ATLANTA, GA. — In the age of global terrorism and demands for bigger, better surveillance systems, SteelBox Networks has found a sweet spot.

SteelBox, a three-year-old startup focused on video surveillance applications and networks, has closed on $10 million in new financing. This is the firm’s third round of funding.

Sierra Ventures, which is based in California, and other existing investors contributed to the round. Sierra is a new investor.

“Sierra’s investment will help us in several ways,” said SteelBox co-founder and Chief Executive Officer Richard Howes. “First, we will be able to expand our operations to help meet product development and manufacturing goals for the strong demand we are already seeing in the surveillance market. More importantly, Sierra brings with it the business contacts and corporate relationships that will facilitate rapid growth in the surveillance market, as well as expansion into follow-on markets to capitalize on the broader video revolution.”

SteelBox was formed by a team of engineers with experience at Cisco, Nortel, Scientific Atlanta and other firms.

The company is developing large-scale solutions for video that enable hundreds of streams of content to be handled through video over Internet Protocol equipment. In its first 18 months of operation SteelBox developed and began selling two systems. In December of 2005, its European partner landed a contract for SteelBox gear to be used as part of the National Roads Services Telecommunications Services (NRTS) project in the United Kingdom.

“We have high hopes for SteelBox Networks,” said Sierra Venture Partner Mike Scanlin in a statement. “The SteelBox team has developed a superior product that enables hundreds of video streams per system, compared to the tens of streams that competing products offer. Plus, the SteelBox solution can expand to support thousands of streams with storage capacity into the petabytes. Such high density gives SteelBox unmatched price/performance in the network video switching and recording space for large-scale video surveillance projects.”

SteelBox has sold systems in the United States, Europe and Asia for use in monitoring highway and sybway systems as well as ports.