Transformable In Vivo Robotic Laparoscopic Camera With Optimized Illumination System for Single-Port Access Surgery: Initial Prototype

This paper presents an initial prototype of an in vivo robotic laparoscopic camera that features optimized illumination to address the problems, i.e. inferior lighting uniformity and low optical efficiency, in the state-of-the-art designs of in vivo laparoscopic cameras. Benefiting from the transformable structure of the robotic camera, sufficient on-board space is created without sacrificing the camera's compactness to carry three dedicatedly designed freeform optical lenses for achieving the optimized illumination requirements. Designing miniature freeform optical lenses for extended light sources, such as LEDs, is a very challenging task that usually involves solving a nonstandard Monge-Ampère equation. In this paper, we approach the illumination optical design based on a ray-mapping method that is governed by a standard Monge-Ampère equation. We propose an effective numerical solver to compute the ray-mapping solution for constructing freeform lens surfaces. Experimental results prove the predicted performance of the illumination system design: greater than 97\% illuminance uniformity, greater than 80\% optical efficiency, and greater than 14,323 lx illuminance on a target plane with a distance of 100 mm. The effectiveness of this prototype is also experimentally verified by performing a suturing task in a simulated abdomen.