Pyramid Approach for the Reduction of Parallax-Related Artefacts in Optical Recordings of Moving Translucent Volumes

摘要

Functional optical imaging (OI) of intrinsic signals (like blood oxygenation coupled reflection changes) and of extrinsic properties of voltage sensitive probes (like voltage-sensitive dyes (VSD)) forms a group of invasive neuroimaging techniques, that possess up to date the highest temporal and spatial resolution on a meso- to macroscopic scale. There are different sources that contribute to the OI signal of which many are noise. In our previous works, we have used dense optical flow for the reduction of movement artefacts. The translucent surface of the cortex allows contributions from multiple depths. Due to the depth of field (DOF) effect, we get an implicit relation of depth and 2D frequency components. In this work, we introduce registration on the levels of a Laplacian pyramid to remove movement artefacts which have different motion components in different spatial frequency bands. This aims to resolve artefacts that remain after normal registration and are caused e.g. by parallax motion, dead pixels or dust on the sensor and other high frequent, moving particles on the cortex surface without the compromise of using high smoothness weights.