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What are the common types of zoom mechanisms and their advantages? 1. Slide transmission mechanism: This mechanism is simple in structure and compact in size. The slide matches the inner wall of the main lens tube with high-precision zoom. It can be designed into a multi-finger configuration for flexibility and can meet the design of multiple evenly distributed cam curve grooves. At the same time, both the slide and the main lens tube are made of industrial-grade hard aluminum, with the same temperature expansion coefficient, so that can meet the environmental conditions of large temperature changes. 2. Guide rod transmission mechanism: This mechanism uses two cylindrical guide rods as sliding guide rail components with high precision. However, it is an over-positioning mechanism, which, combined with a large aperture, can get stuck. 3. Rotary disk switching mechanism: This mechanism mounts multiple zoom lens groups onto a rotating disk, allowing for different focal length changes by rotating switch different zoom lenses to achieve the purpose of zoom. This is only suitable for zoom lenses without compensation groups and continuous zoom cannot be achieved. Most of Quanhom's continuous zoom lenses use the first slide transmission mechanism. That is, when the motor drives the cam to rotate, the cam transmits the motion to the zoom slide and the compensation slide through the guide pins. The zoom slide and the compensation slide, under the guidance of straight grooves on the main lens tube, convert the rotation of the cam into parallel movement of the slide along the optical axis, so as to realize the zoom.

Assuming that NETDA It is not entirely correct. NETD (Noise Equivalent Temperature Difference) is a critical parameter for assessing the performance of IR imaging systems. It reflects the system's temperature resolution for low-frequency scenes (uniform large objects) but does not represent the system's temperature resolution capability for scenes with higher spatial frequencies. Thus, it is incomplete to judge the temperature resolution capability of two IR imaging systems based only on the value of NETD. Even if infrared imaging system A has a smaller NETD than system B, it only indicates that system A performs better with low-frequency scenes, not that system A has a superior temperature resolution capability for all types of scenes compared to system B. To evaluate the temperature resolution capability of two IR imaging systems, key indicators include both NETD (Noise Equivalent Temperature Difference) and MRTD (Minimum Resolvable Temperature Difference). These two indicators directly reflect the sensitivity and resolution of the IR imaging system to temperature difference. In the image examples provided: Figure (a) represents the original image; Figure (b) is the image with high spatial frequency filtered out, preserving low spatial frequency. This image lacks outlines and appears very blurred, reflecting global information. Figure (c) is the image with low spatial frequency filtered out, preserving high spatial frequencies, resulting in distinct outlines and detailed information.  Note: NETD is a measure of a thermal imaging detector's ability to discern minute differences in thermal radiation within an image, typically expressed in milliKelvin (mK).

1）Impact of Light Conditions - Low-light night vision device is a night observation device that enhance faint reflected light from targets using image intensifiers so that the human eye can see the target image. Its imaging principle is significantly affected by environmental factors especially light conditions; observation range decreases as light diminishes. In total darkness, these devices require supplementary infrared light sources and are susceptible to glare though many traditional models featuring glare protection. However, wide changes in ambient brightness can severely impact observation. - Infrared thermal cameras convert invisible infrared energy emitted by objects into visible thermal images, where different colors indicate varying object temperatures. They are unaffected by light conditions and provide clear observations of target objects regardless of day or night or rainy, snowy or foggy days. Consequently, top- level vehicle-mounted night vision systems often opt for infrared thermal imaging technology. 2）Imaging effect - Low-light night vision devices and typical infrared thermal cameras offer completely different observation feelings. Traditional low-light night vision devices directly observe targets through lenses, presenting a circular field of view similar to that of binoculars, displaying images in green. With sufficient clarity, they can recognize facial features and identify individuals. - Infrared thermal cameras display images on internal LCD screens rather than directly observing targets, resulting in square-shaped fields of view. The imaging of the infrared thermal camera is distributed according to the temperature. Higher temperatures appear brighter, while lower temperatures appear darker. The main purpose is target detection and classification, recognizing between humans, animals, vehicles, etc. 3) Practical Applications - Low-light night vision devices find widespread use in wildlife observation and hunting, offering clear vision at night without disturbing animals. Low-light-level night vision devices are also used in police operations, especially in night missions, as night super vision for long-range and close-range observation and identification, which greatly improves the observer's vision at night. - Infrared thermal cameras are commonly employed in search and rescue missions as they can detect heat in darkness, smoke, or fog. They are particularly suited for dense jungles or environments with thick fog where traditional low-light night vision devices may be less effective. Regardless of dense forest or heavy fog, infrared thermal cameras can reliably detect heat. Additionally, they are extensively used in security applications, as well as for maintenance in construction and power facilities.

1. Why install a shutter ? The shutter is installed between the lens and the detector, and can be started either manually or by setting time intervals. Its purpose is to compensate for temperature measurement deficiencies of the detector. Currently, due to limitations in process technology and software, both low-end foreign detectors and domestic detectors are unable to adaptively adjust based on external temperature and humidity conditions. Therefore, after observing for a period of time or when the temperature and humidity of the observed object change, thermal camera needs to use the shutter to block the detector to reset its parameters, achieving temperature measurement and image calibration. 2. What are the differences between thermal imaging cameras with and without a shutter? A thermal imaging camera detector without shutters has higher performance than one with shutters. The design without shutters indicates that the thermal imaging camera's detector can adapt to environmental changes. Coupled with advanced software algorithms, it can automatically achieve optimal observation results. In contrast, a thermal imaging camera with a shutter undergoes periodic shutter zero-calibration when observing objects. During the shutter opening and closing stage, there will be lagging in the thermal imaging camera's image and video transmission, which will be reflected in the data as frame loss. This occurs because no data is collected while the shutter is opening or closing. Therefore, during temperature measurement, thermal imaging cameras with a shutter will experience stuttering, whereas those without a shutter will provide smooth image performance. 3. Advantages and disadvantages of thermal imaging cameras with and without shutters: 1）With Shutters Advantages: · Strong anti-interference ability: The use of a shutter in thermal imaging cameras effectively prevents the influence of light and other disturbances, ensuring the accuracy of thermal imaging. · Reduced lens absorption: Shutter materials may have higher transmittance for infrared radiation, thus reducing the amount of infrared radiation absorbed by the lens and improving detector sensitivity. · Relatively lower cost: Thermal imaging cameras with shutters are more affordable compared to those without shutters, suitable for general applications. Disadvantages: · Reduced transmittance: Even shutter materials have high transmittance, there will still be some optical loss, which decreases the intensity of infrared radiation from the target to the detector, affecting image brightness and clarity. · Increased complexity: Shutters increase the optical complexity of infrared thermal cameras, potentially making installation and adjustment more cumbersome and increasing the likelihood of system failures. · Increased cost: Shutters requires additional manufacturing and installation costs, and may need regular maintenance and replacement, thus raising overall costs. 2)Without Shutters Advantages: · Higher transmittance: Without a shutter, it means higher transmittance, which allows more infrared radiation to enter the lens, improving image brightness and clarity. · Increased sensitivity: Thermal imaging cameras without shutters have higher sensitivity and can detect smaller temperature changes, offering significant advantages in certain applications. · Enhanced performance: Higher transmittance and simplified design may lead to higher system performance, such as faster image capture speed and higher spatial resolution. Disadvantages: ·Higher environmental requirements: Detectors in thermal imaging cameras without shutters need to operate in more stringent environments, requiring special features such as waterproofing, dustproofing, anti-interference to ensure stability and reliability. · Higher calibration costs: Thermal imaging cameras without shutters requires more complex non-uniformity correction algorithms and needs calibration under different environmental conditions, increasing calibration time and costs. In summary, when deciding whether to use a shutter, it's important to consider comprehensively factors such as the thermal imaging camera's application scenario, requirements, and budget.

1.What are the thermal characteristics of large-aperture infrared lenses at different temperatures? As the temperature drops, the thermal deformation of the optical lens increases. This is because the lens barrel,O-ring and other mechanical parts squeeze the lens, which increases the thermal stress of the lens. The surface shape of the lens changes uniformly in a low temperature environment. This is because the lens is radially squeezed by the mechanical structure. When the temperature rises to 60°C, the surface shape of the lens changes irregularly, Larger thermal deformation also occurs in a relatively normal temperature environment, but less thermal deformation than in low temperature environment, this is because there will be a gap between mechanical components and lens in high temperature environment, which reduces the thermal stress of the lens, and the thermal deformation of the lens is correspondingly reduced; compared with high temperature and low temperature environment The image quality will decrease in normal temperature environment, and the imaging performance in low temperature environment is worse than that in high temperature environment. 2.What effect does stray radiation have on large-aperture infrared lenses? Generally, the first lens of a large-aperture infrared lens has a larger aperture than a conventional infrared lens, and the luminous flux entering the infrared system is more, causing external stray light to easily enter the opto-mechanical system. When there is a strong radiation source outside the field of view, the observed target signal energy is very weak, causing the non-target imaging energy outside the field of view to exceed the target imaging energy, so that the low-contrast target image or image details are overwhelmed, causing stray light on the image surface of the detector system.

The curve of the infrared radiation received by the detector varies with the parameters, and the change trend is clear: at low altitude, the infrared radiation received by the detector decreases linearly with the increase of the detection height; it shows a Gaussian distribution with the change of the azimuth angle; The increase of visibility increases exponentially. When the visibility is less than a certain distance, with the increase of visibility, the increasing trend of infrared radiation gradually strengthens, and after reaching a certain distance, its increasing trend gradually slows down; with the increase of relative humidity, it is logarithmic When the relative humidity is low, the change is relatively slow, when the relative humidity is close to saturation, the rate of decline accelerates sharply; it decreases linearly with the increase of carbon dioxide content. Under the same conditions, the radiation attenuation in the long-wave band is smaller than that in the medium-wave band, and the attenuation rate of radiation in summer is significantly smaller than that in winter. (The Gaussian distribution curve is bell-shaped, low at both ends and high in the middle, and symmetrical to the left and right because the curve is bell-shaped.) （Quote—Li Fei. Analysis of Atmospheric Transmission Impact on Mid-wave and Long-wave Infrared Radiation [J]. Infrared Technology, 2019, 41(4): 315.）

1. What are the advantages and disadvantages of 2D drawings and 3D models? 2D Drawings: Advantages: It can completely express parts of all necessary information for manufacturing and processing, including dimensions, technical specifications, tolerance. The drawings can be converted into various formats, and printed (or output) drawings can be moved, shared and read in various environments. Disadvantages: The drawing is complex and people requires certain professional knowledge to fully understand the information presented. 3D Models: Advantages: The model is intuitive and clear, with well-defined relationships between parts. Even non-professionals can have a general understanding of the designed product through the 3D model. In addition, 3D models are easy to design and modify, which can greatly save design time and improve work efficiency. Moreover, 3D models are also convenient for sharing resource information. Disadvantages: Specific software is needed to view detailed information. 3D models cannot intuitively express dimension data, surface roughness, and technical specification. In short, customers can use 2D drawings to understand the product's approximate dimensional information, structure, shape, and so on. If you want to have a deeper understanding of the product, you can use 3D models, which can provide a more intuitive and three-dimensional display of the product, and offer a more comprehensive design understanding and evaluation. (Take the GCZ92513KD as an example) 3D Model    2D Drawing 2. Does the dimensional deviation of the parts need to be consistent? No need to keep consistent. Dimensional deviation refers to the extent to which the dimension and shape of a part deviate from the design requirements due to various factors during the machining process. Each dimension of a part can have different dimensional deviations. Designers need to set appropriate dimensional deviations based on specific design requirements and actual manufacturing processes. 3. What are the factors that affect part dimensional deviation? Factors affecting the dimensional deviation of parts include human factors, equipment, process and materials. Analyzing the main factors affecting parts machining errors is crucial for improving machining quality and reducing errors.

In winter, not only low temperature is a factor that affects infrared cameras, but also the sealing performance of each component is a significant challenge. Low temperature will impact the performance of electronic components, such as decreased battery life, electro-optical system malfunctions, etc. Low temperature, rain or snow will also cause internal fogging and condensation, affecting the lens and the inside of the body. So you need to pay attention to the following points:1. Cold weather protectionBefore use, make sure the battery is fully charged to maintain normal voltage. Facilitate battery preheating to enhance chemical activity internally, ensuring the normal functioning of all components. Avoid voltage dips and prevent damage to fragile plastic components in low-temperature environments. Prevent safety hazards such as freezing of components.2. Snow and Rain ProtectionRain, snow and icing are also serious problems. Be sure to promptly clean up any ice or snow covering the camera's surface. If liquid is observed on the camera's surface, wipe it clean to prevent potential freezing during use.After the ice and snow melt, moisture in the gaps will more easily enter the interior of the camera. When clearing, we can use various tools, but try to avoid using substances with chemical reagents, as they may corrode internal circuit boards. If fogging occurs inside the lens, you can accelerate the dissipation of water vapor in the lens by turning on and preheating.3. Static electricity and precautionsWinter clothing tends to be thick, contributing to a higher likelihood of static electricity buildup. And static electricity is the most easily ignored topic in winter. Given that static electricity can lead to poor contact or even short circuits, it is essential to power off the camera when operating. Additionally, it is advisable to touch a metal object before operating to avoid the risks associated with static electricity.4. Dryness and moisture-proof precautionsIn addition to moisture protection, it is crucial to prevent excessive dryness during winter. Overly dry environments will also produce certain hazards, especially to lens components. In severe cases, it can cause the coating to crack and peel off, and easily lead to cracks in the rubber of the camera.

In the process of performing reconnaissance and strike missions, UAVs need to carry various electro-optical payloads, such as infrared thermal imaging cameras, laser rangefinders, etc. During flight, the UAV’s attitude movement and the windage torque will cause the boresight pointing to be unstable. These external factors will seriously affect the imaging quality of the electro-optical equipment carried by the UAV, resulting in blurred images and reduced clarity. In aviation electro-optical imaging equipment, inertial sensors are usually used to measure carrier disturbance information, and control algorithms are used to compensate for the disturbance to achieve stable control of the boresight in the inertial space. However, the control of the electro-optical stabilization platform is a complex, coupled, and nonlinear problem, involving many factors such as the field of mechanical design, mathematical modeling methods, servo control systems, and sensor measurement technologies.The main function of the airborne electro-optical platform is to isolate external disturbances, such as the aircraft's own shaking, wind drag disturbances during flight, and internal disturbances of the electro-optical platform. This ultimately enhances the pointing precision of the electro-optical platform's boresight and improves imaging quality. Operating within a complex airborne environment, the platform is affected by complex multi-source factors during flight, making the compensation of external disturbances crucial for achieving high-precision pointing of boresight.Passive vibration reduction and isolation stability: Use vibration isolators installed on the outer frame or inner frame of the electro-optical platform to isolate external disturbances.Active compensation stabilization is used to obtain image stability, including overall stabilization, electronic stabilization, and mirror stabilization. The overall stability is to use the inertial components installed inside the electro-optical platform to monitor the position and attitude of the platform in real time, and provide timely feedback of the monitored data, and then adjust the parameters and motor drive circuits to maintain the stability of the boresight.

1. Security SurveillanceWidely employed in video security surveillance for sensitive areas such as shopping malls, communities, banks, warehouses, etc., especially for night security.2. Personal consumptionCommonly used in outdoor activities like adventures and field scientific expeditions. Some manufacturers have developed mobile phones with plug-in thermal imaging devices for daily temperature measurement and personal entertainment.3. Driver AssistanceInstalled in vehicles, boats and other transportation to provide drivers auxiliary observation information of the road conditions ahead by displaying infrared thermal images, thereby avoiding potential road traffic safety hazards such as haze, smoke and heavy rain.4. Fire and policeUtilized in search and rescue operations for various accidents, including earthquakes, fires, traffic accidents, aircraft accidents, and beach scenarios. Infrared detection enables police officers to conduct searches, observations, or tracking during night or concealed conditions.5. Industrial monitoringApplicable to control processes in almost all industrial manufacturing, especially the monitoring and temperature control of production processes under smoke, effectively ensuring product quality and production processes.6. Power monitoringUsed for observing the operating status of mechanical and electrical equipment. It can express equipment faults in the form of temperature images and find the source of danger before the equipment is damaged by high temperatures and conduct maintenance in advance, thereby improving equipment production capacity, reducing maintenance costs, and shortening downtime for maintenance.7. Medical quarantineBy observing the temperature differences of affected bodies or pathological tissues, and distinguishing sick bodies among groups for inspection, infrared thermal imaging cameras play a vital role in promptly detecting sick bodies and avoiding the spread of the epidemic.

An infrared optical window is a selectively transparent component designed based on its material to allow specific wavelengths of light to pass through. These windows are carefully designed to maintain optical clarity, withstand environmental conditions, and minimize any distortion or alteration of the light passing through them. They are primarily used to protect precision optical elements, facilitate measurements, and enable observation or imaging in various applications.

EO/IR stands for "Electro-Optical/Infrared," a comprehensive technology that integrates Electro-Optical (EO) and Infrared (IR) sensing. Both technologies are used for the detection and acquisition of light and thermal radiation in different wavelength bands, enabling surveillance, reconnaissance, navigation, and other applications. Specifically:Electro-Optical (EO) sensing technology encompasses visible light and optical sensors, such as cameras and telescopes, used to capture images and videos within the visible light spectrum.Infrared (IR) sensing technology involves infrared sensors that detect the thermal radiation emitted or reflected by objects. IR technology is useful in situations where there is low light or where a heat source needs to be detected.The combined use of these two technologies enables a more comprehensive approach to target detection, identification, and tracking, providing 360° awareness in day&night. Common applications of EO/IR systems include airborne homeland security, patrols, surveillance, reconnaissance, search and rescue missions.

Thermal sensitivity (NETD) stands for Noise Equivalent Temperature Difference, which is a critical parameter for evaluating Medium-Wave Infrared (MWIR) and Long-Wave Infrared (LWIR) thermal imaging cameras. It is a value that represents the signal-to-noise ratio of the temperature difference, which is equivalent to the instantaneous noise of the imaging camera. Therefore, it approximately represents the minimum temperature difference that the thermal imaging camera can resolve, which is directly related to the clarity of its measurement. When selecting sensors with the same pixel configuration and under a fixed thermometric scale, using instruments with different thermal sensitivities to take pictures, the results are as follows:  Under different thermal sensitivities, the pictures presented are very different. The smaller the value of sensitivity, the better the thermal sensitivity and the clearer the picture.  Measurement of NETD(1) Two-point MethodThe two-point method is a common way to measure the NETD of an infrared imaging camera. It is based on two assumptions: 1. The surface of the target is uniform without local heat sources. 2. The noise between the pixels of the imaging camera is independent.The specific steps are as follows: 1. In a completely dark environment, select two pixel points with moderate spacing as the target point. 2. Measure the output signal of the thermal imaging camera and calculate the signal difference between the two pixels.3. Calculate the corresponding NETD according to the temperature characteristics of the thermal imaging camera.(2) Averaging MethodThe averaging method is a simple and commonly used method for measuring the NETD of thermal imaging cameras. It is based on the statistical properties of the imaging camera output signal for higher measurement accuracy.The specific steps are as follows: 1. Select an appropriately sized pixel area under stable environmental conditions. 2. Measure the average and standard deviation of the output signals of all pixels in the area.  3. Calculate the NETD based on the temperature characteristics and standard deviation of the thermal imaging camera.(3) Spectrum Analysis MethodSpectral analysis is a method of measuring the NETD of an infrared imaging camera based on the signal spectrum, which is suitable for thermal imaging cameras with obvious noise frequency characteristics.The specific steps are as follows: 1. The signal output by the imaging camera is subjected to Fourier transform to obtain the spectrum of the signal. 2. Analyze the noise components in the spectrum and calculate the NETD. Factors affecting NETD:(1) Corrected Temperature Measurement Range. Depending on the selected temperature measurement range and object temperature, the noise readings will be different. However, as long as there is significant thermal contrast in the image and the temperature of the target area is much higher than the background temperature, it will not affect the measurement accuracy too much.(2) Detector temperature. If the imaging camera is placed at a higher temperature, the system noise will increase, the extent of which depends on the internal stability of the infrared thermal imaging camera. (3) The F-number of the camera lens. A lower F-number means a larger aperture, which allows more infrared radiation to enter the camera. Generally, a larger aperture (lower F-number) receives more infrared radiation, which helps to improve the signal-to-noise ratio of the imaging. In theory, the lower the F-number, the lower the noise values and the better the image quality.

The infrared sight consists of objective lens, shell, eyepiece, battery, connector, etc., as shown in the diagram 1. Diagram 1 Infrared sight composition1. Objective lens; 2. Shell; 3.Battery;4. Eyepiece; 5. Connector The basic working principles of infrared sight is as shown in the figure below. Figure  Infrared sight’s working principle figure The infrared sight is mounted to the firearm Picatinny rail via the connector; the infrared radiation from the target is focused by the objective lens assembly onto the sensitive element of the infrared uncooled focal plane detector. After thermal-electric conversion, a processable electrical signal is generated. The electronic circuit board performs pre-treatment of the electrical signal and converts it into a digital image signal. Then the digital image signal undergoes non-uniformity correction, blind pixel replacing, image enhancement, brightness and contrast adjustment and overlay of menu, interface and firing table information before being output to the eyepiece, so as to assist the shooter in achieving accurate shooting.