for use with 3 d display could also include two or more cameras the markers may be passive such as for example paint ink chalk or a reflective surface or active such as for example radio transmitters or leds markers may be located or defined upon persons and objects that are within an area of interest or that will pass through an area of interest for example if a football field is the area of interest marker s may be located or defined on all the player 39 s helmets caps jerseys uniforms shoulder pads hip pads gloves shoes hands and feet as well as on sidelines goal lines and even the ball markers may be pre determined or dynamically defined and be of any shape and size for example regarding a ball a marker may be defined as the laces as a stripe applied to the ball or as either of the laces or the stripe depending upon which marker is visible to a camera in a scene cameras and external interfaces according to the present specification can receive and transmit more data using less power if the processing module or external interface can process data faster and more accurately for example using one or more techniques for enhancing edge detection determination allows the processing.