CIS 1 - Kurtz  Santa Monica College 

DIGITAL MEDIA

 

Pixel

Picture Element
Very small dot or rectangle containing a single color
Pixels are “on” or “off” in monochrome displays

Bitmap Graphic

A grid of pixels

Vector Graphic

Formed from “vectors,” lines and shapes which may colored
Contains instructions to create a graphic, rather than individual pixel data

Color Number

An integer associated with a pixel
Contains a code for the color of that pixel
Relates the pixel color to the Color Palette

Color Intensity

A high value assigned to a red, green, or blue signal represents a large amount of that color in the mix
A low value assigned to a red, green, or blue signal represents a small amount of that color in the mix (zero indicates the absence of that color)

Color Palette

A table containing all available color numbers and associated RGB values

RGB Value

A set of three integers containing the intensity of the Red, Green, and Blue levels for a particular color number.
There are typically 256 possible values for each Red, Green, or Blue

0 represents the absence of color

255 is the highest intensity for that color

Scanner

Creates a bitmap by scanning, then digitizing and image

Camera

Creates a bitmap by digitize the image on its sensor

Bitmap Graphic Editors

Called paint programs

Stores screen images in memory as grids of squares representing individual pixels (bitmaps)

Like a toolbox of brushes capable of coloring squares on a sheet of graph paper

Quickest way to create freehand artwork

Only way to retouch photographs

Enlarging may result in jaggies

Vector Graphic Editors

Called Draw Programs

Manipulate Objects as collections of Vectors

More complex and difficult to use than bitmap editors, but more powerful

As drawings are scaled up, the computer or printer recalculates the vectors and produces clean images

Bitmap Graphic Formats

BMP, PCX, TIFF, JPG, GIF, PNG

Vector Graphic Formats

WMF, DXT, MGX, EPS, PICT, CGM

Gradients

Color shadings that make objects more life-like and lend a 3-D effect

3-D Graphics

Three Dimensional Vector Graphics
Wire frame vector graphics are constructed, then rendered into a bitmap to add a realistic surface
Ray tracing adds shadows, highlights, etc.

Video File Formats

AVI, MOV, MPEG, RM, ASF, WMV, FLV, VOB

Quicktime (MOV), Moving Pictures Experts Group (MPEG), Real Media (RM) and Windows Video (WMV) are used on websites and will work across platforms

Streaming Video

Commonly used on the web
Small segments of a video are sent to the web browser in series ("streamed")

Web Cam

Small digital camera
Easily creates low quality video streams

Most often used for conferencing and for creating “talking head” videos.

Connected directly to the computer.

Digital Video Camera

Stores video as a series of bits

Record on tape

miniDV, DVCPro, DVCam

Higher quality than analog

Analog Video Camera

Record to tape

Hi8, S-VHS, VHS

Video Capture Card is required

Analog to Digital technique involves sample and hold

Codec

Compressor/Decompressor Software
MPEG, Indeo, Cinepak, DivX, Video1

MIDI Music

Musical Instrument Digital Interface

Standard for interfacing with instruments

Standard for storing and synthesizing music

.mid, .cmf, .rol file extensions

Specs for pitch, start time, duration, instrument

Very compact, but may not sound “real”

Not suitable for vocals

Speech Recognition

Speech recognition software parses speech into phonemes

Phonemes are grouped and compared to a dictionary

Context sensitivity is now available

Necessary for hands free mobile communications

 

Speech Synthesis

Speech synthesizers assemble strings of phonemes, convert to text, then “read”

IVR (Interactive Voice Response) systems

E-mail readers for mobile user

Adaptive devices and software for the visually impaired (e.g.,JAWS)