An imaging sensor produces spatiotemporal measurement sets of distinct sensing zones of the imaging sensor. A multifocal lens directs electromagnetic radiation from distinct three-dimensional spatial zones to distinct sensing zones. A focus analyzer processes the spatiotemporal measurement sets to determine a sequence of in-focus status of the distinct sensing zones independent of other distinct sensing zones. A displacement processor generates object displacement vector(s) based on a sequence of in-focus status indicative of an object moving between distinct three-dimensional spatial zones.