Optical camera communication system based on orbital angular momentum beams combined with deep learning

Abstract

Disclosed is an optical camera communication system based on orbital angular momentum beams combined with deep learning, comprising: a transmitting-end device and a receiving-end device. The transmitting-end device encodes communication data using topological charges and radial indices to generate and transmit a Laguerre-Gaussian beam with a corresponding flower-shaped mode. The receiving-end device, optically connected to the transmitting-end device, performs image recognition on a flower-shaped mode pattern of the Laguerre-Gaussian beam and correspondingly decodes it to obtain decoded data equivalent to the communication data.

Claims

1. An optical camera communication system based on conjugate superposition orbital angular momentum beams and deep learning, used for optical communication of multi-bit communication data using a single orbital angular momentum beam. The optical camera communication system includes: a transmitting end mechanism comprising a data encoding device, a spatial light modulation device, and a light source. The data encoding device is configured to convert the communication data into flower-shaped feature information according to a preset encoding correspondence between the arrangement of topological charge parameters and radial exponent parameters of the Laguerre-Gaussian mode and numerical encoding. The spatial light modulation device is connected to the data encoding device and the optical path is connected to the light source. The spatial light modulation device is configured to modulate a beam provided by the light source into a Laguerre-Gaussian beam with a flower-shaped mode having topological charge parameters and radial exponent parameters corresponding to the flower-shaped feature information, using a conjugate superposition method, as the single orbital angular momentum beam. The transmitter is transmitted; and a receiver is optically connected to the transmitter, the receiver including an optical camera and a deep learning demodulation device. The optical camera is configured to receive the single-beam orbital angular momentum beam transmitted by the transmitter and to capture a flower-shaped modal image of the Laguerre-Gaussian beam from the single-beam orbital angular momentum beam. The deep learning demodulation device is connected to the optical camera and is configured to perform image recognition on the flower-shaped modal image using a trained deep learning image recognition model to obtain the corresponding topological charge parameter and radial exponent parameter, so as to decode the data equivalent to the communication data by means of the encoding comparison relationship.

2. The optical camera communication system as described in claim 1, wherein the communication data of multiple bits is 5 bits of data.

3. The optical camera communication system as described in claim 1 or 2, wherein in the data encoding device, the encoding correspondence is a correspondence between 32 of the 33 permutations of the topological charge parameters being ±1, ±2, ±3, ±4, ±5, ±6, ±7, ±8, ±9, ±10, and ±11 and the radial exponent parameters being 0, 1, and 2, and the 5-bit numerical encoding.

4. The optical camera communication system as described in claim 1, wherein the spatial light modulation device comprises: The system comprises a first polarizer, a spatial light modulator, a beam splitter, and a second polarizer. The light source is optically connected to the spatial light modulator via the first polarizer, and the spatial light modulator is optically connected to the second polarizer via the beam splitter. The light beam provided by the light source is projected onto the spatial light modulator in parallel alignment via the first polarizer, and the Laguerre-Gaussian beam is generated by reflection through the grating pattern of the spatial light modulator. The Laguerre-Gaussian beam is then emitted as a single-beam orbital angular momentum beam after passing through the beam splitter and the second polarizer.

5. The optical camera communication system as claimed in claim 4, wherein the spatial light modulation device further includes a first concave lens and a first convex lens, the optical path being connected between the first polarizer and the spatial light modulator for parallel beam expansion and calibration, and the spatial light modulation device further includes a second convex lens, the optical path being connected between the beam splitter and the second polarizer for focusing the Laguerre-Gaussian beam.

6. The optical camera communication system as claimed in claim 4, wherein the spatial light modulator modulates the light beam provided by the light source by means of a fork grating obtained by interfering an orbital angular momentum phase diagram with a blazed grating.

7. The optical camera communication system as described in claim 1, wherein the optical camera device is a charge-coupled device.

8. The optical camera communication system as claimed in claim 1, wherein the deep learning demodulation device is an image recognition device for performing image recognition using the deep learning image recognition model of YOLOv8.

9. The optical camera communication system as claimed in claim 1 further includes a pre-encoding device connected to the data encoding device, the pre-encoding device being configured to convert raw data into communication data of multiple bits.

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