CCTV Cameras Explained (Surveillance Cameras)
CCTV camera technology is advanced and sophisticated, necessitating the expertise of a CCTV installer to install and set it up correctly. There are numerous options available, as well as terminology you may not be familiar with. So we decided to write this guide to help you better understand CCTV cameras when considering a home or business CCTV installation. If you have any questions while reading this guide, please contact us at +254722555289.
Rapidtech Digital Solutions not only installs CCTV systems but also supplies CCTV surveillance equipment such as CCTV cameras, DVRs (Digital Video Recorders), NVRs (Network Video Recorders), and tools for CCTV installation.
Many factors must be considered when purchasing a CCTV surveillance camera system, such as how the system will be used, technical CCTV camera specifications, and the constraints of the environment in which the system will be installed. Each section of the buyer’s guide below will educate you on various aspects of CCTV cameras.
CCD Chip Size & Chip Sets
The primary function of a CCTV camera is to capture light and convert it into a video signal. A CCD sensor is the heart of a CCTV camera (Charge Coupled Device). This converts light into an electrical signal. Signal processing converts an electrical signal into a video signal that can be displayed on screen or recorded.
Surface sizes for CCDs are typically 1/2 inch, 1/3 inch, 1/4 inch, and 1/8 inch. To summarize, these are not the actual sizes of the sensors, but rather their video camera tube equivalent. Because image sensors were historically used to replace video camera tubes, a sensor with a 1/4-inch digital sensor is more accurately described as a ‘1/4-inch video camera tube equivalent’.
Analogue Versus Digital
Analogue Camera System
In an analog camera system, the camera captures an analog signal, which is then transmitted to the DVR via a coax cable (Digital Video Recorder). The DVR converts the analog signal to a digital signal, compresses it, and stores it on the DVR’s hard drive. The footage can be viewed on monitors connected to the DVR or sent across a network to be viewed on a computer screen. The DVR can be configured to transmit over the internet, and when done with an analog system, all of the cameras’ signals are sent as a single stream using a single IP address, making it very efficient.
Digital IP Network Camera
Each digital IP (Internet Protocol) camera captures an analog signal, which is then converted to a digital signal within the camera. Digital processing may also take place within the camera. The digital signal is then routed through a LAN (Local Area Network). Ethernet cables, such as Cat 6 Lan cables, are used in this case.
Instead of an analog system’s DVR, the video from each IP camera is compressed and recorded onto an NVR (Network Video Recorder). The main difference is that the signal is digital and has a much higher resolution. The NVR streams video from all cameras and broadcasts it over LAN and the internet for remote viewing.
DSP – Digital Signal Processing
Digital signal processing cameras use a DSP chip to convert analog video signals to digital signals. A CCD chip (charge-coupled device – see above) generates the analog signal, which is then converted to digital by the DSP chip. DSP camera benefits include increased brightness, image stability, sharper images, and improved power efficiency. There is also less sensitive to noise.
Camera Cables and Connections
An effective CCTV camera system necessitates proper and high-quality cabling and connectors to connect the system’s components.
This cable is made up of two cables that are connected together to supply power and video signal. This cable is also known as RG59. The video element of the cable allows video signals to be transmitted from the camera to the DVR. The power cable connects the camera to the power box. A BNC connector is used for the power cable. This cable is compatible with analogue camera systems as well as High Definition (HD) systems that use coax, such as HD-CVI or HD-TVI cameras.
Cat5e LAN Ethernet Cables
Cat5e cable can be used for either analogue or IP cameras and can transmit video up to 3000 feet.
The RJ45 connector is used on this cable. This is a common cable used in CCTV systems and is essential in IP camera systems. Cat5e is ideal for analogue systems, but it requires the use of a video balun (converter) to replace traditional coax.
Cat5 cables are of poor quality and should not be used with CCTV systems; Cat5e is a better cable for these purposes.
Another consideration with Cat5e is how you power your cameras. PoE, or Power over Ethernet, is a system that we will discuss now.
PoE – Power over Ethernet
Power over Ethernet (PoE) is a network technology that allows cameras to be powered by a single network cable. A camera normally requires two cables: one for video signal and one for power. When a camera is PoE enabled, only one cable is required to supply power and handle the video signal.
Saves time and money by not having to install electrical cabling. Installation of network cables does not necessitate the use of a qualified electrician.
Benefits of PoE
- Camera placement – because cameras do not require a power outlet, they can be placed anywhere and easily relocated if necessary.
- Safety – PoE is an intelligent system that protects equipment from incorrect installation, power overload, or underpowering.
- Power is more reliable when it comes from a single source rather than multiple wall sockets. In the event of a power outage, PoE can be backed up with another power supply.
- PoE allows for easier network distribution.
Wired and Wireless Cameras
Wired cameras use PoE cables (Power over Ethernet). PoE means that each camera has only one cable, making installation easier.
Because the signal from wired cameras is unaffected by internet outages or interference, it is more reliable. Wireless cameras are impacted by a loss of Wi-Fi or a weak Wi-Fi signal caused by obstacles such as walls and weather.
Wireless cameras have the significant advantage of not requiring holes to be drilled into walls, and removing the wireless camera installation leaves the property unaffected and as it was prior to the installation.
Wired cameras are typically used in commercial and business settings, whereas wireless cameras are more common in residential settings.
WIRED CAMERAS | |
ADVANTAGES | DISADVANTAGES |
Limited interference from other devices | More difficult to install |
Signal is not easily hacked or jammed | Holes drilled in walls to feed cables |
Good for different protected zones | Not portable and easily moved to another location. |
Good for large buildings | |
Picture quality better than wireless | |
Signal more stable than wireless |
WIRELESS CAMERAS | |
ADVANTAGES | DISADVANTAGES |
Quick and simple to install | Can be affected by interference causing failure or false trigger of motion detection |
No holes in wall required | Potential to be hacked |
Cameras can be located anywhere but need to be within Wi-Fi range | More expensive than wired systems |
Portable and can easily be moved to another building | Needs one cable for power |
Camera resolution is defined as the amount of detail that a CCTV camera can capture. Pixels are the unit of measurement for resolution. A higher pixel count means more detail and larger images that aren’t blurry or grainy. Resolutions are measured in Megapixels, which is slightly more than one million pixels (1,048,576 to be exact). The horizontal resolution is multiplied by the vertical resolution to get the total value in megapixels. The best CCTV resolution can be found at the bottom of the table below.
CCTV Camera Common Video Resolutions
CCTV CAMERA COMMON VIDEO RESOLUTIONS | |
NAME | PIXELS (W X H) |
720p HD | 1280 x 720 |
960p HD | 1280 x 960 |
1.3 Megapixels | 1280 x 1024 |
2 Megapixels | 1600 x 1200 |
1080p HD | 1920 x 1080 |
3 Megapixels | 2048 x 1536 |
4 Megapixels | 2592 x 1520 |
5 Megapixels | 2592 x 1944 |
HD – High Definition.
Analogue HD CCTV supports resolutions of 720p and 1080p as of 2017, whereas digital IP cameras support resolutions ranging from 720p to 5 Megapixels.
The Frame Rate
CCTV cameras typically have frame rates of 25 FPS (frames per second). This results in smooth video while also reducing file size on the DVR hard drive.
Lenses
A CCTV lens is made of glass and focuses light from the scene onto the image sensor of the camera.
Viewing Angle
This is the width or height of the scene that the CCTV camera is watching.
Depth of Field
Depth of Field (DoF) is the zone of focus within a video image that runs from front to back. As a result, there will be a focus area in front and behind the target area in all videos. A small zone of focus is referred to as shallow depth of field, while a large zone of focus is referred to as deep depth of field. DoF is influenced by three factors: aperture, camera distance from subject, and lens focal length.
Focal Length
The focal length of a lens determines its field of view at different distances.
Fixed vs. Varifocal Lenses
A fixed lens does not allow you to change the focal length, zoom, or angle of view. The majority of fixed lens cameras have a wide angle. These settings on a varifocal lens can be changed.
Varifocal lens security cameras are generally more expensive than fixed lens cameras, but they have the following advantages. With a fixed lens, your installer would have to physically move and reinstall the camera to adjust the field of view. The installer can change the field of view by adjusting the focal length of a varifocal lens. The settings on a varifocal lens can be adjusted to capture a specific localised area at your premises, such as a doorway or a window. Even if a camera is placed far away across a room, it is possible to zoom in and focus on the doorway. In other words, varifocal makes it easier to capture the action you need. People or objects in that area will be larger and thus easier to identify and use as evidence. When the only place for a camera outside is under a roof overhang, but this may be too far away from the area you want to view, the solution is to use a varifocal lens and zoom in to the scene you want to capture.
We recommend and use varifocal lenses for our installations as we can adjust the lens easily and they are generally easier to work with.
Types of Iris: Auto, Fixed, and Manual Iris
What is an iris?
An iris is an opening or aperture that regulates the amount of light that passes through the lens. This is referred to as ‘exposure.’ The iris of a CCTV camera functions similarly to that of a still camera; the more open the iris, the brighter the image. Controlling the iris is critical for improving image quality. The iris controls the amount of light that reaches the CCD image sensor, resulting in images that are clear, sharp, and have good resolution and contrast (see further down this guide).
Fixed Iris
A CCTV camera with a fixed iris is ideal for settings with consistent light levels, such as indoors. These are the cheapest and cannot be adjusted.
Manual Iris
When installed, they are similar to fixed irises but can be adjusted manually. Indoor use only.
Auto Iris
An auto iris is a component of a motorized lens that can automatically adjust to maintain a constant level of light in the video image – useful in environments where light levels change, such as outdoors.
P-Iris
This is a ‘precise’ iris. It auto adjusts like the auto iris, but the camera’s software also allows for improved video clarity and depth of field. The primary goal of the P-Iris is to improve image quality by allowing optimal iris position so that the central, best performing part of the lens is used as much as possible.
Rapidtech Digital Solutions typically employs auto iris because it is widely available and because the camera adjusts itself in various lighting conditions, saving time and money.
Pan, Tilt, and Zoom (PTZ)
Pan, tilt, zoom (PTZ) IP cameras allow users to control the position and movement of the camera lens remotely via an Internet browser or specialized software.
Panning is the horizontal movement of the lens to the left and right. Tilting is movement in the vertical axis, up and down. Zooming is the process of changing the focal length of a lens to bring the subject closer or further away.
The advantages of PTZ are that remote operation of pan, tilt, and zoom allows an operator to cover a much larger area with a single camera, saving money. Furthermore, automatic presets can cover large areas.
The advantages of PTZ are that remote operation of pan, tilt, and zoom allows an operator to cover a much larger area with a single camera, saving money. Furthermore, automatic presets can cover large areas.
Some PTZ cameras can track moving targets by using their PTZ functions.
Video Motion Detection
A CCTV system’s ability to detect movement and begin recording is known as video motion detection (VMD). The VMD is managed by the Digital Video Recorder.
In a business setting, VMD allows the operator monitoring the CCTV to not be constantly focused on camera footage where there is no change in the image. The cameras are constantly monitored by the VMD system processor. When there is no operator present, VMD can save hard drive space on the DVR by only recording footage when motion is detected. Furthermore, all recorded footage will have movement events that can be replayed to monitor, saving time on monitoring.
Motion detection compares the current image to the previous one, and if many of the pixels have changed, it has detected movement.
Auto -Tracking Objects with PTZ CCTV Cameras
PTZ auto-tracking, a type of camera software closely associated with motion detection, can be used to automatically track moving objects. Auto-tracking takes motion detection a step further by calculating which part of the image is moving and classifying it as an object. The camera will then move to keep that object in frame. This is useful for tracking down an intruder and gathering evidence.
Contrast
Contrast is the separation of the video image’s brightest and darkest areas. Increasing contrast increases the separation between light and dark, making shadows appear darker and light areas appear brighter. When the contrast is reduced, the shadows become lighter and the highlights become darker, bringing them closer together.
Monochrome Versus Color
There are cameras that can capture video in color, monochrome (black and white), or both. Switching cameras are used in low-light environments because monochrome is more sensitive to low-light conditions. Monochrome can also be used with infrared lighting.
Night Vision
The ability of a camera system to see in complete darkness or to improve vision in low light is referred to as night vision.
A popular method of night vision is near-infrared illumination. The camera’s CCD detector is sensitive to near-infrared radiation, which is invisible in this method. This is combined with LEDs on the camera that emit infrared light. At night, the camera’s lux (unit of illuminance) sensor detects low light levels and switches the camera chip to monochrome, turning on white led lights and red infrared lights. The camera then records in black and white, and you can see a clear picture recorded on the system.
License Plate Recognition
LPR can also be enabled on camera systems (License Plate Recognition). The British Police invented LPR in 1976, and it was initially a crude system with limitations, but several decades later it is advanced and reliable.
LPR captures images or videos of license plates, which are then processed to produce a text entry of the license plate.
Branded Versus Non-Branded cameras
Branded CCTV cameras are preferable to non-branded models. Branded cameras go through a quality control process, meet all relevant European standards, and are more durable and reliable. Unbranded cameras are not certified products. We use branded products because they are higher quality.
Although QVIS is a high-quality brand, high-security organizations such as banks prefer Honeywell because they provide even higher quality. Sony and Samsung are also excellent.
Physically, unbranded and branded cameras may look the same or similar, but unbranded cameras do not perform as well in terms of image quality.
In Conclusion
As you can see from reading this article, there are numerous factors to consider when selecting a CCTV camera. The variety of options can be befuddling, and for the uninformed, selecting the right cameras for a specific application is difficult. From the actual camera and its functionality to cabling and electrical power considerations, every link in the chain in a CCTV system is critical. To deliver the best possible video image, each element must work in unison. We hope you now have a better understanding of CCTV cameras and how they can be used.
You can also check:
Understanding Analogue HD versus IP CCTV Cameras
Business Surveillance Cameras in Kenya
CCTV Installations Services in Kenya
Home CCTV Installation Services in Nairobi, Kenya
Business and Commercial CCTV Installations Services in Nairobi, Kenya
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