Identifying Security Failures

Posted on: 14 November 2015

You want to protect your business with a full digital video surveillance system that includes several security cameras. While most security cameras can get a good picture in bright lighting, you'll need special cameras designed to capture images in low-light conditions if you want to have truly comprehensive security.

For a long time, analog cameras were better capable of capturing images in low light. Digital technology in the types of systems that small and medium-sized businesses might purchase wasn't quite good enough to provide clear images from darker environments.

But now there are two features you should know about that are available in affordable digital security cameras to help enhance and display good-quality images.

1. Day/Night capability.

There are two types of light that digital security cameras can utilize: visible light (which is the spectrum that humans can see) and infrared (IR) light. The ideal would be to use both types of light available, but using IR makes colors display incorrectly. 

The Day/Night feature in a security camera utilizes a filter that removes IR light during the day when there is plenty of visible light so that you get a high-quality color image. When light drops below a certain level, the filter is automatically removed, so the camera can use reflected IR light. In this night mode, the camera's software will filter out the incorrect color information that can produce graininess in the image, and you'll get a sharp black-and-white picture.

The best quality cameras have actual infrared cut filters that move into place, rather than a soft day/night feature where the cameras go black-and-white in low light. The latter type of camera has no ability to take away the cut filter so it doesn't use all the visible and IR light available. Either type is acceptable for lower-end business applications, but if you require very high-quality images, look for a true cut filter that physically moves away in brighter light.

2. Noise reduction.

For the best picture, you'll want to find a camera that is capable of masking or cleaning up noise (the static, spots, fuzziness or other visual artifacts that show on the image and reduce its quality). There are two types of Digital Noise Reduction (DNR) that you'll find in security cameras:

• 2D-DNR. This cleans up the foreground of an image, so things close to the camera are more visible and areas further away may be grainy. Moving things tend to be slightly blurry with 2D-DNR.
• 3D-DNR. This removes noise throughout the frame and helps to make moving objects more clear than is possible in 2D-DNR.

In addition to having clearer images, the reduction of noise makes for smaller file sizes, which is useful if you are storing digital video on a recorder. You'll be able to fit more data on the recorder at one time.

For the best results, test one digital security camera in the area where you will be using it before investing in several. Talk to your video surveillance dealer if you have questions or need more information. One company you may want to consider contacting is American Wireless Alarm Inc.