An implementation provides a method for determining a trajectory of an object in a particular image in a sequence of digital images, the trajectory being based on one or more previous locations of the object in one or more previous images in the sequence. A weight is determined, for a particle in a particle-based framework for tracking the object, based on distance from the trajectory to the particle. A location estimate is determined for the object using the particle-based framework, the location estimate being based on the determined particle weight.