New video system good news for skid site safety

In 1999, 36 percent of lost time resulted from injuries at skid sites, with rolling logs or machinery the most common sources of injury. A study by the Forest Research Centre for Human Factors and Ergonomics (COHFE) found Bell Loggers - one of the most common vehicles found on skid sites – reversed on average every four seconds, yet had very limited rear vision capability. Bell Logger’s main reversal tool, mirrors, rapidly became obscured by mud or were damaged in the sites’ demanding conditions, the study found.

However, a recent joint Industrial Research Limited and COHFE project which examined hooking a computer up to a rear vision video camera inside a Bell Logger cabin, looks set to help operators detect people working around them.

The project aimed to increase the effectiveness of rear vision cameras already on trial in skid site vehicles, by using a computer to analyse the camera’s images. The project looked at a system that would scan the rear view image caught on video, analyse it to pick up people wearing high visibility (HV) clothing, and then activate a visual or audible warning to alert drivers if people were present.

Alan Caughley, of Industrial Research’s Advanced Manufacturing team, demonstrated that introducing computer intelligence to the system could help analyse the camera’s images and highlight people wearing high visibility clothing. The study also came up with some interesting results about HV clothing.

"It’s a legal requirement people on skid sites wear high visibility clothing, but the research showed fluorescent yellow-green colours usually found on such clothing often gave us false warnings because yellow-green are common colours in New Zealand industrial forestry environments," Alan says.

"Our study determined red-pink high visibility colours, less common in nature, could be searched for without false warnings using our system. The downside of this was some colour-blind workers had difficulty distinguishing pink. Subsequently, a multi-coloured solution including both yellow-green and red-pink may be recommended," he says.