Motivation: Optical flow is a key method used for quantitative motion
estimation of biological structures in light microscopy. It has also been used as a key
module in segmentation and tracking systems and is considered a mature technology in the
field of computer vision. However, most of the research focused on 2D natural images,
which are small in size and rich in edges and texture information. In contrast, 3D
time-lapse recordings of biological specimens comprise up to several terabytes of image
data and often exhibit complex object dynamics as well as blurring due to the
point-spread-function of the microscope. Thus, new approaches to optical flow are required
to improve performance for such data.Results: We solve optical flow in large 3D time-lapse microscopy datasets by
defining a Markov random field (MRF) over super-voxels in the foreground and applying
motion smoothness constraints between super-voxels instead of voxel-wise. This model is
tailored to the specific characteristics of light microscopy datasets: super-voxels help
registration in textureless areas, the MRF over super-voxels efficiently propagates motion
information between neighboring cells and the background subtraction and super-voxels
reduce the dimensionality of the problem by an order of magnitude. We validate our
approach on large 3D time-lapse datasets of Drosophila and zebrafish
development by analyzing cell motion patterns. We show that our approach is, on average,
10 × faster than commonly used optical flow implementations in the Insight Tool-Kit
(ITK) and reduces the average flow end point error by 50% in regions with complex
dynamic processes, such as cell divisions.Availability: Source code freely available in the Software section at
http://janelia.org/lab/keller-lab.Contact:
amatf@janelia.hhmi.org or kellerp@janelia.hhmi.orgSupplementary information:
Supplementary data are available at Bioinformatics
online.