A single shot multibox detector based on welding operation method for biometrics recognition in smart cities.

• The identification of the working status of the welder. • Promoting the intelligentization of welding work monitoring. • An improved algorithm based on SSD(single shot multibox detector). • Replacing the backbone of SSD with MobileNet, and adding a feature fusion module. As enhance of safety requirement in the smart cities, biometrics recognition, as an approach for society safety, has been greatly researched and developed. The identification of working status of welders will help judge whether they are wearing personal protective equipment correctly. We proposed an improved algorithm based on SSD (Single Shot Multibox Detector) that can identify three mainstream manual welding methods including SMAW (shielded metal arc welding), GMAW (gas metal arc welding) and TIG (tungsten inert gas), which has never been researched before and can promote the intelligentization of welding monitoring to construct smart cities. The improvement includes two parts. Firstly, the backbone of SSD is replaced with MobileNetV3. Then, a feature fusion module is added to enhance the information of low-level feature maps to improve detection accuracy. The experimental results of our welding behavior detector show that, the mAP is 87.45%, detection speed is 25FPS, and parameter memory is 87.5 MB, which has a relatively excellent performance considering speed, accuracy and memory. [ABSTRACT FROM AUTHOR]