Binary L3
Representing bitmap images
Representation of text, images and sound
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Representing bitmap images
Representation of text, images and sound
I can describe why Bitmap images use pixels.
Describe bitmap image representation
Light reflecting off the object is captured through the lens of the device.
The colour of light detected at each part of the image is stored as single points known as pixels, (picture elements).
Describe bitmap image representation
This ‘map of pixels’ is referred to as a
bitmap image.
As with any data in a computer, this must be represented as a sequence of bits (0 or 1).
Each pixel is represented by a binary sequence.
Fill in the blanks
A bitmap image is a grid of pixels
Each of these pixels in the image need to be represented by a binary sequence
Describe bitmap image representation
The shortest possible binary sequence for a pixel is 1 bit.
Each state can be used to represent a different colour.
The amount of colours available is called Colour Depth
1 = black
0 = white
As the colour depth is increased, more colours can be represented.
Describe bitmap image representation
11 = green
10 = red
01 = black
00 = white
What happens to the amount of colours we can use if we increase the colour depth?
The image becomes black and white
The amount of colours decreases
Nothing
The amount of colours increases
Compare different resolutions and colour depths
As the colour depth of an original image is reduced, the detail and quality also reduces as a result of using less colours.
24-bit
8-bit
2-bit
Compare different resolutions and colour depths
Having fewer colours to use means that the image has to use the closest colour it can from what is available.
16,777,216 colours
256 colours
4 colours
Why might an image look less realistic if its colour depth is reduced?
It has fewer available colours to represent each pixel
It has a lower resolution
It has a larger file size
Slide heading
Open this game and turn the binary back into images
Extension - Create your own art, copy the binary sequence and email it to a friend, then have your friend recreate the image from binary
Instructions:
Create new picture on Piskel that you want to make, You can draw anything appropriate, each pixel must have colour in it and you can only use 4 colours.
Representing bitmap images
Bitmap images are made from pixels, the smallest
element of an image.
Each pixel identifies the colour it should display.
The colour depth of a bitmap image is the number of bits used per pixel to display a colour.
The resolution of an image identifies the dimensions, in pixels, of the image and therefore the total amount of pixels used.
