Data Representation - Images

Question 1

What do we call the smallest unit of data that can be represented in an image?

Answer 1

Pixel

Question 2

What are the most common image file types?

Answer 2

PNG
JPEG
Bitmap
Vector

Question 3

What is meant by a Pixel?

Answer 3

• Smallest element that makes up an image

- A picture/image element.

Question 4

How a bitmap image is stored on a computer?

Answer 4

• An image is made up of / consists of pixels
• A pixel can be one colour
• Each colour has a unique / corresponding binary number
• Each pixel / square is given the binary number of its colour
• The binary numbers are stored in order in the file E.g. White = 000, Red = 010, Blue= 110, top line would be 000000010010010110110

Question 5

What is meant by Colour Depth?

Answer 5

The number of colours available for each pixel

Question 6

What happens to the size of the file if you increase the image’s colour depth?

Answer 6

The file size increases (gets larger)

Question 7

What happens to the size of the file if you decrease the image’s colour depth?

Answer 7

The file size decreases (gets smaller)

Question 8

What is the term used to define information about an image?

Answer 8

Metadata

Question 9

In modern technology what unit of measurement would be used for screen size?

Answer 9

Pixels per inch (PPI)

Question 10

What is image resolution?

Answer 10

The resolution of an image is the number of pixels per unit (pixels per inch).

Question 11

How does the resolution of an image affect the size of the file?

Answer 11

The more pixels per inch the larger the file size.

Question 12

How many colours can be represented with a 4 bit colour depth?

Answer 12

16

Question 13

How many colours can be represented with a 1 bit colour depth?

Answer 13

2

Question 14

How many colours can be represented with a 3 bit colour depth?

Answer 14

8

Question 15

How many colours can be represented with a 8 bit colour depth?

Answer 15

256

Question 16

What is the name of the type of graphic that uses shapes of solid colour?

Answer 16

Vector

Question 17

What is the name of the type of graphic that uses pixels?

Answer 17

Bitmap

Question 18

Why is metadata included in a file?

Answer 18

A computer needs to know the size of the image in terms of height, width and colour depth in bits per pixel (bpp

…this allows the computer to recreate the image from binary.

Question 19

What is the common metadata is held about images?

Answer 19

• dimensions
• height
• width
• number of bits per pixel
• colours used
• location
• date
• file type