SSVEP visual stimulation coding and metasurface space-time coding fusion system

Abstract

The invention discloses an SSVEP visual stimulation coding and metasurface space-time coding fusion system, which comprises SSVEP-based brain-computer interface equipment and a brain-computer space-time coding metasurface, and is characterized in that the brain-computer space-time coding metasurface is composed of a plurality of brain-computer space-time coding metasurface units; the brain-machine space-time coding metasurface unit is formed by integrating a space-time metasurface unit with a light emitting diode, the light emitting diode provides an SSVEP visual stimulation signal with a specific frequency, and the SSVEP visual stimulation signal is used for exciting an electroencephalogram signal with a specific frequency of the brain of a user. The space-time metasurface unit is formed by integrating a programmable unit with a switching diode, and the light emitting diode and the switching diode of the brain-computer space-time coding metasurface unit use the same brain-computer space-time coding metasurface signal. A brain wireless remote control intelligent equipment system is designed based on a brain-computer space-time coding metasurface, and the on-off state of the intelligent equipment is realized according to the brain intention.

Description

Technical Field

[0001] The present invention relates to the technical fields of brain-computer interfaces and novel artificial electromagnetic materials, and particularly relates to a fusion system of SSVEP (steady-state visual evoked potential) visual stimulus coding and metasurface spatio-temporal coding. Background Art

[0002] Brain-computer interfaces have opened up an innovative way of communication and control, allowing the brain to bypass the conventional neuromuscular output path and directly collect and transmit neural activity signals through an electrode cap to a computer or other electronic devices for processing, directly recognizing the intention of the brain according to specific neural information responses, and then realizing direct interaction with the outside world. Brain-computer interfaces have become a frontier technology in the field of human-computer interaction and have great application potential in fields such as metaverse interaction and smart home. Electroencephalogram signals occupy a relatively important position among many electroencephalogram signals due to advantages such as low cost, non-invasiveness, and relatively low technical difficulty, mainly including electroencephalogram paradigms such as motor imagery, P300, and SSVEP. The collected electroencephalogram signals can be accurately decoded into corresponding external machine control commands through brain-computer interface technologies based on P300, SSVEP, or motor imagery, realizing in-depth interaction between the human brain and the machine.

[0003] Spatio-temporal coding metasurfaces, with their precise regulation of electromagnetic waves in the time and space dimensions and excellent ability for digital information processing, have inspired strong research interests among a large number of scientific researchers. Compared with traditional spatial modulation metasurfaces, spatio-temporal coding metasurfaces can generate a series of novel physical phenomena that are difficult to achieve under traditional technologies. More importantly, by using spatio-temporal coding metasurfaces, through a specially designed spatio-temporal coding matrix, the amplitude, phase, and polarization at different harmonic frequencies can be precisely controlled, providing new possibilities for developing more efficient and reliable advanced communication schemes.

[0004] In the past, the visual flicker stimuli of brain-computer interfaces were usually isolated from the backend information processing, and in-depth information processing and interaction in the electromagnetic field could not be achieved. The existing research on brain-computer metasurfaces has not deeply explored the fusion of metasurfaces and brain-computer interfaces. Only the electromagnetic waves are regulated in the spatial domain through brain-computer interface devices, and multi-dimensional regulation of electromagnetic waves has not been achieved. Summary of the Invention

[0005] Technical Problem: The purpose of the present invention is to design a fusion system of SSVEP visual stimulus coding and metasurface spatio-temporal coding to deeply explore the fusion of spatio-temporal metasurfaces and brain-computer interfaces. The designed system can not only provide visual flicker stimuli of different frequencies but also realize the regulation of harmonic beams in the electromagnetic domain, thus constructing an intelligent device system supporting wireless remote control and opening up a brand-new technical path for intelligent interaction and brain-computer communication.

[0006] Technical solution: To achieve the above object, a fusion system of SSVEP visual stimulus coding and metasurface spatio-temporal coding of the present invention adopts the following technical solutions:

[0007] The fusion system includes a brain-computer interface device based on SSVEP and a brain-computer spatio-temporal coding metasurface. The brain-computer spatio-temporal coding metasurface is composed of multiple brain-computer spatio-temporal coding metasurface units. The brain-computer spatio-temporal coding metasurface unit is composed of a spatio-temporal metasurface unit integrated with a light-emitting diode. Among them, the light-emitting diode provides an SSVEP visual stimulus signal with a specific frequency. The SSVEP visual stimulus signal is used to stimulate specific frequency electroencephalogram signals of the user's brain. The spatio-temporal metasurface unit is composed of a programmable unit integrated with a switching diode. The light-emitting diode and the switching diode of the brain-computer spatio-temporal coding metasurface unit use the same brain-computer spatio-temporal coding metasurface signal.

[0008] The brain-computer spatio-temporal coding metasurface signal is to fuse the spatio-temporal metasurface unit signal with a high switching frequency into the electroencephalogram stimulation signal with a low frequency flicker. The brain-computer spatio-temporal coding metasurface changes the switching states of the switching diode and the light-emitting diode according to the requirements of different visual stimulus flicker frequencies and different harmonic beams, regulates the electromagnetic responses of different spatio-temporal coding units to generate different harmonic beams, and at the same time provides an SSVEP visual stimulus signal with a corresponding flicker frequency. Finally, a brain wireless remote control intelligent device system is designed based on the brain-computer spatio-temporal coding metasurface, and the on-off state of the intelligent device is realized according to the brain intention.

[0009] It includes the following steps:

[0010] Step 1: The brain-computer interface user gazes at the light-emitting diodes with different flicker stimulation frequencies on the brain-computer spatio-temporal coding metasurface, and the user's brain generates corresponding SSVEP electroencephalogram signals. Then, the brain-computer interface device extracts the SSVEP electroencephalogram signals and classifies and identifies the electroencephalogram signals using a convolutional neural network.

[0011] Step 2: After sending the recognized SSVEP electroencephalogram signal result to the field programmable gate array, the designed spatio-temporal metasurface signal is fused into the high level of the flicker stimulation signal to form a brain-computer spatio-temporal metasurface signal.

[0012] Step 3: According to the brain-computer spatio-temporal metasurface signal, change the switching states of the switching diode and the light-emitting diode, regulate the electromagnetic wave to generate beams with different harmonic frequencies and harmonic directions, and at the same time provide an SSVEP flicker stimulation signal.

[0013] Step 4: After the receiving end receives the harmonic beam generated by the brain controlling the brain-computer spatio-temporal coding metasurface, it automatically controls the single-chip microcomputer to change the on-off state of the intelligent device.

[0014] The brain-computer spatio-temporal coding metasurface is composed of multiple spatio-temporal metasurface units. The spatio-temporal metasurface unit is composed of a programmable unit integrated with a switching diode. The spatio-temporal metasurface unit sequentially includes a first metal layer, a first dielectric layer, a second metal layer, an adhesive sheet layer, a third metal layer, a second dielectric layer, and a fourth metal layer arranged from top to bottom. A first metal pillar passing through the second metal layer connects the first metal layer and the third metal layer, a second metal pillar connects the first metal layer and the second metal layer, a third metal pillar passing through the second metal layer connects the fourth metal layer, and a fourth metal pillar passing through the second metal layer connects the third metal layer.

[0015] The brain-computer spatio-temporal coding metasurface unit integrates a light-emitting diode and two switching diodes. The two switching diodes are connected in series, and a programmable gate array provides the same time-varying signal to the light-emitting diode and the switching diodes of each brain-computer spatio-temporal coding metasurface unit.

[0016] The brain-computer spatio-temporal coding metasurface is divided into four metasurface partitions, and each metasurface partition provides different-frequency flicker stimulation signals: 8.5 Hz, 11.5 Hz, 10 Hz, and 7 Hz. Each partition generates harmonic beams pointing at 10°, 30°, -15°, and -45° respectively at the -2, -1, +1, and +2 harmonic frequencies.

[0017] The user uses the brain to control the brain-computer spatio-temporal coding metasurface to generate different harmonic beams, and then wirelessly remotely controls the states of intelligent devices at different positions.

[0018] Advantageous effects: Compared with the prior art, the present invention has the following advantages:

[0019] 1. By integrating the light-emitting diodes for SSVEP visual flicker stimulation on the spatio-temporal metasurface and fusing SSVEP visual stimulation coding and metasurface spatio-temporal coding, the present invention realizes both SSVEP visual stimulation and electromagnetic wave regulation on the same platform. This fusion enables the system not only to improve efficiency but also to regulate electromagnetic waves in the spatial and frequency domains.

[0020] 2. By using a programmable gate array to fuse SSVEP visual stimulation signals and spatio-temporal coding signals, the present invention is easy to implement different flicker stimulation frequencies and electromagnetic regulation, improving the efficiency of the system.

[0021] 3. The present invention divides the brain-computer spatio-temporal coding metasurface into four metasurface partitions. By independently designing and regulating the flicker frequency and electromagnetic function of each partition, the design flexibility and function diversity of the system are improved.

[0022] 4. The present invention does not require an external visual stimulus source, simplifies the device, reduces the connection of external devices, improves the compactness, mobility and reliability of the system, while reducing costs and complexity, has higher scalability and applicability, and is easy to implement.

[0023] 5. Through the brain-computer spatio-temporal coding metasurface, the present invention realizes the wireless control of remote intelligent devices by the brain, eliminates the traditional physical interaction method, improves the control efficiency and convenience, and provides an innovative solution for special scenarios such as medical rehabilitation, disability assistance and industrial automation. BRIEF DESCRIPTION OF THE DRAWINGS

[0024] Figure 1 It is a schematic diagram of the fusion coding of SSVEP visual stimulus coding and metasurface spatio-temporal coding;

[0025] Figure 2 It is a structural diagram of the brain-computer spatio-temporal coding metasurface unit; In the figure: the first metal layer 1, the first dielectric layer 2, the second metal layer 3, the adhesive sheet layer 4, the third metal layer 5, the second dielectric layer 6, the fourth metal layer 7, the first metal column 8, the second metal column 9, the third metal column 10, the fourth metal column 11.

[0026] Figure 3 It is a curve graph of the reflection amplitude of the brain-computer spatio-temporal coding metasurface unit changing with frequency;

[0027] Figure 4 It is a curve graph of the reflection phase of the brain-computer spatio-temporal coding metasurface unit changing with frequency;

[0028] Figure 5 It is a schematic diagram of the partition of the brain-computer spatio-temporal coding metasurface;

[0029] Figure 6 It is a distribution diagram of the spatio-temporal coding matrix of the brain-computer spatio-temporal coding sub-metasurface with a beam pointing of 10° at the -2nd harmonic frequency;

[0030] Figure 7 It is a distribution diagram of the spatio-temporal coding matrix of the brain-computer spatio-temporal coding sub-metasurface with a beam pointing of 30° at the -1st harmonic frequency;

[0031] Figure 8 It is a distribution diagram of the spatio-temporal coding matrix of the brain-computer spatio-temporal coding sub-metasurface with a beam pointing of -15° at the +1st harmonic frequency;

[0032] Figure 9 It is a distribution diagram of the spatio-temporal coding matrix of the brain-computer spatio-temporal coding sub-metasurface with a beam pointing of -45° at the +2nd harmonic frequency;

[0033] Figure 10 It is a schematic diagram of the brain-computer spatio-temporal coding metasurface control signal of the fusion of the 8.5Hz SSVEP visual flicker stimulus and the spatio-temporal coding M3;

[0034] Figure 11 Schematic diagram of the brain-computer spatio-temporal coding metasurface regulation signal integrating the SSVEP visual flicker stimulus at 11.5 Hz and spatio-temporal coding M2;

[0035] Figure 12 Schematic diagram of the brain-computer spatio-temporal coding metasurface regulation signal integrating the SSVEP visual flicker stimulus at 10 Hz and spatio-temporal coding M1;

[0036] Figure 13 Schematic diagram of the brain-computer spatio-temporal coding metasurface regulation signal integrating the SSVEP visual flicker stimulus at 7 Hz and spatio-temporal coding M4;

[0037] Figure 14 Schematic diagram of the SSVEP signal generated when the user gazes at different partitions of the brain-computer spatio-temporal coding metasurface;

[0038] Figure 15 Far-field pattern result of the brain-computer spatio-temporal coding sub-metasurface with a beam pointing direction of 10° at the -2nd harmonic frequency;

[0039] Figure 16 Far-field pattern result of the brain-computer spatio-temporal coding sub-metasurface with a beam pointing direction of 30° at the -1st harmonic frequency;

[0040] Figure 17 Far-field pattern result of the brain-computer spatio-temporal coding sub-metasurface with a beam pointing direction of -15° at the +1st harmonic frequency;

[0041] Figure 18 Far-field pattern result of the brain-computer spatio-temporal coding sub-metasurface with a beam pointing direction of -45° at the +2nd harmonic frequency;

[0042] Figure 19 Schematic diagram of the wireless remote control intelligent device system based on the brain-computer spatio-temporal coding metasurface;

[0043] Figure 20 Schematic diagram of the intelligent device experimental setup; Figure 20 In [a], it is a schematic diagram of the intelligent device experimental setup for wireless remote control; Figure 20 In [b], it is the schematic diagram of the radio frequency detector device; Figure 20 In [c], it is the curve of the output voltage of the radio frequency detector varying with the input power. Detailed implementation manners

[0044] The present invention will be further described below with reference to the accompanying drawings.

[0045] The present invention proposes a fusion system of SSVEP visual stimulation coding and metasurface spatio-temporal coding. The system consists of a brain-computer interface device based on SSVEP and a brain-computer spatio-temporal coding metasurface. By using a programmable gate array to fuse the visual flicker stimulation signal and the spatio-temporal coding metasurface signal, a brain-computer spatio-temporal coding metasurface that can simultaneously achieve visual stimulation and electromagnetic regulation can be realized. The brain-computer spatio-temporal metasurface is composed of 32×32 spatio-temporal metasurface units integrated with light-emitting diodes. The light-emitting diodes are used to provide SSVEP visual stimulation signals with specific frequencies. Each spatio-temporal metasurface unit integrates a switching diode, and the programmable gate array provides the same time-varying signals to the light-emitting diodes and switching diodes of the brain-computer spatio-temporal coding metasurface. The brain-computer user can generate SSVEP responses with different frequencies by gazing at the light-emitting diodes with different flicker stimulation frequencies on the brain-computer spatio-temporal coding metasurface. When the brain-computer interface device recognizes the corresponding SSVEP response instruction, the spatio-temporal coding is integrated into the flicker stimulation signal to form a brain-computer spatio-temporal coding metasurface signal. On the one hand, the brain-computer spatio-temporal coding metasurface signal provides flicker stimulation signals with different frequencies, and on the other hand, it controls the brain-computer spatio-temporal coding metasurface to regulate the harmonic frequency and beam direction of electromagnetic waves. Finally, a brain wireless remote control intelligent device system is designed based on the brain-computer spatio-temporal coding metasurface to realize the on-off state of intelligent devices in the far-field area according to the brain intention.

[0046] Figure 1 It is a schematic diagram of the fusion coding of SSVEP visual stimulation coding and metasurface spatio-temporal coding. The spatio-temporal metasurface unit loaded with a switching diode integrates a light-emitting diode for SSVEP visual flicker stimulation, forming a brain-computer spatio-temporal coding metasurface unit, and the brain-computer spatio-temporal coding metasurface is composed of 32×32 such units. Since the switching frequency of spatio-temporal coding is much higher than the frequency of visual flicker stimulation, by integrating the spatio-temporal metasurface signal into the SSVEP visual flicker stimulation signal, a brain-computer spatio-temporal coding metasurface signal is formed, thereby controlling the brain-computer spatio-temporal coding metasurface to simultaneously achieve different visual flicker stimulations and electromagnetic wave regulations.

[0047] Figure 2It is a structural diagram of a brain-machine spatio-temporal coding metasurface unit. The brain-machine spatio-temporal coding metasurface unit is composed of a programmable unit integrated with a switching diode and a light-emitting diode. The brain-machine spatio-temporal coding metasurface is composed of multiple spatio-temporal metasurface units. The spatio-temporal metasurface unit is composed of a programmable unit integrated with a switching diode. The spatio-temporal metasurface unit includes a first metal layer 1, a first dielectric layer 2, a second metal layer 3, an adhesive sheet layer 4, a third metal layer 5, a second dielectric layer 6, and a fourth metal layer 7 arranged in sequence from top to bottom. A first metal column 8 passing through the second metal layer 3 is used to connect the first metal layer 1 and the third metal layer 5, and a second metal column 9 connects the first metal layer 1 and the second metal layer 3. A third metal column 10 passing through the second metal layer 3 connects the fourth metal layer 7, and a fourth metal column 11 passing through the second metal layer 3 connects the third metal layer 5. The feeding of the switching diode and the light-emitting diode are connected together and use the same DC voltage signal. The first dielectric layer 2 and the second dielectric layer 6 are polytetrafluoroethylene substrates with thicknesses of 3 mm and 0.5 mm, model F4BM265, and relative dielectric constants of 2.65. The adhesive sheet layer 4 is an FR4 glass fiber epoxy resin substrate with a thickness of 0.2 mm and a relative dielectric constant of 4.4. The basic unit structure is square, and the side length of the unit is 19 mm. A 10 nH radio frequency inductor is welded at the position where the first metal layer 1 is connected to the DC bias line to isolate the radio frequency alternating current signal.

[0048] Figure 3 and Figure 4 It is a curve graph showing the variation of the reflection performance of the brain-machine spatio-temporal coding metasurface unit with frequency. The Figure 2 brain-machine spatio-temporal coding metasurface unit structure is simulated in a full-wave simulation software to verify its scattering characteristics. At about the designed center frequency of 6.9 GHz, the reflection phase difference between the two states of the unit switch reaches about 180°, and the reflection amplitude is greater than -1 dB, proving that the designed unit has excellent 1-bit phase modulation ability.

[0049] Figure 5 It is a schematic diagram of the partition of the brain-machine spatio-temporal coding metasurface. The entire brain-machine spatio-temporal coding metasurface is composed of 32×32 units and is divided into four partitions. Each partition sub-metasurface is composed of 16×16 units. Each partition provides visual flicker stimuli at different frequencies: 8.5 Hz, 11.5 Hz, 10 Hz, and 8 Hz. After identifying the corresponding electroencephalogram signals, the corresponding spatio-temporal coding signals are fused into the SSVEP visual flicker stimuli signals of different partitions through a programmable gate array to control the electromagnetic wave to generate different harmonic beams.

[0050] Figures 6 - 9Shows the spatio-temporal coding matrix distribution map of the brain-machine spatio-temporal coding sub-surface at the -2, -1, +1, and +2 order harmonic frequencies, where the harmonic beam directions are 10°, 30°, -15°, and -45°. Its dimension is (16, 16, 11), indicating that the partitioned sub-surface representing the brain-machine spatio-temporal coding super-surface contains 16×16 units, and the length of the time coding sequence for each unit is 11. The "0" and "1" coding blocks with different grayscales represent the off and on states of the unit switching diodes respectively.

[0051] Figures 10 - 13 Schematic diagram of the control signal of the brain-machine spatio-temporal coding super-surface for the fusion of SSVEP visual flicker stimulus signal and spatio-temporal coding. The switching frequency of the spatio-temporal coding is 1 kHz, which is much higher than the frequency of the visual flicker stimulus. Therefore, the periodic cyclic spatio-temporal codings M3, M2, M1, and M4 can be respectively fused into the visual flicker stimulus frequencies of 8.5 Hz, 11.5 Hz, 10 Hz, and 7 Hz to control different partitioned sub-surfaces of the brain-machine spatio-temporal coding super-surface to generate specified harmonic beams.

[0052] Figure 14 Schematic diagram of the SSVEP signals generated when the user gazes at different partitions of the brain-machine spatio-temporal coding super-surface respectively. When the user gazes at different partitions of the brain-machine spatio-temporal coding super-surface respectively, corresponding raw electroencephalogram (EEG) signals will be generated. The raw EEG signals of the user are collected through a brain-machine interface device and are preprocessed through operations such as filtering, downsampling, and normalization. Strong resonance peaks can be clearly observed in the preprocessed SSVEP signals at 8.5 Hz, 11.5 Hz, 10 Hz, and 7 Hz. By extracting the characteristic data in the SSVEP EEG signals, recognition and classification can be achieved using the convolutional neural network algorithm.

[0053] Figures 15 - 18 Is the far-field pattern result of different partitions of the brain-machine spatio-temporal coding super-surface. The far-field pattern of Figures 6 - 9 can be obtained through numerical calculation, and then the super-surface is actually tested in a far-field microwave anechoic chamber. The sub-surfaces of different partitions of the brain-machine spatio-temporal coding super-surface can respectively control the harmonic beam directions to be 10°, 30°, -15°, and -45° at the -2, -1, +1, and +2 order harmonic frequencies. The measured results are in good agreement with the numerical simulation results, proving that the brain-machine spatio-temporal coding super-surface can achieve electromagnetic wave regulation.

[0054] Figures 19 - 20 Schematic diagram of the wireless remote control intelligent device system based on the brain-machine spatio-temporal coding super-surface. The whole system consists of a brain-machine interface device and a brain-machine spatio-temporal coding super-surface. An incident electromagnetic wave with a single tone frequency of 6.9 GHz is emitted through a horn antenna connected to a signal source to excite the brain-machine coding super-surface. The receiving end is connected by four receiving horn antennas Figure 20An experimental device for an intelligent device a, the experimental device includes a detector, a single-chip microcomputer and an intelligent device (LED lamp), where the schematic diagram of the radio frequency detector is as Figure 20 shown in b, which can convert radio frequency energy into DC voltage. The change of the output voltage of the radio frequency detector with the input power is as Figure 20 shown in c. Four receiving horn antennas are respectively placed in the directions of 10°, 30°, -15° and -45° to receive different harmonic beam energies. Once the user's electroencephalogram signal is recognized, the sub-surfaces of the corresponding partition of the brain-computer spatio-temporal metasurface are controlled to generate specified harmonic beams. After the horn antennas at the specified positions receive the beam energy, the intelligent device can be directly turned on through the constructed experimental device.

[0055] The above is only the preferred implementation mode of the present invention. Since the design idea of the present invention is clear and the application prospect is wide, the same concept can be extended to the terahertz, infrared and visible light bands. It should be pointed out that for those of ordinary skill in the art, without departing from the principle of the present invention, several improvements and retouches can be made, and these improvements and retouches should also be regarded as the protection scope of the present invention.

Claims

1. A fusion system of SSVEP visual stimulus coding and metasurface spatio-temporal coding, characterized in that: The fusion system includes a brain-computer interface device based on SSVEP and a brain-computer spatio-temporal coding metasurface. The brain-computer spatio-temporal coding metasurface is composed of multiple brain-computer spatio-temporal coding metasurface units. The brain-computer spatio-temporal coding metasurface unit is composed of a spatio-temporal metasurface unit integrated with a light-emitting diode. Among them, the light-emitting diode provides an SSVEP visual stimulus signal with a specific frequency. The SSVEP visual stimulus signal is used to stimulate specific frequency electroencephalogram signals of the user's brain. The spatio-temporal metasurface unit is composed of a programmable unit integrated with a switching diode. The light-emitting diode and the switching diode of the brain-computer spatio-temporal coding metasurface unit use the same brain-computer spatio-temporal coding metasurface signal.

2. The fusion system of SSVEP visual stimulation coding and metasurface spatio-temporal coding according to claim 1, characterized in that: The brain-computer spatio-temporal coding metasurface signal is to fuse the spatio-temporal metasurface unit signal with a high switching frequency into the low-frequency flashing electroencephalogram stimulation signal; according to the requirements of different visual stimulus flashing frequencies and different harmonic beams, the brain-computer spatio-temporal coding metasurface changes the switching states of the switching diode and the light-emitting diode with the brain-computer spatio-temporal coding metasurface signal, regulates the electromagnetic responses of different spatio-temporal coding units to generate different harmonic beams, and at the same time provides an SSVEP visual stimulus signal with the corresponding flashing frequency; finally, a brain wireless remote control intelligent device system is designed based on the brain-computer spatio-temporal coding metasurface, and the on-off state of the intelligent device is realized according to the brain intention.

3. A fusion system of SSVEP visual stimulus coding and metasurface spatio-temporal coding according to claim 1 or 2, characterized in that: It includes the following steps: Step 1: The brain-computer interface user gazes at the light-emitting diodes with different flashing stimulus frequencies on the brain-computer spatio-temporal coding metasurface, and the user's brain generates corresponding SSVEP electroencephalogram signals. Then, the brain-computer interface device extracts the SSVEP electroencephalogram signals and classifies and identifies the electroencephalogram signals using a convolutional neural network. Step 2: After sending the recognized SSVEP electroencephalogram signal result to the field programmable gate array, fuse the designed spatio-temporal metasurface signal into the high level of the flashing stimulus signal to form a brain-computer spatio-temporal metasurface signal. Step 3: According to the brain-computer spatio-temporal metasurface signal, change the switching states of the switching diode and the light-emitting diode, regulate the electromagnetic wave to generate beams with different harmonic frequencies and harmonic directions, and at the same time provide an SSVEP flashing stimulus signal. Step 4: After the receiving end receives the harmonic beam generated by the brain controlling the brain-computer spatio-temporal coding metasurface, automatically control the single-chip microcomputer to change the on-off state of the intelligent device.

4. The fusion system of SSVEP visual stimulation coding and metasurface spatio-temporal coding according to claim 3, characterized in that: The brain-computer spatio-temporal coding metasurface is composed of multiple spatio-temporal metasurface units. The spatio-temporal metasurface unit is composed of a programmable unit integrated with a switching diode. The spatio-temporal metasurface unit sequentially includes a first metal layer (1), a first dielectric layer (2), a second metal layer (3), an adhesive sheet layer (4), a third metal layer (5), a second dielectric layer (6), and a fourth metal layer (7) arranged in order from top to bottom. A first metal pillar (8) passing through the second metal layer (3) connects the first metal layer (1) and the third metal layer (5), a second metal pillar (9) connects the first metal layer (1) and the second metal layer (3), a third metal pillar (10) passing through the second metal layer (3) connects the fourth metal layer (7), and a fourth metal pillar (11) passing through the second metal layer (3) connects the third metal layer (5).

5. The fusion system of SSVEP visual stimulus coding and metasurface spatio-temporal coding according to claim 4, characterized in that: The brain-computer spatio-temporal coding metasurface unit integrates a light-emitting diode and two switching diodes. The two switching diodes are connected in series, and a programmable gate array provides the same time-varying signal to the light-emitting diode and the switching diodes of each brain-computer spatio-temporal coding metasurface unit.

6. The fusion system of SSVEP visual stimulus coding and metasurface spatio-temporal coding according to claim 5, characterized in that: The brain-computer spatio-temporal coding metasurface is divided into four metasurface partitions, and each metasurface partition provides different frequency flashing stimulation signals: 8.5 Hz, 11.5 Hz, 10 Hz, and 7 Hz. Each partition generates harmonic beams pointing at 10°, 30°, -15°, and -45° at the -2, -1, +1, and +2 order harmonic frequencies respectively.

7. The fusion system of SSVEP visual stimulation coding and metasurface spatio-temporal coding according to claim 6, characterized in that: The user uses the brain to control the brain-computer spatio-temporal coding metasurface to generate different harmonic beams, and then wirelessly remotely controls the states of intelligent devices at different positions.

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