Transportation Management Centers: Streaming Video Sharing and Distribution - Final Report
Chapter 8. Camera and Communications Equipment
The types of cameras used by agencies can impact an agency's streaming capabilities. It can also affect the desire for third-party access. Legacy cameras can be analog instead of digital/IP, and they can have different aspect ratios, lenses, and communication protocols—all of which can dramatically affect image quality, zoom capabilities, field of view, and the potential cost associated with streaming those camera feeds to third parties. Most consumer televisions are either HD or 4K resolution, and broadcasters want to deliver equivalent quality video to consumers. This means that these broadcasters typically desire a much higher quality of images than most agencies stream today. Figure 7 depicts 12 resolution types found in cameras and in consumer television monitors. Most legacy CCTV cameras output video towards the far lower left quadrant of this chart. Quarter Common Intermediate Format or QCIF (shown in the lower left corner) is what many legacy CCTV cameras broadcast—640 x 480px.
IP camera resolutions can come in a wide variety of forms. Table 2 shows an example of the more common IP camera resolutions.
|Name||Horizontal Pixels||Vertical Pixels||Megapixel|
|CIF (Common Intermediate Format)||320||240||0.1|
|VGA (Video Graphics Array)||640||480||0.3|
|WVGA (WideVideo Graphics Array)||752||480||0.4|
|SXGA (Super Extended Graphics Array)||1280||1024||1.3|
|UXGA (Ultra Extended Graphics Array)||1600||1200||1.9|
|QXGA (Quantum Extended Graphics Array)||2048||1536||3.1|
|QSXGA (Quad Super Extended Graphics Array)||2560||2048||5.2|
The higher the resolution of an agency's CCTV camera, the greater potential value it will have to broadcasters and other stakeholders. Figure 8 shows how, at higher resolutions, greater detail can be detected in each frame of video—in this example, text printed on a highway sign can't be seen at the lower resolution.
However, just because an agency has a high-resolution camera does not mean that the agency must rebroadcast its CCTV feed at the same resolution as is seen back at the TMC. Most streaming solutions will allow the agency to specify the format and resolution of the broadcast—thus saving the agency in bandwidth costs (if that is a concern). Some agencies make their lower-resolution streams available free of charge and only charge for higher resolution feeds to recoup increased networking costs. Others simply make the receiving agency or media outlet pay for a dedicated feed.
Ideal IP Camera Specifications
IP cameras come in many types with many different specifications. Each specification can impact the eventual cost of rebroadcasting to third parties. To keep costs lower and to enable greater control over who ultimately can see the video feeds, agencies should replace older cameras with updated ones that support "independent multiple profiles concurrently." Agencies should be aware that some camera manufacturers state that they support multiple profiles, but in practice, they only support one of the profiles at a time. This is particularly important when agencies want to maintain a high-resolution streaming capability for internal operations, but need to be able to simultaneously stream to third parties at a lower resolution.
Table 3 includes specifications that an IP camera must support in order to maximize capabilities and reduce costs. The camera(s) must support these parameters in a separate profile, which means the cameras must support multiple stream profiles.
|Video Compression||H.264 sometimes referred to as MPEG4 Part 10 AVC (Advanced Video Coding).|
|Resolutions||Bare minimum target is CIF which is anywhere from 320 X 240 to 352 X 240 and others in this general range.|
|Frame Rate||Target is 15 fps (frames per second) Most specification sheets will give max numbers like 30 fps. This usually indicates "up to" which means they will support 15 frames per second.|
|Protocols||The preferred protocol is *RTSP (Real Time Streaming Protocol)|
|Bandwidth or (Bit Rate)||The target is 192 Kbps (Kilobits per second). Ensure that the camera supports adjustable/controllable bandwidth.|
|Separate Stream Profile Preferred||It is preferred that cameras support separate streaming profiles to provide video to share without impacting the organization's ability to provide internal video for its internal core mission.|
Emerging Features & Technologies
CCTV and IP Camera technologies are constantly evolving. Below are a list of current and emerging CCTV features that agencies may want to evaluate as they deploy new cameras or replace existing ones.
|Technology||Why it might be useful|
|HD or higher resolution cameras||Higher resolution cameras enable more details to be gleaned from each camera—especially when the camera is a long distance from the roadway. HD resolution cameras can also provide greater coverage per camera at lower zoom levels.|
|Ultra zoom lenses||Ultra-zoom lenses allow for a single camera to cover a wide area at a great distance. For example, a camera can be placed high atop a radio or cell-phone tower or building and be located many miles away from the roadway while still providing for equivalent monitoring capabilities as a side-of-road camera. Attaching cameras to far-off locations can reduce costs as power and networking may be more readily available. A single camera with pan/tilt/zoom capabilities can also be leveraged to scan a wide area. Ultra-zoom lenses will need to be stabilized as small movements in the camera due to wind or vibrations can be exaggerated at high zoom levels.|
|Innovative lenses||Some camera manufacturers deploy fish-eye lenses or upwards facing lenses that look at cone-shaped mirrors. These lenses, when coupled with the right software, can allow for a stationary camera to provide virtual Pan/Tilt capabilities to multiple users at the same time—allowing two or more individuals to look in different directions.|
|Finer control PTZ with zero drift||Fine control PTZ cameras make zooming into and targeting incident locations easier. Most newer cameras also enable better position locking, which prevents the camera from drifting over time.|
|Integrated Detection||While more difficult to find on PTZ cameras, some manufacturers are rolling out embedded detection technologies in cameras that can detect anomalies, count vehicles, detect weather, etc.|
|Low-light and no-light cameras||Low and no-light cameras are a must for night operations. The newest cameras have advanced filtering and contrast control, which all but eliminate headlight glare and allow for night-time surveillance that comes much closer to typical daylight capabilities. These cameras can also help with other contrast issues at sunrise/sunset or going into or out of tunnels.|
|Thermal cameras||While still quite expensive, thermal imaging cameras offer the greatest night-time detection and monitoring capabilities of any camera technology today. They are also particularly useful for surveillance and infrastructure monitoring use-cases.|
|Dual cameras||Some agencies are deploying dual-camera technologies. For example, a single mount might include a standard HD color camera positioned directly next to a night-vision or thermal imaging camera.|
|Orientation Sensors||Most newer IP cameras can provide tile and rotation data back to the TMC to allow the agency to map which direction (north, south, east, west, etc.) the camera is facing at any given time.|
|Mobile Cameras||Several agencies are now deploying mobile PTZ cameras to the top of their Service Patrol and/or maintenance vehicles. When coupled with in-vehicle streaming solutions, these mobile CCTV assets can allow TMC operators boots on the ground viewing capabilities.|
|Camera/Sensor integration||A few manufacturers are now integrating additional sensors into cameras—understanding that some agencies may want to deploy more capabilities at each site. For example, some manufacturers may integrate CCTV cameras into RWIS stations, Doppler radar, pavement temperature sensors, etc.|