Weld Visualization Using 3D-Welding Helmet

Nonprofit research center SRI International (SRI; Menlo Park, CA) collaborated with Kawada Technologies, Inc. (KTI; Toyko, Japan) and their subsidiary Kawada Industries to develop Xtreme Dynamic Range (XDR) weld visualization technology that uses image processing to safely visualize live weld details to the welder. Applied to a next-generation 3D-welding helmet using cameras that completely transform the world of welding, XDR enables welders to improve their welding quality by greatly enhancing their visibility of the welding tip, welds and surrounding welding scene using ordinary image sensors rather than special high-cost units. The technology manages shutter speed and the time when images are captured with microsecond resolutions to acquire images and perform real-time XDR Fusion. These captured frames with different exposure conditions are image-processed by a wearable battery-operated GPU that synthesizes the frames in real-time into one 3D stereo vision stream for visualization within the helmet.

As a result, instead of the limited commercial camera dynamic ranges of 60 dB to 70 dB, the dynamic range of the visualized scene using commercial cameras in the XDR welding helmet expands up to 150 dB without the need for special image sensors. Using commercially available devices also allows the welding helmet to benefit from high-volume costing and proven component reliabilities. The helmet equipped with XDR acquires and synthesizes images as a stereo camera unit. These images are displayed, with minimal delay, inside the helmet on a head-mounted display (HMD) as a stereo image. This helmet system runs on wearable hot-swappable batteries, meaning it can be used indefinitely in environments that have no external power source. A welder wearing the next-generation 3D-welding helmet can weld more reliably due to the ability to view weld beads, the welded items and the working environment that are, collectively, difficult to see using traditional welding helmets.

The helmet also includes display and recording functions of various real-time welding status parameters related to welding (temperature, voltage, current, etc.), allowing welders to easily collect and check useful information to ensure a high quality weld that, in turn, accelerates the learning curve. The welder’s eyes are completely protected from arcs because the weld is viewed indirectly through the screen in the helmet. “Kawada came to us with a need to greatly shorten the time required to train new welding technicians while continuing to pass down welding knowledge in an effective manner to new welders,” said Mike Piacentino, a senior technical director of vision systems for SRI. “This real-time weld visualization technology provides higher dynamic range to allow humans and robotic welders to see more than just the welding tip. The ability to view real-time welds maintains quality and informs the welder of low quality or possibly failing welds – a critical advantage over conventional welding, where precision welds are critical to structural integrity and public safety of infrastructure, such as construction and bridge engineering.”

This helmet will be improved over the next year and utilized to teach technical welding skills at Kawada Industries. “Welding is the most important and difficult skill to transfer from skilled technicians to novice beginners,” said Noriyuki Kanehira, the project leader and director of Kawada Technology Research Center. “Visualization is the key: In conventional welding, the operator can see only the tiny bright area of the arc while everything else is darkened by the thick shading filter attached to a welding helmet. This new technology clearly visualizes the entire area of the workspace with appropriate brightness and contrast. Welding visualization leads directly to stabilizing weld quality and providing traceability.”

SRI International, 333 Ravenswood Avenue, Menlo Park, CA 94025-3493, 650-859-2000, www.sri.com.

Kawada Technologies, Inc., 1-3-11 Takinogawa, Kita-Ku, Tokyo, Japan 114-0023, +81-339 1543 21, www.kawada.jp.