Pixel (short for Picture Element). In graphics and video applications digital, is the basic unit that makes up the image the digital representation of a point. We generally use the pixel term to refer to each of the cells or zones sensitive aligned on the surfaces of electronic sensors, although strictly speaking there is not always a direct correspondence between the pixels of the sensors and the pixels of the digital video delivered by the camera.
CCD (Charge Coupling) Device). What we know as a CCD is a sensor photosensitive electronic, a composite device that allows transform light into orderly electrical charges. A CCD consists of an array of photosensitive cells that convert light into electrical charge, they store it and then deliver it serially to circuits that use these current variations to form a signal video. CCD devices lend themselves very easily to capture images on analog cameras, although there are currently many capture systems that deliver signals digital natively.
IT (Interline Transfer). Architecture of the first CCD sensors, in which it is used an array of photosensitive cells to capture a picture of video, and another to store this information while they are delivery to the camera circuits. Sensitive elements are discharge "to the side", in an array of storage that shares the space exposed to light with the useful pixels. End result: slow processing, effects of image persistence and loss of useful area.
FIT (Frame Interline Transfer). Family of CCD sensors in which uses an intermediate storage array to speed up the load transfer, communicate faster with the camera and reduce image persistence effects. In many cases, sensor construction is more complex and transfer of loads occurs "down", which allows to improve the useful area. The manufacture of FIT devices is more expensive and its energy consumption is generally greater than that of equivalent IT devices. In most cases, manufacturers introduce CCD FIT as an option with cost extra for users.
Microlenses. In in many implementations, CCD sensors use a grid of microlenses carefully placed over sensitive areas to conduct more light into each cell. This resource allows compensate for the reduction of the useful area of the CCDs and significantly improve the sensitivity of devices.
CMOS (Complementary Metal) Oxide Semiconductor).. CMOS sensors do the same task that CCD sensors: when exposed to light generate a variable electric current that can be encoded as a signal video. However, its operation is completely different from that of CCDs: a CMOS functions as an array that quantifies light variations and can deliver information in parallel, making it a device extraordinarily fast and very suitable for applications Digital.
Useful area. All electronic sensors have a limitation Important: not all of the area exposed to light is capturing image. In early IT-type CCD designs, the useful area it could reach only 60% of the plane. CMOS sensors have similar conditions, because in current designs next to each sensitive area there is always a set of transistors that control each cell, and until today have not achieved build the devices in such a way that the transistors are below the sensitive cells. The improvement of the area useful is one of the most important development spaces in the advance of electronic sensors, which in the case of CCDs already it is close to reaching its ceiling.
