Hardware

Question 1

What is an advantage of 2D barcodes over 1D barcodes?

Answer 1

2D barcodes an contain more information in the same amount of space as a 1D barcode

Question 2

What is a disadvantage of 2D barcodes compared to 1D barcodes?

Answer 2

1D barcodes require more processing in order to extract their contents

Question 3

What is a barcode?

Answer 3

A barcode is a printed diagram that consists of light and dark portions

Question 4

Name the four parts of a barcode reader

Answer 4

Laser light source
Lens
Photodiodes
Mirror

Question 5

Describe the principles of operation of a barcode reader

Answer 5

1. The mirror directes light from the laser onto the printed barcode
2. The light reflected by the barcode passes through the lens and is incident on the
   photodiode
3. The photodiode turns light into electrical charge which can be measured and
   processed to form a digital signal
4. Light portions of a barcode reflect the most light while dark sections absorb incident
   light
5. The pattern of light and dark stripes in a barcode corresponds to binary 1s and 0s

Question 6

What are the two main types of sensor in a digital camera?

Answer 6

CMOS and CCD

Question 7

Describe the role of a shutter in the a camera

Answer 7

1. Sensors consist of cells, each of which represent a pixel in the final image
2. Sensors covert incident light into electrical charge
   Sensors consist of cells, each of which represent a pixel in the final image