Definitions Flashcards
Active Sources
Monitors, projectors
Emits wave lengths
Passive Sources
Printed documents
Absorbs/ reflects light
HSL
Hue
Saturation
Lightness
Size of visible light
400-700nm
Order of colour sensitivity
Green
Red
Blue
Half-Toning
Uses dots
One colour per ink pass
Dithering
Diffusion of coloured pixels
Uses different algorithms
GIF
Graphical Interchange Format
Palette Colour
LZW compression
Transparency
PNG
Portable Network Graphic
Lossless
True colour
Transparency
TIFF
Tagged Image File Format
Adobe
Any image
Variety of compression
JPEG
Joint Photographic Expert Group True Colour 1: Y Cr Cb 2: Chroma subsampled 3: DCT intensity -> frequency 4: Quantised 5: Huffman Compression
Huffman Compression
Replaces frequently occurring pixel values with shorter code
LZW
Replaces sequences in the data with a code that points to a dictionary
MPEG
Moving Picture Expert Group
Temporal compression: removes data that doesn’t change
Spatial Compression: motion vectors
I frames, B frames, P frames
FFT
Fast Fourier Transform
Spatial Convolution
Smoothing/ sharpening
Acoustics
When objects move it forces air to move causing compression in the molecules
Wavelength
Distance travelled through one cycle of pressure
Frequency
number of vibration cycles that pass a point in a second
Bandwidth
Difference between max and min rate
Amplitude
Strength/ power
Pressure displacement
Pascal
Treble
Short waves
Easily blocks
Human hearing directionally sensitive
Surround sound
Bass
Long wavelength
Easily bends
Human hearing not directionally sensitive
Sampling
Low pass filtering
Nyquist
Audio Compression
Threshold of hearing Amplitude masking Temporal masking Critical band Perceptual code
