What is a large space?
Large space monitoring refers to the continuous space open without visual partition. In the field of monitoring, the main difference between small space monitoring is that large space monitoring cannot be achieved with a single camera but need to use a combination of multiple cameras or PTZ camera monitoring to achieve most covering.
For example, the highway toll station and service area, all belong to large space.

  
The importance and complexity of large space monitoring
Compared with the small space monitoring, large space monitoring range is bigger, more moving object, lack of physical isolation, etc. The openness and liquidity of the large space determines its frequently happened violations. A lot of illegal and criminal behavior and mass incidents occurred in the large space area. So large space monitoring has been a top priority in the field of monitoring.
But due to the large space is usually open public area, with more moving object and need to monitor more complete coverage. A single camera can't do, it has blind spot. Therefore, large space monitoring is the most complex one in monitoring field. It's hard to make early warning in the large space monitoring, a lot of them become decorations. Unclear image or blind angle found during replay, can't see the violations.

Large space monitoring term introduction 1 - "pixel density" -requirement for clarity
Below picture 1shows the different resolution required "pixel density", such as a 2 million pixels (1920 x 1080 resolution) camera, if it illuminates the target scene with width of 10m, then its pixel density in width= 1920 / 10 = 192 pix/m. Resolution between 164 pix/m and 246 pix/m in picture 1.
When monitoring goes into the digital age, the pixel density should be an important basis when we design definition of monitor system.
In practice, if monitoring system only requires monitoring of overall situation, doesn't need to identify the faces, identify license plate, and even look at the cashier's note denomination, the pixel density of 70 pix/m will be enough. Otherwise, 130 pix/m or even as many as 250 pix/m pixel density is your basic requirement.

Picture 1 Effects in different resolution (pix/m)

Large space monitoring term introduction 2 - "invalid pixels" - waste of pixels
In the design and implementation of the monitoring system, often appear "invalid pixels".
It is a kind of surveillance cameras vision beyond monitoring body, occupies camera pixels with irrelevant area, so these pixels are wasteful, namely "invalid pixels.
Shown in the following picture (picture 2), if our purpose is to monitor the parking lot, so area outside of red box is "invalid pixels.

  
Equipment parameters:

1. 14 million & 20 million pixel automatic tracking high-definition video camera
Pixels: 14 & 20 million pixels
Max perspective: 180 & 360 ° 
Color black conversion: electric infrared filter color black
Minimum illumination:color black and white 0 lux @ infrared sensitive
Dynamic range: up to 100 db
Signal-to-noise ratio: 51 db
Automatic gain control: > 120 db
Shutter speed: 1/1000 s ~ 1/2 s adjustable
Compression way: h. 264 and MJEPG
Protocol support: TFTP, HTTP and RTSP, RTP/TCP, RTP/UDP
Backlight compensation: support
The white balance: automatic and manual
Support electronic through fog and strong inhibition, three-dimensional positioning, 3D noise reduction
Support 9 video output, can define stream, resolution, frame rate
Function: when there are mobile vehicles or person, the camera automatically capture and use the maximum resolution separate output of a moving vehicle and mobile person tracking video, up to8 independent video output at the same time.
Network interface: 100/1000 m Ethernet network interface
Working temperature: - 40C ~ + 50 C
Humidity: 0% ~ 90% of condensation
Protection grade: IP66 waterproof and dustproof