CN116919335A - Retina imaging control circuit for realizing high-speed real-time eyeball tracking - Google Patents

Abstract

The invention provides a retina imaging control circuit for realizing high-speed real-time eye tracking. The circuit comprises a main control board and a signal acquisition and control board, wherein the signal acquisition and control board is connected to the main control board; the signal acquisition and control board is respectively connected with a light source and a galvanometer, the light source is used for providing incident light for retina, and the galvanometer is used for modulating the incident angle of the incident light entering the retina; the main control board is directly connected with the optical detector or connected with the optical detector through signal acquisition and control board, and the optical detector is used for detecting feedback light beams reflected from retina; the main control board obtains a first signal detected by the light detector, calculates and generates a first control signal and transmits the first control signal to the signal acquisition and control board, and the signal acquisition and control board controls the deflection state of the vibrating mirror according to the first control signal. The circuit can realize high-speed eye movement tracking and/or real-time aberration compensation, and further can realize high-precision image acquisition, image tracking and other functions.

Description

Retina imaging control circuit for realizing high-speed real-time eyeball tracking

Technical Field

The invention relates to the technical field of light path control, in particular to a retina imaging control circuit for realizing high-speed real-time eyeball tracking.

Background

The retina is an important part of human eyes, and more than one billion people suffer from retina-related diseases worldwide at present, in order to more effectively realize the treatment of the retina-related diseases, the optimization of a treatment device of the retina-related diseases is indispensable, that is to say, a high-resolution imaging device of the retina has great significance for the diagnosis and curative effect evaluation of the retina-related diseases.

Early retinal imaging devices were mainly based on slit lamps or fundus cameras, but these techniques were affected by the aberrations of the imperfect human eye, resulting in low imaging resolution and inability to observe microscopic cell-level structures of the retina.

Researchers LiangJunzhong et al (Liang et al, "Supernormal vision and high-resolution retinalimaging through adaptive optics," J.Opt.Soc.Am.A/Vol.14, no. 11/Nov.1997) have proposed a confocal-based adaptive optical retinal imaging apparatus that can dynamically detect, compensate for aberrations of the human eye in real time, improving lateral resolution by an order of magnitude.

Researchers donald.miller et al (Yan Zhang, jungtaeRha, ravi s.jonnial, and Donald t.miller "Adaptive Optics parallel spectral domain optical coherence tomography for imaging the living retina", optics Express, vol.13, no. 12/jun.2005) have proposed an imaging device that combines optical coherence tomography (Optical Coherence Tomography, OCT for short) with adaptive Optics that can further enhance longitudinal resolution while maintaining high lateral resolution. However, the imaging device cannot track eye movement, and image acquisition efficiency may be affected by eye movement.

Existing ophthalmic retinal imaging devices, such as SLO, LSO, AO, OCT ophthalmic imaging systems, are provided with galvanometers for changing the optical path to effect scanning of the target area. The scanning imaging modes of these devices can be divided into two types: one line of data in a two-dimensional image can be acquired at a time by adopting line camera imaging; one type of imaging that uses point scanning generally utilizes a photovoltaic module to convert an optical signal into an analog voltage signal. Because of the different scanning modes, the imaging system needs to be separately provided with a control circuit suitable for each scanning mode.

Therefore, it is desirable to have a general control circuit suitable for different optical systems to acquire high-resolution retinal images in real time, and to have a simple, reliable, high-speed control process to achieve high-precision image acquisition and image tracking functions.

Disclosure of Invention

In view of the above, the present invention provides a retinal imaging control circuit for realizing high-speed real-time eye tracking, which has the following technical scheme:

a retina imaging control circuit for realizing high-speed real-time eyeball tracking comprises a main control board and a signal acquisition and control board, wherein the signal acquisition and control board is connected to the main control board;

The signal acquisition and control board is respectively connected with a light source and a galvanometer, the light source is used for providing incident light for retina, and the galvanometer is used for modulating the incident angle of the incident light entering the retina; the main control board is directly connected to the optical detector or connected to the optical detector through the signal acquisition and control board, and the optical detector is used for detecting the feedback light beam reflected from the retina;

the main control board obtains a first signal detected by the light detector, calculates and generates a first control signal and transmits the first control signal to the signal acquisition and control board, and the signal acquisition and control board controls the deflection state of the vibrating mirror according to the first control signal so as to realize eyeball movement tracking.

Preferably, in the above retinal imaging control circuit for implementing high-speed real-time eye tracking, the main control board generates a real-time two-dimensional retinal reflection image according to the first signal, calculates the transverse and longitudinal relative displacement values of the current frame of the two-dimensional retinal reflection image relative to the previous frame or the stored static image, and then superimposes a transverse and longitudinal deflection value equal to the relative displacement value on the first control signal, so as to implement high-speed real-time eye movement tracking.

Preferably, the main control board is configured to: when the data detected by the optical detector meet the preset line number, the data are taken as the first signal to be acquired;

The real-time two-dimensional retinal reflection image generated by the main control board according to the first signal is specifically a part of one frame of two-dimensional retinal reflection image, and the transverse and longitudinal relative displacement values are specifically calculated according to the part of the two-dimensional retinal reflection image of the current frame relative to the last frame or the stored static image.

Preferably, the main control board is further connected with an OCT detector, and the OCT detector is configured to detect OCT light in the feedback beam; the main control board generates a retina three-dimensional image from the signals detected by the OCT detector;

the main control board is further configured to: when the data detected by the optical detector meet the preset line number, synchronously acquiring a section of signal detected by the OCT detector, wherein the signal is specifically a part of a whole three-dimensional retina image; and the main control board also determines the position of the partial image in a whole three-dimensional retina image according to the transverse and longitudinal relative displacement values, accumulates a plurality of partial three-dimensional retina images according to the position, and combines the partial three-dimensional retina images into the whole three-dimensional retina image.

Preferably, in the retinal imaging control circuit for implementing high-speed real-time eye tracking, the main control board is further connected to a wavefront detector and a compensation mirror, where the wavefront detector is used for detecting a part of reflected light in the feedback beam, and the compensation mirror is used for modulating a wavefront phase of the incident light; and the main control board calculates and generates a second control signal according to a second signal detected by the wavefront detector, and controls the compensation state of the compensation mirror according to the second control signal so as to realize real-time aberration compensation.

Preferably, in the retinal imaging control circuit for implementing high-speed real-time eye tracking, the signal acquisition and control board includes a level conversion circuit and a digital-to-analog conversion circuit, the level conversion circuit is connected with the light source, and the digital-to-analog conversion circuit is connected with the galvanometer; when the signal acquisition and control board is connected with the light detector, the signal acquisition and control board further comprises a signal acquisition circuit, and the signal acquisition circuit is connected with the light detector.

Preferably, in the retinal imaging control circuit for implementing high-speed real-time eye tracking, the digital-to-analog conversion circuit specifically includes a first DA converter, a second DA converter, a voltage follower circuit connected to the first DA converter, and a voltage amplifier circuit connected to the second DA converter; the voltage follower circuit is connected with the light source, and the voltage amplifying circuit is connected with the vibrating mirror;

the signal acquisition circuit specifically comprises an AD converter and a signal amplification circuit connected with the AD converter, and the signal amplification circuit is connected with the optical detector;

the first DA converter, the second DA converter, the AD converter and the level conversion circuit are all in communication connection with the main control board.

Preferably, in the retinal imaging control circuit for implementing high-speed real-time eye tracking, the galvanometer includes a first galvanometer and a second galvanometer, and the first galvanometer is used for feeding back longitudinal scanning and longitudinal tracking of the light beam; the second galvanometer is used for feeding back the transverse tracking of the light beam; the voltage amplifying circuit outputs a first differential analog signal and a second differential analog signal to control deflection states of the first vibrating mirror and the second vibrating mirror respectively.

Preferably, in the above-mentioned retinal imaging control circuit for realizing high-speed real-time eye tracking,

the galvanometer further comprises a third galvanometer, and the third galvanometer is used for feeding back the transverse scanning of the light beam; the third galvanometer is connected with the voltage follower circuit, and the voltage follower circuit outputs an analog signal to control the deflection state of the third galvanometer.

Preferably, in the above-mentioned retinal imaging control circuit for implementing high-speed real-time eye tracking, the galvanometer further includes a fourth galvanometer, and the fourth galvanometer is used for lateral scanning of OCT light; the fourth vibrating mirror is connected with the voltage amplifying circuit, and the voltage amplifying circuit outputs a third differential analog signal to control the deflection state of the fourth vibrating mirror; the frequency of the third differential analog signal is an integer multiple of the frequency of the first differential analog signal.

Compared with the prior art, the invention has the following beneficial effects:

the retina imaging control circuit for realizing high-speed real-time eyeball tracking provided by the invention adjusts the light path state in the retina imaging device through the main control board and the signal acquisition and control board so as to realize high-speed eyeball motion tracking and/or real-time aberration compensation, further realize the functions of high-precision image acquisition, image tracking and the like, and can be simultaneously adapted to a point scanning imaging system and a line scanning imaging system, and has the advantages of strong compatibility, low cost, simple realization process, reliable control and the like.

Drawings

In order to more clearly illustrate the embodiments of the present invention or the technical solutions in the prior art, the drawings that are required to be used in the embodiments or the description of the prior art will be briefly described below, and it is obvious that the drawings in the following description are only embodiments of the present invention, and that other drawings can be obtained according to the provided drawings without inventive effort for a person skilled in the art.

Fig. 1 is a schematic diagram of a retina imaging control circuit for implementing high-speed real-time eye tracking according to an embodiment of the present invention;

Fig. 2 is a schematic diagram of a retina imaging control circuit for implementing high-speed real-time eye tracking according to an embodiment of the present invention;

fig. 3 is a schematic structural diagram of a retinal imaging device according to an embodiment of the present invention;

fig. 4 is a schematic structural diagram of another retinal imaging device according to an embodiment of the present invention.

Detailed Description

The following description of the embodiments of the present invention will be made clearly and completely with reference to the accompanying drawings, in which it is apparent that the embodiments described are only some embodiments of the present invention, but not all embodiments. All other embodiments, which can be made by those skilled in the art based on the embodiments of the invention without making any inventive effort, are intended to be within the scope of the invention.

In order that the above-recited objects, features and advantages of the present invention will become more readily apparent, a more particular description of the invention will be rendered by reference to the appended drawings and appended detailed description.

Referring to fig. 1, fig. 1 is a schematic diagram of a retina imaging control circuit for implementing high-speed real-time eye tracking according to an embodiment of the present invention; referring to fig. 2, fig. 2 is a schematic diagram of a retina imaging control circuit for implementing high-speed real-time eye tracking according to another embodiment of the present invention.

The control circuit comprises a main control board and a signal acquisition and control board, wherein the signal acquisition and control board is connected to the main control board.

The signal acquisition and control board is respectively connected with a light source and a galvanometer, the light source is used for providing incident light for retina, and the galvanometer is used for modulating the incident angle of the incident light entering the retina; the main control board is directly connected to the optical detector or connected to the optical detector through signal acquisition and control boards, and the optical detector is used for detecting feedback light beams reflected from retina.

The main control board obtains a first signal detected by the light detector, calculates and generates a first control signal and transmits the first control signal to the signal acquisition and control board, and the signal acquisition and control board controls the deflection state of the vibrating mirror according to the first control signal so as to realize eyeball movement tracking.

Optionally, the main control board generates a real-time two-dimensional retina reflection image according to the first signal, calculates the transverse and longitudinal relative displacement values of the current frame of the two-dimensional retina reflection image relative to the previous frame, and then respectively superimposes a transverse and longitudinal deflection value equal to the relative displacement value on the first control signal, thereby realizing real-time eyeball motion tracking.

Optionally, the control circuit further includes: and a power supply control board.

The power supply control board is connected with the main control board and the signal acquisition and control board respectively.

The power control board is connected with an external power supply, and a main control board and a signal acquisition and control board required working voltage are formed through a module inside the power control board.

Optionally, the main control board is further connected to an OCT detector, where the OCT detector is configured to detect OCT light in the feedback beam; and the main control board generates a three-dimensional retina image from the signals detected by the OCT detector.

Optionally, the main control board is further connected to a wavefront detector and a compensation mirror, where the wavefront detector is used to detect a part of reflected light in the feedback beam, and the compensation mirror is used to modulate the wavefront phase of the incident light; and the main control board calculates and generates a second control signal according to a second signal detected by the wavefront detector, and controls the compensation state of the compensation mirror according to the second control signal so as to realize real-time aberration compensation.

Optionally, the main control board comprises a CPU (Central Processing Unit ) module and an FPGA (Field Programmable Gate Array, field programmable gate array) module;

the FPGA module is connected with the signal acquisition and control board, and the CPU module transmits a first control signal to the signal acquisition and control board through the FPGA module; and the signal acquisition and control board controls the deflection state of the vibrating mirror according to the first control signal so as to realize the scanning and tracking of the feedback light beam.

The CPU module is also used for completing the initialization configuration of each module in the signal acquisition and control panel through the FPGA module; the CPU module is also used for configuring the working states of all the modules in the signal acquisition and control board through the FPGA module so as to control the retina imaging device to perform scanning imaging; the FPGA module is used for realizing signal communication between the CPU module and the signal acquisition and control board.

Specifically, the main control board comprises two main core processing modules, namely a CPU module and an FPGA module; the CPU module is connected with the FPGA module through a data bus Date and an address bus Cmd; after power-on, the CPU module completes signal acquisition and initialization configuration of each module in the control panel through the FPGA module; when the equipment operates in a normal mode, the CPU module configures each module in the signal acquisition and control panel through the FPGA module to start scanning imaging, and the FPGA module transmits a conversion value of the acquisition channel in the signal acquisition and control panel to the CPU module through the data bus, and the CPU module can display an image on the touch screen after internal data processing.

Optionally, the CPU module includes multiple USB interfaces and multiple ethernet interfaces, so as to be suitable for different imaging devices. The USB interface is connected with a corresponding detector in the retinal imaging device, for example, as shown in fig. 1, the USB1 is connected with an OCT detector in the retinal imaging device, so as to realize communication between the OCT detector and the CPU module.

The USB interface is also connected to a corresponding compensation mirror in the retinal imaging device, for example, as shown in fig. 1, and the USB2 is connected to the compensation mirror in the retinal imaging device to enable communication between the compensation mirror drive and the CPU module.

It should be noted that more USB interfaces may be added to connect with other devices in the retinal imaging apparatus that need to communicate with the CPU module, which is not illustrated in the embodiment of the present application, and may be flexibly set based on practical situations.

The Ethernet interface is connected with a corresponding detector in the retinal imaging device, for example, as shown in fig. 1, ethernet1 is connected with a wavefront detector in the retinal imaging device, so that communication between the wavefront detector and the CPU module is realized; as shown in fig. 1, ethernet2 is connected to a line camera (as a photodetector) in the retinal imaging device, and communication between the line camera and the CPU module is achieved.

The signal acquisition and control board comprises a level conversion circuit and a digital-to-analog conversion circuit, wherein the level conversion circuit is connected with the light source, and the digital-to-analog conversion circuit is connected with the galvanometer; when a photodetector (e.g., a photodiode) is connected to the signal acquisition and control board, the signal acquisition and control board also includes a signal acquisition circuit that is connected to the photodetector (as shown in fig. 2).

The signal acquisition circuit, the digital-to-analog conversion circuit and the level conversion circuit are all in communication connection with the FPGA module.

The digital-to-analog conversion circuit specifically comprises a first DA converter (namely, the DA converter 1 in fig. 1 or 2), a second DA converter (namely, the DA converter 2 in fig. 1 or 2), a voltage follower circuit connected with the first DA converter and a voltage amplifier circuit connected with the second DA converter; the voltage follower circuit is connected with the light source, and the voltage amplifying circuit is connected with the vibrating mirror; the light source is also connected with a level conversion circuit, the level conversion circuit is used as a switch for controlling the working state of the light source, and the voltage follower circuit is used for adjusting the power of the light source.

As shown in fig. 2, the signal acquisition circuit specifically includes an AD converter and a signal amplification circuit connected to the AD converter, where the signal amplification circuit is connected to the photodetector.

The first DA converter, the second DA converter, the AD converter and the level conversion circuit are all in communication connection with the main control board.

Specifically, as shown in fig. 1, the galvanometer includes a first galvanometer G1 and a second galvanometer G2, where the first galvanometer G1 is used for longitudinal scanning and longitudinal tracking of the feedback beam, and the second galvanometer G2 is used for transverse tracking of the feedback beam; the voltage amplifying circuit outputs differential analog signals to control the deflection states of the first vibrating mirror and the second vibrating mirror G2 of the G1.

Specifically, as shown in fig. 2, the galvanometer includes a first galvanometer G1 and a second galvanometer G2, where the first galvanometer G1 is used for feeding back the longitudinal scanning and longitudinal tracking of the light beam; the second galvanometer G2 is used for feeding back the transverse tracking of the light beam; the voltage amplifying circuit outputs differential analog signals to control the deflection states of the first vibrating mirror and the G1 second vibrating mirror G2; optionally, as shown in fig. 2, the galvanometer further includes a third galvanometer G3, and the third galvanometer G3 is used for lateral scanning of the feedback beam; the third galvanometer G3 is connected with a voltage follower circuit, and the voltage follower circuit outputs an analog signal to control the deflection state of the third galvanometer G3. Optionally, as shown in fig. 2, the galvanometer further includes a fourth galvanometer G4, and the fourth galvanometer G4 is used for lateral scanning of OCT light; the fourth vibrating mirror G4 is connected with a voltage amplifying circuit, and the voltage amplifying circuit outputs a differential analog signal to control the deflection state of the fourth vibrating mirror G4. The frequency of the differential analog signal for controlling the fourth galvanometer is set to be an integer multiple of the frequency of the differential analog signal on the first galvanometer, for example, the first galvanometer scans 1 round trip longitudinally, and the fourth galvanometer is set to scan 8 rounds simultaneously. The linkage control mode can effectively shorten the time for acquiring the three-dimensional retina image.

When the tracking mode is started, the CPU module can calculate the deviation between the image and the last frame of image (or the previously stored static image) according to the acquired image, and the FPGA module controls the position of the vibrating mirror, so that the scanning imaging position is changed, and the function of tracking object imaging is realized.

Specifically, a touch screen in the control circuit is used as a terminal of man-machine interaction, and is directly communicated with the compensation mirror, the wavefront detector, the OCT detector and the FPGA module through the CPU module to realize control. On one hand, a user can give an instruction through the touch screen to realize control functions of changing the fundus imaging position, real-time tracking and displaying, compensating mirrors, wavefront detectors and the like; on the other hand, the CPU module displays images and data on the touch screen in real time by acquiring the data acquired by the FPGA module, and the images and the data are used as references for users.

The following retinal imaging devices based on different optical path structures are combined with the control circuits provided in the foregoing embodiments, and control procedures thereof are respectively described:

a first embodiment will be described by taking a retinal imaging device that performs point scanning as an example:

referring to fig. 3, fig. 3 is a schematic structural diagram of a retinal imaging device according to an embodiment of the present invention, and the control circuit shown in fig. 2 is used to control the operation of the retinal imaging device.

The retinal imaging device as shown in fig. 3 includes: the light source detection module, the light beam modulation module and the acquisition control module are integrated in the control circuit.

The light source in the light source detection module generates reflected light or two-channel illumination light, wherein one of the two-channel illumination light is reflected light (used for illuminating retina and generating reflected signals (namely first signals)), and the other is OCT light (used for illuminating retina and generating interference signals), and after being combined inside or outside the light beam detection module, a scanning light beam is formed to enter the light beam modulation module.

The galvanometer in the light beam modulation module modulates the incidence angle of the scanning light beam, and the modulated scanning light beam enters the eyeball; the feedback light beam reflected by the retina returns to the light source detection module in a primary path, namely the feedback light beam reflected by the retina is incident to the light source detection module through the light beam modulation module; the light detector in the light source detection module processes the feedback light beam to generate a corresponding detection signal, and the detection signal is acquired and processed by the acquisition control module; the acquisition control module acquires the detection signal and controls the light path state of the light beam modulation module based on the detection signal so as to at least realize eyeball movement tracking.

Further, as shown in fig. 3, when the dual-channel illumination light is generated, the light sources for operation in the light source detection module are a reflected light source and an OCT light source. Wherein the reflected light source is used for outputting reflected light; the OCT light source is used for outputting OCT light. At this time, an OCT detector may be provided in the light source detection module, and the OCT detector is connected to the main control board for generating an OCT light detection signal according to the OCT light in the feedback beam. Correspondingly, the main control board collects the OCT optical detection signals and generates a three-dimensional retina image according to the OCT optical detection signals.

It should be noted that, as shown in fig. 3, the reflected light source and the OCT light source may be two independent light source devices, and respectively output the reflected light and the OCT light; or one OCT light source outputs a beam of light which is used as both reflected light and OCT light, and the beam of light is split into two beams of light by an optical device in the light source detection module after being reflected by the eyeball and is received by the light detector and the OCT detector respectively.

Furthermore, a compensation mirror may be further disposed in the beam modulation module, and a wavefront detector is disposed in the light source detection module, where the wavefront detector is configured to generate a wavefront detection signal (i.e., a second signal) according to a portion of the reflected light in the feedback beam. Correspondingly, the main control board collects the wavefront detection signals, calculates and generates second control signals, and controls the compensation state of the compensation mirror according to the second control signals so as to realize real-time aberration compensation.

Specifically, as shown in fig. 3, taking an example of generating two-channel illumination light as an illustration, the light source detection module includes: a reflected light source, an OCT light source, a fiber coupler, a spectroscope C1, a spectroscope C2, a spectroscope C3, a lens, a pinhole, a photodetector, an OCT detector and a wavefront detector.

When the retina imaging device works, firstly, a main control board sends out a control instruction to turn on a reflected light source and an OCT light source, and OCT light output by the OCT light source is collimated and incident to a spectroscope C1 after passing through an optical fiber coupler; the reflected light output by the reflected light source is combined with the OCT light at the beam splitter C1 through the beam splitter C2, the scanning light beam after the beam combination enters the light beam modulation module through the reflector SM1, and the reflector SM1 can be arranged in the light beam modulation module.

Further, the feedback light beam reflected by the retina returns to the light source detection module in a primary way, namely, the feedback light beam reflected by the retina enters the light source detection module through the light beam modulation module, OCT light in the feedback light beam is reflected to the optical fiber coupler by the spectroscope C1 and then reaches the OCT detector, and the OCT detector generates an OCT light detection signal CJ3 according to the OCT light in the feedback light beam; after the reflected light in the feedback light beam projects the spectroscope C1 and spectroscope C2, a part of reflected light is reflected by the spectroscope C3 to reach the wavefront detector, another part of reflected light projects the spectroscope C3 to be focused by the lens, reach the photodetector through the aperture; wherein the light detector generates a reflected light detection signal CJ2 (i.e. a first signal) according to a part of the reflected light in the feedback light beam, and the wavefront detector generates a wavefront detection signal CJ1 (i.e. a second signal) according to another part of the reflected light in the feedback light beam.

A main control board in the control circuit generates a three-dimensional retina image based on the OCT optical detection signal; generating a first control signal based on the reflected light detection signal, and controlling the deflection state of the galvanometer to realize eyeball movement tracking; and generating a second control signal based on the wavefront detection signal, and controlling the compensation state of the compensation mirror to realize real-time aberration compensation.

The light beam modulation module of the present embodiment includes: mirror SM2, beam splitter C4, mirror SM3, mirror SM4, mirror SM5, mirror SM6, mirror SM7, mirror SM8, mirror SM9, mirror SM10, and mirror P1.

Five eyeball pupil conjugation surfaces exist in the light beam modulation module, optical conjugation is formed with the eyeball pupils through nine reflecting mirrors SM2-SM10 and a spectroscope C4, and four vibrating mirrors and a compensating mirror are arranged on the five optical conjugation surfaces. The galvanometer G3 is used for realizing the transverse scanning of the reflected light; the galvanometer G4 is used for realizing the transverse scanning of OCT light; the galvanometer G1 is used for realizing longitudinal scanning and longitudinal tracking of reflected light and OCT light; the galvanometer G2 is used for realizing the transverse tracking of the reflected light and the OCT light; the compensation mirror is used for real-time aberration compensation. The order of placement of the four vibrating mirrors and the compensating mirror is not limited, and the four vibrating mirrors and the compensating mirror can be randomly adjusted and replaced in the light path according to the situation. If the number of the eye pupil conjugate planes needs to be reduced, the reflecting mirrors and the galvanometer/compensation mirrors on the optical path can be correspondingly reduced. The eye pupil conjugate surface can also be realized by adopting a lens type structure.

Specifically, the scanning beam output by the light source detection module enters the beam modulation module through the reflecting mirror SM1, is reflected by the reflecting mirror SM2 and then enters the spectroscope C4, the reflected light projects the spectroscope C4 and then is reflected by the vibrating mirror G3, and the secondary light projects the spectroscope C4 and then reaches the reflecting mirror SM3; the OCT light is reflected for the first time at the spectroscope C4, reflected by the vibrating mirror G4, reflected again by the spectroscope C4 for the second time, and then reaches the reflecting mirror SM3; after the reflected light and the OCT light reach the mirror SM3, they reach the eyeball through the mirror SM4, the galvanometer G1, the mirror SM5, the mirror SM6, the compensation mirror, the mirror SM7, the mirror SM8, the galvanometer G2, the mirror SM9, the mirror SM10 and the mirror P1, that is, reach the retina of the eyeball; the feedback light beam reflected by the retina returns to the light source detection module in a primary path, namely, the feedback light beam reflected by the retina returns to the light source detection module through the light beam modulation module.

Optionally, in the embodiment of the present application, the beam splitter includes, but is not limited to, a dichroic mirror, a flat beam splitter, a thin film beam splitter, a cubic beam splitter, and the like; the compensation mirror is used as a wavefront aberration compensation device of the human eye and comprises, but is not limited to, a deformable mirror, a spatial light modulator and the like; the first to fourth galvanometer are used as mirrors with changeable angles, including but not limited to resonance mirrors, scanning galvanometers, acousto-optic modulators, MEMS galvanometers, etc. The OCT light source comprises, but is not limited to, a super-radiation light-emitting diode, a vertical cavity surface emitting laser, a precious stone laser and other light sources capable of emitting a larger spectrum range; wherein the OCT detector includes, but is not limited to, a spectrometer, a balance detector, etc.; the wavefront sensor includes, but is not limited to, a microlens wavefront sensor, an interference wavefront sensor, etc.; including but not limited to cameras, photomultipliers, avalanche photodiodes, and the like.

Specifically, the main control board calculates and generates a first control signal according to a first signal (reflected light detection signal) of the light detector collected by the signal collection and control board and transmits the first control signal to the signal collection and control board, and the signal collection and control board controls the deflection state of the vibrating mirror according to the first control signal so as to realize eyeball movement tracking.

The FPGA module is connected with the signal acquisition and control board and transmits a first signal (reflected light detection signal) acquired by the signal acquisition and control board to the CPU module; the CPU module transmits a first control signal to the signal acquisition and control board through the FPGA module; and the signal acquisition and control board controls the deflection state of the vibrating mirror according to the first control signal so as to realize the scanning and tracking of the feedback light beam.

The first control signal includes: the first galvanometer control signal is used for controlling the deflection state of the galvanometer G1; the second galvanometer control signal is used for controlling the deflection state of the galvanometer G2; the third galvanometer control signal is used for controlling the deflection state of the galvanometer G3; and a fourth galvanometer control signal for controlling the deflection state of the galvanometer G4. The deflection angle of the vibrating mirror is in direct proportion to the light spot position on the retina and has a linear relation, so that the scanning and tracking functions of the eyeball can be realized by controlling the deflection angle of the vibrating mirror; and the second control signal controls the compensation value of the compensation mirror to realize real-time aberration compensation.

Further, taking the retinal imaging device shown in fig. 3 as an example, the following details the workflow of the FPGA module, which is specifically as follows:

the user gives instructions to the CPU module through the touch screen, and initializes the hardware equipment, including configuring the AD converter, configuring the horizontal and vertical resolutions of the image, the image starting position, the image blanking area step length and the like.

And when the FPGA module operates in a normal mode, the light source is turned on, and then the vibrating mirror G3 is controlled to start vibrating so as to realize transverse scanning of reflected light. Since the oscillating mirror G3 in this embodiment is a fast resonant mirror, a clock reference pulse signal is output, and the signal is taken as a line synchronization signal of the analog-to-digital converter, and the output line synchronization signal is taken as a clock signal of the FPGA module. The sampling frequency may be set to a thousand times the sampling frequency of the line synchronization signal, such as 100 megabits.

Next, the FPGA module changes the optical path of the reflected light by controlling the vibrating mirror G1 to vibrate, so as to realize the longitudinal scanning of the reflected light.

And then the FPGA module acquires the electric signals converted by the optical detector through the A/D converter, so as to acquire the electric signal value of the two-dimensional image of the reflected light, converts the electric signal value into an image gray value after analog-digital conversion, and transmits the image gray value to the CPU module, and the CPU module further processes the image gray value and transmits the image gray value to the touch screen for image display.

On the other hand, the FPGA module realizes OCT optical scanning by controlling the vibrating mirror G4 to vibrate and matching with the vibrating mirror G1.

In the whole process, the FPGA module receives PC instructions in real time while uploading data, wherein the PC instructions comprise light source brightness adjustment, imaging view field size adjustment, imaging position adjustment and the like.

The CPU module acquires a wavefront detection signal of the wavefront detector, calculates a compensation value, and controls the compensation mirror to perform aberration compensation.

In the tracking mode, after processing the data uploaded by the FPGA module, the CPU module can be compared with the static image stored in the previous frame or before, X-direction tracking is realized by changing the position of the vibrating mirror G2, Y-direction tracking is realized by changing the central position of the scanning range of the vibrating mirror G1, the transverse and longitudinal relative displacement values of the current frame of the two-dimensional retina reflection image relative to the previous frame are solved, and then a transverse and longitudinal deflection value as large as the relative displacement value is respectively overlapped on the first control signal, so that real-time eyeball movement tracking is realized. Here, in order to increase the speed, when the data detected by the photodetector satisfies a preset number of lines (for example, 16 lines or 32 lines), the CPU acquires the data as a first signal, and the generated real-time two-dimensional retinal reflected image is a part of a frame of two-dimensional retinal reflected image. In the tracking process of the embodiment, thirty-half of a two-dimensional retina reflection image is taken as a calculation reference each time, and the fastest response speed can reach thousands of times per second, which exceeds the human eye jumping frequency.

Meanwhile, the FPGA module can control the spectrometer, namely the OCT detector, to sample the depth information (namely the Z direction) of the retina, and automatically and synchronously obtain a three-dimensional retina image. When the data detected by the optical detector meet the preset line number, the CPU synchronously acquires a section of signals detected by the OCT detector, specifically a part of a whole three-dimensional retina image. The CPU determines the position of the partial retina three-dimensional image in a whole retina three-dimensional image according to the transverse and longitudinal relative displacement values, and accumulates a plurality of partial retina three-dimensional images according to the positions to form the whole retina three-dimensional image.

The resolution of the image obtained by the embodiment is improved by an order of magnitude (up to 1024 x 1024) compared with that of the image obtained by the existing imaging system on the market, and the highest response bandwidth can reach ten megabits.

In the second embodiment, a retinal imaging device for performing line scanning will be described as an example:

referring to fig. 4, fig. 4 is a schematic structural diagram of another retinal imaging device according to an embodiment of the present invention, and the control circuit shown in fig. 1 is used to control the operation of the retinal imaging device.

The line scan retinal imaging apparatus as shown in fig. 4 includes: the light source detection module, the light beam modulation module and the acquisition control module are integrated in the control circuit.

The light source detection module generates linear imaging light (used for irradiating retina and generating a reflection signal), and the linear imaging light enters the light beam modulation module as a scanning light beam; optionally, the light source detection module is further configured to generate a linear OCT light, where the linear OCT light and the linear imaging light are incident on the beam modulation module together as a scanning beam. The light detector of the embodiment adopts a linear array camera.

The light source detection module comprises a linear array camera and a linear array OCT detector; the linear array camera is used for generating an imaging light detection signal according to imaging light in the feedback light beam; the linear array OCT detector is used for generating an OCT light detection signal according to the OCT light in the feedback light beam.

That is, the light source detection module generates linear imaging light or linear two-channel illumination light, one of which is imaging light (for illuminating the retina, generating a reflected signal (i.e., a first signal)), and the other is OCT light (for illuminating the retina, generating an interference signal), which enters the beam modulation module as a scanning beam.

The galvanometer in the light beam modulation module modulates the incidence angle of the scanning light beam, and the modulated scanning light beam enters the eyeball; the feedback light beam reflected by the retina returns to the light source detection module in a primary path, namely the feedback light beam reflected by the retina is incident to the light source detection module through the light beam modulation module; the light source detection module processes the feedback light beam to generate a corresponding detection signal, and the detection signal is acquired and processed by the acquisition control module; the acquisition control module acquires the detection signals and controls the light path state of the light beam modulation module based on the detection signals so as to realize eyeball movement tracking.

Further, as shown in fig. 4, the imaging light source in the light source detection module is used for outputting imaging light or dual-channel illumination light. When the imaging light source outputs the dual-channel illumination light, a linear array OCT detector can be arranged in the light source detection module and used for generating an OCT light detection signal according to OCT light in the feedback light beam. Correspondingly, the acquisition control module acquires the OCT detection signal and generates a three-dimensional retina image according to the detection signal.

As shown in fig. 4, one beam of light output from one imaging light source may be used as both imaging light and OCT light, or two independent light source devices may output imaging light and OCT light, respectively, and the two beams of light are combined and then are incident to the light source detection module.

Further, as shown in fig. 4, the light source detection module further includes: a first cylindrical lens 11, a second cylindrical lens 12, a spectroscope C1, a spectroscope C2, a spectroscope C3, a spectroscope C4, a reflecting mirror P1, a lens 13, and a slit 14.

When the imaging light source outputs only imaging light, the reflecting mirror P1 and the second lens 12 may be omitted.

Specifically, when the retina imaging device works, firstly, the main control board sends out a control instruction to turn on the imaging light source, the collimated light sent out by the imaging light source is refracted into a linear light beam through the first cylindrical lens 11 and then is incident into the spectroscope C1, part of the light is reflected to the spectroscope C3 and enters the light beam modulation module, and the part of the light forms imaging light; when the light beam includes OCT light, another part of the light transmitting beam splitter C1 is refracted by the second lens 12, returns to collimation, reaches the reflecting mirror P1, is reflected by the reflecting mirror P1, and enters the linear array OCT detector after being reflected by the beam splitter C1 and reflected by the beam splitter C4, and this part of the light constitutes OCT reference light, which is defined as OCT reference light.

Further, the feedback light beam reflected by the retina returns to the light source detection module in a primary way, namely, the feedback light beam reflected by the retina is incident to the light source detection module through the light beam modulation module, an imaging light transmission spectroscope C4 in the feedback light beam reaches the linear array camera through a slit 14 after focusing treatment of a lens 13 to generate an imaging light detection signal CJ2, and an OCT light transmission spectroscope C3 and a spectroscope C1 in the feedback light beam are partially reflected by the spectroscope C4 to enter the linear array OCT detector to interfere with COT reference light to form an OCT light detection signal CJ3.

Furthermore, a compensation mirror can be arranged in the light beam modulation module, and a wavefront detection light source and a wavefront detector are arranged in the light source detection module at the same time, wherein the wavefront detection light source is used for outputting wavefront detection light, and the wavefront detection light is incident to the light beam modulation module after being combined with a scanning light beam; the wavefront detector is configured to generate a wavefront-sensing signal from wavefront-sensing light in the feedback beam. Correspondingly, the acquisition control module acquires the wavefront detection signal and controls the compensation value of the compensation mirror according to the detection signal so as to realize real-time aberration compensation.

After the collimated wavefront detection light emitted by the wavefront detection light source is reflected by the spectroscope C2, the collimated wavefront detection light is combined with linear imaging light or linear imaging light and linear OCT light at the spectroscope C3, and the scanning light beam after the beam combination enters a light beam modulation module through the reflector SM 1; after the wave front detection light in the feedback light beam is subjected to reflection processing of the spectroscope C3, the transmission spectroscope C2 reaches the wave front detector to generate a wave front detection signal CJ1.

The light beam modulation module of the present embodiment includes: mirror SM2, mirror SM3, mirror SM4, mirror SM5, mirror SM6, mirror SM7, mirror SM8, mirror P2, oscillating mirror G1, oscillating mirror G2, and compensating mirror.

That is, there are three eye through hole conjugate planes in the beam modulation module, which are optically conjugate with the eye pupil by seven reflectors SM2 to SM8, and the galvanometer G1, the galvanometer G2 and the compensation mirror are disposed on the three optical conjugate planes. The galvanometer G1 is used for longitudinal scanning and longitudinal tracking of the imaging light and the OCT light; the galvanometer G2 is used for lateral tracking of the imaging light and the OCT light; the compensating mirror is used for performing real-time aberration compensation; therefore, synchronous line scanning of imaging light and OCT light is realized simultaneously, and three functions of scanning imaging, eyeball motion tracking and human eye wavefront aberration compensation are realized.

The order of placement of the galvanometer G1, the galvanometer G2, and the compensation mirror is not limited, and may be optionally adjusted and exchanged in the optical path according to circumstances. The eye pupil conjugate surface can also be realized by adopting a lens type structure.

Specifically, the light beam output by the light source detection module enters the light beam modulation module through the reflecting mirror SM1, and is reflected by the reflecting mirror SM2 and then enters the vibrating mirror G1, and the vibrating mirror G1 can be controlled to point to any longitudinal angle; after being reflected by the vibrating mirror G1, the mirror is continuously reflected by the reflecting mirror SM3 and the reflecting mirror SM4 to reach the vibrating mirror G2, and the vibrating mirror G2 can be controlled to point to any transverse angle; after being reflected by the vibrating mirror G2, the light wave is continuously reflected by the reflecting mirror SM5 and the reflecting mirror SM6 to reach the compensating mirror, and the compensating mirror can modulate the light wave front phase; after being reflected by the compensation mirror, the light is continuously reflected by the reflecting mirror SM7, the reflecting mirror SM8 and the reflecting mirror P2, and is incident to the pupil of human eyes, namely reaches the retina of the eyeballs; the feedback light beam reflected by the retina returns to the light source detection module in a primary path, namely, the feedback light beam reflected by the retina returns to the light source detection module through the light beam modulation module.

Specifically, the main control board calculates and generates a first control signal according to a first signal of the optical detector acquired by the signal acquisition and control board and transmits the first control signal to the signal acquisition and control board, and the signal acquisition and control board controls the deflection state of the vibrating mirror according to the first control signal so as to realize eye movement tracking.

The FPGA module is connected with the signal acquisition and control board and transmits a first signal acquired by the signal acquisition and control board to the CPU module; the CPU module transmits a first control signal to the signal acquisition and control board through the FPGA module; and the signal acquisition and control board controls the deflection state of the vibrating mirror according to the first control signal so as to realize the scanning and tracking of the feedback light beam.

The first control signal includes: the first galvanometer control signal is used for controlling the deflection state of the galvanometer G1; and the second galvanometer control signal is used for controlling the deflection state of the galvanometer G2. The deflection angle of the vibrating mirror is in direct proportion to the light spot position on the retina and has a linear relation, so that the scanning and tracking functions of the eyeball can be realized by controlling the deflection angle of the vibrating mirror; the second control signal controls the compensation value of the compensation mirror to realize real-time aberration compensation.

Further, taking the retinal imaging device shown in fig. 4 as an example, the following details the workflow of the FPGA module, which is specifically as follows:

the user gives instructions to the CPU module through the touch screen, and initializes the hardware equipment, including configuring the horizontal and vertical resolutions of the image, the starting position of the image, the step length of the image blanking area, and the like.

When the system runs in a normal mode, the FPGA module controls the vibrating mirror G1 to start vibrating after the light source is turned on, the state of a light path is changed, the longitudinal scanning and the longitudinal tracking of the imaging light and the OCT light are realized, and the transverse tracking of the imaging light and the OCT light is realized by controlling the vibrating mirror G2 to vibrate.

And then the CPU module acquires the image signals of the linear array camera through the Ethernet2, and the image signals are further processed by the CPU and then transmitted to the touch screen for image display.

In the whole process, the FPGA module uploads data and simultaneously receives instructions of the CPU module in real time, wherein the instructions comprise light source brightness adjustment, imaging view field size adjustment, imaging position adjustment and the like.

The CPU module acquires a wavefront detection signal of the wavefront detector, calculates a compensation value, and controls the compensation mirror to perform aberration compensation.

In the tracking mode, after the CPU module processes the data uploaded by the FPGA module, the data can be compared with the static image stored in the previous frame or before, the X-direction tracking is realized by changing the position of the vibrating mirror G2, and the Y-direction tracking is realized by changing the central position of the scanning range of the vibrating mirror G1.

Meanwhile, the FPGA module can control the OCT detector to sample depth information (namely Z direction) of the retina, so as to obtain a three-dimensional retina image.

The above describes in detail a retinal imaging control circuit for implementing high-speed real-time eye tracking, and specific examples are applied to illustrate the principles and embodiments of the present invention, and the above description of the examples is only for helping to understand the method and core ideas of the present invention; meanwhile, as those skilled in the art will have variations in the specific embodiments and application scope in accordance with the ideas of the present invention, the present description should not be construed as limiting the present invention in view of the above.

It is further noted that relational terms such as first and second, and the like are used solely to distinguish one entity or action from another entity or action without necessarily requiring or implying any actual such relationship or order between such entities or actions. Moreover, the terms "comprises," "comprising," or any other variation thereof, are intended to cover a non-exclusive inclusion, such that a process, method, article, or apparatus that comprises a list of elements does not include, or is intended to include, elements inherent to such process, method, article, or apparatus. Without further limitation, an element defined by the phrase "comprising one … …" does not exclude the presence of other like elements in a process, method, article, or apparatus that comprises the element.

Claims (10)

1. The retina imaging control circuit for realizing high-speed real-time eyeball tracking is characterized by comprising a main control board and a signal acquisition and control board, wherein the signal acquisition and control board is connected to the main control board;

the signal acquisition and control board is respectively connected with a light source and a galvanometer, the light source is used for providing incident light for retina, and the galvanometer is used for modulating the incident angle of the incident light entering the retina; the main control board is directly connected to the optical detector or connected to the optical detector through the signal acquisition and control board, and the optical detector is used for detecting the feedback light beam reflected from the retina;

the main control board obtains a first signal detected by the light detector, calculates and generates a first control signal and transmits the first control signal to the signal acquisition and control board, and the signal acquisition and control board controls the deflection state of the vibrating mirror according to the first control signal so as to realize eyeball movement tracking.

2. The retinal imaging control circuit for implementing high-speed real-time eye tracking according to claim 1, wherein the main control board generates a real-time two-dimensional retinal reflection image according to the first signal, calculates the transverse and longitudinal relative displacement values of the current frame of the two-dimensional retinal reflection image relative to the previous frame or the stored static image, and then superimposes a transverse and longitudinal deflection value equal to the relative displacement value on the first control signal, thereby implementing high-speed real-time eye movement tracking.

3. The retinal imaging control circuit for high-speed real-time eye tracking according to claim 2, wherein the main control board is configured to: when the data detected by the optical detector meet the preset line number, the data are taken as the first signal to be acquired;

the real-time two-dimensional retinal reflection image generated by the main control board according to the first signal is specifically a part of one frame of two-dimensional retinal reflection image, and the transverse and longitudinal relative displacement values are specifically calculated according to the part of the two-dimensional retinal reflection image of the current frame relative to the last frame or the stored static image.

4. A retinal imaging control circuit for high-speed real-time eye tracking according to claim 3, wherein said main control board is further connected to an OCT detector for detecting OCT light in said feedback beam; the main control board generates a retina three-dimensional image from the signals detected by the OCT detector;

the main control board is further configured to: when the data detected by the optical detector meet the preset line number, synchronously acquiring a section of signal detected by the OCT detector, wherein the signal is specifically a part of a whole three-dimensional retina image; and the main control board also determines the position of the partial image in a whole three-dimensional retina image according to the transverse and longitudinal relative displacement values, accumulates a plurality of partial three-dimensional retina images according to the position, and combines the partial three-dimensional retina images into the whole three-dimensional retina image.

5. A retinal imaging control circuit for high-speed real-time eye tracking according to any one of claims 1 to 4 wherein the main control board is further connected to a wavefront detector for detecting a portion of the reflected light in the feedback beam and a compensation mirror for modulating the wavefront phase of the incident light, respectively; and the main control board calculates and generates a second control signal according to a second signal detected by the wavefront detector, and controls the compensation state of the compensation mirror according to the second control signal so as to realize real-time aberration compensation.

6. The retinal imaging control circuit for implementing high-speed real-time eye tracking according to claim 1, wherein the signal acquisition and control board comprises a level conversion circuit and a digital-to-analog conversion circuit, the level conversion circuit is connected with the light source, and the digital-to-analog conversion circuit is connected with the galvanometer; when the signal acquisition and control board is connected with the light detector, the signal acquisition and control board further comprises a signal acquisition circuit, and the signal acquisition circuit is connected with the light detector.

7. The retinal imaging control circuit for implementing high-speed real-time eye tracking according to claim 6, wherein the digital-to-analog conversion circuit specifically comprises a first DA converter, a second DA converter, a voltage follower circuit connected to the first DA converter, and a voltage amplifier circuit connected to the second DA converter; the voltage follower circuit is connected with the light source, and the voltage amplifying circuit is connected with the vibrating mirror;

The signal acquisition circuit specifically comprises an AD converter and a signal amplification circuit connected with the AD converter, and the signal amplification circuit is connected with the optical detector;

the first DA converter, the second DA converter, the AD converter and the level conversion circuit are all in communication connection with the main control board.

8. The retinal imaging control circuit for high-speed real-time eye tracking according to claim 7, wherein the galvanometer comprises a first galvanometer and a second galvanometer, the first galvanometer being used for longitudinal scanning and longitudinal tracking of the feedback beam; the second galvanometer is used for feeding back the transverse tracking of the light beam; the voltage amplifying circuit outputs a first differential analog signal and a second differential analog signal to control deflection states of the first vibrating mirror and the second vibrating mirror respectively.

9. A retinal imaging control circuit for high-speed real-time eye tracking according to claim 8 wherein,

the galvanometer further comprises a third galvanometer, and the third galvanometer is used for feeding back the transverse scanning of the light beam; the third galvanometer is connected with the voltage follower circuit, and the voltage follower circuit outputs an analog signal to control the deflection state of the third galvanometer.

10. The retinal imaging control circuit for high-speed real-time eye tracking according to claim 9, wherein the galvanometer further comprises a fourth galvanometer for lateral scanning of OCT light; the fourth vibrating mirror is connected with the voltage amplifying circuit, and the voltage amplifying circuit outputs a third differential analog signal to control the deflection state of the fourth vibrating mirror; the frequency of the third differential analog signal is an integer multiple of the frequency of the first differential analog signal.