Posts Tagged ‘ digital security system’



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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Construction Site Security Camera Surveillance

Written By:
Friday, December 17th, 2010

If you are looking to increase security in your work zone, consider using construction site security camera surveillance. Digital video security camera systems can help prevent theft of construction site materials, notify you and help prevent intrusion by trespassers, and even monitor the site for safety issues during the work period. In addition, construction site security camera surveillance is an excellent means for providing owners/investors with the ability to follow progress as the construction project proceeds.

Before the technological advances in the digital security system industry, it may have been difficult and costly to obtain construction site security camera surveillance. However, with the advent of new technology including digital video cameras, wireless technology, and Internet Protocol (IP) ready systems, construction site security camera surveillance is reasonably priced and easy to provide, and easy to install.

For particularly large construction jobs, the use of construction site security camera surveillance can reduce or eliminate the need for security guards or a security team. In addition, large jobs can have several cameras or if necessary, multiple systems to provide complete perimeter and site surveillance; indoors our out.

There are so many different types of cameras and systems available that their application is incredibly versatile to the point that there are very few construction site applications where construction site security camera surveillance can’t be used. Let’s take a look at some of these security camera system features and how they can apply to a construction site.

Generally, the number of cameras (also called “channels”) available in a given system is determined by the DVR. The most common DVR types can accept up to four, eight, or sixteen camera inputs. One of these DVRs should accommodate your needs, however if you require more than sixteen cameras, two or more systems can be setup in tandem.

Digital video security cameras require a power supply and a video transmission cable (usually an RG-59 coaxial cable) that must be run from each camera to the DVR. If these cabling hookups aren’t practical for your situation, wireless battery operated cameras can be used instead. Wireless cameras contain their own built-in transmitter and on board antenna that is used to send the video signal via radio waves to a corresponding receiver.

Wireless cameras make use of a variety of different wireless technologies but probably the most common type used today is the 2.8 or 5.8 GHz technology. This is the same technology used to transmit wireless land-line based telephone conversations. It’s incredibly effective and free of interference and can have a relatively long range. Some wireless cameras boast up to a two mile range to the receiver.

These ranges are called “Line of Sight” or LOS ranges because the range specification given by the manufacturer is based on a transmission route between the camera and receiver in a line of sight, meaning without any obstructions between the two. Although objects within the LOS generally reduce the effective range, they seldom prevent reception. If there is an obstruction, the material of the object will determine the reduction in range. Be certain to check the range of wireless cameras before purchasing them to make sure they meet your specific range requirements.

In addition to the wireless transmission feature, some cameras can be operated by batteries (either rechargeable or disposable) instead of a power supply plugged into 120 volt AC service. Even better, cameras can also be purchased with an on-board motion detector.

Construction site security camera surveillance is generally concerned more with activity than non-active video so the motion-detector wireless battery operated camera is an excellent choice. The motion detector is a PIR (Passive InfraRed) sensor that can detect the change in infrared signatures in the camera’s field of view. If a change is detected, it is assumed that this was created by some sort of motion and the PIR connected internally to a relay in the camera housing, turns the camera on to record. The PIR sensor uses significantly less battery power than the camera, increasing the usable life of the batteries.

There are many other options available for construction site security camera surveillance. Night time infrared cameras can record activity using an infrared light source which is invisible to the human eye. Pan-Tilt-Zoom (PTZ) DVR programs with PTZ cameras can actually track or follow an object or person.

Construction site security camera surveillance is a cost-efficient time proven method for preventing and documenting theft, vandalism, and even accidents. This is one tool your construction site shouldn’t be without.

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Digital Security System

Written By:
Friday, November 19th, 2010

A digital security system is any system that integrates digital data for the purpose of creating, sending, or recording information that can be used to protect something. That’s a pretty broad definition, but then again digital security system is a pretty broad phrase.

Since most security alarm systems primarily deal with on/off states (door open/door closed) we could consider them to be inherently digital, but that’s not really what we mean here. What we mean by digital security system is a video security system that operates on the basis of digital data transfer as opposed to an analog system.

For example VHS and Beta video tapes, cassette tape recorders and players, and record albums are all examples of analog devices or media. CDs, DVDs, hard disk drives, and LCD monitors are all examples of digital devices or media.

Older video security systems (often referred to today as “legacy systems”), were strictly analog in nature. The video camera, basically a smaller version of a television studio camera, transferred light energy into electrical energy that could be used to produce a video image. The electrical energy produced by the camera was sent to a Video Tape Recorder (VTR).

The VTR saves the video image as a magnetic recording on magnetic tape. The magnetic recording is in analog form meaning that the signal is recorded with weak spots and strong spots. The analog VTRs used for this purpose are either VHS or Beta format.

The greatest disadvantage of an analog security system is that the analog system is subject to distortion and degradation. Each time the recording is played a slight loss of the signal, especially in the weak spots, is experienced and over time the signal can also deteriorate.

A digital security system or digital video camera initially creates the video image in the same manner as its analog counterpart. However, a digital video camera contains an “analog to digital” converter circuit that transfers the analog signal into a digital signal.

The signals of digital security systems do not have strong and weak points like analog video. The data is only a continuous series of 1s and 0s. This data is sent via a video transmission cable just like the analog video; however instead of using a VTR to record the signal, a Digital Video Recorder or DVR is used. The DVR unit usually contains a highly specialized computer processor called a Digital Signal Processor or DSP the reads the cameras digital data and assembles it into a digital video file that is saved on the DVR.

There are two great advantages of a digital security system as compared to an analog system. First, since digital security systems use digital data, the recording typically doesn’t degrade on magnetic mediums as easy as analog signals do and, the data can be saved to media that doesn’t degrade at all (such as CDs or DVDs). Second, since digital security systems create digital data, the technology and equipment used with personal computers can be integrated for use with the digital security system.

Advances in technology with Integrated Circuit (IC) chips, digital memory storage, use of the Internet, increased speed of computer processors to name of few can all be used to the benefit of a digital security system. For example, miniature IC chips can be used with cameras the size of a pinhole to capture, digitize and transmit video. As computer hard disk drives vastly increase their storage capacity, digital video security systems reap the benefit of longer recording times without rewriting over old data. Faster and broader applications of the Internet allow a user to access their digital system from anywhere in the world there is broadband internet accessibility. And finally, as computer processor speeds and capabilities expand, video quality also gets higher and higher.

Current legacy (analog) security system users don’t despair. Although your systems are typically no longer available for purchase, it is possible to convert them to digital. Thankfully, as the digital revolution has occurred, several devices have been created that help merge some analog devices with digital equipment.

For example, analog security systems can use the internet to monitor their systems like security digital systems can. Users can purchase analog to digital capture cards and servers which transfer the signal from an analog to a digital state and incorporate into files that are computer compatible. For a nominal added expense of these devices, even analog systems can assume some of the advantages of digital security systems.

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