A motion-based interlock apparatus, system, and method prevent an x-ray source in an x-ray machine from activating if the current relative motion between the x-ray source and an image receptor would compromise the quality of the resulting plain radiograph. The system activates the interlock based on either or both of the velocity and acceleration of the tubehead, as measured by instrumentation corresponding to any of the tubehead, the extension arm, or off board the x-ray machine. The system may preferably compare the measured motion against one or more acceptable motion thresholds. If the measured motion exceeds one or more of the acceptable motion thresholds, exposure may preferably be delayed until the motion of the tubehead subsides. By ensuring that the image is not exposed while the tubehead is moving substantially, the quality of the resultant radiograph is improved.
