Archive for the ‘ Product Cameras’ Category

Wide Dynamic Camera

Written By:
Friday, July 8th, 2011

wide dynamic cameraA wide dynamic camera conjures images of an incredibly large (In a horizontal direction) camera, somewhat like an oversized wide-angle lens.   However, that’s not what a wide dynamic camera is at all.  In fact, some ultra-small hidden covert cameras are also wide dynamic cameras.  So just exactly what is the wide dynamic range of a camera?  Read on to find out.

A wide dynamic camera is actually a camera with a highly specialized function to assist the image capture process.  When cameras possess the circuitry to support this function we say that they have Wide Dynamic Range or WDR.

The whole idea behind this business of a wide dynamic camera is to produce a superior image, at least superior when compared to the image from an exact same camera that does not support WDR.  WDR helps to provide clear video images under unbalanced, poor lighting conditions:  Specifically, when the intensity of the light varies such that that there are incredibly bright and dark areas that appear simultaneously in the field of view (which is destined to become the video image) of the camera.

Overly dark areas and overly saturated light areas, especially over saturation of back lighting is the problem that the wide dynamic camera is trying to solve.  The better the WDR of a camera the better video image produced under undesirable backlighting conditions and other over contrast conditions.

Specifically, a wide dynamic camera filters the intensely bright back light that may surround an object therefore enhancing the ability to distinguish features and shapes on the subject that were “washed” out by the intense bright light.  The dynamic range of a camera is normally defined as the ratio of the brightest point of an image to the darkest point of the same image.  Some also refer to this situation as “maximum contrast.”

In essence, what happens in this situation is the intensely bright (back) light is causing the camera to adjust itself to that particular condition.  When this happens, the video image produced is a washed out image near the light source and everything else being to dark to recognize.  This does not necessarily apply to images with steady light sources; it can occur when momentary intense light appears (for what ever reason) throwing the entire camera off balance.

Perhaps one of the best examples of a problem wide dynamic range is when a camera attempts to capture an image in front of a large storefront window.  The object inside the store appears far too dark with the sunlight pouring through the front window and washing out the details of most of the field of view of the camera.

There are several different approaches to the solution of this problem and although each method’s goal is the same result (a balanced, detailed video image) the process they use to go about correcting the situation may be different.  Basically there are two major methods or technical solutions that are used to correct the problem and there are additional methods that “hybridize” the process by combing the two basic methods.

The first solution is “multi-frame imaging.”  Here the wide dynamic camera captures more than one frame of the field of view.  Each of these frames possess their own dynamic range and the camera combines the different frames to produce one WDR image or frame.

The second solution is the use of non-linear sensors (generally logarithmic sensors) where the sensitivity level of the sensor at different light intensities also varies providing the capture of the field of view in one wide dynamic camera frame.

Combinations of the two methods just mentioned are also used. For example, they may include parallel capturing by more than one sensor using a common optical path.  Here each sensor captures different levels of the dynamic range of the scene by either different exposures, different optical attenuation in the final optical path, or different sensor sensitivity.  There are many more combination methods that may be used as well.

The key is that if you intend to use a camera that will be capturing areas of extremely high contrast or that are back lit by an extremely bright light, you’ll want a good wide dynamic camera to capture the image.

If you have any additional questions about wide dynamic cameras or would like to purchase a camera with WDR, please contact one of our security experts today either via on-line “Live Chat” or by telephone at 866-573-8878.


LCD Video Camera Monitor

Written By:
Wednesday, June 22nd, 2011

Most digital video security systems today are designed for use with an LCD video camera monitor.  There are a few reasons for this, but there are also reasons why it may be difficult to use an LCD monitor.  In the following article will discuss LCD monitors how they differ from CRT (Cathode Ray Tube) monitors and some of the advantages of using them instead of a CRT.

First of all, to understand the difference that exists between the two types of monitors let’s briefly discuss how each one works.  The CRT monitor receives an analog radio frequency signal that contains the information for drawing a picture on the front of the CRT or screen.   The CRT shoots horizontal beams of light back and forth from behind the screen very rapidly.  If your camera is a 500 TVL (TeleVision Line) camera and your CRT monitor screen is made up of 500 horizontal lines or more, then you’ll see every bit of the video image that is sent to the CRT in good detail.

In other words, the analog resolution measurement as it pertains to non-digital hardware is the TVL.  The higher the number the TVL the higher the resolution of the picture display.  A 500 TVL display means there are 500 horizontal lines (created by the ray of beams from the CRT).  This obviously will show less detail than say a 380 TVL of the same image.

Remember too that these lines can vary in size from monitor to monitor.  A 19 inch monitor will have much finer (thinner) lines than a 32 inch monitor.

Also, most analog screens have only two types of possible input/output connectors; a 75 ohm cable connector or an RCA plug.  These are a “standard” for analog video connections and are on the backs of most monitors and televisions.

A digital video security camera system Liquid Crystal Display or LCD video camera monitor differs from the CRT type in many ways.  First an LCD monitor is designed for digital input not analog.  This means there are different standards of measurement for the LCD monitor as compared to the CRT.

Another major difference is in the way the LCD video camera monitor displays its images.  Unlike the CRT whose picture consists of horizontal lines, the LCD monitor displays are in pixels.  Pixels are very small dots usually round or square in shape that make up the image and entire LCD screen viewing area.  Like the CRT’s horizontal lines being an indication of resolution or detail, the LCD’s standard for measurement is the pixel.  Keep in mind that pixels vary in size especially from small monitors to large monitors.

However, because these pixels on the average are much smaller than the TVL the LCD video camera monitor automatically makes for a good competitor to the CRT because of the enhanced capability to display a greater resolution or in other words, higher detail.

So the pixel is really the standard of measurement with an LCD video camera monitor.  This can be confusing as well because both resolution and size on an LCD video camera monitor are based on pixel measurements.  For example your monitor may have a screen that is 800 x 600 pixels.  Let’s re-emphasize that the 800 x 600 is the total amount of pixels available for displaying an image.

The image could be 340 x 280 pixels, so what does that tell us?  Basically it tells us the SIZE of the image–on your monitor or anyone else’s, the image will be 340 x 280 pixels.  (Remember that earlier we said pixel size can change with total screen size.)  The actual resolution or detail hasn’t been stated yet but generally speaking, the greatest resolution that can be obtained on an LCD Video Camera Monitor is 96 dpi or dots per inch.

So 96 dpi is actually the resolution.  Any image viewed on the monitor with a resolution greater than 96 would be wasting information.

To summarize then, a CRT monitor’s resolution is displayed as TVL or horizontal lines; the more the TVL the more detailed the picture.  High definition monitors and TV’s display 1080 TVL.  An LCD video camera monitor’s resolution is usually around 96 dots per inch.  The pixel measurement, such as 800 x 600 tells how big the image is but not what the resolution is.

So when shopping for an LCD video camera monitor be sure to keep these things in mind to make sure you get the type/size you need.


Security Camera CCD

Written By:
Tuesday, June 21st, 2011

We are asked quite often about the security camera CCD (Charged Coupled Device) and the CMOS or Complementary Metal Oxide Semiconductor.  In the following article we’ll discuss how a digital video system actually works and what importance a security camera CCD has within this system.

First let’s describe a digital video security and surveillance system.  It normally consists of three components; the camera(s), the Digital Video Recorder, and a monitor(s).  The camera’s function in this system is to capture a video image created by light reflectance and transform it into an electronic image based on electricity.  Both live and recorded material is played back by the DVR and may be seen by watching the monitor.

So now that we have a general idea of what each component does, let’s talk specifically about the camera and the security camera CCD.

A digital video camera works by using a combination of mechanical (lenses) and electronic (Integrated Circuit or IC chips and printed boards).  Whatever direction the camera may be pointed in, the area that you will see as a point of view from the camera is called the camera’s field of view.  The field of view is the specific area that will constitute the video image.

The field of view can be made larger or smaller depending on the focal length of the lens.  A standard lens has one focal length and therefore on field of view.  Varifocal lenses can vary their focal length (either manually or remotely).  The field of view contains objects that reflect light.  This reflected light is captured by the lens and when in focus, the lens focuses the reflected light on a sensor chip which is usually only 1/4 to 1/3 inches square.

This sensor chip, in our case, is the security camera CCD.  As the focused light strikes the security camera CCD, tiny pixels on the sensor emit a very small but measurable electric impulse.  Their may be more than one CCD and their maybe the use of one or more filters involved as well.

Once the light strikes the security camera CCD, the CCD gives off it’s electrical pulses and this are measured and interpreted by the analog to digital processor IC chip.  This is when the video image becomes digital.  As the processing continues in the camera, the camera’s Digital Signal Processor or DSP, in essence another IC chip, makes adjustments to brightness, color intensity, contrast, etc. to make sure the video image is of the highest quality.

Once the video image information, now binary or digital data is sent to the DVR the DVR stores it or plays it live.  Either the camera or the DVR compiles the binary data and creates a digital video file out of it.   These digital video files are the same type of digital video files that can be watched on a personal computer.

The security camera CCD (and the CMOS) has a unique feature about it that makes it even more versatile.  The CCD inherently can also create video images using on infrared light.  Infrared light is invisible to the human eye, so this makes for a very powerful, useful security device.  Most night time infrared cameras have an array of Infrared producing Light Emitting Diodes or IR LEDs that are arranged around the lens of the camera.   The human eye cannot see their light, but to the CCD, they work like using a floodlight.

In addition to the array of LED’s around the camera lens, IR LED illuminators may also be used.   Illuminators are just a group of more IR LEDs to add more light to the picture.  Some illuminators boast IR ranges of as much as 300 feet when using the illuminator along with the camera’s own lights.

Incidentally, since this type of video construction is done with only IR light, the image will be in either black and white or monochromatic.  But very seldom will the detail or resolution degrade so the IR video image is as good of quality as the day time color versions.

Security Camera King has a large variety of security camera CCD cameras and systems.  Be sure to check the “Specification” tab when looking at a camera that you may be considering to purchase to make sure that the camera gets the proper night time range that you will need.


Infrared Wireless Camera

Written By:
Wednesday, June 15th, 2011

You may be wondering what an infrared wireless camera is.  It is a digital video camera that can capture digital video images in total darkness and does not require a coaxial video transmission cable run from the camera to the Digital Video Recorder or DVR.

Let’s start at the beginning.   A digital video security and surveillance system normally has three basic parts or components:  The camera(s); the DVR; and, the monitor(s).  It’s the camera that we are interested in so lets talk about how it works and what it does.

Unlike the infrared wireless cameras, most cameras need some sort of connection wire to send their video data over to the DVR.  Most often, this wire is actually RG-59 coaxial cable.  The signal originates at the camera end and terminates at the DVR end.  There is nothing wrong with this method; in fact this is the way most security systems are set up.  However, if you want to avoid running all that cable, then you may want to consider a wireless camera.

The wireless camera helps to avoid all the time and effort it takes to run the RG-59 cable.  Imagine that you want to install a gate camera at the end of a very long driveway.  Can you imagine the cable run through your house all the way out to that camera at the gate?

On the other hand an infrared wireless camera has its own on-board transmitter and built-in antenna so that it can send the video data to the DVR in radio frequency format instead of cable.  Actually the camera sends the radio transmission to a corresponding receiver made specifically for this purpose.  The receiver is then connected to the DVR by a coaxial cable and relays the camera’s signal to the DVR via this short cable.

The camera at this point is not truly 100% wireless.  All cameras must have some sort of power supply and so a power supply line must be run to the camera.  In this situation, this can still be a bit of an advantage at making installation easy because a single plug-in type transformer, made specifically for the camera can be plugged in to an outlet nearest the camera reducing the power supplies’ cabling run.

A truly infrared wireless camera can be achieved with very little effort.  This is probably the most desirable configuration because there are absolutely no wires or cables that need to be run from the DVR to the camera.  There are many infrared wireless cameras available from Security Camera King that obtain their power supply from on board batteries.  This makes the camera truly wireless.

When purchasing a wireless camera, make sure you know how far (usually in feet) that your camera will be separated from the receiver.  Most cameras employ a wireless transmission type where the maximum range is stated based on Line Of Sight or LOS.  That means that a camera with a wireless range of 300 feet has that range based on LOS.  If there are any objects between the receiver and the camera you could loose the signal entirely, although this is rare.  Generally, depending on the amount and material the radio signal must go through it simply reduces the camera’s range.

The other half of the infrared wireless camera, that is the infrared portion, allows the camera to see in total darkness.  The camera lens focuses the field of view onto a small (usually 1/4 to 1/3 inch square) sensor that when struck by light energy emits electrical impulses that can be measured and used to create an electronic reproduction, or video footage.

The chips that are used are the Charged Coupled Device (CCD) and the Complementary Metal Oxide Semiconductor (CMOS).  Both the CCD and the CMOS have the inherent ability to react not only to the visible light spectrum but they can also see the near red infrared light spectrum (human eyes cannot see this type of infrared radiation–simply put it is invisible to us).

An infrared wireless camera is usually supplemented with an array of InfraRed Light Emitting Diodes (IR LEDs) positioned around the lens.  This is like using a floodlight on a non-infrared camera.  Additional illuminators can be purchased to extend the distance of the camera.

An infrared wireless camera not only has a transmission range, but it also has an Infrared range distance.  Make sure to check the infrared range on the camera before purchasing it as well.


16 Camera Power Supply

Written By:
Saturday, June 4th, 2011

If your digital video security and surveillance system has 16 cameras, you will more than likely need to get a 16 camera power supply.  Unless your cameras are battery operated or PoE (Powered over Ethernet), they will require that a power line be run from a power distribution box or transformer to the camera.

There are two different types of 16 camera power supply, based on the type of current that is needed by the cameras.  It seems as though most cameras these days lean toward the low-voltage Direct Current or DC of 12 volts.  However there are still systems that exist that create 24 volts of AC current.  You CANNOT connect AC voltage supplies to DC cameras or DC voltage supplies to AC cameras with one exception.

Security Camera King does have a few cameras in their inventory that have the ability to accept either 12 VDC or 24 VAC.  However, if the equipment you are providing power to is not rated for dual current use, you can easily ruin your camera and other components of your system by using the wrong type.  So make sure that the camera’s power requirements match the output of the power device you are using.

If most digital video security cameras run off of 12 VDC these days, then why bother with AC voltage systems?  As we mentioned above, many older systems found it more practical to use AC rather than needing to bother with changing the AC to DC.  Alternating Current can be changed to DC by using a rectifier circuit and a transformer to reduce the voltage.  Second, AC can be sent further than DC without degradation of the circuit (mainly loss of voltage).  Most of this is a bit too technical for our needs with security cameras, so suffice it to say that most conventional systems made today are DC and not AC.

However, the security system owner need not feel left out and empty handed if he/she needs to replace a camera and their original system is AC but the new camera is DC.  Security Camera King’s Product# CV-24AC-12VDC is an AC/DC single camera adaptor that can convert 24 VAC into 12 VDC.

Getting back to the subject of a 16 camera power supply, there are many ways this can be accomplished.  First, and probably in many ways the easiest, is to purchase Security Camera King’s 16 Channel Power CCTV Power Distribution Box Product# PWR-16.

The PWR-16 obtains its power from typical household current.  However the box itself contains the rectifiers and transformers to create enough power for up to 16 cameras or other devices.  All you need to do is mount the power distribution box (usually, but not always in the vicinity of the DVR) connect the incoming household current and use the screw posts to connect each camera to the 12 VDC they require.

In addition to the PWR-16 DC unit, Security Camera King also offers a 16 Camera Power Supply suitable for AC cameras.  Product #PWR-16AC-8A provides 24 VAC for up to 16 individual cameras.

For some security system owners, one power distribution box may be impractical.  For example, 8 cameras (for what ever reason) may be on the East side of the building while 8 more occur on the West.  In this case it may be more practical to use two 8 Channel CCTV power distribution boxes instead of one 16 camera power supply.

Lastly, Security Camera King also offers a unique DC power supply transformer for security cameras.  This device plugs into any typical wall outlet and outputs a total of 4 DC power supply leads.  Although this sounds impractical, it may actually be advantageous to use 4 of these devices to provide the power to 16 cameras as well.

No two digital video security systems are alike and likewise, providing a 16 camera power supply may not always entail using the same power supply solution.  Versatility is a key factor in today’s systems so what ever works best for your system is the way to go.

If you have any questions or are considering the purchase of a 16 camera power supply, please contact one of our security experts either via on-line “Live Chat” or by telephone at 866-573-8878 Monday through Friday from 9AM to 6PM EST.