A security system to detect a concealed item carried by a traveler in motion, the security system includes a camera configured to capture an image series of the traveler in a Eulerian or Lagrangian frame of reference, wherein the captured image series contains motions generated by the concealed item; an alarm system configured to produce an alert signal; and an electronic control unit. The electronic control unit is configured to magnify motions generated by the concealed item to generate perceptible motions, provide an output image series that contains the perceptible motion, detect characteristic kinematic behaviors of the concealed item from the output image series, measure characteristic kinematic quantities of the characteristic kinematic behaviors, determine a presence of the concealed item from the characteristic kinematic quantities, and activate the alarm system to produce the alert signal.