Park Police zooms in on crowd surveillance on the Mall
- By William Jackson
- Jul 25, 2013
The U.S. Park Police saw the need for better surveillance technology when an estimated 1.4 million people flocked to the National Mall in 2009 to watch newly elected Barack Obama be sworn in as president.
“We expected the crowd to be big, but we had no idea how big,” said Dave Mulholland, commander of technology services for the U.S. Park Police.
The Park Police are responsible for securing public spaces in Washington, including the National Mall, and the record crowds from four years ago helped to establish the technological support needed to police major events in an area stretching more than two miles from the Capitol Building to the Potomac River.
Mulholland said the department deployed a lot of assets for the 2009 inauguration, including an array of video surveillance cameras. “But we found that we could use more,” he said.
The Park Police has since upgraded its technology with a new generation of IP network cameras that have helped it and other agencies keep an eye on the crowds during big events, such as this year’s inauguration, where the crowd was smaller than four years ago, but still large.
The department worked with Axis Communications to deploy five new high-definition cameras around the mall and the parade route (the exact locations were not disclosed) to provide detailed real-time images of the activities.
“The inauguration gave us a living lab experience to put the equipment through its paces,” Mulholland said. “We were thrilled to see that the cameras performed above our expectations.”
The new equipment, model Q6035-E and Q6032-E pan-tilt-zoom cameras, were used together with Axis cameras the Park Police already had and with cameras from other agencies, including the Secret Service, that pooled resources for the event. They delivered IP video feeds for real-time monitoring and were also sent to servers for storage and analysis. They could be controlled remotely to focus on up to 100 preset positions or to pan through 360 degrees and tilt through 220 degrees.
“One significant difference was the responsiveness to commands,” Mulholland said. The cameras moved to position and focused more quickly than earlier models. The difference often was only about a second, “but that second could be the second that makes the difference.”
The biggest difference in the new generation of cameras was performance in low light, however. The cameras are for use during the day or night, but as light dims the images go from color to black and white to provide more detail in darker conditions. “The new cameras held their color in low-light situations far longer,” he said. “The ability to see in color could be a critical factor.”
Axis, which made its first IP network camera in 1996, has been producing high-definition cameras since 2008. Megapixel imaging and high-quality optics allow the cameras to zoom in on objects more than a mile away, enabling observers to identify individuals and small objects and read text. A license plate can be legible in the image from as far away as 900 feet.
“This was a feature the Park Police wanted to take advantage of,” said Rick Rabell, an Axis field sales engineer who helped with the inaugural installations.
The Q6035 camera has a 20X optical zoom and the 3 megapixel image allows an additional 12X digital zoom to pinpoint details. The Q6032 has a 36X optical and a 12X digital zoom. The cameras also have video motion detection and autotracking, and an Application Programming Interface lets users add their own software for additional programming and analysis. The cameras can provide full motion 30 frames per second at full resolution, and even higher frame rates at lower levels.
The high performance of newer models has been enabled by improved optics and advances in image sensors, along with increased processing power. Axis manufactures its own purpose-designed video processing chips. The cameras also contain a second chip, the Axis Camera Application Platform, which enables third-party image analytics programming so that analysis can be done in the camera rather than waiting for images to be sent to a server, speeding response.
“It’s basically a computer with a lens,” Rabell said. “It’s a network device.”
To get all of that data over the network the camera uses the Motion JPEG video format and H.264 compression, which can reduce by 80 percent the bandwidth needed for full-definition images. This is important for tactical situations in which the Park Police uses the cameras, putting them up for single events and then taking them down to be used elsewhere, Mulholland said. Because there rarely is fixed backhaul available, the cameras often use cellular connections, and getting the most out of the limited bandwidth is necessary.
The Q6035 and Q6032 models added to the Park Police toolkit this year are high-end cameras, and it makes sense to use them in high-security environments. But they are not necessary for every situation.
“A camera is not a camera is not a camera,” Mulholland said. “One size does not fit all.”
For general crowd monitoring and situational awareness, high resolution, advanced analysis and tracking capabilities are not needed. But for some uses, such as monitoring the area in which the president is or will be, keeping an eye on demonstrators, or watching for “persons of interest” in a specific area, “there is a much greater need for detail,” he said.
The U.S. Park Police have three-and-a-half years to prepare for the next inauguration, but there will be events on the Mall and elsewhere around Washington that will require heavy security well before that. There will be a number of events in August marking the 50th anniversary of the 1963 March on Washington at which the Rev. Martin Luther King made his “I Have a Dream” speech. And there are more than a dozen marathons, half-marathons and 5K runs scheduled in Washington through the rest of the year, including the Marine Corps Marathon in October that could have as many as 30,000 participants. These are drawing increased attention in the wake of the Boston Marathon bombing.
“Even before Boston we had already started thinking about these races,” Mulholland said. “But now the ante is upped. That’s the next big thing.”
William Jackson is a Maryland-based freelance writer.