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January 29, 2008

Importance of Frame Rates

[From San Francisco Chronicle: San Francisco security cameras' choppy video]

Another great article by Bulwa reporting on the San Francisco camera system. Before noting the technical flaws, I would like to point out San Francisco is ahead of Chicago in having a good reporter following the developments as well as developing an ordinance for the video surveillance system. (The city is even supporting academic research into the effectiveness of the system, unlike Chicago which rebuffed my attempt).

Because of a lack of funds, San Francisco has cameras running at slower frame rates, which results in choppy video that may miss vital information.

Motion pictures and television programs are shown with a frame rate of at least 24 frames per second. Las Vegas casinos are required by regulators to film many gaming areas at 30 frames per second.

In Chicago, where Newsom sampled anti-crime cameras before starting his program, police get motion-picture-quality footage shot at 30 frames per second. But in the San Francisco footage, as many as 10 seconds pass between frames. Some cars and bicycles going through the intersection show up on just a single frame.

But they [technical staff for the city] acknowledged that most of the city's cameras achieve only 80 percent of the resolution they are capable of, and that they generate, at best, two to four frames per second because the city lacks the data storage space to accommodate more footage.

FYI, the cost for the 68 cameras is around $900,000 with an additional $200,000 budgeted for 25 more cameras.

Posted by rshah at January 29, 2008 01:40 PM

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