What Are Computer Graphics?

Computer Graphics (CG) is a science that uses mathematical algorithms to transform two-dimensional or three-dimensional graphics into a grid form of a computer display. To put it simply, the main research content of computer graphics is to study how to represent graphics in computers and the related principles and algorithms of computing, processing and displaying graphics using computers.

In January 1963, Sutherland, 24, of the MIT Lincoln Laboratory completed

The core goal of computer graphics is to create effective visual communication. In the field of science, graphics can show scientific results to the public through visualization; in the field of entertainment, such as PC games,

The core goal of computer graphics (visual communication) can be decomposed into three basic tasks: representation, interaction, and drawing, that is, how to "represent" and "draw" a colorful subjective and objective world in a computer. The "representation" here is how to put the subjective and objective world into the computer-the representation and modeling of two-dimensional and three-dimensional objects; and "drawing" refers to how to use a visual image of the objects in the computer The way is expresseddrawing of two-dimensional and three-dimensional objects: "Interaction" refers to the technology of realizing "representation" and "drawing" in an effective way through computer input and output devices. Among them, "representation" is the "data layer" of computer graphics, and various geometric representations of objects or objects in the computer; "drawing" is the "view layer" of computer graphics, which refers to the display and display of graphics data come out. "Representation" is modeling and input, and "drawing" is display and output. "Interaction" is the "control layer" of computer graphics. It is responsible for completing effective object input and output tasks and solving interaction problems with users. ^[2]

The main research objects of computer graphics are the mathematical construction methods of points, lines, faces, volumes, and fields, their graphic displays, and their changes at any time. It needs to study the following aspects.

(1) Methods and mathematical algorithms for describing complex object graphics. The representation of 2D and 3D scenes is the premise and basis of computer graphics display, including curve and surface modeling technology, solid modeling technology, and the modeling and simulation of natural scenes such as textures, clouds, and waves; the display of 3D scenes includes raster graphics generation algorithms, Theories and algorithms for wireframe graphics and photorealistic graphics.

(2) Input of object graphic description data.

(3) Storage of geometric and graphic data, including data compression and decompression.

(4) The arithmetic processing of object graphic data, including mixed drawing technology based on images and graphics, natural scene simulation, graphical user interface,

With the continuous development of computer graphics, its application range is becoming wider and wider. The main application areas of computer graphics are as follows.

1. Computer Aided Design and Manufacturing (CAD / CAM)

This is the most extensive and important application area of computer graphics. It has made a huge change in the method of engineering design. The use of interactive computer graphics generation technology for the design of civil engineering, mechanical structures and products is rapidly replacing the traditional manual design method of drawing board processing characters, and shoulders the heavy daily drawing. Optimization of tasks and overall design and detailed design work. In fact, a complex large-scale or ultra-large-scale integrated circuit board is impossible to design and draw by hand. Computer graphics systems can not only design and draw pictures, but also can be completed in a short period of time. The results are directly sent to subsequent processes. For processing.

2. Computer Aided Instruction (CAI)

In this field, graphics is an important means of expression. It can make the teaching process visual, intuitive and vivid, stimulate students' interest in learning, and greatly improve the teaching effect. With the continuous popularization of microcomputers, computer-aided teaching systems have penetrated into the home.

3 Computer animation

Traditional cartoons are drawn by hand. Since the animation requires 24 frames per second, the manual drawing work is quite heavy. For computer-made animation, you only need to generate a few pictures called "key frames", and then the computer interpolates the two key frames to generate a number of "intermediate frames". The two key frames are organically combined during continuous playback. . This can greatly save time and improve the efficiency of animation production.

4 Management and office automation

Computer graphics is most commonly used in the field of management and office automation to draw various graphics, such as two-dimensional and three-dimensional graphics of statistical data, pie charts, line charts, straight-line charts, etc. It can also draw work process charts, production scheduling charts , Stock map, etc. All of these graphs present data models and trends in a concise form, speeding up decision making and execution.

5. Land information and natural resource display and mapping

The Land Information and Natural Resources System organizes past scattered books, photos, drawings and other data into a unified database that records the country's geodetic and gravity survey data, mountain and plain terrain, rivers and lakes, rivers and lakes, roads and bridges, urban villages, and farmland and forest land Vegetation, national and regional boundaries, and place names. Using these stored information can not only draw a flat map, but also generate a three-dimensional topographic map, providing scientific basis for high-level land remediation prediction and decision-making, comprehensive management and resource development research.

6. Visualization of scientific computing

In the information age, large amounts of data need to be processed. The visualization of scientific computing is to use computer graphics to visually represent the intermediate or final results of scientific computing and the data obtained through measurement in the form of graphics. Visualization of scientific computing is widely used in many fields such as meteorology, earthquakes, astrophysics, molecular biology, and medicine.

7. Computer games

Computer games have become a major source of power to promote the research of computer graphics, especially the development of graphics hardware. Computer graphics provides technical support for computer game development, such as the creation of a three-dimensional engine. The two major graphics issues of modeling and rendering are very important in game development.

8. Virtual Reality

The application of virtual reality technology is very wide, and it can be used in military, medical, education and entertainment fields. Virtual reality is to enable people to get immersed in the virtual atmosphere created by computers through the eyes, helmets, or data gloves with vision, hearing, smell, touch and shape or gesture Experience. For example, walking into the microcosm of the molecular structure, and wandering in the newly designed building building graphics. This has also become one of the research hotspots of computer graphics in recent years. ^[4]