Full Synchronization: The overall lock is the best method for two complete synchronizations between precision applications such as broadcast studio cameras. It will be synchronized: horizontal, vertical, even/odd regions, color trigger frequency and phases.
Vertical Sync: It is the simplest method to synchronize two cameras. The vertical drive frequency ensures that the video can use the old switching period or four-segment machine to display several image sources on the same monitor. The vertical drive signal is usually composed of pulses with a repetition rate of 20/16.7 ms (50/60 Hz) and a pulse width of 1 to 3 ms.
Color video composite signal synchronization: Color video composite signals represent video and color trigger signals, meaning that the camera can synchronize with external composite color video signals. However, despite the so-called color video composite signal synchronization, only horizontal synchronization and vertical synchronization are actually performed without color trigger synchronization.
External synchronization: very similar to color video composite signal synchronization. A camera can be synchronized to the video signal of another camera. An external synchronization camera can use the input color video composite signal to extract horizontal and vertical synchronization signals for synchronization.
DC Line Locking: An old technology that uses a DC 50/60 Hz power line current to synchronize the camera. Because DC 24V power is widely used in most building fire alarm systems, it is very easy to obtain. Since old models of switchers and segmentation systems do not have digital memory functions, to maintain stable images, synchronization between cameras is very necessary. DC line locking is the synchronization of the camera to AC 50/60 Hz, and the correlation and level of time between color channels. Unconstrained / vertical signals result in poor color conversion (color phase design), so all users using AC line locks inevitably lose their color conversion. Fortunately, today's splitters and 16-channel composite processors as well as hard disk recorders have internal memory to overcome this problem, eliminating the need for synchronization signals, so AC line locks may be eliminated several years later.
Colorless scrolling: Digital signal processor video cameras used under fluorescent lighting can only produce serious color scrolling images. The image changes from white to blue, pink to white, and so on. This is because of the problems caused by AC power running at 50/60 Hz. The white light bulb provides stable light, and the fluorescent light fluctuates at 8.3 ms due to the intensity and color of the alternating current. The traditional camera calculates the white balance needs 100-150ms (0.1-0.15) , It is 8.5ms slower than alternating current, therefore can never catch up. Color scrolling can be clearly generated by passing the current image through 8 cycles.
Backlight Compensation: Provides ideal exposure of the target in front of very strong background light, whether the primary target moves to the center, up, down, left or right, or anywhere on the screen. An ordinary camera that does not have super dynamic characteristics only has a shutter speed of 1/60 seconds and F2.0 aperture selection, but a very bright background behind a main target or a point light source is unavoidable and the camera will acquire The average of all recent rays determines the level of exposure. This is not a good idea because when the shutter speed increases, the aperture will be closed causing the main target to become too dark to be seen. To overcome this problem, a method called backlight compensation is widely used on most cameras through a weighted area theory. The image is first divided into 7 blocks or 6 areas (two areas are repeated). Each area can be independently weighted to calculate the exposure level. For example, the middle part can be added to the rest of the block by 9 times, so that one is in the middle of the screen. The goal of the location can be seen very clearly, because the exposure is mainly calculated with reference to the light level of the middle region. However, there is a very big flaw. If the main target moves from mid-to-left to the top, bottom, left and right positions of the screen, the target will become very dark, because now it is not differentiated and has not been weighted.
F denotes the aperture of the lens, F stop 2:1 and f3.4 mm means that the focal length of the lens is 3.4 mm.
The lenses F2.0 and f3.4 to 4 are very economical and should be used at low prices. Widely used in single-board cameras, the aperture of the F2.0 lens collects half the light of the human eye, and the f3.4 mm lens There is a 60 degree viewing angle on a 1/4 inch CCD and a 90 degree viewing angle on a 1/3 inch CCD, very close to the human eye. The two eyes of the human eye can contain a larger angle of view, from person to person, typically with an angle of 150 to 180 degrees, but remember that the F stop and f focal length are only basic parameters of a shot and do not represent quality. Ultra-wide dynamics is a feature that allows the camera to see images under very strong contrast. A wide dynamic camera is more than a dozen times larger than a camera with a traditional 3:1 dynamic range. Natural light ranges from 120,000 Lux to 0.00035 Lux at night. When the camera looks out of the window from the room, the indoor illumination is 100 Lux, while the outside scenery may have an illumination of 10,000 Lux. The contrast is 10,000/100=100:1. This contrasting eye can be easily seen because the human eye can handle a contrast ratio of 1000:1. However, traditional closed-circuit surveillance cameras can deal with it with great problems. The traditional camera has a contrast ratio of only 3:1. It can only Choose to use 1/60 seconds of electronic shutter to get the correct exposure of the indoor target, but the outdoor image will be cleared (all white); or alternatively, the camera selects 1/6000 second to get the perfect exposure of the outdoor image, but the indoor The image will be erased (full black).
Peak-sensing mode: The exposure index is determined by replacing the average value of the entire image with the image highlights. Users of the rule system can respond to the most demanding requirements, such as capturing a white point image in the dark and seeing this small Bright white details and colors.
CMOS: The full name is Complementary Metal-Oxide Semiconductor, which translates to complementary metal oxide semiconductors. The manufacturing technology of CMOS is no different from general computer chips. It is mainly made of semiconductors made of silicon and germanium, which make it possible to coexist on the CMOS with N (band-electricity) and P (band + electricity) grades. In semiconductors, the current generated by these two complementary effects can be recorded and interpreted by the processing chip as an image.
CCD: The full name is Charge Coupled Device, and the Chinese translation is a charge coupled device. It uses a high-sensitivity semiconductor material to convert light into electric charge, and then converts the electric signal into a digital signal through an analog-to-digital converter chip. The digital signal is compressed and transmitted to a computer via a USB interface. The captured image.
The concept of depth of field: When an object is in focus, all scenes from a certain distance in front of the object to a certain distance behind it are also clear. The distance from front to back where the focus is quite clear is called the depth of field. Depth of field is divided into depth of foreground and depth of field, and depth of field is greater than foreground depth. The deeper the depth of field is, the farther away from the focal point of the scene can be clear, and the depth of field is shallow, and the scene far from the focus is blurred.
Focal length: is an optical parameter that any optical instrument has. From the optical principle, the focal length is the distance from the focal point to the center of the lens. For the lens, focal length has a very important significance. The focal length is proportional to the size of the image. The longer the focal length, the larger the imaging. The shorter the focal length, the smaller the imaging. The focal length of the lens is inversely proportional to the size of the viewing angle, the longer the focal length, the smaller the angle of view, and the shorter the focal length, the larger the angle of view. The length of focal length is inversely proportional to the depth of field. The longer the focal length, the smaller the depth of field, and the shorter the focal length, the greater the depth of field. The length of the focal length is inversely proportional to the strength of perspective. The longer the focal length is, the weaker the perspective is, and the shorter the focal length is, the stronger the perspective is. The focal length is inversely proportional to the contrast, the longer the focal length is, the smaller the contrast is, and the shorter the focal length is, the larger the contrast is. The farther the focusing distance is, the deeper the depth of field is, and the closer the focusing distance is, the shallower the depth of field is. Therefore, you should select a lens with a larger focusing distance when shooting distant shots, and use a smaller focusing distance when shooting close shots. The lens focusing distance is expressed in cm (centimeters), which is very clear.
Switcher: There are manual switching and automatic switching. The manual mode is to see which way to put the switch to which way; the automatic mode is to make the preset video delay and switch in sequence. The switching time can be adjusted by a knob. , generally between 1 second and 35 seconds. If you do not require monitoring at any time, you can add a switch in the monitoring room and connect the camera output signal to the input of the switch. The output of the switch is connected to the monitor. The input of the switch is divided into 2, 4 6, 8, 12 and 16, the output is divided into single and dual, but also can switch audio (depending on the model).
Video Server: It is a kind of special computer equipment for compressing, storing and processing video and audio data. It is widely used in video surveillance, network teaching, Ip video conference, advertisement insertion and video program on demand. The video server uses M-JPEG, H. 261, H. 263, MPEG-2, MPEG-4 and other compression formats, compress and encode video data in accordance with the technical specifications, to meet the storage and transmission requirements. With multi-channel input and output, a variety of video and audio format interface. Can be equipped with SCSI, FC and other network interfaces for networking, video and audio data transmission and sharing. It consists of video and audio compression encoders, mass storage devices, input/output channels, network interfaces, video and audio interfaces, RS422 serial interfaces, protocol interfaces, software interfaces, video and audio crosspoint matrix, etc., and provides external locks. Phase and video processing functions.
Network Camera: It is a new generation camera that combines the traditional camera and network technology. It can transfer the image through the network to the other end of the network connection port, and the remote viewer does not need to use any professional software, as long as the standard A web browser (such as "Microsoft IE or Netscape") can monitor its image. The webcam has an embedded chip embedded in the real-time operating system. The video signal sent from the camera is digitized and compressed by a highly efficient compression chip and passed through the network bus. Transfer to web server.
Users on the network can directly use the browser to view the camera images on the Web server. The authorized users can also control the actions of the camera pan-tilt lens or operate the system configuration.
Motion detection: The entire monitoring screen is divided into multiple small areas. The user can arbitrarily select the area in the area and can set the sensitivity level of 1-20 for the selected monitoring area. In this way, when something moves, it will be detected by the camera server while recording.
Communication interface: The communication interface in the security monitoring system is mainly for the input and output of video and audio. Therefore, the communication interface generally has the following types: RS-232, RS-485, and general network interfaces. It can support PSTN, ISDN, LAN and various networking environments, and has a USB2.0 ultra-high-speed data interface. It connects the computer to back up important image data. Optional with progressive scan VGA output interface.
Monitor: It is the standard output of the monitoring system. With the monitor we can view the images sent from the front end. The monitor is divided into color, black and white, sizes 9,10,12,14,15,17,21 inches, etc., commonly used is 14 inches. The monitor also has a resolution and is represented by the same number of lines as the camera. In practice, it is generally required that the number of monitor lines matches the camera. In addition, some monitors have audio input, S-video input, RGB component input, etc., except for the audio input monitoring system, the rest of the functions are mostly used for image processing work, and will not be introduced here.
Video amplifier: When the video transmission distance is relatively long, it is better to use a video line with a thicker diameter, and it is also possible to increase the signal strength of the video amplifier in the line to achieve long-distance transmission. Video amplifiers can enhance the video's brightness, chroma, and synchronization signals, but intra-line interference signals can also be amplified. In addition, too many video amplifiers cannot be connected in series in the loop, otherwise saturation may occur, resulting in image distortion.
PTZ: It is an installation platform composed of two alternating currents that can move horizontally and vertically. According to the use of the environment is divided into indoor and outdoor type, the main difference is that the outdoor type sealing performance, waterproof, dustproof, large load. The loading method is divided into side loading and lifting, that is, whether the PTZ is installed on the ceiling or on the wall. The shape is divided into ordinary type and ball type. The ball type PTZ is placed in a hemispherical, spherical protective cover, in addition to preventing dust from disturbing the image, it is also concealed, beautiful and fast.
Embedded system: refers to the operating system and functional software integrated in the computer hardware system. Simply put, the application software of the system is integrated with the hardware of the system, similar to the way of working with the BIOS. With a small software code, highly automated, fast response and so on. Particularly suitable for systems that require real-time and multi-tasking.
Full duplex: At the same time, it can be sent and received. Full-duplex requirements: Receive and send each have a separate channel, can be used to achieve communication between the two stations and star network, ring network, can not be used for the bus network.
Half duplex: It is not possible to send and receive at the same time. Half-duplex requirements: Transmitting and receiving can share the same channel. Local area networks that can be used in various topologies are most commonly used in bus networks. Half-duplex data rates are theoretically half of full-duplex.
Directional Curtain Infrared Detector: Generally, it adopts two-way pulse counting work mode, that is, alarm from direction A to direction B, and direction B to direction A do not alarm. With the ability to identify intrusion direction, the user enters the guard zone from the inside to the outside and will not trigger an alarm. Returning within a certain period of time will not cause an alarm. Only an illegal intruder will trigger an alarm when intruding from the outside, which greatly facilitates the user in the defense. The vigilance within the area does not trigger the alarm system at the same time.
Automatic high-speed tracking fast ball: It is a combination of optics, electronics, machinery, information processing and networking. It is composed of camera, power transmission, motion control device, image analysis, identification, compression and communication based on high-speed parallel processing. With video camera, position control, position and lens presets, moving target detection, identification and tracking, flame and smoke detection alarm and other functions. When the moving target enters the spherical camera's field of view, a high-speed DSP chip is used to perform the difference calculation between the previous frame image and the current image. When a certain value is reached, a certain part of a frame is determined as a moving object, and then The ball machine gives instructions to the dome camera so that it can circulate back and forth, thus controlling the dome camera to achieve continuous tracking of moving objects without the need for human operations and without the support of computer systems. LINE LOCK is a synchronization method that uses AC power to lock the sync pulse of the camera field. When the image is disturbed by a net power caused by the AC power source, turn the switch to the position of the line lock synchronization (LL) to eliminate the AC power interference.
Automatic gain control: The video signal output by the camera must reach the standard level specified by the television transmission. That is, in order to output the standard video signal under different scene illumination conditions, the gain of the amplifier must be within a relatively large range. Make adjustments. This gain adjustment is usually done automatically by detecting the average level of the video signal. The circuit that implements this function is called an automatic gain control circuit, abbreviated as AGC circuit. With AGC-enabled cameras, the sensitivity will be improved in low illumination, but the noise at this time will be more obvious. This is due to the simultaneous amplification of signal and noise.
Source: It is the source of the sound, there is no sound source, and it is impossible to use the sound system to restore the sound. The sound source has two meanings. The first is the carrier that records the sound. Only by first recording the sound on a certain carrier, can we use audio equipment to restore the sound on the carrier. These carriers are the source of sound in the sound system. So called the sound source. The other meaning of the sound source refers to the device that plays the sound source carrier. Signals that are continuous in time and whose amplitude continuously changes with time are called analog signals (for example, sound waves are analog signals, currents transmitted in audio systems, and voltage signals are also analog signals). The sources of recording and processing analog signals are analog sound sources such as tapes. / Deck, LP/LP player. The analog sound source recording and processing signal is the original appearance of the sound (accurately speaking, the electric signal converted from the sound), and can be directly amplified by a conventional amplifier, and the processing is convenient and direct; the digital sound source recording and processing are all 0 The abstract binary data stream formed by combining with 1 permutation is very unintuitive. Acoustic waves are analog and cannot be used directly by digital audio sources. They must be converted to digital signals through conversion equipment before they can be recorded on digital audio sources. During playback, the data read by the digital audio source device cannot be amplified directly by a conventional amplifier and must first be converted to an analog signal. It can be seen that the digital audio signal processing process is much more complicated. However, the advantages of digital audio sources are outstanding: the signal-to-noise ratio and dynamic range are far superior to those of analog audio sources, and the quality of the signal does not decrease after multiple copies and multiple transmission links. This analog audio source cannot be achieved anyway.
AVS: It is an audio and video coding technology standard developed by China. The AVS Working Group was established in June 2002 and the first working meeting began in August of that year. After 7 AVS formal working conferences and 3 video group additional conferences, it took a year and a half to examine 182 proposals and adopted 41 proposals. On December 19, 2003, the AVS video was finally finalized. The core technologies featured in AVS-Video include 8x8 integer transform, quantization, intra prediction, 1/4-precision pixel interpolation, special inter prediction motion compensation, two-dimensional entropy coding, and deblocking effect in-loop filtering. The current AVS-video technology can achieve compression of different formats such as standard definition (CCIR 601 or equivalent) and low definition (CIF, SIF).
Real-time editing technology: means that the hard disk recorder can process the collected raw data in real time and convert it into a standard MPEG-1 or MPEG-2 format image file and store it directly to the hard disk without any backlog or loss of data. This is mainly compared with computer burning. When the computer burns, the original data is collected first, and then the data is processed and converted into a standard MPEG-1 or MPEG-2 format image file. Real-time codec technology requires the entire system to be fast enough. Otherwise, it can only meet the requirements by reducing the quality of the image and reducing the amount of data.
Super HAD image sensor: Built-in CCD image sensor using the "Super Hole Accumulation Diode (HAD)" electronic image quality enhancement technology to improve the CCD sensor performance and strengthen the digital signal processing function, effectively reduce noise and reduce noise when shooting images. Necessary interference will make the picture clearer and brighter, with clearer color gradation, and will be particularly effective when there is not enough light in the scene or when shooting night scenes.
White Balance: White Balance. The color of the object will change due to the color of the projected light. Images captured in different light situations will have different color temperatures. For example, photographs taken in a lighting environment with tungsten light bulbs (light bulbs) may be yellowish. In general, CCDs have no way of automatically correcting light changes like the human eye. Therefore, through the correction of the white balance, it will immediately adjust the intensity of the red, green and blue colors of the entire image according to the image quality in the current image to correct the error caused by the external light. Some cameras provide manual white balance adjustment in addition to white balance function or specific color temperature white balance function.
Variable code stream codec technology: It refers to the codec can automatically adjust the bandwidth according to the size of the data, encountered rapid changes in the image, when the color is more abundant when the allocated bandwidth is greater; the image changes slowly, the color is not rich The allocated bandwidth is smaller, so as to save the hard disk space while ensuring the quality of image recording.
Fixed code stream codec: The provided bandwidth is fixed, regardless of the size of the data, when the image is rich in color and changes rapidly, often the bandwidth is not enough to reduce the quality of the video, it seems that the image is a little pause or color change; and the image data When the volume is not large, there are more bandwidths available, wasting storage space.
Pixels: One of the most important indicators for measuring cameras. Some products are marked with 300,000 pixels or 350,000 pixels in the box. In general, higher pixel products have better image quality. But on the other hand, it is not that the higher the pixel, the better. For the same picture, the higher the pixel, the stronger the ability to analyze the image. In order to obtain high-resolution images or images, the amount of data it records is also large. Much more, the requirements for storage devices are much higher, so you should pay attention to the relevant storage devices when choosing.
Access control system: It is a new way of access management: Permission to allow people to enter the designated area, while rejecting people without authority. The protagonist of this system is a card reader or password pad installed on the door side. They transfer the read data to the local controller and confirm whether it can be used according to the pre-programmed database.
Vertical Sync: It is the simplest method to synchronize two cameras. The vertical drive frequency ensures that the video can use the old switching period or four-segment machine to display several image sources on the same monitor. The vertical drive signal is usually composed of pulses with a repetition rate of 20/16.7 ms (50/60 Hz) and a pulse width of 1 to 3 ms.
Color video composite signal synchronization: Color video composite signals represent video and color trigger signals, meaning that the camera can synchronize with external composite color video signals. However, despite the so-called color video composite signal synchronization, only horizontal synchronization and vertical synchronization are actually performed without color trigger synchronization.
External synchronization: very similar to color video composite signal synchronization. A camera can be synchronized to the video signal of another camera. An external synchronization camera can use the input color video composite signal to extract horizontal and vertical synchronization signals for synchronization.
DC Line Locking: An old technology that uses a DC 50/60 Hz power line current to synchronize the camera. Because DC 24V power is widely used in most building fire alarm systems, it is very easy to obtain. Since old models of switchers and segmentation systems do not have digital memory functions, to maintain stable images, synchronization between cameras is very necessary. DC line locking is the synchronization of the camera to AC 50/60 Hz, and the correlation and level of time between color channels. Unconstrained / vertical signals result in poor color conversion (color phase design), so all users using AC line locks inevitably lose their color conversion. Fortunately, today's splitters and 16-channel composite processors as well as hard disk recorders have internal memory to overcome this problem, eliminating the need for synchronization signals, so AC line locks may be eliminated several years later.
Colorless scrolling: Digital signal processor video cameras used under fluorescent lighting can only produce serious color scrolling images. The image changes from white to blue, pink to white, and so on. This is because of the problems caused by AC power running at 50/60 Hz. The white light bulb provides stable light, and the fluorescent light fluctuates at 8.3 ms due to the intensity and color of the alternating current. The traditional camera calculates the white balance needs 100-150ms (0.1-0.15) , It is 8.5ms slower than alternating current, therefore can never catch up. Color scrolling can be clearly generated by passing the current image through 8 cycles.
Backlight Compensation: Provides ideal exposure of the target in front of very strong background light, whether the primary target moves to the center, up, down, left or right, or anywhere on the screen. An ordinary camera that does not have super dynamic characteristics only has a shutter speed of 1/60 seconds and F2.0 aperture selection, but a very bright background behind a main target or a point light source is unavoidable and the camera will acquire The average of all recent rays determines the level of exposure. This is not a good idea because when the shutter speed increases, the aperture will be closed causing the main target to become too dark to be seen. To overcome this problem, a method called backlight compensation is widely used on most cameras through a weighted area theory. The image is first divided into 7 blocks or 6 areas (two areas are repeated). Each area can be independently weighted to calculate the exposure level. For example, the middle part can be added to the rest of the block by 9 times, so that one is in the middle of the screen. The goal of the location can be seen very clearly, because the exposure is mainly calculated with reference to the light level of the middle region. However, there is a very big flaw. If the main target moves from mid-to-left to the top, bottom, left and right positions of the screen, the target will become very dark, because now it is not differentiated and has not been weighted.
F denotes the aperture of the lens, F stop 2:1 and f3.4 mm means that the focal length of the lens is 3.4 mm.
The lenses F2.0 and f3.4 to 4 are very economical and should be used at low prices. Widely used in single-board cameras, the aperture of the F2.0 lens collects half the light of the human eye, and the f3.4 mm lens There is a 60 degree viewing angle on a 1/4 inch CCD and a 90 degree viewing angle on a 1/3 inch CCD, very close to the human eye. The two eyes of the human eye can contain a larger angle of view, from person to person, typically with an angle of 150 to 180 degrees, but remember that the F stop and f focal length are only basic parameters of a shot and do not represent quality. Ultra-wide dynamics is a feature that allows the camera to see images under very strong contrast. A wide dynamic camera is more than a dozen times larger than a camera with a traditional 3:1 dynamic range. Natural light ranges from 120,000 Lux to 0.00035 Lux at night. When the camera looks out of the window from the room, the indoor illumination is 100 Lux, while the outside scenery may have an illumination of 10,000 Lux. The contrast is 10,000/100=100:1. This contrasting eye can be easily seen because the human eye can handle a contrast ratio of 1000:1. However, traditional closed-circuit surveillance cameras can deal with it with great problems. The traditional camera has a contrast ratio of only 3:1. It can only Choose to use 1/60 seconds of electronic shutter to get the correct exposure of the indoor target, but the outdoor image will be cleared (all white); or alternatively, the camera selects 1/6000 second to get the perfect exposure of the outdoor image, but the indoor The image will be erased (full black).
Peak-sensing mode: The exposure index is determined by replacing the average value of the entire image with the image highlights. Users of the rule system can respond to the most demanding requirements, such as capturing a white point image in the dark and seeing this small Bright white details and colors.
CMOS: The full name is Complementary Metal-Oxide Semiconductor, which translates to complementary metal oxide semiconductors. The manufacturing technology of CMOS is no different from general computer chips. It is mainly made of semiconductors made of silicon and germanium, which make it possible to coexist on the CMOS with N (band-electricity) and P (band + electricity) grades. In semiconductors, the current generated by these two complementary effects can be recorded and interpreted by the processing chip as an image.
CCD: The full name is Charge Coupled Device, and the Chinese translation is a charge coupled device. It uses a high-sensitivity semiconductor material to convert light into electric charge, and then converts the electric signal into a digital signal through an analog-to-digital converter chip. The digital signal is compressed and transmitted to a computer via a USB interface. The captured image.
The concept of depth of field: When an object is in focus, all scenes from a certain distance in front of the object to a certain distance behind it are also clear. The distance from front to back where the focus is quite clear is called the depth of field. Depth of field is divided into depth of foreground and depth of field, and depth of field is greater than foreground depth. The deeper the depth of field is, the farther away from the focal point of the scene can be clear, and the depth of field is shallow, and the scene far from the focus is blurred.
Focal length: is an optical parameter that any optical instrument has. From the optical principle, the focal length is the distance from the focal point to the center of the lens. For the lens, focal length has a very important significance. The focal length is proportional to the size of the image. The longer the focal length, the larger the imaging. The shorter the focal length, the smaller the imaging. The focal length of the lens is inversely proportional to the size of the viewing angle, the longer the focal length, the smaller the angle of view, and the shorter the focal length, the larger the angle of view. The length of focal length is inversely proportional to the depth of field. The longer the focal length, the smaller the depth of field, and the shorter the focal length, the greater the depth of field. The length of the focal length is inversely proportional to the strength of perspective. The longer the focal length is, the weaker the perspective is, and the shorter the focal length is, the stronger the perspective is. The focal length is inversely proportional to the contrast, the longer the focal length is, the smaller the contrast is, and the shorter the focal length is, the larger the contrast is. The farther the focusing distance is, the deeper the depth of field is, and the closer the focusing distance is, the shallower the depth of field is. Therefore, you should select a lens with a larger focusing distance when shooting distant shots, and use a smaller focusing distance when shooting close shots. The lens focusing distance is expressed in cm (centimeters), which is very clear.
Switcher: There are manual switching and automatic switching. The manual mode is to see which way to put the switch to which way; the automatic mode is to make the preset video delay and switch in sequence. The switching time can be adjusted by a knob. , generally between 1 second and 35 seconds. If you do not require monitoring at any time, you can add a switch in the monitoring room and connect the camera output signal to the input of the switch. The output of the switch is connected to the monitor. The input of the switch is divided into 2, 4 6, 8, 12 and 16, the output is divided into single and dual, but also can switch audio (depending on the model).
Video Server: It is a kind of special computer equipment for compressing, storing and processing video and audio data. It is widely used in video surveillance, network teaching, Ip video conference, advertisement insertion and video program on demand. The video server uses M-JPEG, H. 261, H. 263, MPEG-2, MPEG-4 and other compression formats, compress and encode video data in accordance with the technical specifications, to meet the storage and transmission requirements. With multi-channel input and output, a variety of video and audio format interface. Can be equipped with SCSI, FC and other network interfaces for networking, video and audio data transmission and sharing. It consists of video and audio compression encoders, mass storage devices, input/output channels, network interfaces, video and audio interfaces, RS422 serial interfaces, protocol interfaces, software interfaces, video and audio crosspoint matrix, etc., and provides external locks. Phase and video processing functions.
Network Camera: It is a new generation camera that combines the traditional camera and network technology. It can transfer the image through the network to the other end of the network connection port, and the remote viewer does not need to use any professional software, as long as the standard A web browser (such as "Microsoft IE or Netscape") can monitor its image. The webcam has an embedded chip embedded in the real-time operating system. The video signal sent from the camera is digitized and compressed by a highly efficient compression chip and passed through the network bus. Transfer to web server.
Users on the network can directly use the browser to view the camera images on the Web server. The authorized users can also control the actions of the camera pan-tilt lens or operate the system configuration.
Motion detection: The entire monitoring screen is divided into multiple small areas. The user can arbitrarily select the area in the area and can set the sensitivity level of 1-20 for the selected monitoring area. In this way, when something moves, it will be detected by the camera server while recording.
Communication interface: The communication interface in the security monitoring system is mainly for the input and output of video and audio. Therefore, the communication interface generally has the following types: RS-232, RS-485, and general network interfaces. It can support PSTN, ISDN, LAN and various networking environments, and has a USB2.0 ultra-high-speed data interface. It connects the computer to back up important image data. Optional with progressive scan VGA output interface.
Monitor: It is the standard output of the monitoring system. With the monitor we can view the images sent from the front end. The monitor is divided into color, black and white, sizes 9,10,12,14,15,17,21 inches, etc., commonly used is 14 inches. The monitor also has a resolution and is represented by the same number of lines as the camera. In practice, it is generally required that the number of monitor lines matches the camera. In addition, some monitors have audio input, S-video input, RGB component input, etc., except for the audio input monitoring system, the rest of the functions are mostly used for image processing work, and will not be introduced here.
Video amplifier: When the video transmission distance is relatively long, it is better to use a video line with a thicker diameter, and it is also possible to increase the signal strength of the video amplifier in the line to achieve long-distance transmission. Video amplifiers can enhance the video's brightness, chroma, and synchronization signals, but intra-line interference signals can also be amplified. In addition, too many video amplifiers cannot be connected in series in the loop, otherwise saturation may occur, resulting in image distortion.
PTZ: It is an installation platform composed of two alternating currents that can move horizontally and vertically. According to the use of the environment is divided into indoor and outdoor type, the main difference is that the outdoor type sealing performance, waterproof, dustproof, large load. The loading method is divided into side loading and lifting, that is, whether the PTZ is installed on the ceiling or on the wall. The shape is divided into ordinary type and ball type. The ball type PTZ is placed in a hemispherical, spherical protective cover, in addition to preventing dust from disturbing the image, it is also concealed, beautiful and fast.
Embedded system: refers to the operating system and functional software integrated in the computer hardware system. Simply put, the application software of the system is integrated with the hardware of the system, similar to the way of working with the BIOS. With a small software code, highly automated, fast response and so on. Particularly suitable for systems that require real-time and multi-tasking.
Full duplex: At the same time, it can be sent and received. Full-duplex requirements: Receive and send each have a separate channel, can be used to achieve communication between the two stations and star network, ring network, can not be used for the bus network.
Half duplex: It is not possible to send and receive at the same time. Half-duplex requirements: Transmitting and receiving can share the same channel. Local area networks that can be used in various topologies are most commonly used in bus networks. Half-duplex data rates are theoretically half of full-duplex.
Directional Curtain Infrared Detector: Generally, it adopts two-way pulse counting work mode, that is, alarm from direction A to direction B, and direction B to direction A do not alarm. With the ability to identify intrusion direction, the user enters the guard zone from the inside to the outside and will not trigger an alarm. Returning within a certain period of time will not cause an alarm. Only an illegal intruder will trigger an alarm when intruding from the outside, which greatly facilitates the user in the defense. The vigilance within the area does not trigger the alarm system at the same time.
Automatic high-speed tracking fast ball: It is a combination of optics, electronics, machinery, information processing and networking. It is composed of camera, power transmission, motion control device, image analysis, identification, compression and communication based on high-speed parallel processing. With video camera, position control, position and lens presets, moving target detection, identification and tracking, flame and smoke detection alarm and other functions. When the moving target enters the spherical camera's field of view, a high-speed DSP chip is used to perform the difference calculation between the previous frame image and the current image. When a certain value is reached, a certain part of a frame is determined as a moving object, and then The ball machine gives instructions to the dome camera so that it can circulate back and forth, thus controlling the dome camera to achieve continuous tracking of moving objects without the need for human operations and without the support of computer systems. LINE LOCK is a synchronization method that uses AC power to lock the sync pulse of the camera field. When the image is disturbed by a net power caused by the AC power source, turn the switch to the position of the line lock synchronization (LL) to eliminate the AC power interference.
Automatic gain control: The video signal output by the camera must reach the standard level specified by the television transmission. That is, in order to output the standard video signal under different scene illumination conditions, the gain of the amplifier must be within a relatively large range. Make adjustments. This gain adjustment is usually done automatically by detecting the average level of the video signal. The circuit that implements this function is called an automatic gain control circuit, abbreviated as AGC circuit. With AGC-enabled cameras, the sensitivity will be improved in low illumination, but the noise at this time will be more obvious. This is due to the simultaneous amplification of signal and noise.
Source: It is the source of the sound, there is no sound source, and it is impossible to use the sound system to restore the sound. The sound source has two meanings. The first is the carrier that records the sound. Only by first recording the sound on a certain carrier, can we use audio equipment to restore the sound on the carrier. These carriers are the source of sound in the sound system. So called the sound source. The other meaning of the sound source refers to the device that plays the sound source carrier. Signals that are continuous in time and whose amplitude continuously changes with time are called analog signals (for example, sound waves are analog signals, currents transmitted in audio systems, and voltage signals are also analog signals). The sources of recording and processing analog signals are analog sound sources such as tapes. / Deck, LP/LP player. The analog sound source recording and processing signal is the original appearance of the sound (accurately speaking, the electric signal converted from the sound), and can be directly amplified by a conventional amplifier, and the processing is convenient and direct; the digital sound source recording and processing are all 0 The abstract binary data stream formed by combining with 1 permutation is very unintuitive. Acoustic waves are analog and cannot be used directly by digital audio sources. They must be converted to digital signals through conversion equipment before they can be recorded on digital audio sources. During playback, the data read by the digital audio source device cannot be amplified directly by a conventional amplifier and must first be converted to an analog signal. It can be seen that the digital audio signal processing process is much more complicated. However, the advantages of digital audio sources are outstanding: the signal-to-noise ratio and dynamic range are far superior to those of analog audio sources, and the quality of the signal does not decrease after multiple copies and multiple transmission links. This analog audio source cannot be achieved anyway.
AVS: It is an audio and video coding technology standard developed by China. The AVS Working Group was established in June 2002 and the first working meeting began in August of that year. After 7 AVS formal working conferences and 3 video group additional conferences, it took a year and a half to examine 182 proposals and adopted 41 proposals. On December 19, 2003, the AVS video was finally finalized. The core technologies featured in AVS-Video include 8x8 integer transform, quantization, intra prediction, 1/4-precision pixel interpolation, special inter prediction motion compensation, two-dimensional entropy coding, and deblocking effect in-loop filtering. The current AVS-video technology can achieve compression of different formats such as standard definition (CCIR 601 or equivalent) and low definition (CIF, SIF).
Real-time editing technology: means that the hard disk recorder can process the collected raw data in real time and convert it into a standard MPEG-1 or MPEG-2 format image file and store it directly to the hard disk without any backlog or loss of data. This is mainly compared with computer burning. When the computer burns, the original data is collected first, and then the data is processed and converted into a standard MPEG-1 or MPEG-2 format image file. Real-time codec technology requires the entire system to be fast enough. Otherwise, it can only meet the requirements by reducing the quality of the image and reducing the amount of data.
Super HAD image sensor: Built-in CCD image sensor using the "Super Hole Accumulation Diode (HAD)" electronic image quality enhancement technology to improve the CCD sensor performance and strengthen the digital signal processing function, effectively reduce noise and reduce noise when shooting images. Necessary interference will make the picture clearer and brighter, with clearer color gradation, and will be particularly effective when there is not enough light in the scene or when shooting night scenes.
White Balance: White Balance. The color of the object will change due to the color of the projected light. Images captured in different light situations will have different color temperatures. For example, photographs taken in a lighting environment with tungsten light bulbs (light bulbs) may be yellowish. In general, CCDs have no way of automatically correcting light changes like the human eye. Therefore, through the correction of the white balance, it will immediately adjust the intensity of the red, green and blue colors of the entire image according to the image quality in the current image to correct the error caused by the external light. Some cameras provide manual white balance adjustment in addition to white balance function or specific color temperature white balance function.
Variable code stream codec technology: It refers to the codec can automatically adjust the bandwidth according to the size of the data, encountered rapid changes in the image, when the color is more abundant when the allocated bandwidth is greater; the image changes slowly, the color is not rich The allocated bandwidth is smaller, so as to save the hard disk space while ensuring the quality of image recording.
Fixed code stream codec: The provided bandwidth is fixed, regardless of the size of the data, when the image is rich in color and changes rapidly, often the bandwidth is not enough to reduce the quality of the video, it seems that the image is a little pause or color change; and the image data When the volume is not large, there are more bandwidths available, wasting storage space.
Pixels: One of the most important indicators for measuring cameras. Some products are marked with 300,000 pixels or 350,000 pixels in the box. In general, higher pixel products have better image quality. But on the other hand, it is not that the higher the pixel, the better. For the same picture, the higher the pixel, the stronger the ability to analyze the image. In order to obtain high-resolution images or images, the amount of data it records is also large. Much more, the requirements for storage devices are much higher, so you should pay attention to the relevant storage devices when choosing.
Access control system: It is a new way of access management: Permission to allow people to enter the designated area, while rejecting people without authority. The protagonist of this system is a card reader or password pad installed on the door side. They transfer the read data to the local controller and confirm whether it can be used according to the pre-programmed database.
Step Light
SYA LIGHTING The step light install in wall,step,corner. has the characteristics of small size, low power consumption, long service life, sturdy and durable. Low power consumption, long life, easy installation, chic and elegant shape, anti-leakage, waterproof;
1. The LED light source has a long life, no accidents and almost no need to change the bulb, one time construction, several years of use.
2. Low power consumption, no need to pay high electricity bills for lighting and beautification.
3. Waterproof, dustproof, pressure resistant and corrosion resistant
Our other products range:LED Underground Light, LED Underwater Light, LED Wall Washer Light, LED Linear Light , LED Outdoor Flood Light, LED Garden Light , LED landscape light , LED Strip Light , LED Step Light etc.
LED stair Light,Foot Light,Waterproof Step Light,Stair Step Light,path Light
SHENGYA LIGHTING TECHNOLOGY CO., LTD. , https://www.syalighting.com