Contact Image Sensors (CIS) are a relatively recent technological innovation in the field of optical flatbed scanners that are rapidly replacing CCDs in low power and portable applications. As the name implies, CIS's place the image sensor in near direct contact with the object to be scanned in contrast to using mirrors to bounce light to a stationary sensor, as is the case in conventional CCD scanners. A CIS typically consists of linear array of detectors, covered by a focusing lens and flanked by Red, Green, and Blue LEDs for illumination. Usage of LEDs allows the CIS to be highly power efficient, with many scanners being powered through the minimal line voltage supplied via a USB connection. At the moment, CIS's generally produce images of inferior resolution and quality when compared to their CCD brethren, but, as the technology is still young, this is bound to change. In computing, a scanner is a device which analyzes a physical image (such as a photograph, printed text, or handwriting) or an object (such as ornament) and converts it to a digital image. ... A charge-coupled device (CCD) is a sensor for recording images, consisting of an integrated circuit containing an array of linked, or coupled, capacitors. ... Various light-emitting diodes (5 mm reds, 3 mm greens and yellows) A light-emitting diode (LED) is a semiconductor device that emits incoherent monochromatic light when electrically biased in the forward direction. ... Note: USB may also mean upper sideband in radio. ...