(ShareCast News) - Surveillance, security and safety visual intelligence company Digital Barriers posted an update on trading for the six months to 30 September on Wednesday, and also announced the award of a contract with a US government agency to begin implementing its ThruVis technology for public transport security.The AIM-traded firm said overall group revenue for the half-year, which includes a full contribution from Brimtek as acquired on 1 March, is expected to be approximately double that achieved in the same period last year.Both organic revenue and adjusted losses are expected to be broadly flat year-on-year, the board said, although neither of those include the benefit of material US government contracts awarded in September for delivery in the second half of the financial year.Total organic contracted revenue for the period grew 66% over the same period last year.Including the September contract awards, the group has secured approximately 50% of the board's revenue expectation for the financial year as a whole, it explained.The $1.65m US government agency contract will see Digital Barriers begin to implement its ThruVis solution to help protect mass transit systems and other public spaces across the US against 'soft target' terrorist attacks.It described ThruVis as a "unique camera technology" that can detect objects such as weapons and explosives concealed under clothing.The technology is reportedly mobile, rapidly deployed, and operates without compromising passenger throughput, safety or privacy.Digital Barriers said the majority of the contract is expected to be delivered in the current financial year.The contract brings the total value of contracts secured with US federal agencies by the group in September to more than $10m, including an initial contract of $1m for the group's EdgeVis technology from another flagship agency, which is a new customer not yet announced.Digital Barriers expects the vast majority of the contracted revenue to be delivered before the end of the current financial year.Whilst organic US revenues increased fivefold in the first half of the year over the same period last year, the board said growth was somewhat constrained by stock availability as it approached the end of the half.It said it expects further material sales into these and other agencies, both in the second half of this year and in future years."Momentum in the business remains very strong, and the organic revenue growth we delivered last year has continued with very strong sales momentum in the period," said CEO Zak Doffman."US growth is the major news in the first half, illustrating why the Brimtek acquisition was such a significant step forwards for us."Our US customers, the main agencies across the Departments of Justice, Homeland Security and Defense, continue to invest in our capabilities, giving us an excellent platform for future growth."Doffman said the ThruVis contract with the US government agency is a very significant step forward for the company's technology."It serves to establish it as the leading solution of its kind, globally, for protecting soft targets from terrorist attack, and it is particularly pleasing to see it come at the same time as the strategic partnership for ThruVis announced with G4S earlier this week."Doffman said the firm's focus for the remainder of the financial year is clear."We will work to drive continued sales momentum, delivering the revenue growth needed to take the group to break-even and beyond."We will also focus on further licence deals for the group's IP which will bring more material recurring revenues into the group for the first time."