Surgical camera systems consist of two components: the camera head and the camera control unit (CCU).The camera head is attached to the scope, which is inserted into the patient. Some surgical camerasinclude an optical zoom, which allows for easy adjustment of the image size. Optical zoom is superior todigital zoom as it does not sacrifice image quality for magnification. Light, which originates from a lightsource, travels through the scope to the camera head where it hits charge coupled device (CCD) chips thatconvert the visual images produced by the camera into electrical signals. These electric signals are thentransmitted by an electrical cable to the CCU. The CCU contains all the electronics that do not have to befitted in the camera head and processes the video signals it receives from the camera head. HD CCUs canvary in terms of resolution capabilities. Some HD models are backwards compatible, meaning they canreceive and send SD signals as well as HD signals. Once the signals are processed by the CCU, they aresent to a surgical display, an image capture device or a printing device. True HD requires a minimumresolution of 720p or 1080i and 16:9 aspect ratio.