Scanner

•Ngô Thùy Trang

•Nguyễn Ngọc Tiến

•Trần Thị Thùy Hương

•Lê Việt Tiên

•Phạm Thị Như Quỳnh

What is scanner?• An input device that scans (reads) the

image as a series of dots and introduces the information into the computer’s memory.

(Infotech Glossary)

Some definition

• DPI• Electronic code• Digitized image

DPI• DPI (dots per inch):

density of computer or printer image: a measure of the density of the image produced by a computer screen or printer. (Prodic Dictionary)

Electronic code• A scanner ‘see’ images and converts the

printed text or pictures into electronic codes that can be understood by the computer.

Electronic code

Digitized image• A representation of a two-dimensional

image using ones and zeros (binary).

What is inside a scanner?

• Colored filter• Rotating lamps• Software for scanner• OCR software

Rotating lamps

• The scanner operates by using 3 rotating lamps which has a different colored filter

Colored filter• It has 3 different colors: red, green and blue

Software for scanner• Software for scanner translates the API

procedure calls into primitive commands• Some common scanner software:- SANE (Scanner Access Now Easy)- TWAIN- ISIS (Image and Scanner Interface Specification)- WIA (Windows Image Acquisition) (Wikipedia)

OCR software• OCR (Optical Character Recognition)• OCR software let you easily convert

images, such as digital photographs, scanned documents, printed books, etc. into text.

Flatbed scanner• A scanner with a glass scanning surface

on which objects are placed; similar to a photocopier. (Infotech Glossary)

How a flatbed scanner works?• 1: a flatbed scanner ‘see’ images and

converts them into electronic codes.

• 2: The scanning unit moves across the image to be scanned

How a flatbed scanner works?

Process of scanning

a glass pane (platen)

a bright light

Charge-Coupled Devices

• 3: It reads the image as a series of dots and then generates the digitized image.

How a flatbed scanner works?

• 4: Digitized image is sent to computer and stored as a file.

How a flatbed scanner works?

You place a drawing, photograph or other printed document face down on the glass and close or lower the plastic cover. When you activate the scan feature, a light shines from under the plastic and a copy of your paper appears on your monitor.

Uses of Flatbed scanner

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