Autofocus for Event Cameras
This work addresses the problem of poor focus control for event camera users in challenging conditions, representing a novel method for a known bottleneck in this domain.
The paper tackled the lack of effective autofocus methods for event cameras, which rely on manual adjustments, by developing a novel event-based autofocus framework with an event-specific focus measure and robust search strategy, achieving superior efficiency and accuracy over state-of-the-art approaches in challenging real-world scenarios.
Focus control (FC) is crucial for cameras to capture sharp images in challenging real-world scenarios. The autofocus (AF) facilitates the FC by automatically adjusting the focus settings. However, due to the lack of effective AF methods for the recently introduced event cameras, their FC still relies on naive AF like manual focus adjustments, leading to poor adaptation in challenging real-world conditions. In particular, the inherent differences between event and frame data in terms of sensing modality, noise, temporal resolutions, etc., bring many challenges in designing an effective AF method for event cameras. To address these challenges, we develop a novel event-based autofocus framework consisting of an event-specific focus measure called event rate (ER) and a robust search strategy called event-based golden search (EGS). To verify the performance of our method, we have collected an event-based autofocus dataset (EAD) containing well-synchronized frames, events, and focal positions in a wide variety of challenging scenes with severe lighting and motion conditions. The experiments on this dataset and additional real-world scenarios demonstrated the superiority of our method over state-of-the-art approaches in terms of efficiency and accuracy.