Video Surveillance: One Resolution Does Not Fit All

Let the user's needs be your ultimate guide

With HDTV in their homes and megapixel on their phones, security personnel wondered why they couldn’t have the same superior viewing experience and performance from their surveillance systems. As most people became caught up in the megapixel war of more is better, the HDTV standard gave people a real world point of reference for image quality. Manufacturers were already investing R&D in just that, and in January 2009, the security market launched the first HDTV-compliant surveillance camera, forever changing the industry’s outlook on surveillance.

HDTV vs. megapixel

HDTV is a standards-based format governed by the Society of Motion Picture and Television Engineers (SMPTE), which includes:

  • Resolution (720p or 1080p)
  • 30 frames per second
  • Aspect ratio of 16:9
  • Broader palette to render higher color fidelity

Megapixel has its roots in point-and-shoot photography, meaning a megapixel camera refers to the number of pixels produced by the image. In comparison, HDTV provides a better overall video viewing experience. This is why your smartphone takes 8MP snapshots, but records in 720p or 1080p HDTV when you to switch to video recording.

Does HDTV herald the death of the megapixel then? In short, the answer is no. Like any technology, each has its advantages—and it is up to you as the integrator to determine which factors are most important to a customer.

Let’s start with frame rate, which in practical terms relates to situational awareness. At lower frame rates, the video may look choppy, making it difficult to interpret what actually happened in the scene. This can have profound implications in mission-critical surveillance where situational awareness makes a big difference. In casinos, for example, slight-of-hand movements can result in the loss of large sums of money. The HDTV standard of 30 frames per second may be the best fit for an installation requiring situational awareness.

Not all scenes require 30 frames per second though. If high pixel detail is the customer’s priority, then a megapixel camera will meet these needs. For instance, if your customer wants to monitor a well-lit parking lot with slow moving cars, delivering a high level of detail even at a lower frame rate will meet the customer’s needs and deliver a successful solution.

When designing any video surveillance system, storage is an important factor. The frame rate of megapixel video is often dialed back to save on bandwidth and storage. However, if bandwidth and storage are not limiting factors, then megapixel cameras can also record at higher frame rates. Savvy integrators recognize the give and take of frame rate and bandwidth consumption and should be mindful of which factor is of more concern to the customer.

For surveillance of hallways, warehouses and aisle and high-racking shelf environments, HDTV may have the edge. The HDTV standard specifies a widescreen aspect ratio 16:9, which can be turned on its side, known as corridor format, to deliver a 9:16 image. Turning the aspect ratio on its side can provide better coverage of these narrow environments without wasting pixels on the sides. Integrators can set themselves apart from the competition by offering recommendations that are commonly overlooked, such as corridor format, for improved viewing capabilities.

When color rendition is a driving surveillance need, the HDTV standard for high color fidelity can improve image usability. If you compare color images from different manufacturers with similar resolutions, you will often see that color rendition is vastly different. How useable is an image if a black car is rendered as purple or a red coat looks orange?

Today, the majority of high resolution IP surveillance cameras sold in North America are compliant to 720p. Despite the initial race to own the cameras with the most megapixels, savvy security practitioners have learned that more pixels doesn’t always mean better when it comes to usable video.

Where do we grow from here?

While HDTV is the clear choice in the consumer market, the security industry has been slower to adopt. Market research estimates that 35 percent of the surveillance cameras sold in 2012 were IP cameras, and of those IP cameras sold, about half were of higher resolution including HDTV and megapixel. However, industry experts anticipate the adoption of HDTV and megapixel will accelerate in the coming year.