An Uncalibrated Image-Based Visual Servo Strategy for Robust Navigation in Autonomous Intravitreal Injection

Abstract

Autonomous intravitreal injection in ophthalmology is a challenging surgical task as accurate depth measurement is difficult due to the individual differences in the patient’s eye and the intricate light reflection or refraction of the eyeball, often requiring the surgeon to first preposition the end-effector accurately. Image-based visual servo (IBVS) control does not rely on depth information, exhibiting potential for addressing the issues mentioned above. Here we describe an enhanced IBVS strategy to achieve high performance and robust autonomous injection navigation. The radial basis function (RBF) kernel with strong learning capability and fast convergence is used to globally map the uncertain nonlinear strong coupling relationship in complex uncalibrated IBVS control. The Siamese neural network (SNN) is then used to compare and analyze the characteristic differences between the current and target poses, thus making an approximation of the mapping relationships between the image feature changes and the end-effector motion. Finally, a robust sliding mode controller (SMC) based on min–max robust optimization is designed to implement effective surgical navigation. Data from the simulation and the physical model experiments indicate that the maximum localization and attitude errors of the proposed method are 0.4 mm and 0.18°, exhibiting desirable accuracy with the actual surgery and robustness to disturbances. These results demonstrate that the enhanced strategy can provide a promising approach that can achieve a high level of autonomous intravitreal injection without a surgeon.