Optical image processing system and method based on terahertz diffraction

Abstract

The application provides an optical image processing system and method based on terahertz diffraction, and the system comprises: a terahertz source for emitting terahertz waves; a terahertz lens for transmitting the terahertz waves to a terahertz modulation diffraction plate; an optical imaging device for imaging a target to be imaged to the terahertz modulation diffraction plate; the terahertz modulation diffraction plate is used for modulating and diffracting the transmitted terahertz waves according to the target imaging light field, obtaining n beams of terahertz waves with different powers; a terahertz detection device is used for converting the n beams of terahertz waves into n electric signals respectively, and is also used for realizing identification and classification of the target to be imaged according to the n electric signals. The application can solve the technical problem that the optical-electric-optical conversion of the optical diffraction network model in the prior art leads to high system complexity and cost, and large volume and power consumption in optical image processing.

Description

Technical Field

[0001] This invention relates to the fields of all-optical computational processing and image recognition technology, and in particular to an optical image processing system and method based on terahertz diffraction. Background Technology

[0002] In recent years, with the rapid development of the internet and artificial intelligence technologies, machine learning algorithms, represented by artificial neural networks, have achieved tremendous success in fields such as image processing, speech recognition, and natural language processing. These powerful algorithms require high-performance hardware support. Currently, the development of hardware based on electronic computing has deviated from Moore's Law and is struggling to meet the demands of future advanced algorithm deployments in terms of computing power and power consumption. Combining the wide bandwidth and high parallelism of optical signals, photonic neural network technology has been proposed, promising to achieve high-speed, low-power, high-performance computing and meet the needs of artificial intelligence technology development.

[0003] A diffraction neural network, designed based on the principle of optical diffraction and combining it with deep learning methods, is a type of photonic neural network. This network maps the weight parameters and biases of conventional neurons to the transmission or reflection coefficients of an optical system, and the trained transmission or reflection system is etched onto a diffraction plate. In the specific recognition process, the data to be identified or processed is first modulated onto a coherent beam. After passing through multiple levels of diffraction plates, the coherent light exits from corresponding directions and is detected. Different exit directions and orientations represent different data categories, thus achieving data classification. However, this process requires the data, especially data obtained through optical imaging, to be converted from photoelectric signals to electrical signals. These electrical signals are then used to modulate the coherent light, extending the processing chain and adding optical-to-electrical and electro-optical conversion devices, significantly increasing system complexity, cost, size, and power consumption. Summary of the Invention

[0004] This invention provides an optical image processing system and method based on terahertz diffraction, which can solve the technical problems of high system complexity, cost, size and power consumption caused by the optical-electrical-optical conversion of optical diffraction network models in optical image processing.

[0005] According to one aspect of the present invention, an optical image processing system based on terahertz diffraction is provided, the system comprising:

[0006] Terahertz source, used to emit terahertz waves;

[0007] Terahertz lenses are used to transmit terahertz waves onto a terahertz modulation diffraction plate.

[0008] An optical imaging device used to image a target onto a terahertz modulation diffraction plate;

[0009] Terahertz modulation diffraction plate is used to modulate and diffract the transmitted terahertz wave according to the target imaging light field to obtain n terahertz waves with different powers.

[0010] The terahertz detection device is used to convert n terahertz waves into n electrical signals, and also to identify and classify the target to be imaged based on the n electrical signals.

[0011] Preferably, the centers of the terahertz source, the terahertz lens, and the terahertz modulation diffraction plate are located on the same optical axis.

[0012] Preferably, the terahertz modulation diffraction plate includes a modulation plate, a first diffraction plate, and a second diffraction plate arranged sequentially at intervals along the terahertz wave optical path. The modulation plate is used to modulate the transmitted terahertz wave according to the target imaging light field; the first diffraction plate is used to perform a first diffraction on the modulated terahertz wave; and the second diffraction plate is used to perform a second diffraction on the terahertz wave after the first diffraction to obtain n terahertz waves with different powers.

[0013] Preferably, the centers of the modulation plate, the first diffraction plate, and the second diffraction plate are located on the same optical axis.

[0014] Preferably, the modulation board uses a semiconductor silicon wafer for visible light imaging and a semiconductor mercury cadmium telluride material for infrared light imaging.

[0015] Preferably, the first diffraction plate has a specific thickness pattern, and the second diffraction plate has a specific thickness pattern.

[0016] Preferably, both the first diffraction plate and the second diffraction plate are made of plastic material.

[0017] Preferably, the terahertz detection device includes n terahertz detectors and a processing unit. The n terahertz detectors correspond one-to-one with n terahertz waves. Each terahertz detector is used to convert a terahertz wave into an electrical signal. The processing unit is used to identify and classify the target to be imaged based on the n electrical signals.

[0018] Preferably, the center of each terahertz detector coincides with the optical axis of the corresponding terahertz wave.

[0019] Preferably, the terahertz wave spot completely covers the spot of the target to be imaged.

[0020] Preferably, the terahertz source is a terahertz source based on electronic frequency doubling.

[0021] Preferably, the terahertz lens adopts a plano-convex or biconvex structure.

[0022] According to another aspect of the present invention, an optical image processing method based on terahertz diffraction is provided, the method employing any of the systems described above for image processing, the method comprising:

[0023] Terahertz sources emit terahertz waves;

[0024] The terahertz lens transmits terahertz waves onto the terahertz modulation diffraction plate;

[0025] The optical imaging device images the target onto a terahertz modulation diffraction plate;

[0026] The terahertz modulation diffraction plate modulates and diffracts the transmitted terahertz waves according to the target imaging light field, resulting in n terahertz waves with different powers.

[0027] The terahertz detection device converts n terahertz waves into n electrical signals, and uses these n electrical signals to identify and classify the target to be imaged.

[0028] By applying the technical solution of this invention, based on the principles of optical diffraction, terahertz modulation, and artificial neural networks, the target to be imaged is directly modulated onto a terahertz wave and split by a diffraction plate, so that the diffracted terahertz waves converge at different positions, realizing all-optical computation for image classification processing. While maintaining the system's recognition accuracy, this greatly reduces the system's complexity, cost, size, and power consumption, and improves the overall system performance. Attached Figure Description

[0029] The accompanying drawings, which form part of this specification, are provided to further illustrate embodiments of the invention and, together with the textual description, explain the principles of the invention. It is obvious that the drawings described below are merely some embodiments of the invention, and those skilled in the art can obtain other drawings based on these drawings without any creative effort.

[0030] Figure 1 A schematic diagram of the structure of an optical image processing system based on terahertz diffraction according to an embodiment of the present invention is shown;

[0031] Figure 2 It shows Figure 1 A schematic diagram of the structure of the diffraction plate.

[0032] The above figures include the following reference numerals:

[0033] 1. Terahertz source; 2. Terahertz lens; 3. Terahertz modulation diffraction plate; 3-1. Modulation plate; 3-2. First diffraction plate; 3-3. Second diffraction plate; 4. Optical imaging device; 5. Terahertz detection device; 5-1 to 5-n. Terahertz detector. Detailed Implementation

[0034] It should be noted that, unless otherwise specified, the embodiments and features described in this application can be combined with each other. The technical solutions of the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only a part of the embodiments of the present invention, and not all of them. The following description of at least one exemplary embodiment is merely illustrative and is in no way intended to limit the present invention or its application or use. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention.

[0035] It should be noted that the terminology used herein is for the purpose of describing particular embodiments only and is not intended to limit the exemplary embodiments according to this application. As used herein, the singular form is intended to include the plural form as well, unless the context clearly indicates otherwise. Furthermore, it should be understood that when the terms "comprising" and / or "including" are used in this specification, they indicate the presence of features, steps, operations, devices, components, and / or combinations thereof.

[0036] Unless otherwise specifically stated, the relative arrangement, numerical expressions, and values ​​of the components and steps set forth in these embodiments do not limit the scope of the invention. It should also be understood that, for ease of description, the dimensions of the various parts shown in the drawings are not drawn to actual scale. Techniques, methods, and devices known to those skilled in the art may not be discussed in detail, but where appropriate, such techniques, methods, and devices should be considered part of the specification. In all examples shown and discussed herein, any specific values ​​should be interpreted as merely exemplary and not as limitations. Therefore, other examples of exemplary embodiments may have different values. It should be noted that similar reference numerals and letters in the following figures denote similar items; therefore, once an item is defined in one figure, it need not be further discussed in subsequent figures.

[0037] like Figure 1 As shown, the present invention provides an optical image processing system based on terahertz diffraction, the system comprising:

[0038] Terahertz source 1, used to emit terahertz waves;

[0039] Terahertz lens 2 is used to transmit terahertz waves onto terahertz modulation diffraction plate 3;

[0040] Optical imaging device 4 is used to image the target to be imaged onto terahertz modulation diffraction plate 3;

[0041] Terahertz modulation diffraction plate 3 is used to modulate and diffract the transmitted terahertz wave according to the target imaging light field to obtain n terahertz waves with different powers.

[0042] The terahertz detection device 5 is used to convert n terahertz waves into n electrical signals respectively, and is also used to identify and classify the target to be imaged based on the n electrical signals.

[0043] Based on the principles of optical diffraction, terahertz modulation, and artificial neural networks, this invention directly modulates the target to be imaged onto a terahertz wave and splits the beam through a diffraction plate, causing the diffracted terahertz waves to converge at different positions. This enables all-optical computation for image classification processing, which greatly reduces system complexity, cost, size, and power consumption while maintaining the system's recognition accuracy, thereby improving the overall system performance.

[0044] In this invention, the centers of the terahertz source 1, the terahertz lens 2, and the terahertz modulation diffraction plate 3 are located on the same optical axis.

[0045] According to one embodiment of the present invention, the terahertz modulation diffraction plate 3 includes a modulation plate 3-1, a first diffraction plate 3-2, and a second diffraction plate 3-3 arranged sequentially at intervals along the terahertz wave optical path. In this case, the target to be imaged is projected onto the surface of the modulation plate 3-1, and the terahertz wave is irradiated onto the surface of the modulation plate 3-1 through a terahertz lens 2. The modulation plate 3-1 is used to modulate the transmitted terahertz wave according to the target imaging light field; the first diffraction plate 3-2 is used to perform a first diffraction on the modulated terahertz wave; this first diffraction... Plate 3-2 has a specific thickness pattern, which is obtained through training. After the terahertz wave is diffracted once, it propagates freely in space for a certain distance and then enters the second diffraction plate 3-3. The second diffraction plate 3-3 is used to perform secondary diffraction on the terahertz wave after the first diffraction to obtain n terahertz waves with different powers. The second diffraction plate 3-3 has a specific thickness pattern, which is obtained through training. The centers of the modulation plate 3-1, the first diffraction plate 3-2 and the second diffraction plate 3-3 are located on the same optical axis.

[0046] Specifically, the modulation plate 3-1 uses a semiconductor silicon wafer for visible light imaging and a semiconductor mercury cadmium telluride material for infrared light imaging. The modulation principle of the modulation plate 3-1 is as follows: when the modulation plate 3-1 is irradiated by the target imaging light field, the valence electrons of the semiconductor material in the corresponding irradiated area are excited to the conduction band, becoming photogenerated carriers. This causes the corresponding area to change from an insulating state to a metallic state. These semiconductor materials in the metallic state reduce the transmittance of the corresponding area to terahertz waves. Thus, when the modulation plate 3-1 is irradiated by the target imaging light field, the concentration of photogenerated carriers generated at different light intensities is different, and the terahertz transmittance is also different. In this way, the spatial modulation of terahertz waves by the target imaging light field is achieved through the modulation plate 3-1.

[0047] Specifically, both the first diffraction plate 3-2 and the second diffraction plate 3-3 are made of plastic material. The first diffraction plate 3-2 and the second diffraction plate 3-3 have similar structures, such as... Figure 2 As shown, it can be divided into N×M regions, and each region (i,j) has the same thickness d. i,j Furthermore, since the thickness varies in different regions, the phase of the terahertz wave transmitted through each region is affected by the different thicknesses d. i,j Modulation. According to Huygens' principle, any point (region) on the diffraction plate can be considered a secondary wave source. The wavefront of the terahertz wave after passing through the diffraction plate is the envelope of the emitted wavelets from these secondary wave sources. The terahertz wave modulated by modulation plate 3-1 is diffracted by the first diffraction plate 3-2 and the second diffraction plate 3-3, and then converges at different positions. The number of convergence positions, n, is set to be greater than the number of target image categories to be imaged.

[0048] According to one embodiment of the present invention, the terahertz detection device 5 includes n terahertz detectors and a processing unit. The n terahertz detectors correspond one-to-one with n terahertz waves. Each terahertz detector is used to convert a terahertz wave into an electrical signal. The processing unit is used to identify and classify the target to be imaged based on the n electrical signals.

[0049] Specifically, the n terahertz detectors can be room-temperature terahertz detectors such as Gore-Ley detectors. A terahertz detector is placed at each possible terahertz convergence point behind the diffraction plate to detect the terahertz wave at that location, and finally image recognition is achieved based on the detection results.

[0050] According to one embodiment of the present invention, the center of each terahertz detector coincides with the optical axis of the corresponding terahertz wave.

[0051] According to one embodiment of the present invention, the terahertz wave spot completely covers the spot of the target to be imaged. By setting the system parameters of the optical imaging device 4, the imaging is located at the center of the modulation plate 3-1, wherein the optical imaging device 4 uses existing mature components.

[0052] According to one embodiment of the present invention, the terahertz source 1 is an electronically frequency-doubled terahertz source 1. The frequency of the electronically frequency-doubled terahertz source 1 can be selected from 0.3THz to 1THz to have good monochromaticity and a certain power.

[0053] According to one embodiment of the present invention, the terahertz lens 2 is used to adjust the divergence angle of the terahertz wave. The terahertz lens 2 adopts a plano-convex or biconvex structure so that the terahertz wave irradiates the modulation plate 3-1 at a smaller emission angle.

[0054] The present invention also provides an optical image processing method based on terahertz diffraction, wherein the method uses any of the above-described systems for image processing, and the method includes:

[0055] Terahertz Source 1 emits terahertz waves;

[0056] Terahertz lens 2 transmits terahertz waves onto terahertz modulation diffraction plate 3;

[0057] The optical imaging device 4 images the target to be imaged onto the terahertz modulation diffraction plate 3;

[0058] The terahertz modulation diffraction plate 3 modulates and diffracts the transmitted terahertz waves according to the target imaging light field to obtain n terahertz waves with different powers.

[0059] The terahertz detection device 5 converts n terahertz waves into n electrical signals, and uses the n electrical signals to identify and classify the target to be imaged.

[0060] In summary, this invention provides an optical image processing system and method based on terahertz diffraction. According to the principles of optical diffraction, terahertz modulation, and artificial neural network mechanisms, the target to be imaged is directly modulated onto a terahertz wave and split by a diffraction plate, so that the diffracted terahertz waves converge at different positions, realizing all-optical computation for image classification processing. While maintaining the system's recognition accuracy, it greatly reduces the system's complexity, cost, size, and power consumption, thereby improving the overall system performance.

[0061] The parts of this invention not described in detail are techniques known to those skilled in the art.

[0062] In the description of this invention, it should be understood that the orientation or positional relationship indicated by directional terms such as "front, back, up, down, left, right", "horizontal, vertical, horizontal" and "top, bottom" is generally based on the orientation or positional relationship shown in the accompanying drawings, and is only for the convenience of describing this invention and simplifying the description. Unless otherwise stated, these directional terms do not indicate or imply that the device or element referred to must have a specific orientation or be constructed and operated in a specific orientation, and therefore should not be construed as a limitation on the scope of protection of this invention; the directional terms "inner" and "outer" refer to the inner and outer contours relative to the outline of each component itself.

[0063] For ease of description, spatial relative terms such as "above," "on top of," "on the upper surface of," "above," etc., are used herein to describe the spatial positional relationship of a device or feature as shown in the figures to other devices or features. It should be understood that spatial relative terms are intended to encompass different orientations in use or operation beyond the orientation of the device as described in the figures. For example, if the device in the figures were inverted, a device described as "above" or "on top of" other devices or structures would subsequently be positioned as "below" or "under" other devices or structures. Thus, the exemplary term "above" can include both "above" and "below." The device may also be positioned in other different ways (rotated 90 degrees or in other orientations), and the spatial relative descriptions used herein will be interpreted accordingly.

[0064] Furthermore, it should be noted that the use of terms such as "first" and "second" to define components is merely for the purpose of distinguishing the corresponding components. Unless otherwise stated, the above terms have no special meaning and therefore should not be construed as limiting the scope of protection of this invention.

[0065] The above description is merely a preferred embodiment of the present invention and is not intended to limit the invention. Various modifications and variations can be made to the present invention by those skilled in the art. Any modifications, equivalent substitutions, improvements, etc., made within the spirit and principles of the present invention should be included within the scope of protection of the present invention.

Claims

1. An optical image processing system based on terahertz diffraction, characterized in that, The system includes: Terahertz source, used to emit terahertz waves; Terahertz lenses are used to transmit terahertz waves onto a terahertz modulation diffraction plate. An optical imaging device used to image a target onto a terahertz modulation diffraction plate; Terahertz modulation diffraction plate is used to modulate and diffract the transmitted terahertz wave according to the target imaging light field to obtain n terahertz waves with different powers. The terahertz detection device is used to convert n terahertz waves into n electrical signals, and also to identify and classify the target to be imaged based on the n electrical signals.

2. The system according to claim 1, characterized in that, The centers of the terahertz source, the terahertz lens, and the terahertz modulation diffraction plate are located on the same optical axis.

3. The system according to claim 1 or 2, characterized in that, The terahertz modulation diffraction plate includes a modulation plate, a first diffraction plate, and a second diffraction plate arranged sequentially at intervals along the terahertz wave optical path. The modulation plate is used to modulate the transmitted terahertz wave according to the target imaging light field. The first diffraction plate is used to perform a first diffraction on the modulated terahertz wave. The second diffraction plate is used to perform a second diffraction on the terahertz wave after the first diffraction to obtain n terahertz waves with different powers.

4. The system according to claim 3, characterized in that, The centers of the modulation plate, the first diffraction plate, and the second diffraction plate are located on the same optical axis.

5. The system according to claim 3, characterized in that, The modulation board uses a semiconductor silicon wafer for visible light imaging and a semiconductor mercury cadmium telluride material for infrared light imaging.

6. The system according to claim 3, characterized in that, The first diffraction plate has a specific thickness pattern, and the second diffraction plate has a specific thickness pattern.

7. The system according to claim 6, characterized in that, Both the first diffraction plate and the second diffraction plate are made of plastic.

8. The system according to claim 1, characterized in that, The terahertz detection device includes n terahertz detectors and a processing unit. The n terahertz detectors correspond one-to-one with n terahertz waves. Each terahertz detector is used to convert a terahertz wave into an electrical signal. The processing unit is used to identify and classify the target to be imaged based on the n electrical signals.

9. The system according to claim 8, characterized in that, The center of each terahertz detector is aligned with the optical axis of the corresponding terahertz wave.

10. The system according to claim 1, characterized in that, The terahertz wave spot completely covers the spot of the target to be imaged.

11. The system according to claim 1, characterized in that, The terahertz source is a terahertz source based on electronic frequency doubling.

12. The system according to claim 1, characterized in that, The terahertz lens adopts a plano-convex or biconvex structure.

13. An optical image processing method based on terahertz diffraction, characterized in that, The method employs the system described in any one of claims 1-12 for image processing, and the method includes: Terahertz sources emit terahertz waves; The terahertz lens transmits terahertz waves onto the terahertz modulation diffraction plate; The optical imaging device images the target onto a terahertz modulation diffraction plate; The terahertz modulation diffraction plate modulates and diffracts the transmitted terahertz waves according to the target imaging light field, resulting in n terahertz waves with different powers. The terahertz detection device converts n terahertz waves into n electrical signals, and uses these n electrical signals to identify and classify the target to be imaged.

Images