In an example detection system for vehicles or other objects of interest, objects are detected in real-time at full VGA 30 frame per second resolution. A preprocessor may perform run-length encoding (RLE) to provide detected edges. The image may then be scanned from the bottom up to identify vertical clusters or “stacks” or RLEs. Vertical clusters with low vertical density may be eliminated as poor vehicle candidates. Vertical clusters not eliminated may then be processed with a histogram of gradients algorithm, and confirmed with a support vector machine algorithm. A range to the nearest object may also be calculated, and a warning provided if the object is too close.