Tài liệu về scanner pdf

• 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... Electronic code• A scanner ‘see’ image

•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 (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

Thank you for your attention!