Introduction to Computer Graphics

Overview of Key Concepts in Computer Graphics

What is an Image?

An image consists of objects, lighting, and a viewer (or camera), representing visual information in digital or traditional mediums like films or paintings. Digital images can be obtained via scanners and digital cameras.

Image Synthesis

Image synthesis refers to the construction of images from scratch rather than processing existing images. Rendering is the term used most commonly to describe the synthesis of a 2D image from a 3D scene description.

Definition of Computer Graphics (CG)

Computer graphics (CG) encompasses the generation, storage, and manipulation of images and models using computers. It focuses on producing 2D images from 3D models and involves both the tools for creating images and their effective representation.

Main Tasks of Computer Graphics

  • Modeling: Creating and representing the geometry of objects in 3D space.

  • Rendering: Generating 2D images from 3D object descriptions, taking into account aspects like light and perspective.

  • Animation: Describing how objects evolve over time, contributing to movement and interaction within graphics.

Differences Between 2D and 3D Graphics

  • 2D Graphics: Represent images that lack depth; they only contain (x, y) coordinates with color values.

  • 3D Graphics: Involves representation of objects in three dimensions (x, y, z), hence providing a notion of depth and perspectives.

Importance of Computer Graphics

Computer graphics enable efficient visual representation production across various applications like user interfaces, simulations, virtual reality, and entertainment. They are essential for conveying complex data through visualization techniques, graphs, and charts.

Applications of Computer Graphics

  • Data Visualization: Aiding in understanding and analyzing complex processes through visual techniques.

  • Computer-Aided Design (CAD): A vital tool for engineering and architectural design.

  • Virtual Reality (VR): Enabling immersive experiences where users interact with 3D environments.

  • Medical and Scientific Visualization: Transforming raw scientific data into understandable images that can improve analysis and understanding.

Distinction Between Computer Graphics and Computer Vision

While computer graphics involves creating images, computer vision focuses on interpreting and analyzing real-world images. It extracts useful information from images for tasks like medical analysis and autonomous driving.

Interactive vs Non-Interactive Computer Graphics

  • Interactive Graphics: They allow real-time user interaction, necessary for applications like video games and simulations. They require systems that can respond quickly to user inputs.

  • Non-Interactive Graphics: These graphics do not respond to user input after initial creation, applicable in animated films and presentations where high-quality rendering predates user interaction.

Conceptual Framework for Interactive Graphics

This system comprises several components: the application model which holds the data, a graphics library that bridges the application and hardware, and the graphics system which includes the GPU executing rendering commands. The interaction of user inputs changes the displayed image or model.

Graphics Libraries

Graphics libraries such as OpenGL provide a suite of functions for creating graphical content, including basic primitives like points, lines, and polygons, as well as advanced materials and transformations. They generally operate in immediate or retained modes, determining how graphics are processed and displayed.

Basic Command Types in Graphics Libraries

  • Primitives: Basic elements (points, lines, polygons).

  • Attributes: Material properties, such as color and line style.

  • Transformations: Facilitate the movement and alteration of graphics in a scene.

Basic Components of a Graphics System

A graphics system typically comprises:

  1. Input Devices: Hardware to capture user commands.

  2. Central Processing Unit (CPU): Executes normal and graphical processing.

  3. Graphics Processing Unit (GPU): Accelerates image generation and rendering.

  4. Memory: Stores graphics and data.

  5. Frame Buffer: Manages pixel storage for image rendering.

  6. Output Devices: Devices that display images generated.

Common Display Technologies

These include CRT, LCD, LED, and OLED displays. Each technology varies notably in how they render images, with CRT using electron beams and OLED producing images through emitted light from individual pixels. Each has its strengths and weaknesses regarding image quality, power consumption, and physical size.