# 06 - Representing Images using Binary

1. Look at the binary code given that has been used to create the image sequence. Which line has not been represented correctly?

The last line

The first line

All lines are represented incorrectly

All lines are represented correctly

2. The colour depth of an image is measured in bits. The number of bits indicates how many colours are available for each pixel. In the black and white image, only ___ colours are needed. This means it has a colour depth of 1 bit. (1 bit can be either 0 or 1

five

three

two

four

3. A 2-bit colour depth would allow ______ different values: 00, 01, 10, 11. This would allow for a range of colours such as shown in the image below.

4

2

8

6

4. So what about the human eye? Some experts estimate that we can distinguish perhaps as many as 10 million colors. Others estimate about 1 million, but 10 million is the top estimate. True or False?

False

True

5. The image below shows a creative website that made a million dollars by creating a website with a million pixels and selling pixels to customers. What is a pixel?

pixels are large images that can be broken down into binary bits

pixels are just numbers that represent an image.

pixels are microscopic numbers that make up binary numbers

Graphics or Images are made up of tiny blocks (dots that make up an image) called pixels.

6. True or False? The more pixels on the screen, the higher the resolution and the better the quality of the picture will be.

False

True

7. Image files can be either bitmaps or vectors. Which of the following statements are true of bitmap images?
```#1---
Bitmap images are widely used on digital cameras, smartphones and
online. Common bitmap image file types include JPEG, GIF and PNG.
Bitmaps are also known as pixelmaps or raster graphics.

#2---
Bitmap images are organised as a grid of coloured squares called
pixels (short for 'picture elements'). When zooming in or enlarging
a bitmap image, the pixels are stretched and made into larger blocks.
This is why bitmap images appear as poor quality when enlarged too
much.```

Neither statement is true

Both statements are true

Statement #2 is true

Statement #1 is true

8. Each colour of an image is stored as a binary number. In the black-and-white image below, each pixel is either_________________________________

0 or 1

1 or 9

black or white

non binary or binary

9. In the image below, what represents a black square?

00

1

1111

0

10. For a simple black and white bitmap image, you only need 1 bit. A 0 could represent a white pixel and a 1 could represent a black pixel. Remember that 1 bit can be either "on" (0) or "off" (1).

False

True

11. Read the excerpt below and see if you could suggest a solution to the given problem.
```The colour depth of an image is measured in bits. The number of bits
indicates how many colours are available for each pixel.

In the black and white image, only two colours are needed.
This means it has a colour depth of 1 bit.

What about if we needed four colours?
e.g. Dark Grey, Light Grey, Black and white?

What could be done?```

This cannot be done. Images on a computer can only be black and white

This cannot be done easily as it is only possible to have 1 bit available.

A 4-bit colour depth would allow only four different values and this would solve the problem.

A 2-bit colour depth would allow four different values: 00 (white), 01(black), 10(dark grey), 11(light grey)

12. The greater the colour depth (bits per pixel), the more colours are available.From the table below how many colours would be available with a colour-depth of 8 bit?

256

128

1

8

13. Most computer systems and digital cameras use _____-bit images. ______ in binary is 1111 1111 1111 1111 1111 1111. This means there are over 16 million possible colours per pixel.

32

12

2

24

14. __________ is a measure of pixel density, usually measured in dots per inch (dpi). Images on websites usually have a ____________ of 72 dpi.

Resolution

Responsification

Pixelation

Revolution

15. High quality printed images in books and magazines have a ________ resolution than computer screens. Magazines often use either 300 dpi or even 600 dpi.

lower

darker

higher

lighter