Super-Resolution Semantic Segmentation of Droplet Deposition Image for Low-Cost Spraying Measurement

In-field in situ droplet deposition digitization is beneficial for obtaining feedback on spraying performance and precise spray control, the cost-effectiveness of the measurement system is crucial to its scalable application. However, the limitations of camera performance in low-cost imaging systems, coupled with dense spray droplets and a complex imaging environment, result in blurred and low-resolution images of the deposited droplets, which creates challenges in obtaining accurate measurements. This paper proposes a Droplet Super-Resolution Semantic Segmentation (DSRSS) model and a Multi-Adhesion Concave Segmentation (MACS) algorithm to address the accurate segmentation problem in low-quality droplet deposition images, and achieve a precise and efficient multi-parameter measurement of droplet deposition. Firstly, a droplet deposition image dataset (DDID) is constructed by capturing high-definition droplet images and using image reconstruction methods. Then, a lightweight DSRSS model combined with anti-blurring and super-resolution semantic segmentation is proposed to achieve semantic segmentation of deposited droplets and super-resolution reconstruction of segmentation masks. The weighted IoU (WIoU) loss function is used to improve the segmented independence of droplets, and a comprehensive evaluation criterion containing six sub-items is used for parameter optimization. Finally, the MACS algorithm continues to segment the remained adhesive droplets processed by the DSRSS model and corrects the bias of the individual droplet regions by regression. The experiments show that when the two weight parameters α and β in WIoU are 0.775 and 0.225, respectively, the droplet segmentation independence rate of DSRSS on the DDID reaches 0.998, and the IoU reaches 0.973. The MACS algorithm reduces the droplet adhesion rate in images with a coverage rate of more than 30% by 15.7%, and the correction function reduces the coverage error of model segmentation by 3.54%. The parameters of the DSRSS model are less than 1 M, making it possible to run it on embedded platforms. The proposed approach improves the accuracy of spray measurement using low-quality droplet deposition image and will help to scale-up of fast spray measurements in the field.