1. A method for video processing, comprising: determining a set of calibration parameters for a video camera, comprising: selecting a calibration sample in a video frame, estimating coarse calibration parameters, iteratively estimating fine calibration parameters based on the estimated coarse calibration parameters, determining mean matching error based on the estimated fine calibration parameters, comparing the mean matching error to a predetermined threshold, based on the comparison, estimating a verification target, selecting a calibration verification sample in the video frame, the calibration verification sample being different from the selected calibration sample, comparing the estimated verification target with the selected calibration verification sample, and one of accepting the calibration parameters or determining a new set of calibration parameters; receiving video of a scene from the video camera; detecting moving pixels in the video; detecting line segments or motion blocks in the video based on the detected moving pixels; identifying targets in the video based on the detected line segments or motion blocks; tracking targets in the video based on the identified targets; and managing the tracked targets in the video; wherein a computer or application-specific hardware performs said receiving video, detecting moving pixels, detecting line segments or motion blocks, identifying targets, tracking targets, and managing the tracked targets.