1. BTEC
Level 3 Extended Diploma in Creative Media Production
Unit 64: Motion Graphics and Compositing Video
Pixels

2. BTEC
Level 3 Extended Diploma in Creative Media Production
Unit 64: Motion Graphics and Compositing Video
Pixels
In digital imaging, a pixel, or pel, (picture element) is a physical
point in a raster image, or the smallest addressable element in a
display device; so it is the smallest controllable element of a
picture represented on the screen. The address of a pixel
corresponds to its physical coordinates. http://en.wikipedia.org/wiki/Pixel

3. BTEC
Level 3 Extended Diploma in Creative Media Production
Unit 64: Motion Graphics and Compositing Video
Pixels
The term pixel is actually short for Picture Element. These small
little dots are what make up the images on digital. The screen is
divided up into a matrix of thousands or even millions of pixels.
Each pixel can only be one colour at a time. However, since they
are so small, pixels often blend together to form various shades
and blends of colours. The number of colours each pixel can be is
determined by the number of bits used to represent it. http://www.techterms.com/definition/pixel

4. BTEC
Level 3 Extended Diploma in Creative Media Production
Unit 64: Motion Graphics and Compositing Video
Pixels and Colour
Colour Depth
Colour "depth" is defined by the number of bits per pixel that can
be displayed on a computer screen. Data is stored in bits. Each bit
represents two colours because it has a value of 0 or 1. The more
bits per pixel, the more colours can be displayed. Examples of
colour depth are shown in the following table:
Colour Depth No. Of Colours
1 bit colour 2
4 bit colour 16
8 bit colour 256
24 bit colour 16,777,216 or True Colour

5. BTEC
Level 3 Extended Diploma in Creative Media Production
Unit 64: Motion Graphics and Compositing Video
Pixels and Colour
Determining Colour Depth - Since each bit represents 2 colours, it
is easy to work out the number of colours for the various colour
depths. The number of possible colours would be 2 to the power
of the number of bits per pixel:
A colour depth of 4 bits would be 2 times itself 4 times:
2 x 2 x 2 x 2 = 16 colours
A colour depth of 8 bits would be 2 times itself 8 times:
2 x 2 x 2 x 2 x 2 x 2 x 2 x 2 = 256 colours.
A colour depth of 24 bits would be 2 times itself 24 times:
2x2x2x2x2x2x2x2x2x2x2x2x
2 x 2 x 2 x 2 x 2 x 2 x 2 x 2 x 2 x 2 x 2 x 2 = 16,777,216 colours

6. BTEC
Level 3 Extended Diploma in Creative Media Production
Unit 64: Motion Graphics and Compositing Video
Converting Light - Cameras
Instead of film, a digital camera has a sensor that converts light
into electrical charges.

7. BTEC
Level 3 Extended Diploma in Creative Media Production
Unit 64: Motion Graphics and Compositing Video
Converting Light - Cameras
Instead of film, a digital camera has a sensor that converts light
into electrical charges.
A digital camera takes light and focuses it via the lens onto this
sensor made out of silicon. It is made up of a grid of tiny
photosites that are sensitive to light. Each photosite is usually
called a pixel, a contraction of "picture element". There are
millions of these individual pixels in the sensor of a digital camera.

8. BTEC
Level 3 Extended Diploma in Creative Media Production
Unit 64: Motion Graphics and Compositing Video
Converting Light - Cameras

9. BTEC
Level 3 Extended Diploma in Creative Media Production
Unit 64: Motion Graphics and Compositing Video
Converting Light - Cameras
Each photosite or pixel on the sensor absorbs photons and
releases electrons through the photoelectric effect.
In the photoelectric effect, electrons are emitted from matter
(metals and non-metallic solids, liquids or gases) as a consequence
of their absorption of energy from electromagnetic radiation of
very short wavelength, such as visible or ultraviolet light.

10. BTEC
Level 3 Extended Diploma in Creative Media Production
Unit 64: Motion Graphics and Compositing Video
Converting Light - Cameras
The image sensor employed by most digital cameras is a charge-
coupled device (CCD), although some cameras use
complementary metal oxide semiconductor (CMOS) technology
instead.
Both CCD and CMOS image sensors convert light into electrons. A
simplified way to think about these sensors is to think of a 2-D
array of thousands or millions of tiny solar cells.
Once the sensor converts the light into electrons, it reads the value
(accumulated charge) of each cell in the image. This electric charge
is then transferred and converted to an analog voltage that is
amplified and then sent to an Analog to Digital Converter where it
is digitised (turned into a number).