Monday, 10 August 2015

Video Surveillance [CCTV]

Image result for video surveillanceVideo surveillance, commonly known as CCTV.

What is CCTV?

Closed Circuit Television (CCTV) is a system where the circuit in which the video transmitted is closed and all the elements (camera, display monitors, recording devices) are directly connected. This is unlike broadcast television where any receiver that is correctly tuned can pick up and display or store the signal. In the past, these signals would be transmitted to a monitor equipped with a video cassette recorder, but these h
ave been all but totally replaced by digital video recorder (DVR) systems that can store far more video and back up data automatically.

What is CCTV Used For?

Image result for video surveillanceThe most common use of CCTV is in security surveillance systems. They’ve been found for years in areas like large retail shops, banks, and government institutions. Thanks to reduced costs in the manufacture of cameras and video recording equipment, camera systems are becoming more and more commonplace in smaller businesses, and even private homes.

CCTV has become ubiquitous in large cities, along major highways, and areas that host large events. On streets and roads, CCTV is often used in traffic law enforcement, but it’s used to monitor traffic patterns, allowing emergency services to react quickly to accidents and for maintenance departments to better plan necessary construction projects. In hotels, stadiums, and convention centers, CCTV is often used in private television networks, broadcasting sporting events or special events throughout their facilities.

CCTV Cameras

Any camera that broadcasts a signal can be attached to a CCTV system, whether it’s wired or wireless, but they are most often associated with high-end surveillance cameras. Pan/tilt/zoom (PTZ) cameras allow a user to remotely control a camera. The type of lens used will depend on the application and area the camera will be installed

Beyond this list, there are many other names that cameras go by, but most of those are more related to the application in which the unit will be used vs. the type of camera (i.e., front door cam, nanny cam, license-plate cam, elevator cam, etc.). Other references speak to the housings, such as tamper-proof, weatherproof, etc.

Image result for video surveillanceBullet A bullet CCTV camera is a wall-mount or ceiling-mounted unit that is typically designed for indoor use, but can also be fill some outdoor applications. The camera derives its name from its sleek, thin cylindrical shape. Many bullet cameras also tout themselves as being waterproof. The camera is not typically designed to have pan/tilt/zoom control but instead to capture images from a fixed area. The unit is mounted pointing at a particular area.
Dome: A dome cameras get their name from the dome-shaped housing in which they sit. These housings are designed to make the cameras unobtrusive… not covert or hidden. Typical applications are retail, where the camera is designed to be unobtrusive, but visible.

These units serve a dual purpose: “bad guys” will know the facility is being watched and patrons will feel at ease knowing the facility is being protected. Units that allow the camera to spin quickly within the housing are often referred to as “speed domes.”
Image result for video surveillance
Covert/Desktop/Board Cameras: These tiny cameras are well suited for desktop use for Skype and other low-resolution teleconference applications.

Discreet Cameras: It’s clock… it’s a smoke detector… it’s motion sensor. The real answer is none of the above. These are just some of the disguises for covert cameras. Of course, covert cameras can also be characterized by conventional cameras placed in discreet locations.

Infrared/Night Vision: These night-vision cameras have the ability to see images in pitch black conditions using IR LEDs. In some cases they are for mobile applications.

Outdoor: The key to outdoor cameras is the housing itself, which must be impenetrable to moisture, insects, dust and other elements.

Day/Night: Day/night cameras compensate for varying light conditions to allow the camera to capture images. These are primarily used in outdoor applications where the security camera is positioned for an outdoor parking lot, for example. In many cases, units are dubbed as having a wide dynamic range to function in glare, direct sunlight, reflections and strong back light 24/7.

Varifocal: A camera with a varifocal lens allows the operator to zoom in or out while still maintaining focus on the image.

Network/IP: These cameras, both hardwired and wireless, transmit images over the Internet, often compressing the bandwidth so as not to overwhelm the web. IP cameras are easier to install than analog cameras because they do not require a separate cable run or power boost to send images over a longer distance.

Wireless: Not all wireless cameras are IP-based. Some wireless cameras can use alternative modes of wireless transmission. But no matter what the transmission method, the primary benefit to these units is still the same: extreme flexibility in installation.

PTZ/Speed Domes: Pan/tilt/zoom cameras give the surveillance operator the ability to move the camera left or right (pan); up and down (tilt); and zoom the lens closer or farther. These are relegated to surveillance situations where there is an actual live guard or surveillance specialist monitoring the images. There are cameras that have automated pan/tilt/zoom functionality where the camera is moving on a timed basis. These are many times used to cover a wide area with only one camera, or to avoid poor light conditions, such as a setting sun.

High-Definition Cameras: Ultra high-definition cameras are often relegated to niche markets, such as casinos. These give the operators the ability to zoom in with extreme clarity (to look at poker players, for example, who might have something up their sleeve). In the past, these cameras were tube-based analog cameras, but today’s digital technology has displaced those older units. The cameras can also transmit their images using HDcctv