Data Representation in Computer Science
Digital images are composed of individual pixels pictureelements arranged in a grid pattern. The size of a digital image is determined by multiplying its width and height in pixels. Color depth, measured in bits, defines how many different colors each pixel can represent. Understanding these fundamentals is crucial for AQA GCSE Computer Science Paper 1.
Definition: A pixel is the smallest addressable element in a digital image display, representing a single point of color.
Sound digitization involves two key concepts: sample rate and sample resolution. Sample rate, measured in Hertz Hz, determines how frequently amplitude measurements are taken from an analog sound wave. CD-quality audio typically uses 44,100 Hz. Sample resolution, specified in bits per sample, affects the accuracy of amplitude representation and ultimately the sound quality.
Data compression techniques are essential for managing file sizes effectively. Lossy compression reduces file size by permanently removing some data, making it suitable for images, audio, and video where minor quality loss is acceptable. Lossless compression, conversely, preserves all original data while reducing file size through efficient encoding, making it ideal for text documents and executable files.
Highlight: File size calculation for digital images:
Width × Height × Color depth inbits