stance and swing phases, dynamic distribution of plantar pressure centers, landing angle, and symmetry of limb movements.

[0032] Example 2 This embodiment provides a method for small animal gait analysis based on a circular track, such as... Figure 5 As shown, it includes the following steps: S1. Place the experimental animal in a specific imaging area of ​​the circular track 1 and ensure that the semi-enclosed limiting module is in place to prevent the experimental animal from escaping.

[0033] The experimental animal is gently placed within the pre-defined imaging area on the circular track 1. Then, it must be ensured that the side baffles 11 and end baffles 12 of the semi-enclosed restraint module are correctly installed and securely positioned using the trapezoidal bracket 13. The purpose of this step is to effectively restrict the animal's range of motion within the imaging field of view without affecting its basic mobility, preventing it from jumping off the track or escaping from either end of the imaging area during the experiment, thus ensuring the integrity and continuity of subsequent image acquisition. After placement, the animal can be given a short period to adapt and become familiar with the environment.

[0034] S2. Start the rotation drive module to drive the circular track 1 to rotate at the set speed, so that the experimental animals can run spontaneously on the circular track 1 in the opposite direction of the rotation of the circular track 1.

[0035] The rotation drive module is activated, controlling motor 7 to operate at a preset speed. Power is transmitted to shaft 3 via drive wheel 8, belt 10, and driven wheel 9, driving the entire circular track 1 to rotate uniformly at the set speed. At this time, to maintain their relative position in space, the experimental animals will instinctively run spontaneously in the opposite direction to the rotation of the circular track 1. This step successfully simulates an infinitely long straight path, inducing the animals to produce continuous and stable gait movements, creating crucial conditions for the subsequent acquisition of standardized motion image sequences. Initially, a lower speed can be started, gradually adjusting to the target experimental speed as the animals adapt.

[0036] S3. During the running of the experimental animal, the LED light strip 6 is continuously powered through the conductive slip ring 4, and the imaging module is activated at the same time to capture a dynamic optical image sequence formed when the sole of the experimental animal's foot comes into contact with the circular track 1.

[0037] While the experimental animal maintains its reverse running motion, a continuous and stable power supply is provided to the rotating LED light strip 6 via a conductive slip ring 4, ensuring uniform and sufficient illumination of the specific imaging area. Once the illumination conditions are met, the imaging module is immediately activated. A high-speed camera 14 located below the track captures images at a preset high frame rate, with its lens optical axis precisely aligned with the contact area between the animal's foot and the inner surface of the circular track 1. The camera continuously captures light scattering images formed on the circular track 1 due to contact pressure during the animal's running, thus recording a complete dynamic optical image sequence containing temporal information. This image sequence clearly presents detailed changes in the shape, area, position, and pressure distribution of the foot contact area during each gait cycle, providing raw data for subsequent analysis.

[0038] S4. The dynamic optical image sequence is preprocessed through the gait analysis module to identify the spatiotemporal changes of each foot contact area and calculate gait parameters.

[0039] First, image preprocessing is performed on the original image sequence, including noise reduction, contrast enhancement, and background subtraction to highlight the target area. Crucially, geometric distortion correction is also performed. This step uses the curvature parameters of the circular runway 1 in the imaging area and the pre-calibrated internal parameters (such as focal length and distortion coefficients) and external position parameters of the high-speed camera 14 in the imaging module to perform geometric correction on the image sequence. This eliminates image distortion caused by the runway's curved surface structure and the camera's non-orthographic viewing angle, ensuring the spatial accuracy of subsequent measurement data.

[0040] After preprocessing, the module uses computer vision algorithms to identify and segment the contours of the contact areas between the experimental animal's feet (such as forelimbs and hindlimbs) and the track, and tracks the spatiotemporal changes of these areas in continuous image frames to accurately obtain the time points when each foot touches the ground and lifts off, as well as temporal information such as the centroid position and area of ​​the contact area.

[0041] Based on the aforementioned high-precision spatiotemporal tracking data, the gait analysis module automatically calculates a series of quantitative gait parameters. These parameters typically include, but are not limited to: gait cycle, cadence, stride length, duration and ratio of the stance and swing phases, dynamic distribution of plantar pressure centers, landing angle, and symmetry of limb movements. Finally, the module generates structured analysis reports and visualizations, completing the entire analysis process from raw images to quantified gait characteristics.

[0042] The rest is the same as in Example 1.

[0043] The preferred embodiments of the present invention have been described in detail above. It should be understood that those skilled in the art can make numerous modifications and variations based on the concept of the present invention without creative effort. Therefore, all technical solutions that can be obtained by those skilled in the art based on the concept of the present invention through logical analysis, reasoning, or limited experimentation on the basis of existing technology should be within the scope of protection defined by the claims.

Claims

1. A small animal gait analysis device based on a race track, characterized in that, It includes a circular track (1), a rotation drive module, a semi-enclosed limiting module, an imaging module, and a gait analysis module. The circular track (1) is used for experimental animals to run on. One side of the circular track (1) is fixedly connected to the rotating shaft (3) by multiple connecting rods (2). A conductive slip ring (4) is sleeved on the rotating shaft (3). An LED light strip (6) is provided on the edge of the side where the circular track (1) is connected to the rotating shaft (3). The conductive slip ring (4) is used to continuously transmit external electrical energy to the LED light strip (6) that rotates with the circular track (1) when the circular track (1) rotates. The rotation drive module is used to drive the rotating shaft (3) to rotate, thereby realizing the rotation of the circular track (1); The semi-enclosed limiting module is used to confine the experimental animal to a specific imaging area at the bottom of the circular track (1); The imaging module is used to capture a sequence of dynamic optical images formed when the soles of the feet of the experimental animals come into contact with the track as they run on the circular track (1); The gait analysis module is used to process the dynamic optical image sequence acquired by the imaging module and perform gait analysis.

2. The small animal gait analysis apparatus based on a race track according to claim 1, characterized in that, The circular track (1) is made of transparent acrylic.

3. The small animal gait analysis apparatus based on a race track according to claim 1, characterized in that, The conductive slip ring (4) includes a rotor (401) and a stator (402). The rotor (401) is interference-fitted with the shaft (3). The stator (402) is fixedly connected to the triangular bracket (5). The rotor (401) is connected to the LED light strip (6) through a wire. The stator (402) is connected to an external power source through a wire.

4. The small animal gait analysis apparatus based on a race track according to claim 3, characterized in that, The wires connecting the rotor (401) and the LED light strip (6) are arranged along the connecting rod (2).

5. The small animal gait analysis device based on a circular track according to claim 3, characterized in that, The rotation drive module is located on one side of the triangular bracket (5) and includes a motor (7), a drive wheel (8) and a driven wheel (9). The drive wheel (8) is located on the output shaft of the motor (7), and the driven wheel (9) is located on the rotating shaft (3). The drive wheel (8) and the driven wheel (9) are connected by a belt (10).

6. The small animal gait analysis device based on a circular track according to claim 1, characterized in that, The semi-enclosed limiting module includes a side baffle (11) and an end baffle (12). The side baffle (11) is used to prevent experimental animals from jumping out from the side of the circular track (1) and is fixed on both sides of a specific imaging area of ​​the circular track (1) by a trapezoidal bracket (13). The end baffle (12) is used to restrict the range of activity of experimental animals to a specific imaging area of ​​the circular track (1) and is fixed at both ends of the specific imaging area of ​​the circular track (1) by a trapezoidal bracket (13).

7. The small animal gait analysis device based on a circular track according to claim 1, characterized in that, The imaging module includes a high-speed camera (14) and a background plate (15). The background plate (15) is used to provide contour contrast for the high-speed camera (14). The high-speed camera (14) is mounted on a base (16), and the background plate (15) is fixed to the top of a trapezoidal bracket (13).

8. The small animal gait analysis device based on a circular track according to claim 7, characterized in that, The optical axis of the lens of the high-speed camera (14) is on the same straight line as the center point of the specific imaging area of ​​the circular track (1) and the center point of the background plate (15), and the surface of the background plate (15) is set parallel to the imaging plane of the high-speed camera (14).

9. A method for small animal gait analysis using the small animal gait analysis device based on a circular track as described in claim 1, comprising the following steps: The experimental animals were placed in a specific imaging area of ​​the circular track (1), and the semi-enclosed limiting module was in place to prevent the experimental animals from escaping. Start the rotation drive module to drive the circular track (1) to rotate at the set speed, so that the experimental animals can run spontaneously on the circular track (1) in the opposite direction of the rotation of the circular track (1). During the running of the experimental animal, the LED light strip (6) is continuously powered by the conductive slip ring (4), and the imaging module is activated at the same time to capture the dynamic optical image sequence formed when the sole of the experimental animal's foot comes into contact with the circular track (1). The dynamic optical image sequence is preprocessed by the gait analysis module to identify the spatiotemporal changes of each foot contact area and calculate gait parameters.

10. The method for small animal gait analysis based on a circular track according to claim 9, characterized in that, The image preprocessing includes noise reduction, contrast enhancement, background subtraction and distortion elimination. The distortion elimination is based on the curvature parameters of the circular track (1) and the calibration parameters of the imaging module to perform geometric distortion correction on the acquired dynamic optical image sequence in order to eliminate image distortion caused by the track curvature and shooting angle.

Images