Probe-based rapid hybrid hyperspectral and tissue surface imaging aided by fully convolutional networks

Abstract

Tissue surface shape and reflectance spectra provide rich intraoperative information useful in surgical guidance. We propose a hybrid system which displays an endoscopic image with a fast joint inspection of tissue surface shape using structured light (SL) and hyperspectral imaging (HSI). For SL a miniature fibre probe is used to project a coloured spot pattern onto the tissue surface. In HSI mode standard endoscopic illumination is used,with the fibre probe collecting reflected light and encoding the spatial information into a linear format that can be imaged onto the slit of a spectrograph. Correspondence between the arrangement of fibres at the distal and proximal ends of the bundle was found using spectral encoding. Then during pattern decoding,a fully convolutional network (FCN) was used for spot detection,followed by a matching propagation algorithm for spot identification. This method enabled fast reconstruction (12 frames per second) using a GPU. The hyperspectral image was combined with the white light image and the reconstructed surface,showing the spectral information of different areas. Validation of this system using phantom and ex vivo experiments has been demonstrated.