Composition and functionality of modern processors.
Speaking about modern video surveillance, you can often hear the phrases «digital video signal processing», «video signal processing processor», «digital video camera functions» … They all refer to the chip installed in modern video cameras. Their common name is Image signal processor (ISP). In this article, we will try to understand the composition and functionality of modern processors that significantly help to get a high-quality image from a video camera.
First, let's consider the structure of a modern analog (non-IP) video camera using the NextChip NVP2170 chip as an example.
The image (light flux) that has passed through the lens and is formed in the CCD matrix using the CFA – color filter array (a set of optical filters for forming color components of the video signal) is fed to the analog-to-digital converter (AFE in the diagram) and then in digital 10-bit form directly to the chip-processor of the signal processing. The formed video signal that has been processed in the chip is fed to the consumer (for example, to a video recorder) through an amplifier. The analog interface of the chip includes a black level binding circuit, a distortion correction circuit, a 10-bit ADC. The clock generator forms all the clock pulses necessary for the CCD: RG, frame and line sync pulses, sensitivity adjustment pulses and pulses of the substrate and its offset (CCD Control Timing Pulse bus). V-Driver is responsible for the formation of horizontal scanning and brightness.Among other interfaces of the chip we note control of the IRIS drive lens, the possibility of external synchronization of the video signal, control of the processor menu via the RS485 protocol, control of the IR illumination, connection of the OSD menu control buttons, the information channel of the motion detector. The chip control firmware is located in the flash memory, if necessary, the user can access not only the user OSD menu, but also the technical menu with the ability to change the factory settings.
The structural diagram of the processor itself (as an example, NextChip NVP2170) is shown in Fig. 2
The functionality of modern processors is so wide that it is quite difficult to imagine a function that would be necessary but would be absent in a modern chip. Let's list the main functional capabilities:
BLC – Backlight Compensation, or in the Russian variation of the name “Backlight Compensation”. The function allows you to get a high-quality image even if a bright light source is directed at the camera or the object is against a brightly lit background. There is an option called HS BLC (Highlight Suppression Backlight Compensation) (HBLC, HLC-Highlight Compensation) – this function inverts the brightest areas of the frame. In the OSD menu, you can adjust the location of the processed area of the frame, the processing level, the operating time (all day or only night). In some chips, you can adjust 2 frame segments and select the color that replaces the super-bright areas of the frame, as well as the intensity of the inversion.
The WDR function (in simple terms, the dynamic range is defined as the ratio of the maximum brightness value of the image to its minimum value) allows you to organize high-quality viewing of both light and dark areas of the frame. Double scanning of the frame using fast modern processors divides the frame into two components consisting of dark and light areas of the frame. Each component is processed separately (the dark part becomes brighter, the light part remains the same or slightly decreases in brightness), then these two parts are combined into a frame. The result is a picture of equally high-quality processed dark and light areas. In addition to brightness, the image contrast is also automatically adjusted.
DNR (Digital Noise Reduction) is a noise reduction system in a color image under low light conditions. There are many names for this function, depending on the manufacturer of the chip or camera. It should be noted that 2DNR and 3DNR differ in the method of signal processing and, accordingly, in the quality of the result.
Adjustment of brightness and contrast of video signal, full adjustment of white balance in several automatic and manual modes.
Setting the GAMMA value. Gamma correction of the video signal for comfortable perception of the video sequence on the monitor by the human eye. If the main monitor in the past was a monitor based on a cathode-ray tube (CRT), for which the optimal GAMMA value was 0.45, now it is possible to set this value both for the monitor used (for LCD this value is 0.55), and in manual setting mode.
Control of the lens shutter with a large number of values in manual mode and the presence of an automatic mode (SHUTTER in the menu).
AGC is an automatic system for amplifying the video signal to a standard level.
SENS-UP – charge accumulation function. Allows for surveillance in very low light conditions. Especially relevant for perimeter surveillance. Usually, when specifying the minimum possible illumination at which the camera generates a readable video signal, this particular function in the chip is taken into account.
Day-night mode operation in various versions: only color/only monochrome/automatic state transition according to settings in the lighting levels menu/joint operation with IR illumination from an external sensor.
D-Zoom – digital zoom, in different models from 4x to 16x.
PRIVACY – the ability to close private zones in the video frame. From 4 to 12 depending on the chip.
MOTION DETECT – a motion detection function that can be adjusted by sensitivity and location in the frame. Usually, cameras do not have a dry contact at the output, and the user does not receive anything except information on the screen.
CAM TITLE – the ability to designate a camera with an alphanumeric name with a choice of the location of the camera name in the frame.
DIS (Digital Image Stabilization) – a digital image stabilization system. The function allows you to compensate for minor camera shakes.
SmartIR – control of the brightness of the IR diodes. Smart-IR allows not to illuminate areas of the image when the object of observation approaches the camera. For example, when a person approaches, Smart-IR will reduce the intensity of the backlight, and his face will not turn into a bright spot.
LANGUAGE – the ability to select the menu language. Many manufacturers supply cameras with a Russian-language menu to Russia.
The functional components of the chips can vary depending on the price niche and model ranges.
The wide range of settings for cameras with a processor allows you to more accurately prepare the camera for work in a specific situation. At the same time, the same model with different settings can work perfectly both on the perimeter and on vehicle license plates or as an overview.
It is safe to say that at the moment there is a race not only for increasing the resolution of matrices, but also for the power and functionality of DSP — signal processors. Let's hope that functionally filled chips will gradually fall in price and will find their application not only in the medium and professional niche of surveillance cameras, but also in the lower price range. And, accordingly, the power and functionality of the chips used will increase.
It is probably also worth noting the following: the use of processors and the need to configure cameras through the menu requires a higher level of training from the installer. Both in understanding the functionality of cameras and in knowledge of foreign languages. Therefore, training and preparation of installers should be carried out more often and with the use and demonstration of the most modern technologies. And the consumer should pay attention to the professional training of the installation organization.
CN8 Arctic (DiGiVi)
Outdoor IR camera CN8 Arctic camera of Korean assembly is equipped with a Nextchip digital signal processor, which in tandem with the latest generation Sony matrix provides video with a resolution of 600 TVL. In terms of functionality, the camera is an analogue of the CN3-CH2-VFA16IR DNR model and is distinguished by the presence of a control joystick directly on the body of the camera unit.
The Nextchip processor provides control and configuration via the OSD menu of the following functionality: 3D-DNR noise reduction, WDR dynamic range, HS BLC backlight compensation, AGC, white balance, Sens-up, Smart IR illumination (range of at least 30 m), DIS image stabilization and a number of others.
CN8 Arctic DiGiVi with dual power supply and cold start from -50 °C. An additional thermal relay has been added to the camera circuit, which first turns on the camera heating. When the internal temperature reaches -5 °C, power is supplied to the camera electronics.
СHVD-ITW650RFA (Infinity)
CHVD-ITW650 RFD is an intelligent dome camera based on the SONY Effio processor and the SONY 960H matrix, which forms an ultra-clear image with a resolution of 650 TVL in color and 700 TVL in black and white mode. The camera has an extended set of functional capabilities, including a WDR system, 3D noise reduction, intelligent backlight compensation system, privacy masking, etc.In addition to the standard functions, the SONY Effio processor allows automatic monitoring of the viewing area, analyzing the image in real time. There are motion detectors with the ability to digitally zoom in on the area and abandoned/missing objects. There are functions for face recognition, taking into account the direction of movement and counting moving objects, monitoring scene changes.
TK-C2201WPE (JVC) Vandal-proof Dome Video Camera
Designed for outdoor surveillance. When an optional heater is installed, it works reliably at temperatures down to -30°C. The camera produces high-quality color/black-and-white (mechanical IR filter) images with a resolution of 600 TVL at illumination levels of up to 0.05/0.006 lux. The latest 14-bit DSP processor provides four times the improvement over 12-bit in terms of improved depth and greater image realism.
The TK-C2201WPE features JVCSuper LoLux™ technology, which provides correct color rendition in low light conditions; AreaWhiteBalance, which allows you to apply automatic white balance to individual areas of the frame; BLC for «aligning» light and dark areas in conditions of backlighting; 3DNR noise reduction mode; selection of gamma correction type by switching LCD1/LCD2/CRT modes.
LSR700P (LG)
High-resolution day/night color outdoor video camera with built-in varifocal lens, 70m IR illumination, mechanical IR filter (ICR) and wide dynamic range (WDR).
CCD matrix —. Resolution – 540 TVL color/570 TVL b/w mode. Built-in digital DSP-processor XDI. Varifocal lens 6–50 mm with auto iris. Minimum illumination – 0 lux. Built-in IR illumination – 45 LEDs. Dynamic noise reduction, backlight compensation. OSD menu. Built-in digital effects. 4 areas of privacy masking. Power – 12 V DC, power consumption – 8.4 W. Overall dimensions – 96 x 170 mm. Operating temperature from -40 ° C to 50 ° C. Housing protection rating IP66.
All-weather IR video camera camera JTW 6600TDN-V212IR (Jetek Pro)
It is based on the latest generation DSP processor NextChip NVP 2170 along with a high resolution of 600 TVL, additional features, the main goal of which is to achieve a clear image under any conditions and lighting.
The Smart-IR function allows you to effectively compensate for strong illumination of the observed object from an infrared light source. The sensitivity of the camera, equipped with the function of accumulation of charge on the matrix (DSS), is up to 0.00002 lux.
D-WDR – electronic expansion of the dynamic range allows you to get a contrast image regardless of the intensity of illumination and backlight HSBLC – compensation for bright backlight. 3D-DNR image noise filtering technology gives a clear picture in low light and allows you to save up to 70% of the hard drive space of the video recorder.
All-weather video camera CNB-XHB-21CS (CNB Technology)
The CNB-XHB-21CS ultra-high-resolution video camera with built-in IR illumination and varifocal lens is based on the Blue-I processor.
The Blue-I processor's WDR system provides a clean, balanced picture thanks to shooting in two sensitivity modes. High resolution of 580 TVL and automatic adjustment, as well as correction of color transition edges, provide a more vivid, natural picture. The Blue-I processor's 3D-DNR noise reduction system forms the most optimal image quality in low light, applying average noise filtering. And the Global Motion system automatically eliminates moire on moving objects.
The Eclipse eclipse function, working in conjunction with analog signal amplification at low light levels, darkens bright light sources and forcibly increases the sensitivity of the video camera. Image stabilization allows you to completely eliminate image shaking and get a perfectly clear picture with any camera vibrations.
Anti-fog television cameras «EVS»
The cameras have an automatic image contrast adjustment mode of up to 15 dB and can significantly improve the image when observing in difficult weather conditions (fog, haze, snowfall, etc.). Contrast is necessary not only in difficult weather conditions, but also to improve the efficiency of detecting low-contrast objects, especially when using long-focus lenses or microscopes with high magnification, where the contrast level can be reduced several times due to optical limitations. The contrast circuit automatically detects a decrease in image contrast and, if necessary, automatically increases it in the specified conditions up to 20 times.
SCO-2370 (Samsung)
The SCO-2370 camera uses the W5 chipset (processor) (also known as W-5,
WV). This chipset consists of 2 microcircuits (DSP, AFE). Supports horizontal resolution of 600 TV lines (color), 700 TV lines (b/w). ADC bit depth of 10 bit. Up to 32 masking zones. Increased sensitivity (frame integration). Motion detection, day/night mode. Supports AFD (autofocus detector). 2D+3D noise reduction technology (SSNRIII). Electronic zoom x256. Remote control via coaxial cable or RS-485.
Operating temperature from -50°C to +50°C with 24V AC power supply.
1/4″ Super HAD II CCD matrix. 37x optical zoom (3.5 — 129.5 mm), 16x digital. On-screen menu in 15 languages, including Russian. Backlight compensation. Extended dynamic range SSDR. Digital image stabilization. Sensitivity increase (frame integration) from 2 to 512 times.