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Selecting the Right IP Camera System
Understanding all the pieces
http://www.kintronics.com/neteye/neteye.html
by Ed

When selecting a Network Attached or “IP” based camera system, there are many things to consider.  The core components include the camera, the lens, an enclosure for your camera, storage for your recorded video and the software that ties it all together.  So how exactly do you determine which components you need for your system?   By answering the following series of questions, you will have the information that you need to be part of the “IP Camera Revolution”!

What Do You Want To See?
Seems like a simple question, right?  The reality is that this is a critical piece of information that you will need to know in order to specify the type of camera and lens that is most appropriate for your application.  The “subject” of your surveillance and its characteristics will help define your viewing area.  Once you define your viewing area, you can then determine the lens that isneeded to properly capture that viewing area.

When defining a viewing area, you must determine 2 main factors…

·         How far away is the subject that you would like to view? Is it 10 feet away or 210 feet away?  If it’s close, a wide angle lens may be needed; if far, a zoom lens may be in order.

·         How wide is the area that you are viewing?  Are you looking at a 10 ft wide driveway to capture a car license plate or are you viewing the bleachers at a stadium?  The viewing angle in combination with the distance to the object will be used to calculate the camera lens.

Armed with this information, you can determine the millimeter or “mm” specification for your lens.  The higher the “mm”, the smaller the field of view and the more magnification you get.  For example, a 4 mm lens provides a viewing angle of about 60 degrees and a 400mm lens provides a viewing angle of about 7 degrees.  In addition, the 40mm lens provides about 9X magnification. You can use our lens calculator to calculate the appropriate lens for most situations:


Do You Want To PTZ?
Although it may sound like a new dance move, most experienced folks know whether or not they want their camera to Pan, Tilt and Zoom.  That is, the ability for your camera to selectively focus on a smaller part of a “big picture”.  Let’s look at the traditional type of PTZ camera and then a newer type that is only available in the IP world.

A traditional PTZ camera can physically move both horizontally and vertically, and can optically zoom in on a particular object.  These cameras can be moved and zoomed using a web browser or IP surveillance software, or they can be placed in an auto-patrol mode where they automatically step through pre-determined positions. In this patrol mode the software can detect motion and then stop the camera so it can record the video. Once the motion stops the camera returns to its patrol.  It's a great way to view a large area like a parking lot.  The Axis 233D PTZ camera and the Videolarm FDW7CN-9 are examples of PTZ cameras with enough durability to be used in patrol mode.  One thing to be aware of is that you can miss some activity when the PTZ camera is moving through its patrol mode.  If the camera isn’t pointed at what you need to view at that moment, you may miss it.

A second type of camera that can be used to PTZ, is actually a fixed mega-pixel camera.  The IQinvision IQ752 is an example of a mega-pixel camera that can provide “digital PTZ”.  It works because it has such a high resolution image that it allows the user to digitally zoom in on a smaller parts of the image.  The camera itself never physically moves, but the image that the user sees can be enhanced and enlarged from any area of the original picture. There are several advantages to this type of camera.  First, there is no wear and tear due to physical movement.  Secondly and most importantly, since the recorded video contains the entire picture, you can zoom in on any part of the picture at a future time and never have to worry about losing sight of your subject.

Are You A Night Owl?
More importantly, is your camera a night owl?  For some applications, the ability to view images in the absence of light is imperative.  There may be some residual light, but not quite enough to capture a clear image.  Think of it this way…  light is measured using the term “lux”.  For comparative purposes, 1 lux is equal to moonlight and 400 lux is equal to a brightly lit office.   Depending upon your application, there are IP cameras that have varying degrees of low light capability.  Some can capture a reasonable image in low light; others will switch from color to black and white in order to view in an even darker environment.  There are even cameras that are “infrared sensitive” and can view an image with no natural light what so ever.  These cameras work with the assistance of an infrared illuminator that will enable us to view a subject using infrared light that is not visible to the human eye, but can be used by the camera to illuminate a subject.  The illuminator can either be integrated into the camera or can be a separate unit depending on the area that needs to be illuminated.  Take a look at our other article about “Seeing in the Dark”, for more information about using cameras in low light.

The Proof Is In The Details!
As with most everything in life, detail can be the key to a properly designed IP camera system.  The detail I’m referring to is in the image that you see through your cameras.  How important is detail to you?  Do you need to see the poor dead bug on the windshield of the car pulling into the parking lot or maybe just the license plate of the car?  Perhaps you need to view the waves at your favorite beach spot before you grab your surf board or maybe the precise mixing of a drug in a laboratory?

Whatever level of detail you need to see can be narrowed down to one word:  RESOLUTION!  Resolution is a measure of the “image sharpness” of a picture and it is usually measure in dots or “pixels”.

When thinking of resolution, the important thing to know is how many pixels are required to be able to see the level of detail that you need to see.  Pixels are the thousands of individual dots that compose each image in an IP camera.  For example, in order to be able to recognize a person’s face in an image, you need approximately 40 horizontal pixels per foot of the width of your picture.  So…  if you have a standard resolution camera of 640 pixels wide x 480 pixels high, you will be able to recognize a face in a viewing  area up to 16 feet wide (640 pixels / 40 pixels per foot = 16 feet).  Conversely, if you are using a high resolution 5 megapixel camera such as the IQEye 755 (which has a resolution of 2584 x 1936) you will be able to recognize a face in a viewing  of about  65 feet wide (2584 pixels / 40 pixels per foot = 64.6 feet).  Using this knowledge, you can now determine the resolution of the camera that you need and the number of cameras that you need to cover your viewing area.

Are You In Or Out?
The requirements for cameras that operate indoors can be very different than those that are designed for an outdoor environment.  The most obvious of these differences is one of climate and lighting.  Let’s ask some questions…

·         Are there weather extremes in your outdoor viewing area?   Excessive heat, cold, sun and rain (amongst other adverse conditions) are the arch enemies of sensitive electronic equipment, such as IP Cameras.   There are many excellent environmental enclosures available to provide complete protection and the perfect operating environment for your IP camera.  If it's too hot…. maybe you need a blower.  If it’s too cold… maybe you need a heater.  Are you in a really corrosive environment like near the ocean where you may be exposed to salt spray?  You may very well need a pressurized housing that will totally seal your camera from the elements. You can see some of the environmental enclosures available on our web site.

·         Dark or bright?  An important feature of any camera is the ability to allow the perfect amount of light through the lens.  This is accomplished by opening or closing the lens iris.  If you let in too little light, your picture is dark.  If you let in too much light, your picture will be washed out and unrecognizable.   When dealing with an indoor viewing area, chances are the lighting will consistent and predictable.  For this situation, a manually adjustable iris is fine.  However, when your lighting situation changes on a regular basis (as in an outdoor environment), it is important that you select a camera that can support an auto-iris lens. This type of lens will automatically adjust the light entering the camera to account for changing conditions.

You’ve Got Your Cameras… What Do You Do Next?
It’s simple… you find the best software and the best computer you can to control your cameras based on the following criteria:
·         Frame Rate: This is often determined by what it is you are “looking for” in a surveillance video.  If you are counting cars speeding across a bridge, you might need over 20 frames per second.  However, if you are watching someone walking slowly across a room, you may need only 5 frames per second.   Each camera can be specified with its own unique frame rate based on your specifications. The important thing to bear in mind is that frame rate can dramatically increase or decrease the amount of storage needed to capture your video.  The higher the frame rate, the more storage that is required.  It behooves you to always choose the minimum number of frames that you can use for your application.
·         Motion Detection:  In many situations, it is only necessary to record video when there is motion present in your viewing area.  Thus, when there is no motion, there is no need to waste storage recording this video.  The key is to be able to separate those parts of your viewing area that are “motion critical” from other less important parts.  A robust software product such as ONSSI NetDVMS will allow you to precisely define certain areas and record video only when motion is detected in these “motion critical” areas.
·         Number of Cameras:  The number of cameras that you need for your application is a major determining factor for the software that you can use.  Many software products will support up to 32 cameras.  Once you move above that number, you will require more sophisticated software.  ONSSI makes excellent software that can cover almost any situation.
·         Storage:  How long of a period of time do you need to store your video?  This question is directly related to your application and often based on common sense or possibly government or legal regulation.  Once again, the goal is to minimize the storage period while adhering to storage guidelines.   The amount of storage required is determined by the number of cameras, the period of recording time, the resolution of the cameras, the compression and the frame rate used.  Take a look at our article “How to Calculate Video Storage” for more details about this.

Now that you’ve got all the answers you need to build the perfect IP camera system, what do you do?  You call Kintronics and we will be happy to assist you with the detailed specifications you will need to complete your project!  You can reach us at 914-944-3425 or use our contact form.

[PRINTER FRIENDLY VERSION]
Published by Bob Mesnik
Copyright © 2008 Kintronics, Inc.. All rights reserved.
For more information, please contact us 1-800-431-1658 or 914-944-3425 (outside the USA) or by email infohome at kintronics.com
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