How to choose the focal length of the surveillance camera
The following aspects could be considered when selecting the monitoring focal length: * * 1. Choose according to the monitoring range ** 1. * * Small monitoring range and large viewing angle **: For example, in a family living room or small shops, you can choose a surveillance camera with a smaller focal length. For example, a camera with a focal length of 3.6mm or 4mm can have a viewing angle of 75 °-90 °, an effective monitoring distance of more than 5 meters, and can cover a space of 40 - 80 square meters. 2. * * Large monitoring range (10m * 10m or more)**: You need to choose a surveillance camera with a larger focal length, but a larger focal length will reduce the monitoring angle. To achieve complete monitoring, you can consider using a cloud platform ball machine or installing multiple surveillance cameras. 3. * * Surveillance range is fixed and very far away (such as monitoring a parking lot 30 meters away)**: You need to choose a camera with a larger focal length, such as a surveillance camera with a 12mm or higher. * * 2. Choose based on the usage scenario ** 1. * * Narrow space (such as garage, storage room, etc.)**: It is recommended to choose 2.8mm focal length, and the best monitoring distance is within 3 meters. 2. * * Home or small shop environment **: It is recommended to choose 4 mm focal length, and the best monitoring distance is 3 - 5 m. 3. * * Family courtyard, balcony, doorway, etc. **: 6mm focal length is recommended. 4. * * A wide outdoor area without high requirements for details **: A camera with a 4mm focal length is more suitable. 5. * * Need to capture detailed information from a distance (such as license plate number or facial features)**: A camera with an 8mm focal length is more suitable. In addition, the field of view of the surveillance camera is determined by the width, height, and distance from the surveillance camera. Once the scene to be monitored is determined, the correct choice of the focal length of the lens is also affected by the size of the scene to be monitored, the distance between the camera and the scene, and the size of the camera imagers (such as 1/3 ", 1/2", 2/3 "or 1 "). The calculation method is: f = vD/V or f = hD/H (where, f represents the focal length. When f = vD/V, v represents the vertical height of the CCD-target surface, D represents the distance from the lens to the scene, and V represents the height of the object being observed; when f = hD/H, h represents the horizontal width of the CCD-target surface, D represents the distance from the lens to the scene, and H represents the width of the object being observed). After calculating the focal length value, if there was no corresponding focal length lens, one could choose a similar model according to the product catalog. Generally, one would choose a smaller lens than the calculated value, so that the viewing angle would be larger. Read more exciting novels for free
Normal focal length of glasses
Normal glasses included short-sighted glasses and far-sighted glasses (presbyopic glasses). The focal length was related to the degree of the glasses. For short-sighted glasses, the degree and focal length were in an inverse relationship, that is, the shorter the focal length, the higher the degree. For long-sighted glasses (presbyopic glasses), the degree of the concave lens (far-sighted lens) was positive, and there was a similar relationship between the degree and focal length. To be specific, the power of the lens was equal to 100 divided by the focal length (in meters). For example, a 100-degree spectacles would have a focal length of 1 meter. However, it was not clear whether "normal glasses" were short-sighted or farsighted, so it was impossible to determine a specific focal length value. This was because different degrees of glasses had different focal lengths. From correcting mild vision problems to high vision problems, the focal length would vary greatly. <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>
Laser engraving machine focal length
In the laser engraving machine, the focal length is the distance from the center of the lens to the focal point of the light. For example, the focal length of the 3DJQL- * 00L series laser engraving machine was 960 - 1440mm. In the laser marking equipment, after the laser was shaped by the laser, it would illuminate the focusing field lens (usually a concave lens) with a parallel beam. The concave lens would be refracted by the optical refraction to focus the parallel beam onto a focal point, forming a focal surface. The vertical distance from the center of the concave lens to the focal surface was the focal length, which was generally represented by F =. Most of the laser equipment's matching focusing field lens would have a label on it. <a href="/?from=ask_words" style="color:red" target="_blank">Read more exciting novels for free</a>
How big is the focal length of the monitor?
The focus of the monitor depended on a number of factors. First, he had to consider the scope of surveillance. If the monitoring range is small and the viewing angle is large, such as a family living room, small shops, etc., you can choose a surveillance camera with a smaller focal length. For example, a camera with a 3.6mm or 4mm focal length can have a viewing angle of 75°-90 °, and the effective monitoring distance can reach more than 5 meters, covering a space of 40 - 80 square meters. If the monitoring range is large, such as a space of 10m × 10m, you need to choose a surveillance camera with a larger focal length. Secondly, pay attention to the size of the scene to be monitored, the distance between the camera and the scene, and the size of the camera's imaging device (such as 1/3", 1/2", 2/3", or 1"). The appropriate focal length can be determined by the calculation method f = vD/V or f = hD/H (where f represents the focal length, f = vD/V: v represents the vertical height of the CCD-target surface, D represents the distance from the lens to the scene, and V represents the height of the observed object;f = hD/H: h represents the horizontal width of the CCD-target surface, D represents the distance from the lens to the scene, and H represents the width of the observed object). In addition, different focal lengths had different shooting effects. The larger the focal length, the farther the view, but the smaller the field of view. The smaller the focal length, the closer the view, and the larger the field of view. At the same distance, the larger the focal length, the smaller the angle of view, but the clearer the relative details. At the same focal length, the further the distance, the wider the angle of view, but the lower the degree of recognition. If one wanted to see a human face or figure clearly, the further the distance, the greater the focal length needed. <a href="/?from=ask_words" style="color:red" target="_blank">Read more exciting novels for free</a>
Surveillance camera dedicated traffic card
The dedicated traffic card for surveillance cameras was an Internet of Things data communication card designed for surveillance cameras. It was more cost-effective than traditional data cards. It could choose the appropriate data package according to the scene and functional requirements of the surveillance camera, thereby reducing costs. This kind of data card could break through the limitations of traditional data cards. According to the specific usage of the equipment and the environment, the appropriate data package could be selected to effectively control the cost. In addition, the fee for the dedicated data card for surveillance cameras was relatively low. There were more types of data cards than ordinary data cards, which could effectively reduce the cost of use and avoid wasting network costs. Therefore, choosing a dedicated traffic card for surveillance cameras could meet the needs of surveillance scenes, reduce costs, and improve the use effect.
Is there a surveillance camera in the icu that can be checked?
At present, most hospitals 'intensive care units (ICU) were not equipped with monitoring equipment, such as the respiratory intensive care unit of the Central Hospital affiliated to Zhengzhou University and many provincial hospitals. Although there was a special case where the ICU of the Heart Center of the Women's and Children's Hospital in Shandong Province installed a camera in each bed in 2011, it was generally difficult to monitor the internal situation of the ICU. Moreover, he had not found any policy documents regarding the need to install surveillance cameras in the ICU. Therefore, in most cases, there were no surveillance cameras in the ICU. "The Island of Life" is also a wonderful novel. Everyone is welcome to read it!
The real ghost was seen on the surveillance camera
At present, there was no scientific evidence to prove that ghosts really existed. The so-called " ghosts " seen in surveillance could often be explained by science or other reasonable explanations. For example, in Material 3, the British woman thought that the surveillance camera had captured a ghost, but some netizens in the news comment section pointed out that it might just be dust. In Material 5, the hotel surveillance video seemed to have captured a supernatural phenomenon, but after analysis, there were many doubts in the video, such as the contradiction between the audio and the image, the unreasonable number of surveillance cameras, and the illogical recording of screams. Some seemingly supernatural surveillance images might be caused by equipment malfunction, shooting angle, lighting effects, or human misunderstandings or pranks. While waiting for the TV series, you can also click on the link below to read the classic original work of "Dafeng Nightwatchman"!
Is there a surveillance camera on the right turn of the vehicle?
Under normal circumstances, if there was no right-turn signal at the intersection, the right-turn vehicle did not need to look at the signal light and would usually not be photographed by the electronic police. However, if you turn right under the following circumstances, you will be photographed by the surveillance camera: 1. The intersection signal light had a right turn indicator light, and when turning right, the red light (such as the arrow-shaped right turn sign, turning right when the red light was lit) would be photographed. The electronic eye would take three photos (instant violation image, license plate recognition image, panoramic image) for capture. The shooting was continuous for 24 hours, and the image was usually retained for a week. 2. In some places, surveillance cameras were added, such as the intersection of Taiyang Lake Road and Guangchuan Avenue, Tianqu East Road and Chongde First Avenue, etc. If large vehicles turned right without stopping (driving a motor vehicle in violation of the prohibition sign), they would be captured. 3. When the circular traffic light at the intersection turned red, if there was a reminder above the traffic light that said,"Don't turn right at the red light," turning right at this time would be considered a violation of the regulations, and surveillance equipment would also be captured. 4. In order to prevent traffic accidents caused by right-turning vehicles not giving way according to law, some places use traffic monitoring systems to capture illegal actions such as right-turning vehicles disobeying pedestrians. For example, since February 26,2024, Yueqing City has used the traffic monitoring system to capture vehicles turning right disobeying pedestrians; Since February 7,2024, Zoucheng City has carried out special regulation on traffic illegal behaviors such as non-motor vehicles and pedestrians who turn right without stopping and use the monitoring system to capture photos. <a href="/?from=ask_words" style="color:red" target="_blank">Read more exciting novels for free</a>
What are the basic parameters of the surveillance camera?
The basic parameters of the surveillance camera were as follows: 1. ** focal length **: The distance between the lens and the sensor. By changing the focal length, one could change the lens's magnification and the size of the captured image. When the distance between the object and the lens is very far, the lens's amplification factor equals to focal length/object distance. The larger the focal length, the larger the magnification, and the closer the distant view, the smaller the image range, and the clearer the details of the distant view. 2. ** Field of view **: In engineering practice, the horizontal field of view is often used to reflect the shooting range of the image. The larger the focal length f, the smaller the field of view, and the smaller the range of the image formed on the light-sensitive element. Conversely, the smaller the focal length f, the larger the field of view, and the larger the range of the image formed on the light-sensitive element. 3. ** Aperture **: Mounted at the back of the lens. The larger the aperture, the greater the amount of light passing through the lens, and the higher the image clarity; the smaller the aperture, the smaller the amount of light passing through the lens, and the lower the image clarity. It is usually expressed as F (luminous flux), where F = focal length (f)/aperture. In the case of the same focal length f, the smaller the F value, the larger the aperture, the greater the luminous flux reaching the CCD-chip, and the better the lens. <a href="/?from=ask_words" style="color:red" target="_blank">Read more exciting novels for free</a>