APCSP unit 1

Binary

A way of representing information using only two options

Bit

A contraction of "Binary Digit"; the single unit of information in a computer, typically represented as a 0 or 1

Byte

8 Bits

Overflow Error

Error from attempting to represent a number that is too large

Round-off Error

Error from attempting to represent a number that is too precise. The value is rounded

Analog Data

Data with values that change continuously, or smoothly, over time. Some examples of analog data include music, colors of a painting, or position of a sprinter during a race

digital data

Data that changes discretely through a finite set of possible values

Sampling

A process for creating a digital representation of analog data by measuring the analog data at regular intervals called samples

Lossless Compression

A process for reducing the number of bits needed to represent something without losing any information. This process is reversible

Lossy Compression

A process for reducing the number of bits needed to represent something in which some information is lost or thrown away. This process is not reversible

Intellectual Property

A work or invention that is the result of creativity, such as a piece of writing or a design, to which one has rights and for which one may apply for a patent, copyright, trademark, etc.

Creative Commons

A collection of public copyright licenses that enable the free distribution of an otherwise copyrighted work, used when an author wants to give people the right to share, use, and build upon a work that they have created

* The digital versions of images we produce differ from the original analog images. Analog images change smoothly and continuously.

With digital images, we are limited by the number of bits we use. Even if we use a lot of bits, we can still only represent a finite number of colors, and gradual color changes can only happen discretely through a finite set of pixels.

So we should understand how sampling, pixels, and binary work together to make a digital approximation of an analog image. We should also understand that while analog images are able to change color values smoothly and continuously, digital images rely on pixels to change from a fixed number of color values discretely using squares of equal size.

We can see that a digital image is made up of several layers that work together to represent the analog image.

This is an example of abstraction because we don’t always look at the details of what’s going on in all of these layers, but they are working behind the scenes.