A method for real time processing of a sequence of video frames. The video frames are received in synchronization with a recording of the video frames in real time for triggering an alert. The method is implemented by execution of program code on a processor of a computer system. Each frame includes a two-dimensional array of pixels and a frame-dependent color intensity at each pixel. An algorithm determines whether a static object in a current frame of the video frames is an abandoned object or a removed object. The determined status, the current frame time, the static region, and the static object are stored in a data storage medium of the computer system. An alarm is triggered in response to satisfaction of requirements that include a persistence requirement, a non-persistence duration requirement, and a persistence duration requirement.