Micro-light night vision camera halo test device and test method
By using a low-light night vision camera halo testing device and method, and employing halogen tungsten lamp light source and precision motion control to simulate different focal lengths and fields of view, the problem of high cost and poor compatibility of traditional testing methods is solved, and efficient halo testing is achieved.
Patent Information
- Application Number
- CN202411712586.4
- Authority / Receiving Office
- CN · China
- Patent Type
- Patents(China)
- Current Assignee / Owner
- Filing Date
- 2024-11-27
- Publication Date
- 2026-05-15
- Estimated Expiration
- 2044-11-27
AI Technical Summary
Traditional low-light night vision camera halo detection methods require specialized darkrooms and large-size target plates, which are costly and cannot simultaneously meet the detection needs of different focal lengths and fields of view, resulting in low testing efficiency.
A low-light night vision camera halo testing device is used, including a halogen tungsten lamp light source, an adjustable aperture, an integrating sphere, a switchable reticle, and an adjustable focus collimator. Through precise motion control and image processing, halo tests are simulated for different focal lengths and fields of view.
It improves testing efficiency, reduces system size and construction costs, and enhances the testing capabilities for low-light night vision cameras with different focal lengths and fields of view.
Smart Images
Figure CN119788838B_ABST
Abstract
Description
Technical Field
[0001] This invention belongs to the technical field of night vision detection imaging, and particularly relates to a halo testing device and method for low-light night vision cameras. Background Technology
[0002] Pilot night vision systems are widely used on platforms such as fighter jets, helicopters, bombers, and drones. As the eyes of the aircraft platform, these systems effectively enhance pilots' ability to fly and perform combat missions in low-light conditions such as dusk, dawn, moonlight, and starlight, thereby improving the night vision and night combat capabilities of combat aircraft. Low-light night vision cameras, as a crucial component of pilot night vision systems, utilize the night light spectrum reflected from targets and backgrounds, including moonlight, starlight, and atmospheric glow. Through low-light sensors, they perform photoelectric conversion and enhancement processing, outputting video signals to the display system, enabling pilots to detect and identify targets and backgrounds. However, when low-light night vision cameras are in use, if the captured image contains high-brightness targets such as city lights or interfering light sources, the camera may experience localized oversaturation of charge. This excess charge overflows and affects surrounding pixels, producing a halo effect. This negatively impacts the low-light night vision camera's ability to detect and identify targets; therefore, it is necessary to test and analyze the halo effect of low-light night vision cameras.
[0003] Traditional halo detection methods require the construction of specialized darkrooms and large-sized transmission targets, each requiring a uniformly sized illumination source. This results in high system construction costs and a large footprint. Furthermore, due to laboratory size limitations, accurate focusing is impossible for low-light night vision cameras with large relative apertures and long close-up distances; and for low-light night vision cameras with excessively wide field of view, the field of view may not be filled. Therefore, highly integrated methods and equipment are needed that have low requirements for laboratory lighting conditions and strong compatibility with testing low-light night vision cameras of different focal lengths and fields of view, leading to reduced efficiency in night vision camera halo testing. Summary of the Invention
[0004] In view of this, the low-light night vision camera halo testing device and testing method provided by the present invention improve testing efficiency, reduce the overall system size and construction cost, and improve the testing capability for low-light night vision cameras with different focal lengths and fields of view.
[0005] A halo testing device for low-light night vision cameras is provided, which performs halo testing on low-light night vision cameras as the test object. The device includes a light source, an adjustable aperture, an integrating sphere, a switchable reticle, and an adjustable-focus collimator.
[0006] The light source is a halogen tungsten lamp light source, and the light source is processed by an adjustable aperture and an integrating sphere in sequence before illuminating the switchable reticle. The adjustable aperture is used to adjust the luminous flux of the light source, and the adjusted light source is processed by the integrating sphere for uniform light treatment.
[0007] The switchable reticle includes a focus test target plate and an adjustable rectangular aperture target plate, as well as a CNC motor and a guide rail. The focus test target plate is used to assist the test piece in focusing, and the adjustable rectangular aperture target plate is used to dynamically simulate the target source during halo testing.
[0008] The CNC motor and guide rail are described. The focusing test target plate and the adjustable rectangular aperture target plate are adjacent to each other and movably mounted on the guide rail. The output end of the CNC motor is connected to both the focusing test target plate and the adjustable rectangular aperture target plate, enabling the focusing test target plate and the adjustable rectangular aperture target plate to switch positions on the guide rail. The CNC motor is controlled by a controller. The light source transmits light to the adjustable focus collimator through the switchable reticle.
[0009] The switchable reticle is located at the focal plane of the adjustable focus collimator. The adjustable focus collimator collimates or projects the target source of the focusing test target plate and the adjustable rectangular aperture target plate into parallel light. The parallel light is transmitted to the test object. The adjustable focus collimator can be focused along the optical axis of the adjustable focus collimator to transmit the target source of the focusing test target plate and the adjustable rectangular aperture target plate to different distances to simulate targets at different object distances.
[0010] The light outlet of the adjustable-focus parallel light tube is mechanically connected to the dark box.
[0011] Secondly, a testing method for the halo effect of low-light night vision cameras is provided, using the aforementioned low-light night vision camera halo testing device. The testing method includes...
[0012] Step 1: Install the test piece in the dark box, align the lens end of the test piece with the light outlet of the adjustable focus collimator, connect the test piece to the controller, and connect the controller to the light source, adjustable aperture, integrating sphere, switchable reticle and adjustable focus collimator respectively.
[0013] Step 2: Switch to the focus test target plate, the controller acquires the image captured by the test piece, and adjusts the size of the adjustable aperture opening to a preset range so that the image of the test piece is not overexposed, and the adjustable collimator is used for focusing to adjust the clarity of the image captured by the test piece.
[0014] Step 3: Switch the focus test target to the adjustable rectangular aperture target, and adjust the rectangular window or light aperture of the adjustable rectangular aperture target to the preset magnification of the image captured by the test according to the parameters of the test part;
[0015] Step 4: Adjust the luminous flux of the light source through the adjustable aperture until the halo signal intensity at the boundary of the adjustable rectangular aperture target plate is a preset percentage of the white signal at the adjustable rectangular aperture target plate, and record the illuminance L1 of the integrating sphere; an illuminance meter is installed at a preset position of the integrating sphere, and the collected value of the illuminance meter is fed back to the controller.
[0016] Step 5: Reduce the opening size of the adjustable aperture until the white signal of the image of the adjustable rectangular aperture target plate captured by the test object drops to 100%, and record the illuminance L2 of the integrating sphere.
[0017] Step 6: Calculate the actual halo value of the test piece based on the values of illuminance L1 and illuminance L2, and output the result.
[0018] The beneficial effects of the present invention are as follows:
[0019] To address the shortcomings of traditional halo detection methods, such as high requirements for laboratory lighting environment, large footprint, and inability to simultaneously test telephoto and wide-angle cameras, this paper provides a halo testing device and method for visible light-near infrared digital cameras based on precision motion control, optical target simulation, and image processing technologies. This method can improve testing efficiency, reduce the overall system size and construction cost, and enhance the testing capability for low-light night vision cameras with different focal lengths and fields of view. Attached Figure Description
[0020] To more clearly illustrate the technical solutions of the embodiments of this disclosure, the drawings used in the embodiments will be briefly introduced below. Obviously, the drawings described below are only some embodiments of this disclosure. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.
[0021] Figure 1 This is a schematic diagram of the structure of the present invention;
[0022] Figure 2 This is a schematic diagram of the focusing test target plate of the switchable reticle of the present invention;
[0023] Figure 3 This is a schematic diagram of the adjustable rectangular aperture target plate with switchable reticle of the present invention. Detailed Implementation
[0024] The embodiments of this disclosure will now be described in detail with reference to the accompanying drawings.
[0025] The following specific examples illustrate the implementation of this disclosure. Those skilled in the art can easily understand other advantages and effects of this disclosure from the content disclosed in this specification. Obviously, the described embodiments are only a part of the embodiments of this disclosure, and not all of them. This disclosure can also be implemented or applied through other different specific embodiments, and the details in this specification can also be modified or changed based on different viewpoints and applications without departing from the spirit of this disclosure. It should be noted that, in the absence of conflict, the following embodiments and features in the embodiments can be combined with each other. Based on the embodiments in this disclosure, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of this disclosure.
[0026] It should be noted that various aspects of embodiments within the scope of the appended claims are described below. It will be apparent that the aspects described herein can be embodied in a wide variety of forms, and any particular structure and / or function described herein is merely illustrative. Based on this disclosure, those skilled in the art will understand that one aspect described herein can be implemented independently of any other aspect, and two or more of these aspects can be combined in various ways. For example, any number of aspects set forth herein can be used to implement the device and / or practice the method. Additionally, this device and / or method can be implemented using other structures and / or functionalities besides one or more of the aspects set forth herein.
[0027] like Figures 1 to 3 The low-light night vision camera halo testing device shown uses a low-light night vision camera as the test object to perform halo testing. It includes a light source, an adjustable aperture, an integrating sphere, a switchable reticle, and an adjustable-focus collimator.
[0028] The light source is a halogen tungsten lamp with a color temperature of 3100K±100K. The light source is processed by an adjustable aperture and an integrating sphere in sequence and then illuminates a switchable reticle. The adjustable aperture is used to adjust the luminous flux of the light source, and the adjusted light source is processed by the integrating sphere for homogenization.
[0029] The switchable reticle includes a focusing test target plate and an adjustable rectangular aperture target plate, a CNC motor, and a guide rail. The focusing test target plate assists in focusing the part under test (DUT), while the adjustable rectangular aperture target plate serves as the target source for dynamically simulating halo testing; for example, it can be an adjustable rectangular window or a light-transmitting aperture. The focusing test target plate and the adjustable rectangular aperture target plate are mounted adjacently and movably on the guide rail. The output of the linear CNC motor is connected to both the focusing test target plate and the adjustable rectangular aperture target plate, enabling them to switch positions on the guide rail. This allows for switching between assisting in focusing the DUT and serving as the target source for dynamically simulating halo testing. Alternatively, a rotary switching method or other switching methods can be used. The CNC motor is controlled by a controller, and the light source transmits light to the adjustable-focus collimator through the switchable reticle.
[0030] The switchable reticle is located at the focal plane of the adjustable-focus collimator. The adjustable-focus collimator collimates or projects the target source of the focusing test target plate and the adjustable rectangular aperture target plate into parallel light. The parallel light is transmitted to the test object. In actual use, the test object is placed in a dark box to prevent ambient light from interfering with the parallel light or the testing process. The adjustable-focus collimator includes a set of focusing lenses. The focusing lenses can focus along the optical axis of the adjustable-focus collimator to transmit the target source of the focusing test target plate and the adjustable rectangular aperture target plate to different distances to simulate targets at different object distances.
[0031] The light outlet of the adjustable-focus collimator is connected to the mechanical light of the dark box.
[0032] like Figures 2 to 3 The low-light night vision camera halo test method shown uses the aforementioned low-light night vision camera halo test device. The test method includes,
[0033] Step 1: Install the test piece in the dark box, align the lens end of the test piece with the light outlet of the adjustable focus collimator, connect the test piece to the controller, and connect the controller to the light source, adjustable aperture, integrating sphere, switchable reticle and adjustable focus collimator respectively.
[0034] Step 2: Switch to the focus test target plate. The controller acquires the image captured by the device under test and adjusts the size of the adjustable aperture to a preset range (the preset range value is determined according to the model and characteristics of the device under test) so that the image of the device under test (e.g., a low-light night vision camera) is not overexposed, and the adjustable collimator is used for focusing to adjust the clarity of the image captured by the device under test.
[0035] Step 3: Switch the focus test target to the adjustable rectangular aperture target, and adjust the rectangular window or light aperture of the adjustable rectangular aperture target to 0.3 times the size of the image captured by the test device according to the parameters of the test device;
[0036] Step 4: Adjust the luminous flux emitted from the light source onto the adjustable rectangular aperture target plate by adjusting the adjustable aperture until the signal intensity at the white signal boundary of the adjustable rectangular aperture target plate captured by the test object is 50% of that at the white signal boundary of the adjustable rectangular aperture target plate (the brightness of the target plate boundary is half that of its central area), and record the illuminance L1 of the integrating sphere; an illuminance meter is installed at a preset position on the integrating sphere, and the illuminance meter's collected value is fed back to the controller;
[0037] Step 5: Reduce the opening of the adjustable aperture until the signal intensity at the white signal point of the adjustable rectangular aperture target plate captured by the test piece drops to 100%, that is, the image at the white signal point of the adjustable rectangular aperture target plate is just not overexposed, and record the illuminance L2 of the integrating sphere.
[0038] Step 6: Calculate the actual halo value of the test piece based on the values of illuminance L1 and illuminance L2, and output the result.
[0039] For example
[0040] Step 1: Install the low-light night vision camera under test in a dark box, align the lens end with the light output port of the adjustable focus collimator, and connect the low-light night vision camera to the computer with a data cable;
[0041] Step 2: Start the lower-level machines such as the light source controller, light source, and illuminance meter through the computer's built-in testing software;
[0042] Step 3: Switch the switchable reticle to the focus test target plate. Use a computer to capture the image of the focus test target plate taken by the low-light night vision camera, calculate the gray value of the white area of the image, and determine whether the image is overexposed. If it is overexposed, control the adjustable aperture to reduce the size of the adjustable aperture opening. If the image is too dark, control the adjustable aperture to increase the size of the adjustable aperture opening, so that the image is in a better exposure state. The switchable reticle includes an adjustable rectangular aperture target plate. The target plate is opaque around the edges and has a rectangular light-passing hole in the center. The horizontal and vertical dimensions of the rectangular light-passing hole can be adjusted independently.
[0043] Step 4: Adjust the focus state of the adjustable collimator by using the focus controller to simulate different object distances, collect images captured by the low-light night vision camera in real time, calculate the edge sharpness of the image, determine whether the image is in the best focus state, and repeatedly adjust until the image reaches the best focus state.
[0044] Step 6: Switch the switchable reticle to the adjustable rectangular aperture target plate using the reticle controller, calculate the size of the rectangular light-transmitting area of the rectangular aperture target plate captured by the low-light night vision camera, and adjust the horizontal and vertical opening sizes of the rectangular aperture so that the horizontal size of the opening in the image is 0.3 times the total horizontal pixels and the vertical size is 0.3 times the total vertical pixels.
[0045] Step 7: Control the size of the adjustable aperture opening through the light source controller, acquire images from the low-light night vision camera in real time, calculate the gray value of the halo image at the boundary of the central light-transmitting area of the adjustable rectangular aperture target plate through software to be 50% of the central light-transmitting area, and acquire the illuminance value L1 of the light-emitting surface of the integrating sphere at this time as monitored by the illuminance probe through the illuminance meter.
[0046] Step 8: Reduce the size of the adjustable aperture opening by using the light source controller, and collect images from the low-light night vision camera in real time, so that the gray value of the central light-transmitting area of the adjustable rectangular aperture target plate is lower than 100%. Then increase the size of the adjustable aperture opening so that the gray value of the central light-transmitting area of the adjustable rectangular aperture target plate is exactly 100%. Collect the current illuminance L2 of the integrating sphere using a lux meter.
[0047] Step 9: Quantify the camera's halo value using the following formula, expressed as:
[0048]
[0049] To address the shortcomings of traditional halo detection methods, such as high requirements for laboratory lighting environment, large footprint, and inability to simultaneously detect telephoto and wide-angle cameras, this paper proposes a method based on precision motion control, optical target simulation, and image processing technologies. This method improves testing efficiency, reduces the overall system size and construction costs, and enhances the testing capabilities for low-light night vision cameras with different focal lengths and fields of view.
[0050] The above are merely specific embodiments of this disclosure, but the scope of protection of this disclosure is not limited thereto. Any variations or substitutions that can be easily conceived by those skilled in the art within the scope of the technology disclosed in this disclosure should be included within the scope of protection of this disclosure. Therefore, the scope of protection of this disclosure should be determined by the scope of the claims.
Claims
1. A halo testing device for low-light night vision cameras, used as the test piece to perform halo testing, characterized in that, It includes a light source, an adjustable aperture, an integrating sphere, a switchable reticle, and an adjustable-focus collimator, among which, The light source is a halogen tungsten lamp light source, and the light source is processed by an adjustable aperture and an integrating sphere in sequence before illuminating the switchable reticle. The adjustable aperture is used to adjust the luminous flux of the light source, and the adjusted light source is processed by the integrating sphere for uniform light treatment. The switchable reticle includes a focus test target plate and an adjustable rectangular aperture target plate, as well as a CNC motor and a guide rail. The focus test target plate is used to assist the test piece in focusing. The adjustable rectangular aperture target plate is used to dynamically simulate the target source during halo testing. The adjustable rectangular aperture target plate is opaque around its perimeter and has a rectangular light-transmitting hole in the center. The horizontal and vertical dimensions of the rectangular light-transmitting hole can be adjusted independently. The CNC motor and guide rail are described. The focusing test target plate and the adjustable rectangular aperture target plate are adjacent to each other and movably mounted on the guide rail. The output end of the CNC motor is connected to both the focusing test target plate and the adjustable rectangular aperture target plate, enabling the focusing test target plate and the adjustable rectangular aperture target plate to switch positions on the guide rail. The CNC motor is controlled by a controller. The light source transmits light to the adjustable focus collimator through the switchable reticle. The switchable reticle is located at the focal plane of the adjustable focus collimator. The adjustable focus collimator collimates or projects the target source of the focusing test target plate and the adjustable rectangular aperture target plate into parallel light. The parallel light is transmitted to the test object. The adjustable focus collimator can be focused along the optical axis of the adjustable focus collimator to transmit the target source of the focusing test target plate and the adjustable rectangular aperture target plate to different distances to simulate targets at different object distances. The light outlet of the adjustable-focus parallel light tube is mechanically connected to the dark box.
2. The low-light night vision camera halo testing device according to claim 1, characterized in that, The color temperature of the light source is 3100K±100K.
3. A method for testing the halo effect of a low-light night vision camera, characterized in that, Using the low-light night vision camera halo testing device as described in claim 1 or 2, the testing method includes... Step 1: Install the test piece in the dark box, align the lens end of the test piece with the light outlet of the adjustable focus collimator, connect the test piece to the controller, and connect the controller to the light source, adjustable aperture, integrating sphere, switchable reticle and adjustable focus collimator respectively. Step 2: Switch to the focusing test target plate. The controller acquires the image captured by the device under test and adjusts the size of the adjustable aperture to a preset range so that the image of the device under test is not overexposed. The adjustable collimator is used for focusing to adjust the sharpness of the image captured by the device under test. The luminous flux of the light source is adjusted through the adjustable aperture so that the halo signal intensity at the boundary of the adjustable rectangular aperture target plate is 50% of the white signal intensity at the adjustable rectangular aperture target plate. Step 3: Switch the focus test target to the adjustable rectangular aperture target, and adjust the rectangular window or light aperture of the adjustable rectangular aperture target to the preset magnification of the image captured by the test according to the parameters of the test part; Step 4: Adjust the luminous flux emitted from the light source to the adjustable rectangular aperture target plate by adjusting the adjustable aperture until the signal intensity at the white signal boundary of the adjustable rectangular aperture target plate captured by the test device is 50% of that at the white signal of the adjustable rectangular aperture target plate, and record the illuminance L1 of the integrating sphere. Step 5: Reduce the opening of the adjustable aperture until the signal intensity at the white signal point of the adjustable rectangular aperture target plate captured by the test piece drops to 100%, ensuring that the image at the white signal point of the adjustable rectangular aperture target plate is not overexposed, and record the illuminance L2 of the integrating sphere. Step 6: Calculate the actual halo value of the test piece based on the values of illuminance L1 and illuminance L2, and output the result.
4. The test method according to claim 3, characterized in that, Adjust the rectangular window or light aperture of the adjustable rectangular aperture target plate to 0.3 times the size of the image captured by the device under test, based on the parameters of the device under test.