Police say bandwidth limits reach of cameras

Arkansas Democrat-Gazette/BENJAMIN KRAIN --11/21/2013--
Lt. Casey Clark demonstrates the capabilities of 53 video cameras the Little Rock Police Department has placed in public areas around the city to deter and solve crimes by monitoring live streams from each location. The cameras can be easily moved to other locations and can broadcast prerecorded audio warnings and flash a blue light when suspicious activity occurs.
Arkansas Democrat-Gazette/BENJAMIN KRAIN --11/21/2013-- Lt. Casey Clark demonstrates the capabilities of 53 video cameras the Little Rock Police Department has placed in public areas around the city to deter and solve crimes by monitoring live streams from each location. The cameras can be easily moved to other locations and can broadcast prerecorded audio warnings and flash a blue light when suspicious activity occurs.

Little Rock police cameras positioned across the city last year in a $500,000 Internet-based surveillance network are yielding lower-quality footage because of bandwidth limitations.

Although the cameras can record fluid motion at 30 frames per second -- higher than the film industry standard of 24 frames per second -- they're capturing footage at less than half that speed, according to Lt. Casey Clark, who oversees the camera operation for the Little Rock department.

As with streaming video services Netflix and Hulu, bandwidth availability for the police cameras can affect the quality of the images being transmitted, Clark said.

"Realistically, we're never going to get that 30 frames per second," he said. "I think what we're pushing for is 12-15. We're not there yet. But I think in the real world, you'll see 12-15 frames per second is as good as a public entity can get with our limited resources."

Live footage is relayed from the cameras to a central police server via cellular, cable and fiber-optic Internet. Fiber-optic is the fastest, and cellular is the slowest.

Clark said police are in the process of integrating the surveillance system with a citywide fiber-optic network completed last month. Camera frame rates will likely increase, but data usage will remain a concern. The cameras operate 24 hours day.

"If you set the frame rate too high, then the data retention starts going off the chart and it eats up too much bandwidth. It really is a balancing act," Clark said.

Verizon, Comcast and AT&T provide Internet for the surveillance network. Each company is contracted by the city in case the others have service failures.

Clark said the network's new fiber-optic "backbone" is expected to be completed in about a month.

Police positioned 53 new Canon VB-C60 cameras across the city in 2013. Most of the cameras were positioned according to crime trends and historical data and have helped police make numerous arrests, Clark said.

Twenty of the cameras were arranged in and around downtown's River Market because of high pedestrian traffic. When someone fired a gun in the crowded district July 9, a police camera mounted atop the southeast corner of Ottenheimer Market Hall recorded the incident. But the blocky and disjointed footage, transmitted via cable Internet, was of no use to investigators.

"There is no muzzle flash or any other clue that would identify a shooter," police spokesman Lt. Sidney Allen said of the footage after it was released to local media outlets.

Police reported that about 9:45 p.m., a large group of teenagers was escorted from a free summer movie series in Riverfront Park because of their "unruly behavior." Shots were fired when the group reached President Clinton Avenue.

The chances of recording a muzzle flash, which lasts milliseconds, are very low at the cameras' current frame rate, Clark said.

Officers detained and searched an 18-year-old man but released him after they didn't find a weapon in his possession.

Police reported that people ran after the gunfire, but that's difficult to tell from the footage, as is the direction they fled. The group is also obscured by a tree.

No arrests had been made late Sunday in the incident, which happened during a Movies in the Park screening that the Convention and Visitors Bureau estimated was attended by 3,000 people.

The cameras are equipped with 40X optical zoom that can distinguish faraway subjects such as license plate numbers, but that feature wasn't used in the 9 minutes and 57 seconds of footage released by police.

The camera captured the incident and its aftermath in default mode, panned out to record the largest area possible when not being operated by an officer.

Clark said the camera was manned until the crowd of teens became disorderly and additional officers were called to help.

"If we had unlimited resources, i.e. money and personnel, I'm sure we could match CSI step for step. Ironically, here in the real world we have budgets and a finite number of personnel, which limits our abilities," he said.

Manpower and high-speed Internet don't guarantee footage will yield evidence of a crime, however. Clark and North Little Rock police Capt. Leonard Montgomery said their departments' respective surveillance networks are supplemental to investigations and rarely a primary tool.

And even with state-of-the-art cameras that have been carefully placed, variables such as lighting, lens flare and color combinations can affect image clarity, they said. Sunshine might wash out a suspect's face. Darkness might cloak them. And if a passing car's headlights are too bright, the camera lens might close or change direction to protect itself -- much like the human eye.

Montgomery said footage quality from the 64 North Little Rock police cameras placed across the city is also affected by bandwidth limitations.

The Axis 214 cameras are capable of recording at 25 frames per second, but most record about 20 frames per second, according to Montgomery. That's not full motion, but footage still leads to arrests "all the time," he said.

He said the North Little Rock Police Department has 8 terabytes of data every 20 days to store footage from each of the cameras. That breaks down to about 6.25 gigabytes of data per day from each camera.

By comparison, Netflix uses about 1 gigabyte of data per hour for standard definition video streaming.

"You start getting up to 35 or 40 frames per second and the increased resolution, the higher resolution, it's sucking up bandwidth like crazy," Montgomery said.

Verizon and Comcast provide Internet for the North Little Rock department's surveillance network.

To conserve bandwidth, about 90 percent of the cameras are activated by motion. Montgomery said that can be a person walking down the street, a passing vehicle or even a tree swaying in the wind.

The cameras pan from side to side in default mode, which can briefly create blind spots. But like Little Rock's cameras, they can be controlled by officers at multiple viewing stations and have powerful optical zoom.

In both cities, the camera lens can magnify an object with officer-operated optical zoom, yielding crisp close-up images. Digital zoom, by comparison, merely enlarges pixels. That can distort images of people and possible evidence into blobs of color.

"Same thing if you take a picture on your iPhone," Montgomery said. "You take a picture on your iPhone and you start blowing it up, it's going to pixelate because there are only so many pixels that are captured."

Montgomery and Clark said that if optical zoom isn't engaged by an officer, they can only slightly enhance an image using digital zoom.

"[The cameras] are really good if you can have somebody monitor them all the time and watch them," Montgomery said. "But we don't have the personnel to do that."

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