Light detection device, method and radar system
By introducing an addressable aperture stop and an aperture controller into the photoelectric detection device, the position of the aperture's light-passing hole is controlled to block noise signals, thus solving the problem of low signal-to-noise ratio in the photoelectric detection scheme and achieving an improvement in signal-to-noise ratio.
Patent Information
- Authority / Receiving Office
- CN · China
- Patent Type
- Patents(China)
- Current Assignee / Owner
- HANGZHOU HIKVISION DIGITAL TECHNOLOGY CO LTD
- Filing Date
- 2021-06-09
- Publication Date
- 2026-05-19
AI Technical Summary
In applications such as lidar, photoelectric detection schemes suffer from low system signal-to-noise ratios, mainly because the background light across the entire field of view is received by the photoelectric detector, resulting in a poor ratio of useful signal to noise.
An addressable aperture stop and an aperture stop controller are used. By controlling the position of the light-passing aperture of the addressable aperture stop, it is made to allow only the echo signal of the scanning signal to pass through, while blocking noise signals and improving the signal-to-noise ratio.
Without altering the original structure of the photoelectric detection device, the signal-to-noise ratio of the photoelectric detection scenario was significantly improved, enhancing the detection effect.
Smart Images
Figure CN115453494B_ABST
Abstract
Description
Technical Field
[0001] This application relates to the field of photoelectric detection technology, and in particular to photoelectric detection devices, methods and radar systems. Background Technology
[0002] In applications such as lidar, to detect a large field of view, photoelectric detection schemes can deploy a large area of photodetectors on the detection focal plane. Here, when the scanning beam of the photoelectric detection scheme detects a location within the field of view, the echo signal from the local field of view currently scanned by the beam and the background light from the entire field of view are simultaneously received by the photodetector. The ratio of the echo signal (useful signal) from the local field of view to the background light (noise) from the entire field of view determines the signal-to-noise ratio (SNR) of the system. Because the background light from the entire field of view is received by the photodetector, the photoelectric detection scheme suffers from a low SNR. Summary of the Invention
[0003] This application proposes new optical detection devices, methods, and radar systems that can improve the detection signal-to-noise ratio.
[0004] According to one aspect of this application, a light detection device is provided, comprising:
[0005] Photodetector;
[0006] An addressable aperture stop is disposed in front of the photosensitive surface of the photodetector. The position of the light-transmitting aperture of the addressable aperture stop is controllable, and the area outside the light-transmitting aperture of the addressable aperture stop blocks light.
[0007] Aperture controller, used for:
[0008] The arrival position of the echo signal of the scanning signal on the photosensitive surface is determined based on the angle of the scanning signal of the field of view.
[0009] The addressable aperture stop is controlled to align the light-transmitting aperture with the arrival position of the echo signal on the photosensitive surface, so that the addressable aperture stop only allows the echo signal of the scanning signal to pass through.
[0010] In some embodiments, the aperture controller performs the operation of determining the arrival position of the echo signal of the scanning signal on the photosensitive surface based on the angle of the scanning signal of the field of view in the following manner:
[0011] Based on the angle of the scanning signal, the angle of the echo signal is determined, wherein the angle of the echo signal includes a first angle component and a second angle component. The first angle component is the angle between the projection of the echo signal onto a first plane and the optical axis, and the second angle component is the angle between the projection of the echo signal onto a second plane and the optical axis. The first plane is the common plane of the optical axis and the first coordinate axis of the target coordinate system, and the second plane is the common plane of the optical axis and the second coordinate axis of the target coordinate system. The target coordinate system is a two-dimensional coordinate system located at the focal plane, and the photosensitive surface is located at the focal plane. Based on the focal length of the lens module and the angle of the echo signal, the arrival position of the echo signal on the photosensitive surface is determined.
[0012] In some embodiments, the aperture controller performs the operation of determining the arrival position of the echo signal on the photosensitive surface based on the focal length of the lens module and the angle of the echo signal in the following manner:
[0013] Determine the product of the tangent of the first angular component and the focal length, and use it as the first coordinate component of the echo signal in the target coordinate system;
[0014] Determine the product of the tangent of the second angular component and the focal length, and use it as the second coordinate component of the echo signal in the target coordinate system.
[0015] In some embodiments, the aperture controller performs the operation of aligning the aperture of the addressable aperture stop with the arrival position of the echo signal on the photosensitive surface in the following manner:
[0016] Based on the arrival position of the echo signal on the photosensitive surface, the light transmission position on the addressable aperture stop is determined, so that the light transmission aperture is aligned with the arrival position.
[0017] In some embodiments, the addressable aperture stop is a liquid crystal light valve in a two-dimensional array.
[0018] In some embodiments, the addressable aperture stop includes a mirror array and a microelectromechanical system (MEMS), wherein the MEMS controls the position of the light-transmitting aperture in the mirror array.
[0019] In some embodiments, the light detection device further includes a scanner for emitting a scanning signal.
[0020] In some embodiments, the aperture controller is further configured to: control the size of the aperture of the addressable aperture stop according to a predetermined size of the aperture.
[0021] According to one aspect of this application, a light detection method is provided, applied to a light detection device. An addressable aperture stop is disposed before the photodetector of the light detection device. The position of the light-transmitting aperture of the addressable aperture stop is controllable, and the area outside the light-transmitting aperture of the addressable aperture stop blocks light. The light detection method includes:
[0022] The arrival position of the echo signal of the scanning signal on the photosensitive surface is determined based on the angle of the scanning signal of the field of view.
[0023] The addressable aperture stop is controlled to align the light-transmitting aperture with the arrival position of the echo signal on the photosensitive surface, so that the addressable aperture stop only allows the echo signal of the scanning signal to pass through.
[0024] According to one aspect of this application, a radar system is provided, including a light detection device according to an embodiment of this application.
[0025] In summary, the photoelectric detection scheme according to the embodiments of this application, through the addressable aperture stop and aperture controller, can control the position of the light-transmitting hole in the addressable aperture stop according to the angle of the scanning signal, thereby enabling the photodetector to receive only the echo signal of the scanning signal and not the noise signal blocked by the aperture stop. Based on this, the photoelectric detection scheme of the embodiments of this application can improve the detection signal-to-noise ratio in photoelectric detection scenarios. Furthermore, it should be noted that, since the photoelectric detection scheme of the embodiments of this application can easily improve the photoelectric detection device and achieve an improved signal-to-noise ratio without modifying the original structure of the photoelectric detection device, simply by configuring the addressable aperture stop and aperture controller. Attached Figure Description
[0026] Figure 1 A schematic diagram of an Internet of Things (IoT) system according to some embodiments of this application is shown;
[0027] Figure 2 A schematic diagram of a photoelectric detection device according to some embodiments of this application is shown;
[0028] Figure 3 A schematic diagram of a photoelectric detection scenario according to some embodiments of this application is shown;
[0029] Figure 4 A schematic diagram showing the arrival of echo signals at a photodetector according to some embodiments of this application is illustrated;
[0030] Figure 5 A flowchart of a photoelectric detection method 500 according to some embodiments of this application is shown;
[0031] Figure 6 A flowchart of a method 600 for determining the position of an echo signal on a photosensitive surface according to some embodiments of this application is shown;
[0032] Figure 7 A flowchart of a photoelectric detection method 700 according to some embodiments of this application is shown. Detailed Implementation
[0033] To make the objectives, technical solutions, and advantages of this application clearer, the following detailed description is provided with reference to the accompanying drawings and embodiments.
[0034] Figure 1 A schematic diagram illustrating application scenarios according to some embodiments of this application is shown.
[0035] Figure 1 The illustrated photoelectric detection device includes a photodetector 101 and a lens module 102. The photodetector 101 can receive light signals within a field of view 103. When applied to radar and other applications, the photoelectric detection device can be connected via a scanner (…). Figure 1 (Not shown) A scanning signal is emitted to the field of view 103. Here, the scanning signal is, for example, a laser beam. The echo signal 104 of the scanning signal can reach the photodetector 101. In addition, background signals (which can be considered as noise signals) other than the echo signal within the field of view 103 can also reach the photodetector 101.
[0036] In order to improve the signal-to-noise ratio when the photoelectric detection device receives signals, this application proposes a new photoelectric detection device.
[0037] Figure 2 A schematic diagram of a photoelectric detection device according to some embodiments of this application is shown.
[0038] like Figure 2 As shown, the photoelectric detection device 200 includes a photoelectric detector 201, an addressable aperture stop 202, and an aperture stop controller 203.
[0039] An addressable aperture stop 202 is positioned in front of the photosensitive surface of the photodetector 201. The position of the aperture of the addressable aperture stop is controllable. The area outside the aperture of the addressable aperture stop blocks light. In other words, the addressable aperture stop only allows light to pass through the aperture. An addressable aperture stop is a component whose aperture position is controllable, enabling light to pass through a specified location while blocking light from other locations. The photosensitive surface is the photosensitive surface of the photodetector 201.
[0040] The aperture controller 203 determines the arrival position of the echo signal of the scanning signal on the photosensitive surface based on the angle of the scanning signal in the field of view. Based on this, the aperture controller 203 can control the aperture of the addressable aperture to align with the arrival position of the echo signal on the photosensitive surface, ensuring that the addressable aperture allows only the echo signal of the scanning signal to pass through. Here, the aperture controller 203 can also block light signals in the area of the addressable aperture 202 other than the aperture. In this way, the addressable aperture 202 can block noise signals within the field of view.
[0041] In summary, the photoelectric detection device according to the embodiments of this application, through an addressable aperture stop and an aperture controller, can control the position of the light-transmitting aperture in the addressable aperture stop according to the angle of the scanning signal, thereby enabling the photoelectric detector to receive only the echo signal of the scanning signal and not the noise signal blocked by the aperture stop. Based on this, the photoelectric detection device of the embodiments of this application can improve the detection signal-to-noise ratio in photoelectric detection scenarios. Furthermore, it should be noted that the photoelectric detection device of the embodiments of this application can be easily improved by configuring an addressable aperture stop and an aperture controller without modifying the original structure of the photoelectric detection device, thereby achieving an improved signal-to-noise ratio.
[0042] Figure 3 A schematic diagram of a photoelectric detection scenario according to some embodiments of this application is shown.
[0043] like Figure 3 As shown, the addressable aperture stop 202 is arranged parallel to the photodetector 201. The gap between the addressable aperture stop 202 and the photodetector is small. In addition, the size of the addressable aperture stop 202 is not smaller than the size of the photodetector 101.
[0044] The photodetector 201 can detect the light intensity of the optical signal on the photosensitive surface and convert it into the output electrical signal intensity. Here, the size of the photosensitive surface is denoted as l*h (length*width), and the field of view that the photodetector 200 can detect is:
[0045] Horizontal field of view
[0046] Vertical field of view
[0047] In some embodiments, the photodetector 200 further includes a scanner. The scanner can emit a scanning signal. For example, the scanner can emit a laser beam toward the field of view 205. The echo signal of the scanner is, for example, 206. The echo signal 206 reaches the photodetector 201 after passing through the lens module 204 and the light-passing aperture of the addressable aperture stop 202.
[0048] In some embodiments, the aperture controller 203 can determine the light transmission position on the addressable aperture aperture based on the arrival position of the echo signal on the photosensitive surface, so that the light transmission hole is aligned with the arrival position.
[0049] In some embodiments, to determine the arrival position of the echo signal on the photosensitive surface, the aperture controller 203 can determine the angle of the echo signal based on the angle of the scanning signal. Here, the direction of the echo signal is opposite to the direction of the scanning signal, and they can be considered to be on the same straight line. For example Figure 4 A schematic diagram of the echo signal arriving at the photodetector according to some embodiments of this application is shown.
[0050] like Figure 4 As shown, the echo signal reaches the focal plane after passing through the optical center of the lens module. The focal plane is the plane where the photosensitive surface of the photodetector is located. The angle of the echo signal includes a first angular component and a second angular component. The first angular component is the angle between the projection of the echo signal onto the first plane and the optical axis, and the second angular component is the angle between the projection of the echo signal onto the second plane and the optical axis. The first plane is the common plane of the optical axis and the first coordinate axis of the target coordinate system, and the second plane is the common plane of the optical axis and the second coordinate axis of the target coordinate system. The target coordinate system is a two-dimensional coordinate system located at the focal plane. For example, Figure 4 The first angular component u and the second angular component v are shown. Based on this, the aperture controller 203 can determine the arrival position 207 of the echo signal on the photosensitive surface according to the focal length of the lens module and the angle of the echo signal. This arrival position 207 can be represented, for example, as coordinates (x, y) in the target coordinate system XOY.
[0051] In some embodiments, the aperture controller 203 determines the product of the tangent of the first angular component and the focal length, and uses it as the first coordinate component of the echo signal in the target coordinate system. Additionally, the aperture controller 203 determines the product of the tangent of the second angular component and the focal length, and uses it as the second coordinate component of the echo signal in the target coordinate system. For example, the aperture controller 203 can determine the arrival position (x, y) of the echo signal on the photosensitive surface according to the following formula:
[0052] x = f * tan(u)
[0053] y = f * tan(v)
[0054] Based on this, the aperture controller 203 can control the aperture of the addressable aperture stop 202 to align with the arrival position (x, y), so that the echo signal can be projected onto the arrival position (x, y) on the photodetector 201. Furthermore, the addressable aperture stop 202 can block background signals (i.e., noise signals) outside the echo signal within the field of view. In some embodiments, the aperture controller 203 can control the size of the aperture of the aperture stop according to a predetermined size. Here, the predetermined size of the aperture is consistent with the size of the spot area formed by the echo signal on the photosensitive surface. In some embodiments, the aperture controller 203 can be a computational control system composed of ARM, DSP, CPU, FPGA, ASIC, etc.
[0055] In some embodiments, the addressable aperture stop 202 is a liquid crystal light valve of a two-dimensional array. The aperture controller 203 can select a pixel at a specific position of the light valve, so that the light-passing aperture is at that specific position.
[0056] In some embodiments, the addressable aperture stop 202 includes a mirror array and a microelectromechanical system (MEMS). The MEMS controls the position of the light-transmitting apertures in the mirror array. For example, the aperture controller 203 controls the mirror angle of a mirror via the MEMS, such that when the normal of the mirror surface is perpendicular to the optical axis, the mirror surface of that mirror forms a light-transmitting aperture. Conversely, when the aperture controller 203 controls the normal of a mirror surface to be parallel to the optical axis, the mirror surface of that mirror blocks light passing through its location.
[0057] Figure 5 A flowchart of a photoelectric detection method 500 according to some embodiments of this application is shown. The photoelectric detection method 500 is applied to a light detection device. An addressable aperture stop is disposed before the photodetector of the light detection device. The position of the light-passing aperture of the addressable aperture stop is controllable. The area outside the light-passing aperture of the addressable aperture stop blocks light. The light detection device is, for example, a... Figure 2 200. The photoelectric detection method 500 can be executed, for example, in the aperture controller 203.
[0058] like Figure 5 As shown, in step S501, the arrival position of the echo signal of the scanning signal on the photosensitive surface is determined according to the angle of the scanning signal of the field of view. The photosensitive surface is the photosensitive surface of the photodetector.
[0059] In step S502, the light aperture of the addressable aperture is controlled to align with the arrival position of the echo signal on the photosensitive surface, so that the addressable aperture allows only the echo signal of the scanning signal to pass through.
[0060] In summary, the photoelectric detection scheme according to the embodiments of this application, through the addressable aperture stop and aperture controller, can control the position of the light-transmitting hole in the addressable aperture stop according to the angle of the scanning signal, thereby enabling the photodetector to receive only the echo signal of the scanning signal and not the noise signal blocked by the aperture stop. Based on this, the photoelectric detection scheme of the embodiments of this application can improve the detection signal-to-noise ratio in photoelectric detection scenarios. Furthermore, it should be noted that, since the photoelectric detection scheme of the embodiments of this application can easily improve the photoelectric detection device and achieve an improved signal-to-noise ratio without modifying the original structure of the photoelectric detection device, simply by configuring the addressable aperture stop and aperture controller.
[0061] In some embodiments, step S501 may be implemented as method 600.
[0062] like Figure 6 As shown, in step S601, the angle of the echo signal is determined based on the angle of the scanning signal. The angle of the echo signal includes a first angular component and a second angular component. The first angular component is the angle between the projection of the echo signal onto the first plane and the optical axis, and the second angular component is the angle between the projection of the echo signal onto the second plane and the optical axis. The first plane is the common plane of the optical axis and the first coordinate axis of the target coordinate system, and the second plane is the common plane of the optical axis and the second coordinate axis of the target coordinate system. The target coordinate system is a two-dimensional coordinate system located at the focal plane, and the photosensitive surface is located at the focal plane.
[0063] In step S602, the arrival position of the echo signal on the photosensitive surface is determined based on the focal length of the lens module and the angle of the echo signal. In some embodiments, step S602 may determine the product of the tangent of the first angular component and the focal length, and use it as the first coordinate component of the echo signal in the target coordinate system. Additionally, step S602 may determine the product of the tangent of the second angular component and the focal length, and use it as the second coordinate component of the echo signal in the target coordinate system.
[0064] In summary, method 600 can determine the angle of the echo signal based on the angle of the scanning signal, and then determine the arrival position of the echo signal on the photosensitive surface by combining the focal length.
[0065] Figure 7 A flowchart of a photoelectric detection method 700 according to some embodiments of this application is shown. The photoelectric detection method 700 is applied to a light detection device. An addressable aperture stop is disposed before the photodetector of the light detection device. The position of the light-passing aperture of the addressable aperture stop is controllable. The area outside the light-passing aperture of the addressable aperture stop blocks light. The light detection device is, for example, a... Figure 2 200. The photoelectric detection method 700 can be executed, for example, in the aperture controller 203.
[0066] like Figure 7 As shown, in step S701, the arrival position of the echo signal of the scanning signal on the photosensitive surface is determined according to the angle of the scanning signal of the field of view. The photosensitive surface is the photosensitive surface of the photodetector.
[0067] In step S702, the light aperture of the addressable aperture stop is controlled to align with the arrival position of the echo signal on the photosensitive surface.
[0068] In step S703, the size of the aperture stop is controlled according to the predetermined size of the aperture, so that the addressable aperture stop allows only the echo signal of the scanning signal to pass through. Here, the predetermined size of the aperture is consistent with the size of the spot area formed by the echo signal on the photosensitive surface.
[0069] In summary, the photoelectric detection scheme according to the embodiments of this application, through the addressable aperture stop and aperture controller, can control the position of the light-transmitting hole in the addressable aperture stop according to the angle of the scanning signal, thereby enabling the photodetector to receive only the echo signal of the scanning signal and not the noise signal blocked by the aperture stop. Based on this, the photoelectric detection scheme of the embodiments of this application can improve the detection signal-to-noise ratio in photoelectric detection scenarios. Furthermore, it should be noted that, since the photoelectric detection scheme of the embodiments of this application can easily improve the photoelectric detection device and achieve an improved signal-to-noise ratio without modifying the original structure of the photoelectric detection device, simply by configuring the addressable aperture stop and aperture controller.
[0070] The above description is merely a preferred embodiment of this application and is not intended to limit this application. Any modifications, equivalent substitutions, improvements, etc., made within the spirit and principles of this application should be included within the scope of protection of this application.
Claims
1. A light detection device, characterized in that, include: A photodetector is used to receive light signals within the field of view. An addressable aperture stop is disposed in front of the photosensitive surface of the photodetector. The addressable aperture stop is disposed parallel to the photodetector and adjacent to the photodetector. The size of the addressable aperture stop is not smaller than the size of the photodetector. The position of the light-passing aperture of the addressable aperture stop is controllable. The area outside the light-passing aperture of the addressable aperture stop blocks light. Aperture controller, used for: The arrival position of the echo signal of the scanning signal on the photosensitive surface is determined based on the angle of the scanning signal of the field of view. The addressable aperture stop is controlled to align the light-transmitting aperture of the addressable aperture stop with the position where the echo signal arrives on the photosensitive surface, so that the addressable aperture stop only allows the echo signal of the scanning signal to pass through, and blocks the noise signal in the field of view. The aperture controller dynamically adjusts the size of the light-transmitting aperture based on the preset spot size of the backlight angle corresponding to the current scanning angle. The aperture controller performs the operation of determining the arrival position of the echo signal of the scanning signal on the photosensitive surface based on the angle of the scanning signal of the field of view in the following manner: The angle of the echo signal is determined based on the angle of the scanning signal. The direction of the echo signal is opposite to the direction of the scanning signal. The angle of the echo signal includes a first angle component and a second angle component. The first angle component is the angle between the projection of the echo signal onto a first plane and the optical axis. The second angle component is the angle between the projection of the echo signal onto a second plane and the optical axis. The first plane is the common plane of the optical axis and the first coordinate axis of the target coordinate system. The second plane is the common plane of the optical axis and the second coordinate axis of the target coordinate system. The target coordinate system is a two-dimensional coordinate system located at the focal plane. The photosensitive surface is located at the focal plane. The arrival position of the echo signal on the photosensitive surface is determined based on the focal length of the lens module and the angle of the echo signal.
2. The optical detection device as described in claim 1, characterized in that, The aperture controller performs the operation of determining the arrival position of the echo signal on the photosensitive surface based on the focal length of the lens module and the angle of the echo signal in the following manner: Determine the product of the tangent of the first angular component and the focal length, and use it as the first coordinate component of the echo signal in the target coordinate system; Determine the product of the tangent of the second angular component and the focal length, and use it as the second coordinate component of the echo signal in the target coordinate system.
3. The optical detection device as described in claim 1, characterized in that, The aperture controller performs the operation of aligning the light passage of the addressable aperture aperture with the arrival position of the echo signal on the photosensitive surface in the following manner: Based on the arrival position of the echo signal on the photosensitive surface, the light transmission position on the addressable aperture stop is determined, so that the light transmission aperture is aligned with the arrival position.
4. The optical detection device as described in claim 1, characterized in that, The addressable aperture stop is a two-dimensional array of liquid crystal light valves.
5. The photodetector as described in claim 1, characterized in that, The addressable aperture stop includes a mirror array and a micro-motor system, wherein the micro-motor system controls the position of the light-transmitting aperture in the mirror array.
6. The photodetector as described in claim 1, characterized in that, Further includes: A scanner is used to send scan signals.
7. The optical detection device as described in claim 1, characterized in that, The aperture controller is further configured to: control the size of the aperture of the addressable aperture stop according to a predetermined size of the aperture.
8. A photodetector method, applied to a photodetector device, characterized in that, An addressable aperture stop is disposed before the photodetector of a light detection device. The photodetector is used to receive light signals within the field of view. The addressable aperture stop is disposed parallel to the photodetector and adjacent to the photodetector. The size of the addressable aperture stop is not smaller than the size of the photodetector. The position of the light-passing aperture of the addressable aperture stop is controllable. The area outside the light-passing aperture of the addressable aperture stop blocks light. The light detection device includes an aperture controller. The light detection method includes: The arrival position of the echo signal of the scanning signal on the photosensitive surface is determined based on the angle of the scanning signal of the field of view. The addressable aperture stop is controlled to align the light-transmitting aperture of the addressable aperture stop with the position where the echo signal arrives on the photosensitive surface, so that the addressable aperture stop only allows the echo signal of the scanning signal to pass through, and blocks the noise signal in the field of view. The aperture controller is used to dynamically adjust the size of the light aperture based on the preset spot size corresponding to the current scanning angle; in, The step of determining the arrival position of the echo signal of the scanning signal on the photosensitive surface based on the angle of the scanning signal of the field of view includes: The angle of the echo signal is determined based on the angle of the scanning signal. The direction of the echo signal is opposite to the direction of the scanning signal. The angle of the echo signal includes a first angle component and a second angle component. The first angle component is the angle between the projection of the echo signal onto a first plane and the optical axis. The second angle component is the angle between the projection of the echo signal onto a second plane and the optical axis. The first plane is the common plane of the optical axis and the first coordinate axis of the target coordinate system. The second plane is the common plane of the optical axis and the second coordinate axis of the target coordinate system. The target coordinate system is a two-dimensional coordinate system located at the focal plane. The photosensitive surface is located at the focal plane. The arrival position of the echo signal on the photosensitive surface is determined based on the focal length of the lens module and the angle of the echo signal.
9. A radar system, characterized in that, Includes the photodetector as described in any one of claims 1-7.