What is CCTV?
CCTV
Closed-circuit
television, or CCTV as it is more widely known, is used for video surveillance.
"Closed-circuit" refers to transmissions that are often sent to a
small (closed) group of monitors, as opposed to "normal" TV, which is
sent out to the whole public. Although CCTV networks are frequently employed to
identify and discourage criminal activity, as well as to record traffic
violations, they have further applications.
German
scientists created CCTV for the first time in 1942 to watch the launch of V2
rockets. It was subsequently employed by American scientists during atomic
bomb testing.
کلوزڈ سرکٹ ٹیلی ویژن، یا سی سی ٹی وی جیسا کہ یہ
زیادہ مشہور ہے، ویڈیو نگرانی کے لیے استعمال کیا جاتا ہے۔ "کلوزڈ سرکٹ"
سے مراد وہ ٹرانسمیشنز ہیں جو اکثر مانیٹروں کے ایک چھوٹے (بند) گروپ کو بھیجی جاتی
ہیں، جیسا کہ "عام" ٹی وی کے برعکس، جو پوری عوام کو بھیجی جاتی ہے۔
اگرچہ CCTV نیٹ ورک اکثر مجرمانہ سرگرمیوں کی نشاندہی کرنے اور ان کی
حوصلہ شکنی کے ساتھ ساتھ ٹریفک کی خلاف ورزیوں کو ریکارڈ کرنے کے لیے استعمال کیے
جاتے ہیں، ان کے پاس مزید درخواستیں ہیں۔
جرمن سائنسدانوں نے پہلی بار 1942 میں بنایا۔ راکٹ V2 کی لانچنگ دیکھنے
کے لیے CCTV بعد ازاں اسے امریکی سائنسدانوں نے
ایٹم بم کی جانچ کے دوران استعمال کیا۔
The applications of CCTV
Helpful in managing Crime
Potential
offenders may be deterred by CCTV surveillance. Video evidence can aid law
enforcement in their investigation after a crime has been committed and
subsequently serve as proof in court. Audio, thermal, and other forms of
sensors can notify authorities of unusual events, such as a fire or gunshots when used in conjunction with CCTV. CCTV cameras can track and record internal
criminal activity for firms. To stop drones from carrying drugs and other
contraband to inmates, prisons may deploy video surveillance. Security cameras
can keep an eye on places that are difficult to get to, like rooftops.
Helpful to minimize Disaster
Emergency
services and rescue personnel can assess and monitor occurrences in real time
using CCTV cameras, and they can then provide a "situation" to disaster
management teams through video from a variety of locations, including within a
burning structure, from a cave, or from a helicopter hovering over a scene.
Overspeed monitoring and management
Traffic statistics and video evidence for speeding are collected by cameras at traffic lights and other locations across cities. Security cameras are an example of certain sensory nodes that evaluate the images they capture but do not communicate or store them to safeguard people's privacy. In general, only a small number are kept for senior academics to use in "developing the computer vision program." Privacy advocates have expressed some reluctance about the idea.
monitoring and diagnosis of illnesses
About 43 facial muscles are used to convey emotions and thoughts. Intelligent software is better than individuals at recognizing various expressions from photographs, such as pain or worry. CCTV cameras can also keep an eye on patients, such as youngsters or the elderly, to spot potential medical emergencies like a stroke, an epileptic seizure, or an asthma attack.
Beneficial
for social and psychological research
According
to CCTV utilized in a suicide study, 83 percent of those attempting to run in
front of a train exhibited tendencies. These are now utilized to
notify monitor watchers of suspected suicides after being later evaluated from
CCTV footage. Researchers also employ surveillance networks to monitor crowd
activity in public areas and stop antisocial conduct. For security reasons and
to document bullying or playground occurrences, cameras have been employed in
schools.
Other
Marketing research benefits
Videos gathered from consumer video surveillance are being used to analyze purchase habits and enable improved strategizing, for example, how people shop, which aisles they frequent the most, and how likely they are to act on calls to action in various store layouts. Retailers can use heat maps to identify peak buying times, preferred promotion kinds, and staffing needs during these times. They can also indicate the highs and lows of customer flow at points in a store.
Different systems of CCTV
For continuous video transmission over coaxial cables, use Bayonet Neill-Concelman (BNC) connectors. Although they are inexpensive and efficient, they have a low resolution. An analog system has more peripherals, such as the fact that conventional coaxial connections typically don't convey audio. Even with older equipment, going digital is more cost-effective since analog signals can be converted to digital form. The photos can be saved on a PC or tape recorder and require a video capture card. Analog HD is an improvement over conventional systems (1080 pixels), enabling higher resolution, and is backward compatible with analog cameras and BNC.
Signals are digitalized at the camera level. These systems don't need a video capture card because images are saved straight to a computer, but since recordings take up a lot of (relatively) storage space, they are typically severely compressed.
These systems use a video server to stream video over the internet when used with analog or digital cameras. Wi-Fi and audio compatibility, Distributed Artificial Intelligence (DAI) for video analysis, remote access, Power Over Ethernet (POE), and higher resolution are some of the benefits. Additionally, IP cameras have the capacity to combine many cameras into a single unit, enabling them to capture a wide angle that would often need several cameras or camera systems.
Key technical terms for CCTV
Video encoders
With
the help of video encoders, analog CCTV systems can be converted to some
types of network systems, allowing customers to benefit from more affordable
hardware and cutting-edge functionality. In order to deliver video signals to a
wired or wireless IP-based system, the software first permits a wired
connection and digitalizes the video signals.
Image sensors
Different kinds of image sensors, which transform light into
electronic impulses, are used in cameras. Multiple photodiodes, also known as
pixels, make up a sensor. These photodiodes measure the amount of exposed light
and convert it into electrons. CCD and CMOS (complementary metal oxide
semiconductor) are the two most often used formats (charged coupled devices).
- CCD sensors are more expensive than CMOS sensors. Megapixel (using millions of pixels) CMOS sensors could even compete with CCD sensors in terms of quality.
- CCD - These are more expensive and use more electricity. Due to their increased light sensitivity and quieter operation than CMOS scanners, CCD scanners are typically the best choice in dim lighting settings. Although the signal is analog, an analog-to-digital converter transforms the pixel values into numeric values before transmitting them.
Image scanning
- While CMOS and CCD sensors can utilize either progressive or interlaced scanning for digital CCTV, CCD sensors typically use an interlaced scanning approach (immediate exposure). Only interlaced scanning is used by analog cameras.
- Interlaced (common for CCD applications) - In this technique, the odd and even TVLs (where l stands for lines) from an image are transmitted. Good resolution is provided by cameras with more than 400 lines, and high resolution is defined as more than seven hundred lines. By periodically refreshing these messages, less bandwidth is used while yet deceiving the brain into thinking it is seeing a single, complete image. This is true as long as an interlaced recording is viewed on an interlaced monitor; an interlaced image may appear jagged on a progressive scan monitor. To create progressive scans that can be viewed on both analog and progressive scan monitors, modern video software first deinterlaces interlaced scans.
- Progressive (common for CMOS applications): With this technique, the image is not divided into fields (odd and even lines). Instead, the image is scanned, and then a monitor sequentially displays each line (or field).
Recorders
- DVRs typically connect to various internal components within the CCTV system rather than external networks. Analog cameras are usually utilized with DVRs. Every camera in a DVR system needs to be directly connected to the recorder.
- NVR systems encode and process data at the camera level and feed it to the recorder, which is then utilized for storage and remote monitoring, in contrast to DVR systems, which process video themselves. Most NVR systems employ IP cameras. Each IP camera in an NVR system is connected to the same network.
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