astr-1101
cpsc-1480
- Chapter 3 reading
- Lecture outcomes
- Distinguish analog vs digital
- Explain compression and calculate compression ratios
- Do text compression
- Explain the nature of sound
- Explain how RGB define color
- Distinguish between raster/vector graphics Todo
- Explain temporal/spatial video compression
- Data
- Values or facts
- Can be unstructured
- Lack context
- All data is stored as binary digits (bits)
- Information
- Data organized and/or processed in a way that is useful in solving some kind of problem
- Analog vs digital
- Analog --> infinite
- Continuous representation
- Analogous to actual information it represents
- Digital --> finite
- Computers are limited by memory
- Represent enough of the world to satisfy computational needs and our senses
- Discrete representation
- We can only represent data with
0s and 1s
- Breaks up information in separate elements
- Electronic signals
- Analog signal continually fluctuates in voltage
- Digital signal has only high or low state
- Corresponds to two binary digits
- All electronic signals degrade as the move
- Voltage signal fluctuates due to environmental effects
- Audio information
- Digitized by:
- Sampling --> periodically measure the voltage
- Quantization --> represent voltage as a number using finite number of bits
- Color depth