SRI International, a nonprofit research center, recently collaborated with Kawada Technologies (KTI) and Kawada Industries to develop Xtreme Dynamic Range (XDR) weld-visualization technology, which they say uses image processing to safely visualize live weld details for the welder.
XDR was further applied to a next-generation, 3D welding helmet that uses cameras to “completely transform” the world of welding, according to the companies.
“Kawada came to SRI 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, senior technical director of vision systems for SRI International. “The real-time weld-visualization technology developed by SRI provides higher dynamic range to allow humans and robotic welders to see more than just the welding tip.”
XDR Weld Visualization Technology
For this project, their objective was to enable a larger number of welders and improve their welding quality by greatly enhancing visibility of the welding scene, including the welding tip, welds and surrounding welding scene using ordinary image sensors rather than special high cost image sensors. Specifically, the newly developed technique manages shutter speed and the time in which images are captured with microsecond resolutions to acquire images to perform real-time XDR Fusion. These captured frames with different exposure conditions are image-processed by a wearable battery-operated GPU to synthesize 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 60-70 dB, the dynamic range of the visualized scene using commercial cameras in the XDR welding helmet is expanded up to 150 dB without the need for special image sensors. In addition, using commercially available devices allows the welding helmet to benefit from high-volume costing and proven component reliabilities, according to project participants.
Next-Generation, 3D-Welding Helmet
The 3D welding helmet equipped with XDR is designed to acquire and synthesize 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 and therefore can be used indefinitely in environments that have no external power source, the companies claimed.
A welder wearing the helmet will be able to weld more reliably due to the ability to view weld beads, the welded items and the working environment, which 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, like temperature, voltage and current, allowing welders to collect and check useful information to ensure a high-quality weld, in turn accelerating the learning curve.
Finally, the welder’s eyes are completely protected from arcs because the weld is viewed indirectly through the screen in the helmet.
With the cooperation of SRI, KTI Kawada Group developed XDR, which they says shortens the time required to train new welding technicians, while continuing to pass down welding knowledge in an effective manner. KTI Kawada Group also is working on analyzing data obtained by the helmet to perform various tests for improving the quality and reliability of welding.
“The ability to view real-time welds maintains quality and informs the welder of low quality or possibly failing welds, which is 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,” Piacentino said.
The 3D welding helmet will be improved over the next year and utilized to teach welding skills at Kawada. The KTI Kawada group expects to gain insights that can be applied to support new technological and product developments.
"Welding is the most important and difficult skill to transfer from skilled welders to novice welders,” said Noriyuki Kanehira, project leader and director at the Kawada Technology Research Center. “Visualization is the key. In conventional welding, the operator can see only the tiny bright area of the arc and everything else is darkened by the thick shading filter attached to a welding helmet. This new technology developed by SRI clearly visualizes the entire area of the workspace with appropriate brightness and contrast.
“Welding visualization directly leads to stabilizing welding quality and providing trace-ability.”