Posts Tagged ‘ Closed Circuit Television’



CCTV Surveillance

Written By:
Tuesday, March 8th, 2011

Thanks to modern technology, CCTV Surveillance has advanced leaps and bounds over the past several years. Not only have systems advanced but prices have dropped considerably making a home digital video security and surveillance system not just something for the “rich and famous.”

CCTV surveillance or Closed Circuit TeleVision surveillance today inherited its name from many decades ago.  The first CCTV surveillance systems were based on analog and not digital video transmission.  In fact the phrase “Closed Circuit Television” was created in reference to actual television cameras.

Television cameras were originally an analog device; that is their signal was sent as an analog signal.  The analog cameras used for live News, Sporting Events, and other “broadcasts” sent their video signal to the studio for processing.  Here the signal was fine tuned; edited if need be, amplified and sent via large antennas to the open public.  Anyone with a receiver (television set) and an antenna could see and hear the video image and audio sound.

Close Circuit Television used the same type of cameras as the cameras used by television broadcast stations, with one exception.  Instead of broadcasting the signal via an antenna to the open public, CCTV surveillance sent its signal through an individual cable that was connected to a specific video recorder and or monitor.  In this manner, the circuit was not available to just anyone.  It was a “closed circuit” that was dedicated to a particular source; hence the name “Closed Circuit Television” or CCTV.

Although CCTV surveillance originally described television only transmitted through a cable, its meaning is used loosely in that regard today.  CCTV today is not necessarily confined to a video image sent over a cable, but may be wireless as well.  However, even though the video images maybe sent using radio frequency signals, they are still directed for use by a specific or finite group of individuals and not the general public.

As a result of CCTV surveillance becoming digital, it has been able to “piggyback” if you will, on the personal computer industry.  In other words, the digital video security industry has been able to benefit tremendously by the technological advancements of the modern day digital world, namely the personal computer industry.

When technology yields a faster computer processor, so too is there a newer, faster Digital Video Recorder or DVR.  When the computer industry develops a larger hard disk drive, so too is there a larger storage capacity DVR.  When the Integrated Circuit or IC chip becomes smaller and performs more tasks, CCTV surveillance cameras become smaller and so on.  This has resulted in remarkable changes in the video security and surveillance industry.

For example, only those who could afford the older, expensive analog equipment could have a home CCTV surveillance system.  Typically, such a system could only be afforded by the incredibly wealthy or commercial businesses that in essence, had to have them, regardless of the cost (banks, retailers, and industrial applications for example).

Now however, digital video CCTV surveillance systems are economically priced and systems are available that fit just about any budget.  For example, Security Camera King sells its Elite Mini complete package system including cameras, cables, power supply, etc. for only $499.  Compared to today’s average prices, that’s not much of an expense at all.

In addition to reasonable pricing, digital video CCTV surveillance systems have also become incredibly easy to install.  So easy in fact, that a professional installer is not required.  A complete home security system can easily be installed as a do-it-yourself project in one weekend or less.

There are other benefits as well.  A contemporary CCTV surveillance system is no longer a proprietary packaged system.  In other words, these systems are component systems such that cameras, monitors, and DVRs can be used from different manufacturers and with different special functions to “tailor fit” the system to your specific security and surveillance needs.

And the benefits keep coming.  Since CCTV surveillance has become digital that means that transmissions can now be sent via the Internet.  All of Security Camera Kings DVRs have this as a basic feature.  Therefore a security system in Florida can be monitored and controlled by a Internet connected computer or smartphone anywhere in the world there is Internet access.

So, as you can see CCTV surveillance has encountered quite an evolution in less than a century of life.  Only imagination can determine what may be yet to come.

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CCTV Digital Camera

Written By:
Monday, January 31st, 2011

If the Digital Video Recorder or DVR is the heart of a digital video security system, then the CCTV digital camera must be the eyes. The cameras used today are top-notch technological wonders that provide high quality color video images. The have a vast selection of optional features that make their use extremely flexible and easy to use under almost any application.

A Closed Circuit Television or CCTV digital camera are the eyes of a digital security system because they are the devices that “see and capture” the action. There are many types of CCTV digital cameras available but they all “see and capture” using one of two similar methods. To describe how a CCTV digital camera works without getting too technical, we’ll tell you about their sensors and other parts of the cameras and how they integrate to get the job done.

Let’s divide the average CCTV digital camera into three parts: 1) The lens; 2) The sensor; and, 3) The analog-to-digital converter and all other supporting electronics.

The Lens
There are essentially two different type of lenses used in CCTV digital cameras. The first we’ll mention is the “fixed lens.” The fixed lens is so named because the focal length of the lens is stationary or fixed. This indicated that the lens as a definite range of focus as well as a fixed field of view. These lenses are excellent for cameras that are used in applications where the distance between the subject or object being recorded and the camera is usually constant. Examples of these uses include retail store shoplifting coverage, equipment monitoring, gate entrance monitoring, room surveillance, etc.

The varifocal lenses have a variable focal length. This means that these lenses can zoom in or zoom out on subjects or objects and be manually focused. This lens is a bit more expensive than a fixed lens. Applications for this lens would include uses where the camera position is changed on a regular basis or the field of view is changed often.

Either type of lens has basically the same function: Manipulate the light emitted by the image in the camera’s field of vision, so that it presents an incredibly high quality image that is focused on the cameras incredibly small sensor.

The Sensor
There are also two different type of lenses used in CCTV digital cameras. They take the focused light image and convert it into tiny electrical charges that can be used to create a digital video file or image. The two sensors used are the Charged Coupled Device or CCD and the Complimentary Metal Oxide Semiconductor or CMOS. At one time the CCD produced a high quality image than the CMOS at a slightly higher cost in price for the sensor. The CMOS on the other hand, used far less electricity to complete the task of creating the electronic video image. As time and technology progresses, the newer CCDs use less electricity and the newer CMOSs produce a higher quality image so that they are relatively similar in power usage, quality and cost.

Whether it’s a CCD or a CMOS, the sensor, with the help of supporting electronic circuitry, pass the image which at this point is in analog format, to the analog-to-digital converter.

The Analog-to-Digital Converter
CCTV digital cameras produce their finished product, the video image, in a binary or digital format. Since the equipment used along the way to produce the image does so basically using analog methods, the analog-to-digital converter is necessary to transform the analog signal into digital data. This converter is usually a relatively small Integrated Circuit (IC) chip that is designed specifically for this purpose. It must be very powerful and extremely fast in order to convert the signal for use in real-time (live).

When the signal leaves the analog-to-digital converter, it is now in digital form and ready to be sent to the DVR and/or monitor. This is done by one of two different methods as well. Either the signal is carried to the DVR using a video transmission cable (which in most cases is an RG-59 coaxial cable), or wirelessly converting the signal into a radio signal that can be transmitted for the camera to a corresponding receiver.

This should give you some working knowledge on how a CCTV digital camera works. If you need additional information or considering a purchase, please contact one of our security experts today using on-line “Live Chat” or by toll-free telephone at 866-573-8878.

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CCTV Digital Recorders

Written By:
Wednesday, January 26th, 2011

If you are considering the purchase of a security video system and are unsure as to whether you should purchase a DVR or a CCTV digital recorder, you MUST read this article. In the following text we’ll answer this question and many more about CCTV digital recorders and describe three of Security Camera King’s featured units.

So to answer the original question, DVR or CCTV digital recorder? The answer: They are both the same device; whether it’s called a DVR or CCTV digital recorder, it’s still the same piece of equipment. The terms may be confusing because of the evolution of the video security system.

Originally, video security camera systems were analog systems. The video camera was basically just a small version of a television studio camera that was used to record analog video. The term “CCTV” or Closed Circuit TeleVision was used to indicate the difference between a television studio camera that broadcasted its signal via OPEN radio signals to anyone that wanted to receive it and a video security camera that used a CLOSED circuit to send its signal to a designated device.

Analog systems used video recorders, but they recorded the signals using analog methods on tape, such as VHS or Beta. These analog system recorders were either referred to by the tape type designation or were simply called video recorders.

Current video security systems are digital systems. The recorders that are used in these systems are called Digital Video Recorders or DVRs. Basically the terms DVR, CCTV DVR, Digital Recorders, and CCTV Digital Recorders all refer to the same device, a digital video recorder.

There are several advantages to a digital system as compared to an analog system. CCTV digital recorders can instantly jump or skip to a specific time or date recording. Analog tapes had to played and searched while playing to find a specific segment. Digital recorders also save video in digital or binary format so there is no degradation of the quality of the recorded video over time.

About Security Camera King’s CCTV Digital Recorders
Security Camera King offers high-quality CCTV digital recorders that use the latest digital video technology, offer the most features, and use the latest, most efficient CODEC (more about CODECs in a minute). Our three featured CCTV digital recorders are the Elite Mini DVR, the Elite DVR, and the Ultimate DVR. Each of these units is available in four, eight, and sixteen channel units. (In this case “channel” means input or camera, so this is the number of individual cameras or inputs the DVR can handle.)

All three models of CCTV digital recorder use the H.264 CODEC. CODEC is an acronym for COmpression/DECompression. Digital video security systems create digital video files which consist of nothing more than several digital photographs taken in succession in a short period of time. High-quality fluid digital video is often taken at a rate of 29.9 pictures per second or frames per second or fps.

Consider the potential size of a file for one digital photograph; now imagine if you took 30 of these per second. In 60 seconds you would have an uncompressed digital file 1800 times the size of one picture. This size ratio is far too big for even the fastest processors to handle, so the CODEC is an algorithm that is used make this files much easier to handle and store by shrinking their size without sacrificing quality. The H.264 is the latest, most efficient digital video CODEC available.

All three of Security Camera King’s CCTV Digital Recorder models feature an embedded Linux operating system and Internet Protocol (IP) ready features that include internet networking, e-mail alert notification, and access via one of several varieties of smartphones. Our CCTV digital recorders are standalone systems; they can operate without the use of a personal computer (which could be vulnerable to viruses, hacking, and other invasions).

In addition, all of our featured CCTV digital recorders have HDMI, VGA, DNC video outputs with a display resolution of 720 P. This means that more than one monitor can be used with the unit at a time. In fact, with the included Matrix output you can pick and choose your monitor display options.

Our CCTV digital recorders are easy to setup and operate. Their software is a mouse-based point-and-click Graphical Users Interface with an On-Screen Display. The operation is so simple that there is even an included infrared remote control.

For additional information about our CCTV digital recorders, please contact one of our security experts.

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CCTV Digital Video Recorder

Written By:
Wednesday, November 10th, 2010

A closed circuit television or CCTV digital video recorder can provide the security and/or surveillance you need for your home, office, business, or industrial setting. For residential applications, a CCTV digital video recorder can protect your home and give you the peace of mind even when you are away of knowing that things are secure. For commercial applications, nothing provides cost effective security and surveillance as well as documentation than a CCTV digital video recorder.

What exactly is a CCTV digital video recorder? A CCTV digital video recorder is any device that can save and store digital video data, usually in the form of a digital video file that can be retrieved, copied, and played back through a monitor at some later time.

Security and surveillance type cameras first got the name Closed Circuit Television or CCTV to differentiate them from television cameras. The original security and surveillance type video camera was basically just a smaller version of the video camera television studios used to record television shows such as variety shows, sitcoms, dramas, and news reports. Television cameras were attached to transmitters that broadcast the signal over vast areas so that anyone with a television (in essence a receiver and monitor) could monitor the signal.

CCTV was used in reference to video cameras that were each connected to a video recorder. Each camera has a video transmission cable, usually a coaxial type RG-59 cable, which runs from the camera to the recording unit and monitor. The only way to receive the camera’s signal was to be in a closed circuit with it via the video transmission cable. Since these cameras didn’t broadcast their video signals publicly, they were called Closed Circuit Television or CCTV.

Today, CCTV is used a little more loosely, too mean a designated system of cameras, receivers, and recorders not intended for public broadcasting. For example, individual digital video cameras today can transmit their video signals via radio signals to receivers or Digital Video Recorders or DVRs. Although it may be possible for someone to intercept the signal, it is not intended for public broadcasting and in effect, is a closed circuit type of television.

In the security camera industry, a CCTV digital video recorder is usually thought of as one of three integral components in a digital video security system. The other two are the digital video camera(s) and an LCD monitor. For residential or commercial standalone digital video CCTV systems, the DVR is basically the equivalent of a personal computer hard disk drive connected to a high specialized type of computer processor called a Digital Signal Processor or DSP.

On these units, the CCTV digital video recorder unit is still connected to each individual camera in the system; however, as mentioned earlier they may now be connected by a specific radio signal transmission. The DSP interprets the digital data sent to it by each digital video camera and then creates a digital video file. Unprocessed digital video files can become extremely large in a very short period of recording time, so the DSP usually applies some sort of COmpression/DECompression or CODEC utility. This CODEC utility processed the digital data in such a way as to greatly reduce the size of the file while still maintaining high video quality.

Standalone CCTV digital video recorders do not require any additional equipment (such as a computer) for processing or storing the video, hence the name “standalone.” The actual DVR is the same sort of device used for a personal computer’s hard disk drive. As a result, the benefits of advanced computer technology and storage features have been passed on from the computer industry to the security camera industry in regard to the DVR.

These standalone CCTV DVRs today normally have storage capacities that range from 250 gigabytes to over 1 Terabyte. This coupled with modern CODEC utilities this translates to longer periods between overwrites when a disk becomes full and even greater capacity to store multiple cameras at once.

In addition to magnetic disk drives, CCTV digital video recorders may be in other formats as well. Although the hard disk drive is probably the fastest, cost-effective method for storing standalone system digital video, small portable units are becoming popular as well. These units may use any of the portable memory card media (such as Compact Flash, SD, etc.) or even Flash Thumb drives as the storage media of choice.

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Autofocus CCTV Camera

Written By:
Tuesday, July 27th, 2010

An autofocus CCTV or Closed Circuit Television camera is an ideal choice for surveillance and monitoring when the field of view encompasses large differences in distances of the target or the target is moving and often changes its distance to the camera. Most autofocus CCTV camera lenses are zoom lenses; a variation of this type of lens is a vari-focal lens which can vary its focal length by manual adjustment.

Let’s take a look at some of the technology behind autofocus CCTV cameras to see how they work and to understand why an autofocus CCTV camera is unique.

A typical digital video CCTV camera produces an electronic image by using one of two light sensitive electronic chips called Charged Coupled Devices or CCDs or Complimentary Metal Oxide Semiconductors or CMOSs. The sensors create electronic energy from light energy and are often only ¼ to 1 inch in size. The electronic energy can be measured and utilized to make digital video images that can be viewed on a monitor or saved on a storage device.

However, in order for the sensor to produce the electronic image, the light emitted from the actual imaged must be precisely focused on the sensor. This is where the lens comes in to play. The lens works by clarifying and concentrating (focusing) the light image on the sensor chip.

Every lens has a focal length. For CCTV cameras, generally short focal length lenses have wide fields of view which are ideal for close ups or for seeing a large area, although objects will appear relatively small. Long focal length lenses have narrow fields of view but distant targets are easier seen with better definition.

Focal length measurements are not very long. In fact, focal lengths for CCTV cameras are measured in millimeters and range from about 3.5 to 16.0 millimeters in length with each lens having its own unique focal length. When purchasing a digital video CCTV camera with a fixed lens, the purpose or objective of the camera must be considered in order to select the proper lens.

For example, a small focal lengths lens can yield a fairly large field of view. For example, at 50 feet away from the camera, the field of view for a 3.6 mm focal length lens would provide a field of view of approximately 75 feet wide and 50 feet in height. Identification of people would be very difficult because they would appear very small. However, using a lens with a 16.0 mm focal length would create a field of view approximately 13 feet wide by 9.6 feet in height and would make recognition much easier.

However, if a camera needs to provide both a large field of view as well as a short field of view, an autofocus CCTV camera is the ideal choice. By using a combination of lenses that optimize the physical principles of the lenses these cameras can vary their focal length automatically, i.e. autofocus.

Autofocus CCTV cameras take the guess work out of determining which single lens to purchase for your camera. Autofocus zoom CCTV cameras can be used like the telephoto lens on a still image or video camera to “Zoom-in” or enlarge objects while maintaining the proper focus. Autofocus zoom CCTV cameras often have large focal length ranges, from as little as 3.6 mm to over 60 mm.

Autofocus CCTV cameras can be zoomed in or out to account for changes in the field of view. Normally, these cameras’ zoom function is controlled electronically either by a control panel with sliders, levers, knobs, joysticks, or buttons or through the use of programming that is run through the processing unit or Digital Video Recorder (DVR).

Another type of “autofocus” camera lens is the vari-focal lens. Although this lens is not remotely controlled like the true autofocus lens mentioned above, it does have the ability to vary its focal length, making it an autofocus type of lens. The lens is actually adjusted manually allowing the lens to zoom in and out and focus at variable settings.

So if your security or monitoring system requires the camera to zoom in and out, or if you need to vary the size of your camera’s field of view, an autofocus CCTV camera is the right choice for you. Also, for situations where the filed of view may need to change occasionally but not “on-the-fly” a more economical type of autofocus CCTV lens, the vari-focal lens, may be what you need.

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