How to test the image amplification of the surveillance camera
The magnifying factor of the surveillance lens was approximately equal to the ratio of focal length to object distance. To test the image magnification of the surveillance camera, one needed to first determine the focal length and object distance of the lens. The focal length was the distance between the lens and the sensor. It could be obtained by checking the specifications of the lens. The object distance was the distance between the object being photographed and the lens. It could be measured. Then, the focal length was divided by the object distance to obtain the image's magnification. In addition, the horizontal and vertical visual degrees of the surveillance camera have the following relationship with the size of the CCTV target surface hXv and the focal length of the lens f: horizontal visual degrees = 2arctan(h/2f); vertical visual degrees = 2arctan(v/2f). By measuring the degree of horizontal or vertical vision, as well as the known size of the CCD-based target surface, the focal length of the lens could also be deduced, and then the object distance could be combined to calculate the magnification. It should be noted that when selecting the lens, it is also necessary to consider whether the lens specifications correspond to the size of the CCTV target surface of the surveillance camera. Otherwise, there may be problems such as the observation angle not meeting the design requirements or the picture being out of focus. For example, a 1/3"lens was the mainstream application. When a 1/3" lens was used, the size of the CCD-target was 4.8hx3.6u. Read more exciting novels for free
Surveillance camera manufacturer
The brands in the security surveillance camera industry mainly included Seiko, Tenglong, Computar, Fujineng, Tuli, and so on. In addition, there were also Hikvision, EZVI, Dahua, 360, KEDA, Philip, Samsung, D-Link, Ithink, Jooan, VStarcamera, Huamai, Datang Bodyguard, lenova, Huaxin, Anda, Shibojia, Tianshida, Aochman, Tiandi, Longse, Hengsi, Luowice, Transcendence, Watec, Gangqi, Zhongtian Lingzhi, Hongxiang, and other manufacturers. <a href="/?from=ask_words" style="color:red" target="_blank">Read more exciting novels for free</a>
Surveillance camera with a lens
The surveillance camera was just a single video capture device. The resolution and resolution of the lens were higher than that of the computer's video head, but it could not catch up with professional digital cameras or DVs. In reality, cameras and lenses were mostly purchased separately. The user can calculate the focal length of the lens according to the size of the target object and the distance between the camera and the object to determine the required lens. The lens required by each user depends on the actual situation. It cannot be assumed that the camera (head) already has a lens and does not need to be equipped with another lens. The focal length of the lens determined the field of view of the camera. For example, a wide-angle lens was suitable for shooting in a large space and could capture more content. A telephoto lens was suitable for long-distance shooting and could see details in the distance. Indoors, they usually chose short focal lenses, such as 2.8mm or 3.6mm lenses, while outdoors, they chose lenses based on distance. Moreover, different focal length lenses had different imaging effects. Long focal length lenses could see more details of distant objects, but the field of view became smaller and the viewing range became narrower. Wide-angle lenses had a wide viewing range, but it might be difficult to distinguish some details. <a href="/?from=ask_words" style="color:red" target="_blank">Read more exciting novels for free</a>
The surveillance camera on the highway?
The video surveillance on the highway might have a camera function. For example, the violation camera was generally spherical in shape. Its function was to capture and punish the captured vehicle. Many traffic accidents were caused by parking violation. This kind of camera was installed in the no-parking section, and it was also installed in the parking area of the highway bus. Electronic eyes were used to detect illegal behavior while driving, such as running red lights, changing lanes, etc. Although there was no explicit mention of taking photos, detecting these behaviors usually required taking photos for evidence. Therefore, there were video surveillance cameras on the highway. <a href="/?from=ask_words" style="color:red" target="_blank">Read more exciting novels for free</a>
Focus the surveillance camera
If it was a general non-integrated surveillance camera, the method of adjusting the focal length was as follows: First, remove the camera, check the small screw like parts at the lens and loosen it, then turn the circle on the lens to adjust the focal length. When adjusting the focal length, it was best to take it off and adjust it while facing the monitor screen. If it was inconvenient to take it off, two people were needed. One person looked at the screen and cooperated with gestures or words, and the other person adjusted it next to the camera to achieve the best effect. It could also be adjusted manually. Some surveillance cameras had two buttons that could be rotated. One was used to adjust the distance and the other was used to adjust the clarity. There was another adjustment method: first loosen the fixing screw of the camera's rear focal length adjustment ring; adjust the zoom lens to the maximum telephoto position, and use the focal length adjustment ring on the lens to set the focal length until the image is the clearest; then adjust the zoom lens to the maximum wide-angle position, and turn the rear focal length adjustment ring until the image is the clearest; when switching from telephoto to wide-angle, repeat the above two steps until the image is in focus; finally, after the setting is complete, tighten the rear focal length adjustment ring. In addition, he added a new experience of adjusting the lens. He loosened the screw that fixed the standard lens, adjusted the magnification, and adjusted the lens to a telephoto state. Then, he zoomed in on the distant object, and then adjusted the focal length to make the close-up image clear. Then, he pulled the lens back to the wide-angle state by zooming out. The image he just shot should be a panoramic view. Don't adjust the focal length of this panoramic view (even if the image is blurry, don't adjust it). Go straight to the next step, which is to adjust the back focal length to adjust the image to the best picture. Finally, tighten the small screw of the lens, and the back focal length adjustment is completed. <a href="/?from=ask_words" style="color:red" target="_blank">Read more exciting novels for free</a>
Surveillance camera aperture means
In terms of concept, the aperture was a device in the surveillance camera that controlled the light passing through the lens and adjusted the light sensitivity inside the camera. In terms of structure, it was controlled by the amount of light passing through the lens. Usually, the F-value was used to express the size of the aperture. In daily life, 1.0, 1.2, or 1.4 would be used to represent the aperture size of the lens. When the F-value was smaller, the larger the aperture was, and the more light the sensor chip could pass through. <a href="/?from=ask_words" style="color:red" target="_blank">Read more exciting novels for free</a>
Is there a surveillance camera at the entrance of the community?
There were surveillance cameras at the entrance of some residential areas for different purposes. For example, in order to control the phenomenon of random parking of vehicles, high-definition surveillance cameras were installed on the north and south sides of the east entrance of Xingtai International New City to record illegal parking and other behaviors; in order to record vehicles that violated one-way traffic, such as the vehicle bayonet monitoring at the entrance of Mu 'an Community on Changyun Road; In order to regulate the traffic order at the entrance of some districts, such as the north gate of Mindu Elegant Garden, surveillance cameras were installed to capture the situation of vehicles not leaving for a long time. <a href="/?from=ask_words" style="color:red" target="_blank">Read more exciting novels for free</a>
Is there a surveillance camera for illegal parking?
Yes. Sky-eye surveillance cameras had been installed on the roads of many cities to capture traffic violation, including illegal parking. For example, taxi parking could be captured by surveillance cameras and then fined by the traffic police. <a href="/?from=ask_words" style="color:red" target="_blank">Read more exciting novels for free</a>
Surveillance camera lens type
Based on context alone There were many types of surveillance camera lenses, and the following were the common ones: ** I. By focal length ** 1. ** Fixed focus lens ** - [Special characteristic: Fixed focal length.] For example, 3.6mm and 6mm fixed-focus lenses. The 3.6mm fixed-focus lens had a wide field of view and was suitable for monitoring close-up and large-scale scenes, such as the internal monitoring of small shops. The field of view of a 6mm fixed-focus lens was relatively narrow, but it could see further. It was suitable for monitoring long and narrow spaces such as corridors or specific long-distance scenes such as the entrance of a community. 2. ** Zooming lens ** - [Special characteristic: The focal length can be changed within a certain range.] The electric zoom lens could adjust the focal length remotely through the control device, making it convenient to adjust the monitoring range according to the actual monitoring needs. For example, a 2.8 - 12mm zoom lens could be adjusted from a wider field of view to a narrower field of view to focus on distant targets. ** 2. By field of view ** 1. ** Wide-angle lens ** - [Special characteristic: Large field of view, generally greater than 60 degrees.] It could cover a large monitoring range, but the monitoring distance was relatively short, and there might be some distortion at the edge of the screen. It was often used to monitor open indoor spaces or large areas around buildings. 2. ** Telephoto lens ** - [Special characteristic: Small field of view, usually less than 30 degrees.] It could monitor targets far away, but the coverage was narrow. For example, in a large warehouse, it was used to monitor the goods on the distant shelves. ** 3. By function and special lens ** 1. ** Fisheye lens ** - [Description: Field of view is close to or equal to 180 degrees or even larger. It can provide a very wide field of view and can achieve a hemisphere or even global surveillance image.] However, the image was severely distorted and required special image processing technology to restore the normal image. It was often used in places that required comprehensive surveillance, such as the central courtyard of some large shopping malls and other public places. 2. ** Pinhole lens ** - [Special traits: Small and concealed lens, small aperture.] It is suitable for covert surveillance, such as special places that require secret surveillance to ensure safety, but it must be used in accordance with laws, regulations, and ethics. <a href="/?from=ask_words" style="color:red" target="_blank">Read more exciting novels for free</a>
The lens structure, the surveillance camera
In terms of the structure of the surveillance camera lens, it could be divided into a large lens and a small lens. The lens had two important parameters, namely the focal length and aperture. The focal length was usually 4mm, 6mm, 8mm, 12mm, etc. The larger the millimeter, the smaller the range, but the further the distance. For example, the warehouse usually used a 4mm lens, the residential building unit door usually used a 6mm lens, and the small road usually used a 12mm lens. The aperture was the F value that appeared on the lens, generally F1.0, F1.2, F1.4, F1.6, etc. The smaller the F value, the greater the amount of light, and the more expensive the lens. <a href="/?from=ask_words" style="color:red" target="_blank">Read more exciting novels for free</a>
The traffic police surveillance camera
There were several common types of traffic police surveillance cameras: 1. ** Electronic eyes (Electronic police)**: Usually set at intersections. Mainly used to capture illegal activities such as running red lights, pressing the line, illegal lane changes, going against the traffic, driving on the phone, not wearing a seat belt, and so on. There is often a flash device beside it that cannot be rotated. 2. ** Stop violation capture camera **: Most of them are installed on urban roads with heavy traffic, narrow and congested roads, and freeways (used to capture illegal boarding and alighting of passengers on the highway). Usually installed on a pole, the camera can rotate 360 degrees, mostly in the shape of a hemisphere, with a wide range of capture, sensitive response, and can quickly capture the information of illegal vehicles. 3. ** Speed cameras **: Most of them are installed on the highway, and some national roads also have them. By setting up two monitoring points, it was monitored whether the vehicle was speeding. If the time taken to pass the road was shorter than the predetermined time, it was determined that the vehicle was speeding. 4. [Mobile speed camera: There is no fixed location for use. It may appear in the hands of the police, the green belt in the middle of the highway, the top of the police car, etc. The navigation system generally does not broadcast, and the vehicle will be recorded when it passes by.] 5. ** Bayonet gun camera **: It is mainly installed on the highway and national highway. If a car passes by, it will flash its light to record it. If it flashes twice, it may be recorded as a violation. It might be installed on the other end of the bridge and could only be seen from the rearview mirror. 6. [Skynet Surveillance Cameras: There are gun and hemisphere types. They are installed on utility poles or street lamps. They are mainly used for social security monitoring and arresting bad guys instead of traffic violation monitoring.] <a href="/?from=ask_words" style="color:red" target="_blank">Read more exciting novels for free</a>