Posts Tagged ‘ CCTV Camera’



CCTV Cables

Written By:
Wednesday, April 25th, 2012

cctv cablesVarious Types of CCTV Cables

A closed circuit television system is able to withstand a lot of different tasks. It can be anything from watching over a baby asleep in another room, or monitoring the different activities that take place within your business. Depending on what you are planning to do, you are going to need a wide range of different closed circuit television cables to help the whole thing come together and make the system operational. The way your closed circuit television system is designed will depend on what type of data you are going to be sending through the cables, as well as the monitoring that will be required on the opposite end.

BNC Coaxial Cable

Coaxial cables are composed of a copper wire conductor that is encompassed in a non-conducting jacket, which is often referred to as a dielectric. The dielectric will typically be encased in a layering of copper or aluminum shielding. This layer of shielding is then protected by an exterior jacket. On either end of the cable there will be a BNC connector that is screwed in to bring the whole thing together. You will typically find that a closed circuit television system will need a cable that can produce an impedance rating of 75 ohms. There are a lot of different sizes for the cable, which will all be designated by various Radio Guide numbers. Depending on the distance the signal is going to travel, you may need a higher Radio Guide rating for the system to operate effectively.

Siamese Cable

If you have a remote installation performed, you may notice that the closed circuit television cables are also going to need to carry video signals beyond just the electrical power required. If you need to have video signals, you should try and see what Siamese cabling can do for you. You will normally see Siamese cabling with a Radio Guide rating of 59. It will also include a coaxial cable and a duo of stranded power lines to help with the transmission of power. On each end of the coaxial cable there will be BNC connectors. The opposite ends of the stranded duo will be equipped with the male and female DC power adapters.

RCA Cable

If you are going to have a camera cable that is going to end at the monitor or recording device with an RCA input, you should try using a three-wired RCA cables. An RCA cable will feature a white conductor, which is used to transmit the audio portion, and a yellow connector, which is used for the transmission of the video channels. You may also find an RCA cable that has an integrated DC power line, including the male and female plugs on opposite ends in red. It has been stated that the RCA cables are not as shielded as their coaxial counterparts. You should only use them for a short run, or if you are in an area that has a relatively low radio-frequency noise level.

DIN Cables

There are some cameras that will require either a four or a six pin lead in their cables, which are also referred to as a DIN cable. DIN cables will typically end with a round plug that has either four or six pins that are distributed around the area in a circular shaped pattern. These pins are responsible for carrying the DC voltage. However, they are also responsible for getting the output and audio input signals, alarm signals and the video signals to where they need to go. If you need something that is simple to install, a DIN cable is the perfect opportunity for you to use in any two-way audio communication needs. Remote security systems are perfect for use with a DIN cable.

Hooking Up DIN Closed Circuit Television to Your Computercctv cables

1. From the base of your camera you are going to need to run the closed circuit television DIN wire into a location near your computer.

2. Using the six pin connector you are going to plug your camera’s DIN connection cable into the six pin DIN adapter that is designed for female to female connections. You can normally find these adapters at any local electronics stores or through the manufacturer of your closed circuit television.

3. Take the opposite end of the female to female adapter and run it into the male end of the DIN to USB adapter. You are also going to need a six pin connection to make the whole setup work properly.

4. Make sure that all of your connections are secure. If necessary, you may want to wrap the connections with electrical tape to help eliminate any worries about the connections slipping loose.

5. Power on your computer and let the operating system boot up. Do not try to open any programs or plug anything into your computer’s USB ports until after the system is completely powered up.

6. Take the USB end of your DIN adapter and connect it into the USB port located on your computer.

7. Once you see a message come up on your computer that tells you that it has found new hardware you will be able to click on this message and use the wizard to help guide you through the process of identifying the hardware.

8. Click on the button that says next and wait for the computer to go through and search for all of the required information.

9. When you see the message that appears that says generic USB camera you will simply click on the button that says ok.

10. Click on the icon for my computer and you are going to see the camera on your list of available devices. You will be able to use this camera for streaming, recording and viewing video from your closed circuit television camera just like you would a webcam.

VGA Extension Cable

If you are planning on sending your video signal to a computer monitor, you are going to want to use a VGA extension cable. At the end of these 15 lead cables you will find a D shaped plug that will have either a male of a female connector. On either side of the VGA cable you will notice that there are thumb screws, which will connect with the threaded nuts located on the equipment to help provide you with a secure connection. VGA cables are commonly used with connecting computer equipment largely in part because they are protected against any of the electromagnetic interference that is normally generated by processor chips.

cctv cables Connecting My Television to Closed Circuit Television Security Systems

You will commonly find a closed circuit television camera being associated with security cameras. Security cameras will be able to capture the video and then transmit it over to the recording medium and monitoring station. When you connect the closed circuit television camera through a television it is only going to require a coaxial cable or an RCA connection to run everything from the camera and into the television. You can purchase either one of these cables at just about any electronics store for a relatively inexpensive price.

Instructions for Connecting Your System

1. Take the time to go through and determine what type of connections you are going to need for your closed circuit television camera. Your television should have both coaxial and RCA inputs, but at the bare minimum it is going to have at least one of the connections. It is more than likely that your closed circuit television camera is going to have both of the inputs available to you. Take a look at the back of your camera and see what ports it has for you to choose from.

2. Measure out how much distance there is between the closed circuit television camera to get to the television. You are going to need this measurement to be able to determine how much cable you are going to need to purchase.

3. Purchase your choice of either the coaxial cable or an RCA cable. Make sure that you have a long enough cable purchased to be able to connect everything properly. You will be able to get these cables at just about any of the electronics stores in your area.

4. Connect your cable of choice into the rear of your closed circuit television camera. You can take the RCA cable and plug it into the back of your camera by simply matching the colors of the input ports along with the colors of the cable. If you are using a coaxial cable, you are going to have to screw the cable into the back of the camera.

5. Run your cables from the rear of the closed circuit television into the television.

6. Take the cable and connect it to your television input ports. If you are using a coaxial cable, it will be screwed into the television. Whereas, if you are using the RCA cables, you will simply be matching the colors into their appropriate ports. Once you turn on the television you should be able to see all of the live feed coming in from your closed circuit television camera. Your television may need to be turned to a different video input or channel to be able to receive the connection. However, this is all going to be dependent on the specific make and model of the television set in question. Contact Security Camera Kings today for your CCTV cable needs.

 

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Infrared Surveillance Cameras

Written By:
Wednesday, April 18th, 2012

What Are the Benefits of Using Infrared Technology?

Infrared Surveillance CamerasThe basic rule for any security system is that if there is no light, there is no picture. The important thing to understand is how infrared illumination can change the lighting conditions and provide you with the optimal viewing conditions in your modern security system.

How Do I Manage My Bandwidth When Lighting Conditions Are Less Than Optimal?

It doesn’t matter if you are using an analog or a digital camera because just about any CCTV camera will be able to capture very solid images when used in ample lighting conditions. However, the key is how your security system is going to be able to record in the evening hours that will determine just how effective the camera is going to be. Since the vast majority of crimes are going to take place in the evening, it is imperative that you are not left in a vulnerable situation. Your security system needs to be able to handle surveillance at any time of the day or night for an around-the-clock type of surveillance.

Most of the newer cameras are going to be equipped with a lower lux rating that will give you the operation you need when lighting conditions are less than adequate. You may find that without special illumination for your cameras they are only going to be capable of capturing low quality and noisy images in the nighttime conditions.

In order to improve upon the quality of the images you are going to want to make sure that you have the specified amount of illumination for the evening hours. This is where another one of the benefits for a CCTV comes into play. Whenever your lighting levels decrease, there is a small increase in the bit rate on your video stream from every one of your cameras that are connected to the network. If you do not take care of the bit rate, you are going to end up with a large increase for the amount of storage fees you are going to need for all of your video.

Understanding What Automatic Gain Control Means For Night Vision Cameras

Automatic gain control is a form of technology for your camera, which is going to increase your signal strength when there is inadequate lighting for your camera. It works by intensifying the images through amplification, which in turn causes an increase in the video signals and image noise.

For example, if you take your normal security camera, you are going to receive good images that can be used during the daytime. However, in the evening your camera will kick into the automatic gain control to attempt to capture the images. As it gets darker, your camera will continue to increase the AGC and the images will only get that much more noisy and grainy. In the end your image will become almost useless because there is nothing there that can be seen through all of the snow.

What is the Impact of Video Compression Algorithms?

In order to understand why the bit rate increases, it is important to have a basic foundation of how the video algorithms work in the Infrared Surveillance Camerasfirst place. The basic underlying principle is that you are going to need to eliminate anything that is not useful and make the file size that much smaller. Every form of compression is going to require some form of compromise between the size of the file and the quality of the image. The higher the compression ratio is the smaller the size of the files will be, but your images are also going to be a lot less clear. On the other hand, when you have a lower compression ratio, you are going to have a much higher quality image with a lot more space required to house the files.

When the majority of cameras are installed, you can expect the frame rates and resolution settings to be tweaked for your specific needs. Even though there is a huge advantage to lowering your frame rate and resolution, there are also drawbacks to doing this type of thing as well. When you make the decision to sacrifice your resolution and frame rates you are also giving up your quality. You can expect to receive some of the choppiest surveillance footage out there and there may be times where you were unable to determine what was going on because you missed some of the more critical moments in the surveillance footage.

In today’s world the most popular forms of video compression include: JPEG, MPEG and M-JPEG. However, the most recent type of technology used is the H.264 algorithm that will utilize around 30 percent less space than that of the MPEG4 technology. The MPEG4 technology itself is about 80 percent more efficient than that of M-JPEG. There are some basic principles that all of the forms of technology use that will allow them to have some similarities between them all, such as: irrelevancy reduction and redundancy reduction. Irrelevancy reduction will eliminate any portions of the video that may not be noticed by the human eye, such as any slight changes in color. Redundancy reduction will help to remove any duplicate content from the frames, such as stationary objects and large block areas.

What Are the Relationships between Low Light Surveillance and Compression Rates?

In the evening you have probably noticed that there is a lot less activity on the scenes and within the cameras view, which means that the evening video needs to be stored using a smaller bit rate. However, the amount of noise the image will encounter may be created by an increase in the gain from the camera and it can be interpreted as noisy by the encoders. In order to be exact, the compression algorithms are going to construe the noisy automatic gain control images as that of movement and end up creating redundancy in the files because the images will not be able to be reduced in size. You then end up with the nighttime videos being a lot larger than what they need to be and they are not as compressed. You can see how there is a direct relationship between the compression and the lighting conditions.

What Effect Does Bit Rate Have On the Cost of a Surveillance System?

Bit rate can be defined as the amount of data that can be transmitted every second on your camera or recording device. It is also the amount of data every second that needs to be retained and then stored on your device. The larger the amounts of bit rate you have available per channel, the higher the overall requirements are going to be for the system in general. It can be quite expensive to be able to increase the amount of storage space you have available on each channel and it is one of the main expenses for your complete security system.

What Are the Benefits of Combining Your Infrared and Encoding?

Infrared Surveillance CamerasInstead of constantly adding extra storage onto your security system, you should consider the main cause of the problem lies within your bit rate that is being used in the evening hours. It may seem that the easiest solution would be to disable the automatic gain control function. Even though this will reduce the bit rate, it is going to be at the expense of your image details. When you make the decision to disable your automatic gain control you are going to end up with images that are so poor in quality they are almost pointless. One of your best options is to install infrared lighting on the location where your camera is recording. When you use the infrared technology, you are going to notice that you are no longer going to need the high camera gain that you once did and your digital video recorders will work perfectly.

When you are using infrared illumination you are basically allowing the cameras to receive the best resolution available to give you the perfect nighttime images with little to no noise involved. The lower the amount of video noise that you are dealing with, the better compression rates and storage rates you are going to need.

What Can I Expect In Terms of Lighting and Picture Quality for My Security Camera?

Even at your most basic levels, infrared technology is still going to produce light. This light is not visible to the human eye, but it is able to be used by surveillance cameras that are monochrome. It helps them to reveal the nighttime images that may not appear otherwise. They would be almost completely black images, but thanks to the infrared technology the camera is able to see the images in a whole new light. This goes right back to the beginning; where there is light, there is a picture.

The infrared technology is going to prohibit the noisy images in the evening, as well as the whole chain reaction that goes with them. You will not have to worry about the extra expenses like before, or the additional storage needed to save everything from overnight. There are even some of the infrared illuminators that come equipped with the necessary technology to direct the light perfectly into the front and back of the viewing area to produce exceptional nighttime images. You will not have to worry about hotspots or overexposure like some of the other illuminators on the market may cause. The higher you are able to get for image quality, the lower the amount of storage requirements you are going to need, which in turn puts more money back in your pocket.

How Do I Use Infrared to Help Reduce the Amount of Storage Space I Need?

Even though infrared lighting has helped to improve the quality of images and it is used across the security industry, you may not have been aware of how it can be used as a bandwidth tool. Storage is one of the largest expenses that will accompany your security system and with the bonus features of infrared technology you can help reduce your storage needs dramatically when used with digital video applications.

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CCTV Cameras

Written By:
Friday, January 13th, 2012

CCTV cameras are made in a variety of types and for a wide range of uses. Complicating the selection of cameras more are the variety of technologies within each category type.

In order to understand the range of cameras available to the general market, and useful for ordinary consumer applications, this article is divided into three sections: camera types, lenses, and technology types.

For readers who are new to the topic of CCTV, mention should be made of the term. The term is an acronym for “closed-circuit television.” Other terms are used interchangeably that mean virtually the same thing: “security camera,” “surveillance camera,” “spy camera,” and “video camera.” There are some nuances in the meanings, perhaps, but they are very minor. There is no intention in this article to differentiate between them.

Camera Types

Types are basically a reference to the camera body style. There are three basic types for ordinary use: box cameras, dome cameras, and bullet cameras. There is an additional type called a “board camera,” getting its name from the fact that it attaches directly to a circuit board, without a body. They are used in applications such as ATM machines and not for everyday consumer applications; therefore, the discussion will be limited to the three main camera body types listed above.

Box Cameras

The camera body of a box camera, as the name suggests, is in the shape of a box. The camera and lenses are normally bought separately. As they do in a still camera, the lenses are attached to the body and are easily changed if the application requires it.

Box cameras are known for giving high quality images, and with some of the higher specifications, the box cameras are often preferred in low light conditions.

The camera body and lenses for box cameras are more vulnerable to weather conditions and vandalism when mounted unprotected. The body of the box camera is not designed to withstand the elements, making it necessary to enclose the camera in weatherproof and vandal resistant housings.

Housings are designed to protect the camera, and the housing itself has some available features that make them a desirable choice. Some housings come with a heater/blower function that protects the camera from freezing temperatures and ice. The housings come with ratings from NEMA, the National Electronics Manufacturers Association, to give consumers guidance on selecting the best housing for the application.

Box cameras are versatile because of the ease with which the lenses are interchangeable, and the choices that can be made with housings. With the additional advantage of having some of the best specifications in the market, box cameras are still preferred by many users of security cameras.

Dome Cameras

The dome camera is the one commonly seen in public buildings. They are easily spotted because of their dome shape, often with a blue or gray tinted cover. They can be mounted on walls as well as ceilings, and with the proper housing and mounts, they can be mounted as a pendant or on poles.

Unlike the box camera type, dome cameras come in one piece. The lens is internal to the camera body. Though several choices of lenses are available, normally a dome camera’s lens is not changed once it is purchased and mounted. When buying a dome camera, it is important to know the range of distance that the camera will be watching, the lighting conditions, and any other dynamics that exist in the application. Changing lenses on a dome camera is impractical.

In the lens discussion below, there will be more said about the types of lenses. For the current discussion, however, let it be known that the lenses, though internal to the dome camera, should be adjusted and tested while installing. Removing the cover is required, and it is accomplished easily. Changing the lens is difficult and impractical, not the adjustment of the lens.

Bullet Cameras

Another common body type for cameras is the bullet camera. These are cameras that come with the lens already installed, as in dome cameras, and they are already shrouded with an external housing.

Bullet cameras are most often seen in outdoor applications such as building perimeters, light poles, public gathering areas, concourses, and many other areas that are susceptible to weather and vandalism.

Lens choices for bullet cameras are generally the same as with box and dome cameras, and they are most always accompanied with infrared LEDs to give a reddish light in total darkness so the camera can see in the dark.

Quick Word About Infrared (IR) Options vs. Day/Night (DN) Cameras

Infrared LEDs are common, either in cameras or external housings, in most camera types. Buyers should be aware, however, that in many cases, in low light conditions, a day/night camera is preferable to an IR (infrared) camera. The day/night cameras on the market, especially in box cameras, often capture better images than infrared in low light conditions.

Why is this? Infrared LEDs are triggered by darkness. The lens in IR cameras is usually not capable of seeing in low light conditions. If the ambient light is bright enough, as it often is, even though the buyer thinks it is a dark condition, the IR LEDs may not be triggered, or may be ineffective. In total darkness, however, when there is no ambient light, such as moonlight or street lamps, infrared cameras are the best choice. Again, knowing the conditions is vital to making the right choice.

Lenses

There are many specifications for lenses that may make one a better choice than others, but generally speaking, there are just a few basic lenses that need to be discussed here.

Varifocal or Fixed Lens

A fixed lens has only one focal length, which means that the lens is fixed on one space, with no capacity for adjusting the focus. If the optimal distance for a certain lens is to focus on ten feet away from the camera, it will see the ten feet distance very well. However, the further away from the ten feet distance the view gets, whether it is seven or thirteen, nearer or closer, the lens loses its focus.

A varifocal lens is one that can be adjusted within a certain range. It has a variable focal length. Do not be confused with the zoom function, which is discussed next, because it does not change on the fly. It simply means that the lens can be adjusted at the time of installation within a range of settings to accommodate variable distances.

The advantage of the varifocal lens is that a person can choose cameras that are uniform in appearance and function while still having the flexibility to focus each one for its own particular application. Having the focal length adjustment available keeps the buyer from having to replace a camera if the distances are different from what they had planned. There is so little cost difference between the two types of lenses, it is impractical not to use varifocal camera lenses.

Zoom Function

Some lenses come with a zoom function that is controllable from a keyboard by an operator. It allows the operator to zoom in, or to bring an image closer, for a better look. The zoom function for camera lenses operates within the limitations of its designs. If it is a 10x optical zoom, for instance, it means the lens can be zoomed in at ten times the magnification of its basic position. If the focal length is 5mm, the zoom feature on a 10x zoom lens could zoom in to a 50mm range, giving a narrower field, but presenting a larger image for inspection.

Pan-Tilt-Zoom (PTZ)

PTZ cameras are the thoroughbred of the industry. Combining the zoom function with the ability to pan (side-to-side movement), and tilt (up and down movement), the PTZ offers maximum versatility in application.

Normally, the PTZ cameras are housed in domes, though they are typically larger than standard dome cameras.

A PTZ camera comes with a higher price, but it comes with a much higher better versatility. A PTZ camera is an excellent tool for watching large areas, such as parking lots, stadiums, junctions of major concourses within a building.

A PTZ controller is operated from a keyboard or joystick, and through the system software, an operator can switch among PTZs to control one, and then another, camera very quickly.

Another feature worth mentioning here is the auto-tracking function of some PTZ cameras. This is a setting that allows the user to set the PTZ function on automatic so that if a movement takes place within the camera’s view, the camera will track the movement, zoom in, and watch the movement until it is complete. It is a little more complicated than this, however, because a second movement, such as a car traveling in an opposite direction from another, may cause the auto-tracking feature to change over and watch the wrong car. Again, buyers should be cautious in selecting the additional functions. In most cases, there are downsides to making the wrong selection.

Technology Types

There are two basic types of technology that are used in the processing, or encoding, of images: analog, and IP (Internet protocol).

Analog Cameras

Analog is the tried and true technology that has been around since video cameras have existed. In the CCTV world, analog technology is used to transmit captured video footage to a digital video recorder (DVR) that encodes the captured images into digital format for viewing.

Analog cameras do not themselves encode, or digitize, the images. This work is done by the DVR, or a computer based DVR capture card.

IP Cameras

The IP camera is a newer generation of security cameras. Offering higher resolutions of 1, 3, or 5 megapixels, or even higher, many companies promote IP cameras as if analog technology will eventually go away. As a side note, high-definition (HD) technology in analog varieties is making analog very attractive still, primarily because of legacy issues and costs.

In the IP camera, the encoding is done at the camera. In other words, the image is digitized as it appears in the lens, before it is passed along to the network video recorder (NVR) where it is decoded for viewing.

One of the biggest advantages of IP cameras is that they can be implemented wherever a network already exists. There are downsides, however. Unless the bandwidth is large enough to handle the constant feeding of several IP cameras, a network can be slowed down considerably, causing a larger investment in infrastructure to be necessary. Bandwidth can be managed, however, by setting cameras only to show footage when certain triggering events take place.

A Misconception

One common misconception about choosing between IP and analog cameras is the notion that remote access, or viewing, is only possible by using IP cameras. This is simply not true.

Confusion exists on the issue because of the term “IP” and its common use in network jargon. Both IP and analog are capable technologies for offering remote viewing. The IP address of a DVR (analog) allows remote access so that cameras can be viewed over the DVR. IP cameras can be viewed remotely by going directly to an assigned IP address for the camera; however, in many cases, even in IP technology, it is more advantageous to go through the video management software at the NVR so more control can be gained.

Other Considerations

Wireless cameras are available for special needs. There are still infrastructure costs for transmitters and receivers, even though wiring is eliminated to the camera. Practicality is still a concern, and the application will dictate whether wireless is the answer.

Explosion-proof cameras are often brought into the CCTV discussion as well. One misconception about these cameras is that they will not explode if something like a plant explosion occurs. This is a misunderstanding. The meaning of “explosion-proof” is that the camera will not explode in special environments where gases might penetrate other types of housing and set off an explosion within the electronics of the camera. It does not mean the camera will survive a bomb. Explosion-proof cameras are, in essence, a tag placed on the types of housings, rather than the camera inside them.

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CCTV Cameras Remotely Monitored

Written By:
Tuesday, August 24th, 2010

If you are looking for a security and monitoring system that can be viewed away from the site where it is being used you should consider using a CCTV cameras remotely monitored. These systems are useful for monitoring the home from work, the business while at home, or for any monitoring application where the user is not in the same location as the camera.

Before we talk about using a CCTV cameras remotely monitored, let’s go over a few basics. First, CCTV is an abbreviation for Closed Caption Television and actually has a slightly different meaning today than it did 15 or 20 years ago. Television broadcast stations use video television cameras to record their video images. Several years ago these cameras were analog video cameras. These images are enhanced and edited at the studio and broadcast using powerful antennas and radio waves.

Smaller but similar types of cameras were used for security and monitoring systems. They differed from television broadcast cameras in that their video signal was not transmitted through radio waves but via a video transmission cable that ran from each camera to the video recording unit. This created a closed circuit between the camera and the video recorder, hence the name Closed Circuit Television.

However, today CCTV has a slightly looser or different definition. Today most cameras are digital video cameras and they may transmit their images via a video transmission cable or via radio waves. Regardless of the method of transmission, a CCTV camera today refers to a camera that captures video and sends it to a monitor, recorder, or other private device that is not available for public access. In a sense it is still a “closed circuit” in that it is not “open” or available for public distribution.

How are today’s CCTV cameras remotely monitored? This is normally accomplished by using one of two different methods. Either the camera is a wireless camera that transmits its video signal and control data via a radio signal to a corresponding wireless receiver or the camera is connected to the internet and uses it as a network. There variations of these methods and we will attempt to briefly describe each one.

Wireless CCTV cameras remotely monitored normally have their own built in transmitter and antenna. These cameras send their signals using radio signals, the most common using the 2.4 or 5.8 GHz band technology that is often used for land-line based wireless telephones. Some boast ranges of up to 2.5 miles.

These cameras normally operate in such a way that their range is called Line Of Sight or LOS. This means that the range listed is the maximum specified range between the camera and the receiver unit using a Line Of Sight – where no objects stand between the two. However, that doesn’t mean that they will not function is there is something that impedes their LOS (such as a wall, window, building, etc.). If there is an object or objects that impede the LOS the camera usually functions but the range may be reduced. Exactly how much the range is reduced depends on the material the radio signal must pass through and how many objects exist. These cameras can be remotely monitored for this specific range.

Another example is Internet Protocol or IP ready cameras. These digital video cameras contain their own programming technology and server so they can be connected directly to the internet. These cameras can be remotely monitored around the world provided the user has access to a broadband internet connection. The user doesn’t even have to have a personal computer these days as the various electronic personal devices such as cellular telephones and wireless handheld video players can be used to monitor the cameras.

As for the older analog CCTVs? Even they can be monitored remotely. Older CCTV security and monitoring systems that require the coaxial video transmission cable can be connected to servers that connect them to the internet. These servers normally “capture” the analog video and convert it into a digital video signal. These files are normally extremely large so the server also uses programming to compress the file to make it quicker and easier to send over the internet. These servers make remote monitoring of analog systems just as easy as digital video systems.

So if you have a need to keep a watchful eye on your home or business while on travel, vacation, or simply away from the premises you should consider a CCTV cameras remotely monitored system.

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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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