An Optical Character Recognizer is a direct entry input device. These devices can detect alphanumeric characters printed on any paper. The device works on the principle of image processing. When this device is switched ON, it reads the image pattern. A light source converts the alphabets, numbers and similar such characters into electrical signal which are then sent to the computer for processing.
The text to be scanned should be illuminated by low frequency light source. The reflected light from the text is received by the light sensitive cells and generates the signal depending on the type of text. This device is very useful for converting the image into text data.