Reducing Annotating Load: Active Learning with Synthetic Images in Surgical Instrument Segmentation
This work addresses the annotation burden in surgical computer vision, offering a domain-specific incremental improvement.
The paper tackles the problem of reducing annotation workload for surgical instrument segmentation by proposing an active learning method that uses synthetic images generated from selected unlabeled images, achieving considerable performance improvement especially with small annotation budgets on three surgery datasets.
Accurate instrument segmentation in endoscopic vision of robot-assisted surgery is challenging due to reflection on the instruments and frequent contacts with tissue. Deep neural networks (DNN) show competitive performance and are in favor in recent years. However, the hunger of DNN for labeled data poses a huge workload of annotation. Motivated by alleviating this workload, we propose a general embeddable method to decrease the usage of labeled real images, using active generated synthetic images. In each active learning iteration, the most informative unlabeled images are first queried by active learning and then labeled. Next, synthetic images are generated based on these selected images. The instruments and backgrounds are cropped out and randomly combined with each other with blending and fusion near the boundary. The effectiveness of the proposed method is validated on 2 sinus surgery datasets and 1 intraabdominal surgery dataset. The results indicate a considerable improvement in performance, especially when the budget for annotation is small. The effectiveness of different types of synthetic images, blending methods, and external background are also studied. All the code is open-sourced at: https://github.com/HaonanPeng/active_syn_generator.