Automated Masking of Voltage-Sensitive Dye Imaging Data

Abstract

This paper discusses the development of an algorithm to mask poor quality data in fluorescence videos of cardiac tissue stained with voltage-sensitive dye. The aim was to simplify further analysis by eliminating the step of manually masking areas of poor signal quality and areas outside the preparation of interest. Our algorithm estimates signal to noise ratio (SNR) from the power spectral density (PSD) for each pixel. This information is combined with information about the fluorescence intensity in each pixel, according to a user-selectable weighting factor. A threshold is then applied to the resulting combined measure. This approach resulted in an effective algorithm that is capable of automatically creating a "mask" that can be applied to the data to exclude parts of the data from further analysis. The algorithm is sufficiently efficient to allow interactive use, allowing the user to adjust the parameters of the algorithm and instantly view the resulting mask. This tool will be useful as a technique to simplify further analysis of voltage-sensitive dye imaging data.