Information representation and multimedia Flashcards
Bit-map images are made up of ________
Pixels
Colour depths
The number of bits used to represent a pixel
Bit depths
It determines the Color depth of that pixel
An increase in bit depth, increases _________
The number of possible colors
Image resolution
The number of pixels that make up an image.
Screen resolution
The number of horizontal & vertical pixels that make up a screen display.
Pixel density
The number of pixels per square inch
How do you calculate the pixel density?
1) add together the squares of the resolution size
2) find the square root
3) divide by the screen size
What are the drawbacks of using high resolution images?
- Increase in file size
- increase in download time
What are 2 things that must be considered when the file size needed to store a bit-map image?
-image resolution
-bit depth
What are vector images?
Images that use mathematical formulas to draw lines and curves that can be combined to create an image
Vector graphics contains a drawing list which are a _______
set of commands used to define a vector image
Vector images tend to be ______ than bitmap images because a bitmap image has to _________ for each individual pixel that forms the image
- smaller
- store color information
A vector image only has to store mathematical formulas that make up the image, which _______
- takes up less space
The 3 most popular image formats used on the web are _________, and are all bitmap formats
- PNG
- JPEG
- GIF
What are vector graphics?
a graphic consisting of components defined by geometric formulae and associated properties, such as line color and style
Sound is an _______ value
analogue
An ______ is used to digitise sound into files
ADC converter
If the sound is going to be used as a sound file, it gets __________
filtered first to remove higher and lower frequencies
_________ is the number of bits used to represent each sample
Sampling resolution
The higher the sample resolution, the better the audio quality.
Because if more bits are available for each sample, ________
then more levels of the signals can be captured, improving the detail of the recording
________ is the number of sound samples taken per second.
The higher the sampling rate and/or sampling resolution, the greater the file size
Sampling rate
How is sampling used to record a sound clip?
1. ________ of the soundwave is _______ at ________
2. (this gives an approx. representation of the sound wave,)
3. Sound wave is then encoded as a series of binary digits
- amplitude
- determined
- set time intervals
how does a microphone digitise sound?
- microphone measures change in air pressure
- microphone translates air pressure into electrical voltage
- ADC digitizes electrical voltage to bytes of info
- computer displays the digitized sound for manipulation
