Technology-Chapter 8 Flashcards Preview

Fall 2016 > Technology-Chapter 8 > Flashcards

Flashcards in Technology-Chapter 8 Deck (42):
1

Pixels

from picture elements, are small points of colored light arranged in a grid to form a computer display

2

RGB-always in that order

Each pixel is formed from three colors lights: red, green, blue

3

white and black result from,,,

white- high intensity
black-turning off all of them

4

Intensities

All colors are made by using different amounts of intensities by all three lights.

5

Pixels , the light shines directly at our eyes which means

nothing is absorbed nor reflected

6

Thin Film TransiStor (TFT)

A form of liquid crystal display (LCD), known also as active matrix, these are the standard "flat" or "thin" displays used for laptops, phones, and so on.

7

Representing the color os a single pixels requires..

3 bytes

8

Brightness refers to

how close to the white the pixels are

9

Contrast

is the side of the difference between the darkest and lightest portions of the image

10

100%

white point

11

0%

black point

12

gamma point

midpoint

13

The force , or intensity of the push, determines the volume, and the frequency ( the number of waves per second) of the pushes is the ..

pitch

14

analog

the key from a digitization point of view is that the object vibrates continuously, producing a continuously changing wave.

convert data to bits

15

Thomas edison

analog rep.
scratch on a wax cylinder

16

Sample

to take measurements at regular intervals

17

sampling rate

the number of samples in a second

18

Nyquist rule

a sampling rate must be at least twice as fast as the fastest frequency

19

humans can hear

20,000 hz

20

transduscer

converts a sound wave into an electrical wave

21

analog-to-digtal converter (ADC)

digitizing process

an electrical signal is fed into this, which takes the continuos wave and smokes it at regular intervals, outputting for each sample binary numbers

22

Digital-to-analog converter (DAC)

reversed to play sound

The numbers are read from memory into the decompressor which produces binary numbers, they are inputed into this and creates an electrical wave by interpolation between the digital values- that is, filling in or smoothly moving from one value to another.

23

Bits must represent

positive and negative values
the more bits, the more accurate the measurements

24

audio number of bits

16

25

advantages of digital sound

fix and compress it, reproduce exactly

26

compression ratio

number of bits is reduced to about one-tenth of what it was

27

Compression

means to change the representation in order to use fewer bits to store or transmit information

28

Run-length encoding

uses binary numbers to specify how long the first sequence of 0's is , then how long the following sequence of 1's is, then how long the following sequence of 0's is , and so on.

29

Run-length encoding is a lossless compression scheme which means

meaning that the original representation of 0'sand 1's can be perfectly reconstructed from the compressed version.
ex: MP3

30

lossy compression

that the original representation cannot be exactly reconstructed from the compressed form.

31

JPEG

invented by the Joint Photographic Experts Group of the ISO. is a lossy compression technique that exploits the same kinds of "human perception" characteristics that MP3 does, only for light and color.

32

luminance

small changes in brightness

33

chrominance

small differences in color

34

MPEG

Motion Picture Experts Group of the ISO, JPEG-type compression is applied to each frame, but then "interframe coherency" is used.

35

Optical Character Recognition

let you search for a word in the picture, pixel must be converted to text by this process

36

features

When a computer scans a group of pixels looking for edges where the color changes, form these into this, parts of a character to be recognized

37

Classifier

uses the features and matches them to an alphabet to determine which one is close

38

Latency

the time it takes for information to be created or delivered-greatly influences our experience with technology

39

absolute limit

the speed of light, lenders the fastness of seeing an image

40

Bandwidth

a measure of how much information is transmitted per unit of time

41

Bias-Free Universal Medium Principle

bits can represent all discrete information; bits have no inherent meaning

42

Interpretation

the meaning of bits comes from us or by the computer through our programs