If you are in the market for cameras for security or surveillance applications, then you no doubt have been overwhelmed by the broad selection available from online stores. How do you choose a camera for surveillance? What camera features are important for security? What is a reasonable price for a security camera and the components for a complete surveillance system?
In this series of articles I am going to review the key camera features you should consider and what price you should expect to pay. I will also provide a short list of online resources and distributors of surveillance cameras for security.
In this first article I will give a brief overview of the evolution of camera resolution and offer a few scenarios to help guide you in selecting the optimum security camera(s).
Improvements in Security Camera Resolution Required a Leap in Technology
For many years the resolution of video security cameras was fixed on the video standard of 480 scan lines per image and 640 pixels per line, i.e. 640×480 pixels. For many applications that resolution was perfectly fine. But for security applications requiring a wide view, such as retail store surveillance, airport terminal security, or parking lot surveillance, that resolution fell well short of what was needed to identify a suspect or interpret a scene. Such video surveillance applications required the use of an expensive power zoom lens and a pan-tilt camera mount to capture small sections of the scene to provide sufficient image quality.
The development of solid state camera sensor technology ( CCD & CMOS ) and digital readouts lifted the restriction on resolution. By the mid 1990s digital video cameras with resolutions of one, two, and even three million pixels (referred to as megapixel cameras) became available. Megapixel cameras could capture large scenes with sufficient detail to eliminate the need for power zoom optics and pan-tilt systems for many applications. This significantly lowered the cost and raised the performance of small to moderate video security installations.
However, it was not until the development of computer networking technology that megapixel cameras came into wide use for video surveillance. IP, or “Internet Protocol”, network cameras, could be individually addressed on a network, and exchange image data and control commands over common CAT 5 cabling. In a typical installation, multiple cameras are controlled by a single remote computer or dedicated recording device. There is no restriction on camera resolution and in fact, multiple cameras of varying types and resolutions could be run on a single common network.
Choosing the Right Surveillance Camera for the Job
Despite the impressive developments in camera and computer technologies, you don’t necessarily need to jump into a megapixel security camera system solution. Far from it. For many applications, the old analog, standard resolution cameras are just fine, and competitive pressures have made them extremely inexpensive.
Below are a few scenarios and tips to set you in the right direction when choosing cameras for surveillance applications. Do any of these fit your application?
Corridor or Entry Way Surveillance
One or more cameras surveying a scene of 10-25 feet in dimension and mounted less than 25 feet away. In this scenario an analog or digital camera with a standard resolution of 640×480 will provide sufficient detail to identify a person or interpret a scene. You can pay as little as $79 for a simple wireless camera, sold everywhere on eBay, Amazon, and others. These will do the job, but don’t expect great image quality. More realistically, you should expect to spend $200 to $500 for a video camera and lens combination with sufficient quality to produces clear, sharp, images in bright sunlight or low light ( dusk ) conditions.
Busy Corridor or Retail Store Surveillance
In this scenario, a relatively large area, perhaps 30-100 ft wide is surveilled, monitoring multiple subjects. This is where standard video resolutions begin to fail. The cameras are not capable of producing enough detail across the wide scene. So they rely on zoom optics and PTZ camera systems to monitor sections of the scene. Of course, that means they cannot monitor the entire scene at once. So either detail is missed, or multiple cameras are required, greatly increasing costs.
In this application, a one or two megapixel IP network camera excels. Often a single camera of this type with a fixed focus lens will provide sufficient detail to identify a subject or interpret a scene 100 ft in width. No pan-tilt mechanism is required, and the scene can be monitored in a single frame. You can expect to pay between $400 to $1,000 for a camera of this type, inclusive of the lens. They are available both as wireless devices and hardwired via Cat 5 network cable.
Large Scenes, Parking Lot Surveillance
In this scenario, a large expansive scene, such as a shopping mall or factory parking lot is under surveillance. This application requires multiple cameras placed strategically to cover many viewing vantage points across the property. For moderate size properties, such as a parking lot of 100 cars or less, multiple megapixel cameras on fixed mounts may suffice. For larger properties, multiple cameras on remotely controlled pan-tilt platforms may be required.
The choice largely depends on your security plan. Scene interpretation requires less detail then identifying subjects. If your security plan is supported by security personnel, then static scene recording mixed with one or two remote pan-tilt-zoom cameras operated by personnel for detail and identification purposes may be an ideal mix of cameras and hardware.
You should expect to pay between $400 to $1,000 for cameras in this type of installation. The pan-tilt-zoom systems add an additional expense of $1,800-$3,000 per unit depending on camera resolution and zoom optics. These systems are typically fully integrated comprising the camera, PTZ mechanics, zoom optics, and dome enclosure ready for mounting. Camera control and recording for these systems are typically handled by a dedicated computer, running a Linux or Windows operating system and specialized software.
In future articles I will discuss in more detail each of the application scenarios I presented. I will compare some of the popular products, discuss important features for day time versus night time surveillance, provide some technology background on CCD vs CMOS sensors and their performance, and will give an overview of the peripheral devices needed to tie all these components together.
I will begin with a discussion of the Corridor or Entry Way Surveillance application and provide a more detailed list of suppliers for the components that application requires.
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