Unit 3 - Creating Graphics & Images Bit by Bit

ADT

defines a general data type like list that describes a collection of data without worrying about the specific implementation.

algorithm

a step-by-step procedures for solving a particular problem.

analog

refers to data with values that change continuously, or smoothly, over time like sound and music files

API

for a program or web service defines how other programs can communicate with it and use it.

ASCII

short for American Standard Code for Information Interchange is a character encoding scheme in which each character is represented by a 7-bit (originally) or 8-bit binary sequence. For example, the ASCII sequence 01000001 represents the letter 'A'.

assignment

sets a variable to a value or a mathematical expression.

bit

short for 'binary digit'

bitmap

a type of memory organization or image file format used to store digital images.

byte

equals 8 bits.

cloud computing

relies on sharing resources online on the Internet rather than having data and process located on a personal computer.

comment

a non-executable block of text that can be added to a program to provide clarification and documentation of the code.

computer bug

An informal term for error in computer hardware or software -- the term was coined by Grace Hopper.

concatenation

Putting two strings together to make a new string.

cryptography

means secret writing. It is the science of protecting information by transforming it into an unreadable format.

data abstraction

provides a general way to access a collection of data.

data type

The type of data stored in a variable, for example number, string, boolean, or list.

database

one way to store persistent data. Examples include TinyDB and Firebase.

debugging

The process of removing errors from computer hardware or software.

digital

any system based on discontinuous data or events. Computers are digital machines because at the basic level they can distinguish between just two values, 0 and 1.

digital signal processing

refers to manipulating analog information.

download

to copy data (usually an entire file) from an online source to a personal computer.

even parity

the number of 1s in the sequence add up to an even number.

expression

involves values, variables, and operators for example (a+b)/2

GPS

allows people to pinpoint their geolocation (geographic location) on Earth using satellites.

index

the number or position of an element in the list.

list

In computer science, this stores multiple items under one variable name and uses an index to number and access them.

lossless compression

an algorithm is one in which no data are lost; the original data can be completely recovered.

lossy compression

an algorithm is one in which some data are lost; the original data cannot be completely restored.

megabyte

a unit for characterizing the amount of data. It is roughly 1 million bytes or, more precisely, 2

megapixel

one million pixels, used in reference to the resolution of a graphics device.

modeling

the process of representing a real-world object of phenomenon as a set of mathematical equations.

OCR

the process of reading text from paper and translating the images into a form that the computer can manipulate.

odd parity

the number of 1s in the sequence add up to an odd number.

operator

Symbols like +,-,*,/ used for addition, subtraction, multiplication, division.

parity

In math, this usually means the fact of being even or odd.

parity bit

a bit that acts as a check on a set of binary values, calculated in such a way that the number of 1s in the set plus it should always be even or should always be odd.

pixel

short for 'picture element', is a single physical point in a raster image.

procedural abstraction

in computer science is the practice of organizing and encapsulating algorithms in named procedures that can then be invoked by name. An example would be the 'sqrt(x)', square root of x, which encapsulates the algorithm for calculating the square root of x.

pseudocode

A blend of English and code used to write down an algorithm for a program.

raster

the rectangular area of a display screen actually being used to display images.

refactoring

the process of restructuring program code without changing its basic behavior

render

refers to the process of adding realism to a computer graphics by adding 3-D qualities, such as shadows and variations in color and shade.

run length encoding

A compression algorithm that represents an image in terms of the length of runs of identical pixels

sampling

analog data refers to measuring values of the analog signal at regular intervals (usually in time or space) called samples in order to digitize it into a binary representation.

spam

electronic junk mail or junk newsgroup postings.

steganography

the art and science of hiding information by embedding messages within other, seemingly harmless messages.

string

A sequence of characters that can be stored in a variable or list.

substring

Part of an existing string.

upload

data means to transmit data from a computer to an online repository or service such as a bulletin board service, or drop box, or network.

variable

names a memory location to hold different values in your program.