In the security market, it is a headache for users to choose a good surveillance camera. So, what kind of surveillance camera is a good camera? According to the person in charge of China Security First Network Hot Security Network: Regarding what kind of camera is a good camera problem, we must first consider the camera's characteristics and performance indicators to help security personnel better judge The characteristics of the camera. Let's give you a detailed analysis below!
The pixel value pixel is a tiny photosensitive substance mounted on the imaging device, and the more pixels, the higher and clearer the image resolution. Therefore, the number of pixels is a major indicator of the image quality of a camera. Since the working principle of the camera is very different from that of the camera, there is also a distinction between "dynamic pixels" and "static pixels". Therefore, it is different from the camera configuration of millions or even tens of millions of pixels. The camera's pixel count of 40W has been able to meet basic shooting needs. For high-definition cameras, 200W pixels can also meet the shooting needs of special environments.
Horizontal resolution Horizontal resolution is a measure of image sharpness and is usually expressed in terms of line numbers (ie, TV lines, TVL). A line of television is 1.33 pixels when interlaced. In surveillance cameras, both pixel values ​​and horizontal resolution are the main indicators for measuring picture clarity. Under normal circumstances, only the horizontal resolution index exceeds 1080i (2 million pixels) and 720p (92 million pixels) can be called high-definition imaging.
Minimum illumination The minimum illumination, also known as sensitivity, is a measure of the camera's light sensitivity. To put it bluntly, the surveillance camera can see the image in dark conditions, and its imaging effect is related to the aperture size of the lens. In fact, the representation of the minimum illumination makes us judge very well. For example, when we use the lens of F1.2, if the brightness of the shooting environment is at least 0. 04lx, the amplitude of the video signal output by the camera is 50% of the maximum amplitude, that is, 350mV, so the minimum illumination of this camera. It is 0. 04lx/F1. 2. In general, a camera with a minimum illumination of less than 0. lx/F1. 2 can be called a camera with low illumination.
The imaging target surface is also referred to as a scanning area, that is, the size of the imaging device. Currently, the size of the target surface is expressed in inches, that is, the diagonal length of the image sensor. To this day, the camera target has gradually improved from 1/2 inch to 1/4 inch. Although in theory, the smaller the size of the target surface, the higher the technical content, but with 1/4 inch target surface, 1/2 inch has more light throughput, 1/4 inch device will have Greater depth of field, therefore, the specific merits and demerits depend on the shooting environment.
Scanning format This refers to the scanning format of the camera output image. The international scanning format usually has two types: PAL and NTSC. In China, it is usually PAL. The standard is 625 lines, 25 frames per second (25fps). The United States, Japan and other countries implement the NTSC system (29.97fps). Its size affects the playback speed of the picture.
Lens mounting method The lens mounting method is divided into C and CS modes. The difference between the two is that the distance to the photosensitive surface is different. The CS type (17.5mm) is an upgraded version of the C type (12.5mm), which has the advantage of low manufacturing cost and reduced sensor size. In general, the camera interface is CS type.
The signal -to - noise ratio ( SNR) is usually the ratio between the camera's output image signal and the interfering signal. The higher the signal-to-noise ratio, the clearer the imaging effect. In general, the signal-to-noise ratio is 46 dB. If the signal-to-noise ratio is above 50, the imaging effect will generally be very good.
The wide dynamic wide dynamic function is a technique that allows the camera to see the characteristics of the image in a contrasting environment with very intense illumination. Exposure twice at the same time, and then synthesizing makes it possible to see both bright and dark objects on the screen at the same time. The subjective brightness difference between the background image and the main picture is greatly reduced, but the picture quality is guaranteed. It is very helpful for users who have a strong contrast light shooting environment.
Background Light Compensation It uses digital signal processing technology to achieve the best fit by automatically adjusting the "aperture" and "gain" factors to solve the problem of strong background light causing objects to shadow.
White balance white balance is a very important concept in the field of video camera, which can solve a series of problems of color reproduction and tone processing, and improve the authenticity of the picture.
In fact, like digital products such as computers, the above points are also the main factors that determine the quality of surveillance cameras. When we select the camera, as long as we pay attention to these problems, we can basically have a clearer understanding of the imaging effect and application environment of the camera, thus helping us make the right choice.
53Cm Nonwoven Wallpaper,Home Decor Nonwoven Wallpaper,European Retro Wallpaper,Waterproof Non-Woven Wallpaper
JIANGSU ARTSTYLE DECORATION MATERIALS CO..LTD , https://www.artstyledecor.com