Y8 - Image Binary

Y8 - Image Binary
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Slide 1: Slide
ComputingLower Secondary (Key Stage 3)

This lesson contains 27 slides, with interactive quizzes and text slides.

Items in this lesson

Y8 - Image Binary

Slide 1 - Slide

How do you think a computer stores an image?

Slide 2 - Open question

Bitmaps
Pixel based
each pixel stored as a binary number
pixelate when enlarged

Slide 3 - Slide

Slide 4 - Slide

Vector
coordinate based
uses calculations
will not pixelate

Slide 5 - Slide

Slide 6 - Slide

Slide 7 - Slide

Vector Use

Slide 8 - Slide

Bitmap use

Slide 9 - Slide

VECTOR
BITMAP
Uses calculations
smaller in file size
larger in file size
will pixelate
uses pixels
Used for real photos
Will not pixelate
Used for maps

Slide 10 - Drag question

Bit depth
How many bits allocated per pixel

Slide 11 - Slide

1 bit vs 2 bit

Slide 12 - Slide

How many bits per pixel is the standard in modern computers?

Slide 13 - Mind map

RGB 24 bit colour
24 bits per pixel
8 for red
8 for green
8 for blue
16.7 million options

one pixel of pure green would be 000000001111111100000000

Slide 14 - Slide

Hex makes it easier
6 digits of hex
instead of 24 binary digits
Easier to remember
Easy to convert to binary
  • 000000 = black
  • FFFFFF = white
  • 960080 = lilac

Slide 15 - Slide

Try this
Put this number into google
#642240
What do you think it is?

Slide 16 - Slide

Can you remember Hex to binary conversion?
Convert 642240 into binary

Slide 17 - Slide

comparison
The school want a printing company to make several leaflets to advertise a school open evening event.
They could say...
"Use colour #642240"
or
"use 011001000010001001000000 !!!"

Slide 18 - Slide

How many colours could you represent using a bit depth of 3
A
3
B
4
C
8
D
16

Slide 19 - Quiz

How many colours could you represent using a bit depth of 8
A
8
B
64
C
255
D
256

Slide 20 - Quiz

How many bits are assigned per channel in RGB 24 bit
A
4
B
8
C
12
D
24

Slide 21 - Quiz

How many digits of hexadecimal are needed to represent a 24 bit colour
A
6
B
8
C
4
D
1

Slide 22 - Quiz

Image resolution
Number of pixels across the height and width of the image
Density of pixels in a given area (usually dots per inch)

Slide 23 - Slide

Challenge
Research the term "metadata" when linked to storing images
get some examples

Slide 24 - Slide

Examples of metadata for a stored image

Slide 25 - Mind map

Impacts
What do you think happens when you increase either the resolution and/or bit depth for an image?

Slide 26 - Slide

Extension

Slide 27 - Slide