6D Robotic OCT Scanning of Curved Tissue Surfaces

TL;DR

This paper introduces a full 6D hand-eye calibration method for robotic OCT scanning, enabling accurate imaging of curved tissue surfaces without relying on image registration, thus improving consistency and reducing error accumulation.

Contribution

A novel marker-based calibration approach for 6D robotic OCT scanning that enhances accuracy and consistency in imaging curved tissue surfaces.

Findings

Calibration yields highly repeatable transformation estimates.

Robotic scanning of curved surfaces is more consistent with the proposed calibration.

The method outperforms conventional translational scanning approaches.

Abstract

Optical coherence tomography (OCT) is a non-invasive volumetric imaging modality with high spatial and temporal resolution. For imaging larger tissue structures, OCT probes need to be moved to scan the respective area. For handheld scanning, stitching of the acquired OCT volumes requires overlap to register the images. For robotic scanning and stitching, a typical approach is to restrict the motion to translations, as this avoids a full hand-eye calibration, which is complicated by the small field of view of most OCT probes. However, stitching by registration or by translational scanning are limited when curved tissue surfaces need to be scanned. We propose a marker for full six-dimensional hand-eye calibration of a robot mounted OCT probe. We show that the calibration results in highly repeatable estimates of the transformation. Moreover, we evaluate robotic scanning of two phantom surfaces to demonstrate that the proposed calibration allows for consistent scanning of large, curved tissue surfaces. As the proposed approach is not relying on image registration, it does not suffer from a potential accumulation of errors along a scan path. We also illustrate the improvement compared to conventional 3D-translational robotic scanning.