A system for determining and recording the position, size, shape and depth of a defect in a billet or similar workpiece. The workpiece is displayed on the screen of a video display device, and the positions of the defects on the screen are recorded responsive to being manually selected by an operator. In embodiments in which the position of a video camera generating the video image varies with respect to the workpiece, sensors are used to determine the positions of the workpiece with respect to the camera. The position indications from the sensors are applied to a processor which correlates these indications with the position of the defect on the screen to determine the position of the defect on the workpiece.