Towards online monitoring and data-driven control: a study of segmentation algorithms for infrared images of the powder bed

An increasing number of selective laser sintering and selective laser melting machines use off-axis infrared cameras to improve online monitoring and data-driven control capabilities. However, there is still a severe lack of algorithmic solutions to properly process the infrared images from these cameras that has led to several key limitations: a lack of online monitoring capabilities for the laser tracks, insufficient pre-processing of the infrared images for data-driven methods, and large memory requirements for storing the infrared images. To address these limitations, we study over 30 segmentation algorithms that segment each infrared image into a foreground and background. By evaluating each algorithm based on its segmentation accuracy, computational speed, and robustness against spatter detection, we identify promising algorithmic solutions. The identified algorithms can be readily applied to the selective laser sintering and selective laser melting machines to address each of the above limitations and thus, significantly improve process control.