The difference between HD and megapixel surveillance cameras

[Editor's note: John Honovich publishes this and other information on network video at IPVideoMarket.info.]

While 2009 may be the year of megapixel cameras, it may also be the year where confusion between HD and megapixel cameras began. Historically, everyone who sold cameras with 1 million pixels or more called them megapixel cameras. However, in the last 6 months, a number of manufacturers have begun touting their new megapixel cameras as HD.

Indeed, Axis markets its new high-end Q1755 camera specifically as HDTV, not megapixel. This caught me by surprise and confused me. A few colleagues e-mailed me with the same questions.

HD vs. Megapixel

HD is a type of megapixel camera.  All HD cameras are megapixel but not all megapixel cameras are HD.

While standard definition cameras (e.g., analog cameras and 4CIF IP cameras) have no more than 400,000 pixels, all megapixel cameras (including HD) have 1,000,000 or more pixels. [For more extensive analysis, see the 2009 megapixel vendor comparison report].

HD's Key Features Compared to Typical Megapixel

The key features of HD for video surveillance is:

  • Maximum HD resolution is 2.1MP, maximum megapixel resolution is 16MP and up to 5MP cameras are common from numerous vendors
  • HD video format is 1280 x 720 or 1920 x 1080 (megapixel cameras can offer many more formats)
  • HD aspect ratio is 16:9 (compared to 5:4 or 4:3 in other surveillance cameras)
  • HD frame rate is 30/25 (where megapixel cameras are often 3 - 15 frames)
  • HDTV has quality compliance standards (where megapixel simply specifies the number of pixels)

Which is Better?

This is not a clear cut case - it will depend on applications. Some applications really need more than 2.1MP (the maximum for HDTV today) and do not need high frame rates (those should choose non-HD megapixel cameras). Other applications will care more about high frame rate and maximum image quality (where HD cameras will be best).

However, since Axis has put its marketing efforts behind HDTV, expect HD's importance to increase significantly. Indeed, I see this as a cunning competitive move on Axis' part to generate perceived differentiation over incumbent megapixel providers such as Arecont Vision, IQinVision and Mobotix. It also leverages the consumer interest on HDTVs. This aspect may not improve security but it sure does increased perceived quality.

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