High-Speed Focusing Vision: Coupling of Image Processing System with Tunable Optics without Speed Bottleneck

Abstract

Imaging optics is essential for a robot vision to acquire images, since it projects the image of remote object to its imager. In particular, dynamic control of imaging optics has been desired because it enables vision to measure new information, such as depth of scene, that single robot vision with static optics cannot obtain. Conventional imaging optics, however, takes around one second to change its optical property. Thus, measurement frequency of sensing method using dynamic control of optics was limited by the slow response. In this paper, high-speed focusing vision, that is composed of high-speed vision and high-speed imaging optics based on a Dynamorph Lens (DML), is proposed. DML is a liquid variable-focus lens that can dynamically focus by morphing liquid-liquid interface in millisecond order. Since both high-speed vision and high-speed imaging optics have millisecond response time, it can change its focus and zoom ratio almost every frame. High-speed focus-switch experiment in 2 [ms] was observed using a developed prototype. High-speed autofocusing in 15.8 [ms] by capturing and processing 14-images at different focal position, and continuous focusing on quickly moving object by switching focal position in every 5 [ms] were successfully demonstrated to validate the high-speed focusing vision.