Wavelet domain mutual information synchronization of multimodal cardiac microscopy image sequences

Multi-modal microscopy, such as combined bright-fiel and multi-color fluorescenc imaging, allows capturing a sample's anatomical structure, cell dynamics, and molecular activity in distinct imaging channels. However, only a limited number of channels can be acquired simultaneously and acquiring each channel sequentially at every time-point drastically reduces the achievable frame rate. Multi-modal imaging of rapidly moving objects (such as the beating embryonic heart), which requires high frame-rates, has therefore remained a challenge. We have developed a method to temporally register multimodal, high-speed image sequences of the beating heart that were sequentially acquired. Here we describe how maximizing the mutual information of time-shifted wavelet coefficien sequences leads to an implementation that is both accurate and fast. Specificall , we validate our technique on synthetically generated image sequences and show its effectiveness on experimental bright-fiel and fluorescenc image sequences of the beating embryonic zebrafis heart. This method opens the prospect of cardiac imaging in multiple channels at high speed without the need for multiple physical detectors.