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5 - 2 Multimedia Application

(1) CG (Computer Graphics)

CG (Computer Graphics) is a technique of drawing images (i.e., graphics) and performing editing by using a computer.

[Software for CG]

• • Painting software
  It is graphics software by which images are drawn in units of dots. The images thus created are called luster graphics. Since images are created by drawing lines with dots on the path traced by the mouse, this software can be used easily even by beginners.
• • Drawing software
  It is graphics software by which images are drawn by calculating the direction and length (i.e., vector data) of lines. The images thus created are called vector graphics. The notches (jaggies) of the lines are not noticeable even when the drawn image is expanded.

[CG techniques]

• • Anti-aliasing
  It is a technique by which the jaggies that occur in slanting lines and curved lines are made inconspicuous. · 1 question
• • Texture mapping
  It is a technique by which a texture is presented by pasting an image or a pattern onto the surface of a modeled object.
• • Blending
  It is a technique by which the information on the degree of transparency is superimposed to represent a translucent image.
• • Ray-tracing
  It is a technique by which a ray of light that has reached the eye point is traced in the reverse manner to perform rendering.
• • Clipping
  It is a technique by which only the portion to be displayed is cut out from the entire image.
• • Shading
  It is a technique of forming shadows on the surface of an object in order to provide the appearance of solidity.
• • Morphing
  

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It is a technique of changing the nodal points to smoothly change from one shape to another.

• • Rendering
  It is a technique of displaying the data of an object as a two-dimensional image or picture.
• • Polygon
  It is a polygon that is used to approximate a closed solid or a curved surface through three-dimensional CG.
• • Key frame method
  It is a method for generating animation by interpolation between key frames.

(2) Three-dimensional picture (3D)

A three-dimensional picture (3D) is a picture (and the technique of creating pictures) that has depth and the appearance of solidity. It is created by three-dimensional computer graphics (3DCG) and motion capture, which uses a technique of attaching a sensor to each joint of a human body, feeding the information, such as coordinates and acceleration, detected by the sensors during movement to a computer, and then converting it into digital data. Moreover, in combination with virtual surround (e.g., a technique of virtually playing back 5.1-ch sound through two speakers or regular headphones), realistic content can be created. · 1 question

(3) VR (Virtual Reality) / AR (Augmented Reality)

VR (Virtual Reality) refers to experiencing the virtual world that is generated by using CG as an actually existing world. On the other hand, AR (Augmented Reality) refers to extension of the real world by combining the real world and VR. In AR, information is added to actually existing things by VR and also emphasized. · 2 questions

(4) Other examples of application

A multimedia system that uses multimedia data, such as moving images, still images, sound, and text, by integrating it on a computer has several application examples.

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• • Internet broadcasting
  It refers to broadcasting through the medium of the Internet.
• • Non-linear image editing system
  It is a method of editing images as digital data on a computer.
• • CAD (Computer Aided Design)
  It is a computer system that supports the design of a product by using the CG techniques.
• • Simulator
  It is a program or mechanism for a simulation approach to complex scientific phenomena that occur in reality. The prediction of the course of a typhoon and the wind tunnel experiment determining how the surrounding air flows when a car is running can be reproduced by the computer.
• • Video game
  It is a game that can be played on the computer.
• • Video on demand
  It is a service that distributes video according to the request of the user.
• • Virtual mall (Cyber mall)
  It is a virtual shopping mall constructed on the Internet. Although there is no shopping mall, it is possible to actually buy real products.