This document discusses different types of scanners and their working principles. It describes the objectives are to understand scanner types and their workings. It then defines a scanner as a device that optically scans objects and converts them into digital images. The first scanner was a drum scanner developed in 1957. The main scanner types discussed are barcode, flatbed, drum, handheld, and film scanners. It provides details on how barcode scanners work using light reflection and sensors to read barcodes. The laser, pen, and CCD methods of barcode scanning are also explained. Finally, it outlines the process of how a flatbed scanner works using a light source, mirrors, lens, and CCD array to scan documents.

2. OBJECTIVES
TO KNOW ABOUT DIFFERENT TYPES
OF SCANNER
TO UNDERSTAND THEIR WORKING
PRINCIPLE

3. What is Scanner?
Scanner is device that optically scans
images, printed texts, handwriting, or an
object and converts it into digital image.

4. The first scanner developed for use with a computer,
was a drum scanner .
It was built in 1957 at the US National Bureau of
Standards by a team led by Russell A. Kirsch, working
on America's first internally programmable (stored-
program) computer, the Standards Eastern Automatic
Computer (SEAC).

5. TYPES OF SCANNER
BARCODE SCANNER
FLATBED SCANNER
DRUM SCANNER
HANDHELD SCANNER
FILM SCANNER

8. 1= Led/Fluorescent Light emitter
2= Barcodes
3= Photoelectric cell
4= CCD(Charge Coupled Device)
5= Computer

9. 1A bar code consists of white and black bars. Data retrieval is achieved when
bar code scanners shine a light at a bar code, capture the reflected light and
replace the black and white bars with binary digital signals.
2 Reflections are strong in white areas and weak in black areas. A sensor
receives reflections to obtain analog waveforms.
3 The analog signal is converted into a digital signal via an A/D converter.
(Binarization)
4 Data retrieval is achieved when a code system is determined from the
digital signal obtained. (Decoding process)

10. UPC (universal product code)

12. LASER METHOD

13. Laser light is shone on the label
surface and its reflection is captured
by a sensor (laser photo detector) to
read a bar code. A laser beam is
reflected off a mirror and swept left
and right to read a bar code
Using laser allows reading of
distant and wide bar code labels.

14. PEN METHOD

15. This method only has a LED
light source and a sensor to
capture its reflection. Since a
person moves a scanner to read a
bar code, practice is required for
operation.
The mechanism is simple,
making this method
inexpensive.

16. CCD METHOD

17. The CCD method bar code
scanner has a built-in light. A
scanner shines this light at a bar
code and its reflection is
captured via CCD for reading.
A bar code is captured once,
allowing fast reading. There are
no movable parts and impact
resistance is excellent.

20. Along with the glass bed, the scanner has a source of light, which is in-built.
Most commonly the light used is LED or fluorescent. This light is regulated by
a voltage regulator or a similar device. This enables the light to spread evenly
across the document.
This light source then illuminates the document, this is when the actual
encoding of the document takes place. The scanner contains a lens, mirror a
filter and a CCD array, that are fixed on the top, called the scan head. This
combined mechanism then rolls or moves over the entire document. The scan
head takes help of a belt.
The scan head is fixed to a bar that acts like a stabilizer. So the entire process
takes place smoothly, without any wobble or deviation.
An angled mirror then reflects the image of the document, on another mirror.
After the image is reflected on this second mirror, it gets reflected again on the
lens.
This lens then projects the captured image on to the CCD array, through a filter.