A scanner is a device which converts printed images into electronic form so that they can be manipulated by a computer. Color flat-bed scanners are most common. With a flat-bed scanner, one can scan images directly from books and magazines. Similar to printers, one measurement of scanner quality is resolution expressed in "dpi". The resolution at or above 300 dpi is adequate for our purposes. With special software, a scanner can convert printed text into electronic text without manually typing it. This is called "optical character recognition" or "OCR."