1.2 Representing Images

Question 1

What are the two ways of storing images in binary?

Answer 1

Bitmaps and Vectors

Question 2

How does a bitmap work?

Answer 2

• Image made up of different coloured squares
• Each square having a binary value

Question 3

How does a vector work?

Answer 3

• The mathematics to store the square are stored
• e.g. A circle can be drawn just by storing the details of:
  - X and Y co-ordinates from the middle
  - The radius
  - Width
  - Colour

Question 4

How can you calculate the number of colours in an image?

Answer 4

• 2 to the power of n
• n is the number of bits for each pixel

Question 5

What is colour depth?

Answer 5

Colour depth is the number of bits for each pixel

Question 6

What is metadata?

Answer 6

Additional data stored with the image to define the width, height, colour depth and colour palette.

Question 7

How are photographs stored?

Answer 7

• Stored in 24 bit colour depth
• Each pixel is 24 bits
• This is 2 to the power of 24 = over 16 million colours the human eye can see