WO2022109858A1

WO2022109858A1 - Eye movement tracking apparatus and method

Info

Publication number: WO2022109858A1
Application number: PCT/CN2020/131432
Authority: WO
Inventors: 杨琴; 蔚鹏飞; 王立平
Original assignee: 中国科学院深圳先进技术研究院
Priority date: 2020-11-25
Filing date: 2020-11-25
Publication date: 2022-06-02

Abstract

The present invention provides an eye movement tracking apparatus and method for real-time recording of eyeball movement of an animal during free movement. The eye movement tracking apparatus comprises: a head holder used for conveniently mounting and dismounting a device; an eye movement unit apparatus used for photographing the eyeball movement of the animal; a peripheral circuit board provided with a circuit which is not necessarily close to the eyes of a small animal; a conductive slip ring ensuring stable transmission of image signals during the free movement of the animal; and a computer collecting and storing images and extracting eyeball movement data in real time. The eye movement tracking apparatus of the present invention can be used for real-time tracking of the eyeball movement condition of the animal in the free movement state. A portable and firm structure convenient to mount and dismount is equipped, so that the eye movement tracking apparatus can be applied to a plurality of animals, the utilization rate of the device is increased, and the damage of the device due to animal fighting outside an experiment is avoided. For the requirements of neural research, the eye movement tracking apparatus is mounted on both sides of the head of the animal, so that other neural technology implants can be conveniently implanted in the top of the head of the animal to cooperatively detect the brain.

Description

An eye tracking device and method

technical field

The invention relates to the technical field of life sciences, in particular to an eye-tracking device and method for recording eye movements when small animals move freely in real time and can move freely.

Background technique

Eye tracking is a technology that obtains information about changes in eye characteristics and movement. The information obtained by eye tracking is suitable for neuroscience research because the eyeball is controlled by 3 pairs of nerves and 12 pairs of muscles. Compared with the whole body movement, it is sensitive and fast, and the indicators are fine and rich. There are more than 100 eye movement indicators; Some manifestations, such as nystagmus, pupil dilation, and early eye movement are regulated by inherent neural circuits and are less subject to conscious intervention, so the information conveyed by eye movement performance is more stable and reliable. In addition to applications in vision and vestibular science, eye tracking is also widely used in neuropsychological research in visual information processing, reading, motivation and attitude, etc. Physiological analysis indicators of diseases such as autism, schizophrenia, and affective disorders.

Existing eye-tracking devices are basically used in humans and monkeys, but a thorough elucidation of neural mechanisms requires invasive studies in a large number of small animals. Because the research techniques that can be used in the human nervous system, such as MRI, EEG, transcranial magnetic stimulation, evoked potentials, etc., have the disadvantage of limited spatial and temporal resolution, they cannot probe the structure and function of precise neural circuits and cellular networks. The limitations of these technologies make it difficult for us to conduct a thorough analysis of the formation mechanism and development process of emotions and behaviors. Current research techniques including gene editing modification, optogenetics, in vivo electrophysiology, and two-photon imaging to dissect neural circuits from microscopic to mesoscopic scales are invasive and irreversible. Therefore, the research on the dissection of neural circuits is mainly carried out with small animals (large and mouse) as experimental models.

However, the existing neurobehavioral experiments on small animals are mostly based on the free movement of animals in a certain space. For example, the maze test for memory, the elevated cross test for exploratory behavior, and the three-box device test for social barriers have been the international standard experimental paradigms for many years, but these methods only analyze the overall behavior of animals, the detection index is single, and it is inconvenient to compare with human cognition and human cognition. Emotional responses were compared. Therefore, neuroscience urgently needs to introduce stable, accurate and index-rich eye tracking technology under the existing free-motion experimental paradigm.

Most of the existing small animal eye tracking technologies use surgery to fix the head of the small animal somewhere, and then place a camera obliquely in front of the animal to record the pupil activity in the animal's eye. Small animals cannot move freely, so the experimental paradigm of free movement in neuroscience does not apply.

To observe the eye movements of freely moving small animals, the camera should be kept relative to the small animal. If sensors and electric devices are used to make the camera automatically follow the small animal, when the small animal runs and jumps quickly, the image delay and jitter will be more obvious, which will affect the accuracy of the observation results. Therefore, the camera device needs to be fixed on the head of the small animal. In the prior art, there is no device specially designed for eye tracking of small animals. The existing devices that are fixed on the head of small animals to realize the function of eye tracking are complicated in design, and the design of integrated tracking arm light-emitting elements, accelerometers, and nerve electrophysiological electrodes, etc. Used to observe more information, therefore, such devices have the following disadvantages:

1. The volume and weight are large, and the head of the small animal has to bear the entire device. Compared with the small animal, the device is relatively bulky and will affect the movement of the small animal. The long-term load will also interfere with the small animal. The behavior of small animals in the experiment, which in turn affects the accuracy of the information obtained. This disadvantage is exacerbated by devices such as integrated acceleration and electrophysiology.

2. The device was surgically fixed and installed on the head of the small animal one week before the experiment. Due to the large size and complex design of the device, and the relatively small size of the small animal, it is necessary to coordinate the position of the device when installing the device, and it is necessary to coordinate the position of the device during the operation. Operate carefully to avoid damage to the device, which is very troublesome to install and remove. Once the device is installed, it needs to be fixed on the head of the small animal for a long time, the utilization rate of the device is low and it is easy to be damaged outside the experiment.

3. The structure and function of the existing device are fixed, and it is difficult to adapt to the specific needs of the experiment, and the functions provided by the design of the device are not suitable for the experimental research of neuroscience. For example, some devices incorporate accelerometers, but accelerometers are rarely used in neuroscience research, so accelerometers are redundant for most neurological experiments; some devices integrate neural electrophysiological electrodes to test the movement of live animals However, because the structure of the device is fixed, only electrodes can be used and the position cannot be adjusted during the experiment, which cannot be adapted to different experimental designs of brain research. Electrodes are placed in different positions and depths of the brain, The need for optical fibers, microlenses, etc.

In addition, the quality of the eye image obtained by the existing eye tracking device is not good, the pixel resolution is small, and some even the image is blurred. For example, because the light source is set too close to the lens on the camera, the image will produce slight flare , Under the ring light illumination, due to the light-passing characteristics of the pupils, when the eyeballs turn to certain directions, the black pupils will turn into white pupils, which will affect the later image processing. These will affect the accurate acquisition of eye movement information and so on.

As mentioned above, the existing small animal eye tracking technology has the disadvantage that the small animal needs to be fixed in a certain place for observation, and it is not suitable for the experimental paradigm of free movement in neuroscience. Although there is an eye-tracking device fixed on the head of the small animal that allows the small animal to move freely, the device is cumbersome and bulky, lacks pertinence for neurological research applications, and is difficult to coordinate with other neurotechnical equipment applications. The image quality also needs to be further improved.

SUMMARY OF THE INVENTION

In view of this, in order to overcome the above-mentioned defects of the prior art, the present invention proposes an eye tracking device and method that can be flexibly fixed and disassembled, facilitates coordination with other neural technologies, and has good image quality.

Specifically, the eye tracking device of the present invention includes an eye tracking unit device and a computer, and an ultra-micro camera and a near-infrared light source are fixedly arranged in the eye tracking unit device. The entire circuit board of the eye tracking device is divided into two parts: an eye tracking unit circuit board and a peripheral circuit board. The eye tracking unit device is also provided with the eye tracking unit circuit board and a mounting part. The circuit board includes an imaging module and an encoding module; a decoding module corresponding to the encoding module is arranged on the peripheral circuit board, and the peripheral circuit board is arranged outside the eye-tracking unit device and is connected to the computer; the peripheral The circuit board is connected to the eye tracking unit device in a wired or wireless manner. The eye-tracking unit circuit board and the peripheral circuit board respectively carry different functions, so when the eye-tracking device is installed and used, the target only needs to load the part of the eye-tracking unit device, which reduces the burden of the target. load. Moreover, during the image acquisition process, the main heat source of the circuit board is the image decoding module, and the decoding module is arranged on the peripheral circuit board away from the target, which reduces the influence of heat on the behavior of the target.

Specifically, the eye tracking device includes a head holder, the head holder is fixed on the target head, and the eye tracking unit device is detachably mounted on the head through the mounting portion and fixed on the head on the device. The part of the eye tracking device except the head immobilizer can be installed only during the experiment period, so as to improve the utilization rate of the device and prevent the device from being damaged outside the experiment.

Specifically, the head holder includes a pin base and a pin set on the pin base.

Preferably, the head holder is provided with two pin bases with a certain distance, the pins protrude from the pin bases to both sides of the target head, and the target is vacated Top of the head position for use in synergy with other neurotechnologies in neuroscience experiments.

Specifically, the eye tracking unit device and the peripheral circuit board are connected by a signal line, and a conductive slip ring is connected between the peripheral circuit board and the computer. The conductive slip ring enables the signal line to rotate freely when the target rotates freely to avoid knotting.

Specifically, the ultra-micro camera and the near-infrared light source are disposed outside the target eye, on the target visual axis, and directly aimed at the target eye.

In some embodiments, the eye tracking unit device further includes a near-infrared total reflection mirror, the near-infrared total reflection mirror is arranged on the front and outside of the target eye, the ultra-micro camera and the near-infrared light source are arranged Out of the target field of view, toward the near-infrared total reflection mirror. The near-infrared total reflection mirror can transmit visible light, and the target can see any object behind the lens without affecting the target's field of view.

Preferably, the near-infrared total reflection mirror is 45° to the target eye axis and the optical axis of the ultra-micro camera, and is aimed at the target eye, and this structure enables the camera to be indirectly aimed at the target Eyes, and maximize the reflection intensity of near-infrared light, improve the contrast of the final image, and reduce the difficulty of post-image processing. . Correspondingly, according to the position of the mouse's eyes, the near-infrared mirror is finally set so that the angle between the mirror surface and the central axis of the mouse body is 75°, and the angle between the mirror surface and the horizontal plane is 25°.

Preferably, the near-infrared light source is arranged beside the ultra-micro camera, forming an angle of 10-20° with the target eye and the ultra-micro camera, which solves the problem of image quality caused by the light source in the prior art. The suboptimal problem improves the quality of the acquired eye image.

Preferably, the eye tracking unit device further includes a near-infrared band-pass filter, which is arranged in front of the ultra-micro camera lens, and can filter out ambient stray light and prevent visible light from affecting the experiment. The interference of the eye movement image, otherwise the obtained image is the superposition of the eye image and the image of the environment behind the mirror.

Meanwhile, the present invention also provides an eye tracking method.

Fix the eye-tracking unit device on the target head, and set the decoding module on a peripheral circuit board outside the eye-tracking unit device; the peripheral circuit board is connected to the eye-tracking unit device in a wired or wireless manner, and the Peripheral circuit boards are not provided on the target header. The target only carries the part of the eye-tracking unit device, reducing the weight of the target.

using the head holder including a pin base and a pin to fix the eye tracking unit device, the pin being arranged on the pin base;

The pin base is fixed on the target head, and the mounting part of the eye tracking unit device is mounted on the pin. The eye-tracking unit device can be easily and quickly installed and disassembled, and the part of the eye-tracking device other than the head immobilizer can be installed only during the experimental period, thereby improving the utilization rate of the equipment and preventing the equipment from being damaged outside the experiment.

The head holder has two pin bases, and the two pin bases are fixed to the target head at a certain interval, and the pins extend from the pin base to the two pins of the target head. It is extended laterally to vacate the position on the top of the target's head, which is convenient to be used in conjunction with other neurological technologies in neuroscience experiments.

A conductive slip ring is used to connect the peripheral circuit board, so that the signal line can also rotate freely when the target is free to rotate, so as to avoid knotting.

To sum up, in the eye tracking device and method of the present invention, the two parts of the circuit board are designed to load different functions, so that the target only needs to bear the weight of the eye tracking unit when the eye tracking device is installed and used, which reduces the weight of the target. The installation method of the device has been changed so that the device can be flexibly fixed and disassembled, and the parts of the eye tracking device except the head holder can be installed only during the experimental period, thereby improving the utilization rate of the equipment and preventing the equipment from being damaged outside the experiment. The head immobilizer is installed on both sides of the target's head, which is convenient to use in conjunction with other neurological technologies in neuroscience experiments; the eye tracking unit device can change the specific position of the fixation on the head immobilizer, which can ensure that all the target eyes are included in the shooting scope. The optimized design of changing the light source surrounding the camera to the side of the camera in the prior art improves the quality of the acquired eye image.

Description of drawings

In order to illustrate the technical solutions in the embodiments of the present application more clearly, the following briefly introduces the drawings that are used in the description of the embodiments. Obviously, the drawings in the following description are only some embodiments of the present application. For those of ordinary skill in the art, other drawings can also be obtained from these drawings without creative effort.

1 is a schematic diagram of a structural framework of an eye tracking device according to the present invention;

2 is a schematic diagram of the installation state of the eye tracking device of the present invention

3 is a schematic diagram of the internal design scheme of the eye movement unit device of the eye movement tracking device of the present invention;

4 is another schematic diagram of the internal design of the eye movement unit device of the eye tracking device of the present invention;

Figure 5 (a) is a schematic diagram of a ring-shaped light source surrounding a lens in the prior art;

Fig. 5 (b) is the schematic diagram that the near-infrared light source is arranged on the side of the lens in the present invention;

FIG. 6 is a schematic view of fixing the eye movement unit of the eye tracking device of the present invention.

Reference number:

1-eye tracking unit device; 11-supermicro camera; 12-near infrared light source; 13-near-infrared total reflection mirror; 14-near-infrared bandpass filter; 2-head holder; 21-pin; 3 - Peripheral circuit board; 4 - Conductive slip ring.

Detailed ways

The technical solutions in the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings in the embodiments of the present invention. Obviously, the described embodiments are only a part of the embodiments of the present invention, but not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those of ordinary skill in the art without creative efforts shall fall within the protection scope of the present invention.

The present invention provides an eye-tracking device, which is used in small animals (hereafter, mice are used as the tracking object in the embodiment. If the device is available in mice, the volume of other experimental mammals is larger than that of mice. It can be used after the device) to continuously and accurately track and detect eye movements in a free movement state. Referring to Fig. 1 of the description, the eye tracking device mainly includes an eye tracking unit device 1, a head holder 2, a peripheral circuit board 3 and a computer. In some cases, a conductive slip ring 4 may also be included, which will be described later. Specifically, the eye-tracking unit device 1 includes an ultra-micro camera 11, a near-infrared light source 12, an eye-tracking unit circuit board, a housing and a mounting portion. The eye movement unit device 1 is used for photographing eye movements of small animals, and transmits the acquired data to the connected peripheral circuit board 3 through signal lines. The eye tracking unit device 1 is fixed and removed by a head holder 2 surgically embedded in the head of the small animal. The head holder 2 includes two parts, which are respectively arranged on both sides of the head of the small animal. According to the experimental needs, you can choose to install the eye tracking unit device 1 only on the head holder 2 on one side to observe the unilateral eye movement, or install the eye movement unit device 1 on the head holder 2 on both sides. The design of the eye-tracking device provided by the present invention includes two parts of circuit boards: the eye-tracking unit circuit board and the peripheral circuit board 3 arranged on the eye-tracking unit device 1. The circuit that must be close to the small animal is arranged on the ground of the eye-tracking unit. The circuit boards, such as the imaging module and the encoding module; other circuits such as the decoding module, etc., are all arranged on the peripheral circuit board 3 . Therefore, the two parts of the circuit boards respectively carry different functions. For example, the eye tracking unit circuit board can encode the captured eye motion image, and the peripheral circuit board 3 has a decoding function. The specific content of the circuit boards will be described in detail later. Therefore, when the eye-tracking device in the present invention is installed and used, the mouse only needs part 1 of the weight-bearing eye-tracking unit, see FIG. The corresponding hardware, the weight of which is not loaded on the mouse.

In some embodiments, in order to minimize the weight of the small animal, the eye-tracking unit circuit board on the eye-tracking unit device 1 only has an imaging module and an encoding module, so that the eye-tracking unit circuit board only has to be close to the small animal. The circuit part of the eye tracking unit device 1 is minimized.

Further, the eye movement unit device 1 captures the eye movement of the small animal, and converts the captured image into digital signal transmission, so that any long distance can be transmitted without noise, and the eye movement unit circuit board encodes the acquired image and transmits it to the periphery. Circuit board 3, decode in the peripheral circuit board 3 part. Because the circuit board generates strong heat during the image acquisition process, the heat generated by the circuit board will interfere with small animals, and the most important heating part in the circuit board is the image decoding part, so the image decoding part is designed on the peripheral circuit board 3, so that the It is far away from small animals, does not make small animals feel uncomfortable, and reduces the influence of heat on the behavior of small animals. In some embodiments, the peripheral circuit board 3 and the eye movement unit device 1 are connected through a signal line, and the eye movement unit device 1 converts the captured eye movement image into a digital signal, and the image is encoded through a signal line with a length of about 50 cm It is transmitted to the peripheral circuit board 3 for decoding, converted into a USB signal, and then transmitted to the computer. Alternatively, the digital signal transmission encoded by the eye tracking unit device 1 may also be transmitted to the peripheral circuit board 3 by means of wireless transmission.

In the eye tracking unit device 1, the ultra-micro camera 11 and the near-infrared light source 12 are fixed on a fixed position inside the casing, and the casing is made of a material that can transmit near-infrared light, or the casing is formed by the near-infrared light source 12 and the ultra-micro camera 11. The window design is made on the position of the optical path to ensure the smooth transmission of near-infrared light. Since the hardware for realizing some functions does not need to be loaded in the eye tracking unit device 1, the size of the eye tracking unit circuit board can be greatly reduced, and it can be only 1/7 of the size of the circuit board of the device in the prior art, and a pair of eye tracking The total length of the unit device 1 and the head holder 2 can be only 28mm, thereby greatly reducing the volume and weight of the load required by the small animal.

The internal structure of the eye-tracking unit device 1 can be partially changed according to the specific needs of the experiment, see Figure 3 in the description, in this embodiment, a scheme 1 is designed. The light source 12 is composed of an eye-tracking unit circuit board, and a pair of eye-tracking unit devices weighs only 0.8g. The ultra-micro camera 11 is set on the outside of the mouse's eye and is directly aimed at the mouse's eye. The preferred solution provided in this embodiment is to use a 1280*720 pixel 3.8mm endoscope camera to directly aim at the mouse at a distance of about 12mm eye. Further, regarding the problems in the prior art that the quality of the obtained eye image may be poor due to the influence of the light source, for example, the setting of the light source will cause problems such as light spots in the image, which will affect the accurate processing of the eye movement information in the later stage. In order to solve these problems , to further optimize the layout of the light source. Referring to Figure 5 (a) of the description, it is a ring-shaped light source that surrounds the camera used in the prior art. Due to the light-passing characteristics of the pupil, the ring-shaped light source setting of this layout will cause the black pupil to turn into a black pupil when the eyeball is turned to certain directions. White pupils affect post-image processing. Therefore, in this embodiment, referring to Fig. 5(b) of the description, the near-infrared light source 12 is changed to the side of the ultra-micro camera 11, for example, two near-infrared light sources 12 are arranged side by side beside 11, and are directly aimed at the mouse Eye lighting. Preferably, two 940nm near-infrared LEDs are illuminated at 5mm beside the camera, forming an angle of 10-20° with the mouse's eyes and the camera, which will neither cause white pupils nor excessive shadows around the eyeballs Affects black pupil extraction. In order to further improve the imaging effect, optionally, a near-infrared bandpass filter 14 can be set in front of the lens of the ultra-micro camera 11 to transmit near-infrared light, block visible light, and prevent the environment from interfering with the imaging of eye movement recording, otherwise The acquired image is a superposition of the eye and environment images. This is the opposite of the near-infrared cut-off filter of ordinary cameras. The near-infrared cut-off filter in front of ordinary cameras transmits the image of visible light, filters out the near-infrared to adjust the color balance and prevent the image from turning red. The images obtained by tracking eye movements in neuroscience research need to be clear and precise. In this solution, the width of the camera's shooting range is 9mm, and the calculated resolution is 9mm/1280 pixels = 0.007mm/pixel; compared with the 640* The 480-pixel camera has a shooting range of 10mm wide, and the calculated resolution is 10mm/640 pixels = 0.016mm/pixel, the resolution is doubled, and the obtained images are clearer and more detailed. The more the camera is aimed at the pupil, the more accurate the data obtained, but it also blocks the central area of the mouse's field of vision, so this solution is suitable for use in studies that do not require high field of vision and attention.

When conducting some research on vision and attention, it is required that there is no obstruction in the field of view, but the above scheme blocks the mouse field of view because the camera is aimed at the pupil. In order to further meet the high requirements for research on vision, attention, etc., scheme 2 shown in FIG. 4 of the specification is designed. In scheme 2, the eye movement unit device 1 may also include a near-infrared total reflection mirror 13 inside. The near-infrared total reflection mirror 13 is arranged on the front and outside of the mouse's eye. The function of the near-infrared total reflection mirror 13 is to transmit visible light, and the mouse can see any object behind the lens without affecting the mouse's field of vision. At the same time, the near-infrared total reflection mirror 13 The mirror 13 can reflect near-infrared light, so that the near-infrared light emitted by the near-infrared light source 12 is reflected to the mouse eye through the near-infrared total reflection mirror 13 for illumination, and the mouse eye image is reflected to the ultra-micro camera through the near-infrared total reflection mirror 13 11 Imaging. The near-infrared mirror adopts a 45° total reflection mirror, that is, when the incident and exit angles of light are 45°, the reflection is the strongest, the contrast and clarity of the final image are the best, and subsequent image processing is easier. Therefore, both the eye and the camera face toward the near-infrared reflector, and the two lines connecting the eye-reflector and the camera-reflector form an included angle of 45° with the mirror surface. The target mice were lateral-eyed animals, and the eyes were located on both sides of the head, facing obliquely upward and left, and the direction of the mouse body was 60° to the outside of the axis, and then 25° upward. Therefore, according to the characteristics of the total reflection mirror and mouse eyes, the final optimal setting of the near-infrared total reflection mirror is: the position is facing the eyes, and the angle between the direction and the central axis of the mouse body is 180°-60°-45°=75° °, the angle with the horizontal plane is 25°. Deviating from this angle, the reflection ability will gradually decrease, the image contrast will become lower, the picture will be blurred, and the subsequent image processing will make more noise and errors when extracting data. The ultra-micro camera 11 and the near-infrared light source 12 can be arranged on both sides of the rear of the mouse head, facing the near-infrared total reflection mirror 13 , and the near-infrared bandpass filter 14 is in front of the lens of the ultra-micro camera 11 . Therefore, the parts other than the near-infrared total reflection mirror 13 are all outside the mouse's field of vision, and the mouse's sight is no longer blocked, thereby reducing the influence on the mouse's activity. In order to ensure the picture quality, the near-infrared total reflection mirror 13 is made of quartz material, which makes the near-infrared total reflection mirror 13 occupy most of the weight of the eye unit device 1 in this solution. Even so, the near-infrared total reflection mirror is included at this time. Including the 13 and the near-infrared bandpass filter 14, the weight of the pair of eye tracking unit devices 1 is only 2g. Although the mice can bear it, the weight of the eye tracking unit device 1 of the second solution is still 2.5 times heavier than that of the first solution. Therefore, in studies where other brain research techniques are simultaneously applied and other weight-bearing objects need to be immobilized on the head, option 1 is more suitable.

The eye-tracking unit device 1 is fixed by the head holder 2. The head holder 2 is implanted in the head of the small animal and used in conjunction with the mounting part designed on the eye-tracking unit device 1 to realize the quick installation of the eye-tracking unit device 1. , dismantling. The connecting part can be designed as any miniature, lightweight and firm structure such as screw connection, snap connection, etc. Referring to Fig. 6 of the description, preferably, a pin connection is used, and the head holder 2 is a pin base provided with multiple rows of parallel pins 21. The bottom of the pin base is hollow, and the top of the head is exposed after being inserted into the mouse head. position to facilitate the implantation of nerve electrodes, optical fibers, microlenses and other devices in the mouse head. The pin 21 protrudes from the pin base toward the outside of the mouse body. Preferably, in the multiple rows of pins, the distance between two adjacent rows of pins 21 is the same. Correspondingly, the mounting part provided on the eye tracking unit device 1 is a parallel socket, and there are reeds, silica gel or hollow needle cannula inside to prevent the pin 21 from swinging and slipping, and the distance between the adjacent two rows of sockets is Corresponding to the pitch of the pins 21 . During installation, the eye tracking unit device 1 is fixed by inserting the pins 21 into the sockets of the installation part.

Before the experiment, the head immobilizer 2 was surgically implanted into the skull of the small animal. In this embodiment, the pin connection design of the head immobilizer 2 enables the eye tracking unit device 1 to be directly inserted and removed when it is fixed and disassembled, which is convenient to operate. fast. Therefore, only the head holder 2 of the eye-tracking device 1 needs to be fixed on the head of the small animal for a long time, and the rest of the eye tracking device can be used in the experimental period of multiple small animals in time-sharing, so as to improve the utilization rate of the equipment and avoid small animals due to external factors. Battle damage equipment. In some embodiments, the head holder 2 provides three parallel rows of pins 21, and the eye tracking unit device 1 actually only needs two rows of pins 21 to achieve fixation, so there are three or more pins at the pin base In the case of one pin, when the spacing between any pins is equal, two pins can be selected for fixation, so that the position of the eye tracking unit device 1 can be easily adjusted back and forth, which can solve the problems caused by the surgical habits of different experimenters. The experimental brain regions are different, and the position of the implanted head immobilizer 2 is different to a certain extent, which leads to the problem that the mouse's eyes are beyond the imaging range of the eye-tracking device, which further ensures that all the mouse's eyes are included in the shooting range. Furthermore, if the device needs to be applied to animals such as rats, it is only necessary to adjust the dimensions of the head immobilizer 2 and the mounting portion on the eye tracking unit device 1 .

In addition, when the signal of the eye-tracking unit device 1 is transmitted to the computer by wire, in order to solve the problem that the signal wire is easily entangled and knotted when the small animal moves freely, a conductive slip ring 4 can be connected to the signal conduction line. 4. The signal line can also rotate freely when the small animal is free to rotate, avoiding knots, and at the same time, the image signal can continue to be transmitted stably through the conductive slip ring 4. The resistance of the slip ring increases rapidly with the number of conductive channels, so the fewer the number of conductive channels, the better. The eye tracking unit device 1 and the peripheral circuit board 3 transmit signals through 8 lines, and there are only 4 lines between the peripheral circuit board 3 and the computer USB interface, so the conductive slip ring 4 is arranged between the peripheral circuit board 3 and the computer.

In summary, the present invention provides an eye-tracking device and method with a small size and light weight. The circuit board in the design of the eye-tracking device includes two parts of the eye-tracking unit circuit board and the peripheral circuit board. When the device is installed, the mouse only needs the part of the weight-bearing eye-tracking unit, which reduces the weight of small animals. The eye-tracking unit device can be quickly installed and fixed by the head holder embedded in the head of the small animal before the experiment, so that only the head holder part of the eye-tracking device needs to be fixed on the head of the small animal for a long time, and the other parts can be fixed on the head of the small animal for a long time. It is only used during the experiment, which improves the utilization rate of the device and avoids damage to the device due to animal fighting outside the experiment. The specific position of the eye tracking unit device can be changed on the head holder, which can ensure that the eyes of small animals are all included in the shooting range. The hollow design in the middle of the head holder facilitates the eye-tracking device to cooperate with other neurotechnologies to detect small animal brains in neuroscience experiments. The optimized design of changing the light source surrounding the camera to the side of the camera in the prior art improves the quality of the acquired eye image.

The above descriptions are only preferred embodiments of the present invention and are not intended to limit the present invention. In addition to the above embodiments, different modifications are also possible. The technical features of the above embodiments can be combined with each other. Within the scope of the present invention, any modifications, equivalent replacements, improvements, etc. made should be included within the protection scope of the present invention.

Claims

An eye-tracking device installed on the head of an animal, comprising an eye-tracking unit device and a computer, wherein an ultra-micro camera and a near-infrared light source are fixedly arranged in the eye-tracking unit device, characterized in that:

The entire circuit board of the eye tracking device is divided into two parts: an eye tracking unit circuit board and a peripheral circuit board. The eye tracking unit device is also provided with the eye tracking unit circuit board and a mounting part. The circuit board includes an imaging module and an encoding module; a decoding module corresponding to the encoding module is arranged on the peripheral circuit board, and the peripheral circuit board is arranged outside the eye-tracking unit device and is connected to the computer; the peripheral The circuit board is connected to the eye tracking unit device in a wired or wireless manner;

The target head is fixedly provided with a head holder, and the eye tracking unit device is detachably mounted on the head holder through the mounting portion.
The eye tracking device according to claim 1, wherein the head holder comprises a pin base and a pin set on the pin base.
The eye tracking device according to claim 1, wherein the head holder is provided with two pin bases with a certain distance, and the pins are directed from the pin bases to the target. The sides of the head stick out.
The eye tracking device according to claim 1, wherein the eye tracking unit device and the peripheral circuit board are connected by a signal line, and a conductive slip ring is connected between the peripheral circuit board and the computer.
The eye tracking device according to claim 1, wherein the ultra-micro camera and the near-infrared light source are arranged outside the target eye, facing the target eye;

Or, the eye tracking unit device further includes a near-infrared total reflection mirror, the near-infrared total reflection mirror is arranged on the front and outside of the target eye, and the ultra-micro camera and the near-infrared light source are arranged between the animal's field of vision. outside, toward the near-infrared total reflection mirror.
The eye tracking device according to claim 5, wherein the camera and the light source are arranged on the target visual axis, aiming at the target eye;

Alternatively, the near-infrared total reflection mirror and the target eye axis and the optical axis of the ultra-micro camera are both at 45°, and are aimed at the target eye.
The eye tracking device according to claim 5, wherein the near-infrared light source is arranged beside the ultra-micro camera, and forms an angle of 10-20° with the target eye and the camera.
The eye tracking device according to claim 5, wherein the eye tracking unit device further comprises a near-infrared bandpass filter, and the near-infrared bandpass filter is arranged in front of the ultra-micro camera lens , to filter out ambient images.
An eye-tracking method under the free movement of a target, using an ultra-micro camera fixed in an eye-moving unit device to obtain the target eye image, characterized in that,

Fixing the eye-tracking unit device on the target head, and setting the decoding module on a peripheral circuit board outside the eye-tracking unit device; the peripheral circuit board is connected to the eye-tracking unit in a wired or wireless manner device, the peripheral circuit board is not arranged on the target header.
The eye tracking method according to claim 9, wherein,

using the head holder including a pin base and a pin to fix the eye tracking unit device, the pin being arranged on the pin base;

The pin base is fixed on the target head, and the mounting part of the eye tracking unit device is mounted on the pin.
The eye tracking method according to claim 9, wherein,

The head holder has two pin bases, and the two pin bases are fixed to the target head at a certain interval, and the pins go from the pin base to the target head protruding from both sides.
The eye tracking method according to claim 9, wherein,

Use a conductive slip ring to connect the peripheral circuit board and the computer.