Optical characterization of a laser speckle contrast imaging system for intraoperative blood flow monitoring.

Abstract

We present the experimental characterization of a laser speckle contrast imaging system for blood flow monitoring under variable imaging conditions. A tissue phantom setup was used to evaluate system performance across multiple parameters, including laser power, exposure time, vessel depth, and flow velocity. Additionally, two optical configurations were tested to assess their robustness to the variation of these parameters: the conventional arrangement, where the camera is positioned perpendicular to the sample, and an alternative geometry, where the laser is perpendicular to the sample and the camera is placed at an angular offset. The latter was designed to facilitate future integration into multispectral or stereoscopic imaging setups. The analysis includes speckle contrast maps and a discriminability index to quantify the detectability of flow. Results obtained with the alternative configuration indicate that the system reliably detects blood flow across a range of conditions, although acquisition parameters significantly influence performance. A suitable range of laser power and exposure time was identified that enhances the flow detection through experimental selection of discriminability index values. Angular variation in the alternative configuration had a measurable effect; however, both configurations enabled reliable flow detection, opening the possibility of extending this approach to research toward scalable multi-camera imaging platforms.