Techniques, systems, and devices are disclosed for analyzing a point of closest approach (PoCA) image of a volume of interest (VOI) comprising a set of recorded PoCA points from charged particle detector measurements to detect an object within the VOI. The VOI is partitioned into a set of equally-sized bins with each bin including a subset of the PoCA points. A bin metric is determined for each bin. A subset of the bins is selected based on the detected bin metric with the subset of bins being most likely to contain objects. A potential object for each selected bin is determined by determining a location and a size for the potential object based at least on the PoCAs inside the bin. A figure of merit (FOM) of the potential object is determined as a measure of the likelihood that the potential object is truly a threat object.