Character Recognition Device & Microphone

CHARACTER RECOGNITION DEVICE

Character-recognition device enables the user to input text and numerical data by handwriting it in capital letters on the pressure-sensitive surface using a specials pen. An invisible grid of fine wires below the surface detects the shape of the letters, converting them to electrical signals which the computer interprets using special software. Although this device is a genuine replacement for the keyboard, it has never become as popular as keyboard.This powerful tool allows businesses to convert paper documents into electronic files

Optical Character Recognition: It is abbreviated to OCR, is the mechanical or electronic translation of scanned images of handwritten, typewritten or printed text into machine-encoded text. It is widely used to convert books and documents into electronic files, to computerize a record-keeping system in an office.

Optical Character Recognition (OCR) refers to a computer's ability to recognize printed letters, numerals, or symbols (optical characters) as discrete entities rather than as simply an image containing lines, curves, and shading.

In place of a character that they cannot recognize, they will substitute a special symbol. These symbols can be automatically picked out and replaced later on with the aid of spell-checking software.

How does OCR operate/process? When a printed page of text is scanned, the scanner delivers an image of the text to OCR software stored in the attached computer. The software then attempts to identify each letter of each word in the image in order to covert it to an editable text document or to process the information in whatever format is needed as illustrated in the Figure 1, Figure 2 and Figure 3 (Digital Camera is also used in place of scanner).

Figure 1: OCR Operation

  

Figure 2: OCR Operation

 Figure 3: OCR

OCR is increasingly used in conjunction with bar coding and other forms of automatic identification systems. Bar coding is an automatic identification technology that allows data to be collected rapidly and accurately with minimal human effort. Bar codes provide a simple method of encoding text information that can be easily read by electronic scanners integrated with computer systems. It is useful in almost any field that requires unique identification and tracking of a large number of items.

Some OCR programs are designed to recognize correct grammar and common spellings so they automatically highlight words that they have copied, but that they also find questionable.

Original Problems with OCR: What usually confused the OCR software were imperfections on the printed page like stains, extraneous marks, fading, and blurring. Letters had to be crisply printed. Unusual fonts were impossible for the OCR to understand and duplicate. Strikeovers also confused OCR programs. Even slightly blurry, shiny type from thermal fax paper could throw the software into fits.

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THE MICROPHONE

The microphone converts audio signals (sound) to electrical waves and these can be converted by electronic circuitry in the computer to digital form.

HOW DO THEY WORK? A microphone is an example of a transducer, a device that changes information from one form to another. Since the sound information exists as patterns of air pressure; the microphone changes this information into patterns of electric current. The term transducer is applied to any device which converts a mechanical or other measurable phenomenon into an electrical one or vice versa. Examples of transducers are: ·         Microphones  ·         Loudspeakers

A microphone wants to take varying pressure waves in the air and convert them into varying electrical signals. Microphones are transducers which detect sound signals and produce an electrical image of the sound, i.e., they produce a voltage or a current which is proportional to the sound signal. The most common microphones for musical use are dynamic, ribbon, or condenser microphones.

Different types of microphone have different ways of converting energy but they all share one thing in common: The diaphragm. This is a thin piece of material (such as paper, plastic or aluminium) which vibrates when it is struck by sound waves. In a typical hand-held mic like the one shown in Figure (1), the diaphragm is located in the head of the microphone.

Figure (1): Hand-held Mic

When the diaphragm vibrates, it causes other components in the microphone to vibrate. These vibrations are converted into an electrical current which becomes the audio signal. Figure (2) illustrates the USB desktop microphone.

Figure (2): USB Desktop Microphone

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