Computer Graphics and its types

Computer Graphics, Types of Computer Graphics, Applications of Computer Graphics

Introduction

Computer graphics is a field of computer science that deals with creation, manipulation and storage of pictures, images and drawing using a digital computer. Computer graphics provide an effective method to represent data in form of pictures and images such as graphs, charts thereby enhancing the communication between the computer and its users. Graphic displays also improves understanding of complex systems, and visualization of two dimensional (2D), three dimensional (3D) objects.

Thus computer graphics is defined as:

Computer Graphics is a pictorial representation and manipulation of data by a computer.

Computer Graphics is the use of computer hardware and software to create, manipulate and present pictures and images.

Computer graphics is a branch that deals with producing pictures or images using a computer including modeling – creation, manipulation and storage of geometric objects and rendering – converting a scene to an image, or the process of transformation, rasterization, shading, illumination and animation of the image. Today, computer graphics is widely used in various fields such as entertainment, advertisement, medicine, science, engineering, research, government work, education and training, industry and communication.

Computer graphics is particularly used in the field of architectural system. engineering and designing. It is most commonly used in designing various items like aircraft, automobiles, machine parts, building. This field is known as computer aided design (CAD). Graphics systems are also used for applications like animation, film industry, image processing, simulation, morphing etc.

Types of Computer Graphics

There are two types of Computer Graphics:

Passive Graphics
Active Graphics

1. Passive Graphics

Passive graphics is also known as non-interactive computer graphic. In this types of passive computer graphics user has no control over the graphics such as image because there is no interaction between the user and hardware. Examples of this type of computer graphics include the titles shown on TV and other forms of computer art. Such a non-interactive graphics support one way communication as graphics work according to the pre-stored program instructions. User has no control over these instructions. In passive graphics user cannot control motion of any object and not even change or update any object in scene. For example, a screen saver.

2. Active Graphics

Active graphics is also known as interactive computer graphics. These graphics are dynamic in nature and provides user complete control over the graphical images, animations etc. using some input device. The user thereby send signals to computer via input device that leads to changes in graphics as desired by him. Thus, active graphics is an interactive in nature as it involves user interaction in controlling the graphics.

For example, when a user plays a video game he/she can change the position of a player using joystick. As a result, interactive computer graphics involves two-way communication. Now-a-days interactive computer graphics is being used in various fields such as simulation (e.g. flight simulators for training pilots), virtual reality, image processing, education, entertainment, animation etc. Active or interactive graphics provide several benefits as compared to passive graphics such as better quality images, low cost, low analysis and higher productivity. Thus, interactive computer graphics allows comprehensive, high-bandwidth, user computer interactions that helps the user in better understanding of data and better visualization of real or imaginary objects.

Applications of Computer Graphics

With the advancement in graphics technology, now-a-days none of the field has remained untouched by computer graphics. Some of the areas where computer graphics extensively uses discussed in the subsequent sections.

1. Computer Aided Design (CAD)

Computer graphics is most commonly use for designing new products in engineering and architectural field. Such a method used for designing, called Computer Aided Design (CAD). CAD technique is use for designing various parts of automobiles, aircrafts, building, space crafts, ships, textiles and many other products. In such a technique designing and related drafting can done on computer system that involves user interaction. Such a designing can done using basic concepts and design procedures. Thereafter expert systems are use for developing and gradually refining the design to obtain the final product.

2. Entertainment

Computer graphics is most commonly used in the field of entertainment for creating movies, animation and cartooning, video games and music videos. Computer animation developed by placing pictures or figures one after another on the screen at a very fast rate. This may be of automatic or interactive type. In automatice type of animation, figures are move along a path that is previously define by mathematical equations and does not involve any use interaction to run. On the other hand, in interactive animation user controls the movement of pictures at the time of execution of the program. Several different Hollywood movies use animations and special effect to create visually better scenes.

The movies like The Mummy, Jurassic Park and the Lost World have used these animations. Another special effect used in motion pictures is morphing. Morphing is a technique by which one object or image can transformed into another in such a manner that the change appears to be smooth and not rapid. Morphing has used in advertisements, movies. Some of the popular examples of movies where morphing has been used are Terminator and Matrix.

3. Education and Presentation

Now-a-days computer extensively used in teaching/learning process for all ages of people. Graphics systems and software’s are use not only for kindergarten children to Teach them the repetitive tasks but also for adult executive to provide professional training. Computer graphics is use to create models of physical, financial, science and arts concepts to teach students in an interesting way. Also, the computer graphics tools such as Microsoft PowerPoint is commonly use in teaching, seminars and conference presentations for teaching various subjects at various levels. Presentation graphics are commonly use to summarize financial, statistical mathematical, scientific and economic data in form of pie charts, bar charts line graphs, surface graphs etc. that helps in establishing relationship between various parameters.

4. Simulation and Virtual Reality

Virtual Reality is an artificial environment that is created with computer hardware and software and is presented to a user in such a way that it appears and feels like a real environment. Computer graphics is extensively use in virtual reality with such a representation a user can actually participate in and act out fantasies with full colors, shades, sound and touch effects. Such a system can used for training, experimentation, entertainment and gaming etc. An important element of virtual reality is simulation.

Simulation is a technique that enables expensive and complex phenomena and processes to be model in the computer and represent it pictorially to a user. Simulation techniques are use for training aircraft and ship pilots, astronauts, and automobile drivers before undertaking a venture in real environment. In medical colleges, students taught to operate a body in simulated environment on computers before entering the operation theatres.

5. Medical Applications

Computer graphics also used in medical field by doctors, surgeons for the diagnosis and treatment of various problems in human body. CAT (Computerized Axial Tomography) scan used to produce 2D or 3D images of cross section of specific organs and limbs. For example, CAT scan used to detect tumors in human brain. Besides this, computer graphics has used to create virtual anatomical atlas on CD-ROM and DVD along with various kind of simulation and training software’s. This Applications of Computer Graphics is very helpful in medical fields.

6. Visualization

Visualization is the process of representing data as descriptive images. These images are then use in interactive manner to gain additional insight into the data. Visualization techniques used by scientists, engineers medical personnel’s, business analyst etc. in order to study the behavior of certain processes and to analyze large amount of information (For example, data from satellite cameras). Such visualization helps them to find trends and patterns. Another method of visualization, called isosurface used in computational fluid dynamics. It allows the engineers to study features of fluid flow (gas or liquid) around objects such as aircraft wings.

Volume rendering technique of visualization used to display a 2D projection of a 3D discretely sampled data set. A typical 3D data set is a group 2D slice images; acquired by a CT, MRI or MicroCT scanner.

7. Image Processing

Image processing is another applications area of computer graphics. Computer graphics and image processing are the two sides of the same coin. These deals with the synthesis of information to create a picture whereas image processing is a field that deals with manipulation and analysis of existing pictures. The main purpose of image processing is to extract the desired information from an existing image (picture) or to enhance the quality of the picture. Image processing extensively used in the field of remote sensing, weather forecasting, medical science etc. In order to apply image processing, images first converted into a digital form, known as digitization.

Digitization includes sampling of image and quantization of sampled values. After converting the image into bit information (binary form), processing has done. This processing technique may he image enhancement, image reconstruction and image compression. Image processing also used in computer aided surgery. The 2D cross sections of the body obtained using imaging techniques. Medical ultrasonography is another area where image processing is use for imaging fetus in pregnant women. Nuclear medicine also used digital image processing for diagnosis and treatment of diseases in oncology, neurology and cardiology.

8. Graphical User Interface

A graphical user interface (GUI) is a type of user interface that allows people to interact with a computer system by the use of graphical icons. Visual indicators or special graphical elements called “widgets“, along with text and labels. The various actions usually performed through direct manipulation of the graphical elements like windows, buttons, menus, scroll bars etc. These are the main Applications of Computer Graphics.