Issue link: https://securitytechnologyexecutive.epubxp.com/i/530736
22 SECURITY TECHNOLOGY EXECUTIVE • May/June 2015 www.SecurityInfoWatch.com requirements you are looking to achieve and the corresponding scene characteristics with which you have to work. There are circumstances where a 20-megapixel camera at a much lower frame rate can outperform its 4K cousin – such as in monitoring larger swathes of land or get- ting a general overview of a stadium. The sea- soned security integrator will evaluate the needs and make a recommendation that fits the cus- tomer's requirements. Comparison of key parameters for 4K and megapixel cameras are summarized in the fol- lowing table: As with any choice between camera technol- ogies, there are always tradeoffs. High resolution vs. storage and bandwidth consumption: Foremost is resolution because it has a direct correlation between bandwidth demands and storage requirements. The higher the image resolution the more data is gener- ated to be stored and the more bandwidth will be consumed. Advances in compression algo- rithms such as H.264 and the newer High Effi- ciency Video Coding (HEVC), also known as H.265 help mitigate this issue by significantly reducing the files size of the images without degrading their usability or quality. High resolution vs. light sensitivity and dynam- ic range: Higher resolutions reduce light sensi- tivity due to the smaller pixel size that is imple- mented in these cameras. These smaller pixels require higher light levels to activate and thus are not as effective in lower light situations. The same issue plays out in the dynamic range of the camera which measures the cameras ability to capture both the light and dark areas of a scene. Despite these limitations, both 4K and megapixel cameras provide real value for secu- rity practitioners who need to monitor and record large areas. Their higher resolution allows wider field of views while still maintain- ing the appropriate pixels on target to meet operational requirements. With 4K you get the added benefit of a standard that defines expec- tations up front and produces more usable sur- veillance footage. ■ SURVEILLANCE CAMERA TECHNOLOGY prove what you were pretty sure was happening between frames. Megapixel cameras often come with frame rate limitations that are far lower than the 30 FPS you can achieve with 4K. This limitation in frame rate makes them good for general surveillance appli- cations at best leaving 4K a clear winner where seamless situational awareness is a requirement. Round 4: Does 4K Show Surprising Footwork in Aspect Ratio? The consumer electronics adoption of wide-screen TVs eventually became the defacto standard for displays in the security industry as well. Now that 4K TVs are the new rage in the consumer electron- ics and broadcast industries, the security industry will inevitably follow suit. While the wide-screen format (16:9) has done much to improve surveillance coverage, there's another more important application of aspect ratio that is gaining momentum in the security industry. This involves reorienting the camera so that the image represents a 9:16 aspect ratio. Think of hallways, warehouses with high shelves, or even long city blocks in an urban environment. By changing the aspect ratio 16:9 to 9:16, we are able to deliver more pixels in the area of the image where an event will most likely occur. It's the difference between having more pixels on the walls of a hallway versus on the person walking down it. With proliferation of newer displays, 4K with a flexible aspect ratio of 16:9 and 9:16 clearly deliv- ers the knockout punch over megapixel And the Winner Is . . . So should you always go for 4K over megapixel? The answer really depends on the operational About the author: James Marcella has been a technologist in the security and IT industries for nearly two decades. He is currently the Director of Technical Services for Axis Communications. With a broader palette to work from, 4K cameras generate images that accurately depict the tonal values of people, objects, and backgrounds in a scene. Type Resolution Pixels Aspect Ratio Mbit/s Storage (28 days) 3 megapixels 2048x1536 3.145.728 4:3 5.71 1.73 TB 5 megapixels 2560x1920 4.915.200 4:3 8.04 2.43 TB 4K 3840x2160 8.294.400 16:9 13.56 4.1 TB