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WorksheetsImage Representation Lesson 2
Total questions: 10
Worksheet time: 5mins
What does colour depth mean?
The number of colours in a digital image
The number of bits used for each pixel in a digital image
The number of pixels in a digital image
How vibrant a colour is in a digital image
How many colours can you have with a colour depth of 1?
1 colour
2 colours - black & white
4 colours
32 colours
How many colours can you have with a colour depth of 2?
1 colour
2 colours - black & white
4 colours
32 colours
If you have 3 bits for each pixel, what are the 3 colours that each pixel is made up from?
red, green, blue
red, yellow, blue
black, white, red
cyan, magenta, yellow
How many colours can you have with 3 bits per pixel?
3
23 = 8
2 x 3 = 6
3 x 3 = 9
In general, how many colours can you have with a colour depth of n (i.e. n bits per pixel)
2n
n2
2 x n
n
What is metadata?
Extra data that is added to an image which tells the computer how to display it.
Part of the image that helps to reduce the file size
A technique used to hide secret messages in an image
None of these
What essential metadata is included with a bitmap image?
Resolution and Colour Depth
Location and Colour Depth
Resolution and Location
Location and Camera Type
Why does the computer need the Resolution in the metadata? (2 reasons)
To know when to move to the next row when creating an image from the binary values
To know how to display the colours for the image
To know how many pixels to read from the binary file in total
To allow the image to be printed
Why does the computer need the Colour Depth in the metadata?
To know how many bits to read from the binary file for each pixel in the image
To know when to move on to the next row when displaying the image
To know where the light and dark patches are to adjust the colour balance
To allow you to zoom in and out of the file in an image editor
