Mega Pixel CCTV
What does it mean?
The term “megapixel” originates from the digital photographic camera world. Until recently most CCTV systems used PAL – technology first unveiled in 1963 - and this provides images with a resolution roughly equivalent to 0.3 megapixels (standard definition.)
HD and Megapixel
High Definition or “HD” video normally refers to one of two specific resolutions. 720 HD is 1280 x 720 pixels (0.9 megapixels), and 1080 HD is 1920 x 1080 pixels (2.1 megapixels). HD video offers around 3 or 7 times the resolution of a standard definition camera.
Megapixel covers any resolution of 1 million pixels or above so 1080 HD (and arguably 720HD) are forms of megapixel technology.
Why use Megapixel Now?
High definition and Megapixel technology has been slow to catch on in the world of surveillance, mainly due to the difficulty in transmitting and storing the large images that result. However improvements in compression and the falling cost of IT storage mean that megapixel is now a very cost effective solution, particularly if large areas need to be covered.
The benefits
Megapixel technology benefits end users in one of two ways:
- It allows the collection of better evidence through higher resolution images.
- It enables one camera to cover a greater area in the same resolution, thus requiring less cameras overall
Designing HD and Megapixel Solutions
For target detection (particularly by a human operator) the height of the individual relative to the overall height of the screen is still very relevant, however in forensic application the target can be much smaller within the scene and still provide the same resolution. An operational requirement therefore needs to be expressed not just as a percentage of screen height but also in pixels per metre (or millimetres per pixel) as well.