Still, megapixel cameras have had a major impact on the IP-based video market because more pixels mean more detail - especially during forensic searches. However, the lens is often the most limiting part of a megapixel system, making three- and five-megapixel camera performance feasible today if a more expensive megapixel-rated lens is used. There is an obvious place for megapixel in network video, but end-users should realize that it will typically come with a tradeoff of lower frame rate because of bandwidth constraints.
High-Resolution in Analog: HDcctv
For those with analog-based systems who have been following market trends, a fourth higher-resolution option seems to have arisen: High-Definition Closed Circuit Television (HDcctv). HDcctv, sometimes called "analog megapixel," is based on broadcast engineering standards like HDTV, except its claim to fame is that video can be sent over existing coax cable so analog users can finally get a taste of high-resolution image quality.
The main problem, however, is that new equipment - such as HDcctv-compliant cameras and DVRs - must be purchased in order for the system to work. It is true that the end-user will save on up-front installation costs if their coax cable is of high enough quality to transmit the HDcctv signal, but additional hardware costs could make HDcctv less cost-effective than a network-based system. In that case, it begs the question: Why wouldn't you upgrade?
Not only is cost a factor, but so is scalability, availability and performance. An HDcctv user will be clinging onto an outdated infrastructure format (coax) and delaying an inevitable upgrade to UTP cabling, which is actually less expensive today. Higher resolution is just one reason to select IP-based video, joining common off the shelf (COTS) storage and networking hardware, video intelligence, Power over Ethernet, audio, remote zoom and multi-streaming as unique benefits. Additionally, HDcctv products are scarce today and are expected to be quite costly thanks to low volumes. Finally, much more R&D effort and funding is being put into IP by the major manufacturers, so HDcctv and its users will have a hard time keeping pace with performance innovation.
Based on today's usage and tomorrow's predictions, HDTV and megapixel network cameras seem to be the only real options to consider.
Megapixel vs. HDTV: Which is Best?
Because of its standards-based approach, network cameras that operate in HDTV will oftentimes be more eye-pleasing than megapixel, and it has turned into a popular settings request from end-users in all industries. Still, there is a place for both technologies in video surveillance. Fortunately, megapixel cameras today can be manufactured to have an HDTV-compliant video setting. So, for example, the end-user can choose to record video in 3MP or 1080p based on need.
The HDTV setting is typically the most valuable in surveillance because it provides the most accurate real-world representation of the scene, including movement of people and objects in the field of view. Casinos, retailers, schools, city surveillance centers and transportation stations tend to benefit most from the HDTV format because of the fast-moving nature of the scene, as well as the need to identify specific colors - i.e. a red vs. pink chip on a table or a lost child wearing a green jacket. Additionally, a wider field of view will help put more pixels on target, and a 16:9 view can also be flipped using software to provide a 9:16 view that works extremely well to monitor shopping aisles, school corridors and train tunnels/platforms.
If, however, lower frame rate is not an issue and your application (or corporate policy) calls for super-fine detail, selecting the megapixel option might be the right one. These are for slower-moving scenes where identification - especially in post forensic searches - is of vital importance. A bank lobby, hotel front desk, access point or customs registration area could be installations where a three- or five-megapixel setting works best.
But even though it is natural to want the biggest and best, keep in mind two things when purchasing a megapixel camera. First, lenses are extremely important. A poorly matched lens will result in a poor image. While image sensor technology today can produce 10-plus megapixel performance, lens technology has not yet caught up. With advancements such as P-Iris control, the best lenses today are rated to efficiently work up to five megapixels before the image begins to degrade. The best option is to select a megapixel or HDTV camera that ships with the appropriate lens pre-configured. If that is not possible, ensure the lines per millimeter of the image sensor matches the performance rating of the lens.