Multimedia Fundamentals

Multimedia Fundamentals Multimedia means, from the user’s perspective, that computer information can be represented through audio and /or video, in addition to text, image, graphics and animation. For example, using audio and video, a variety of dynamic situations in different areas, such as sports, can often be presented better than just using text and image alone.

Multimedia Fundamentals Computer graphics Computer graphics is the branch of computer science that applies computer technologies to the production and manipulation of visual representations. It is associated with a wide assortment of topics including the presentation of text, the construction of graphs and charts, the development of graphical user interfaces, the manipulation of photographs, the production of video games, and the creation of animated motion pictures.

Multimedia Fundamentals However, the term computer graphics is increasingly being used in reference to the specific field called 3D graphics. In short, 2D and 3D graphics deals with producing images while image processing deals with analyzing images.

2D graphics 艺术字

3D graphics

photograph

Figure 10.2 The 3D graphics paradigm

Figure 10.3 A polygonal mesh for a sphere

Figure 10.8 Specular versus diffuse light

Figure 10.12 A sphere as it might appear when rendered by flat shading

Figure 10.14 A sphere as it might appear when rendered using bump mapping

Multimedia Fundamentals Computer animation Frames : Animation is achieved by displaying a sequence of images, called frames, in rapid succession. These frames capture the appearance of a changing scene at regular time intervals, and thus their sequential presentation creates the illusion of observing the scene continuously over time. The standard rate of display in the motion picture industry is twenty-four frames per second. The standard in broadcast video is sixty frames per second.

Multimedia Fundamentals Frames can be produced by traditional photography or generated artificially by means of computer graphics. Moreover, the two techniques can be combined. For example, 2D graphics software is often used to modify images obtained via photography to remove the appearance of support wires, to superimpose images, and to create the illusion of morphing, which is the process of one object appearing to change into another.

Multimedia Fundamentals key frames: In a project using 2D graphics, the storyboard typically evolves into the final set of frames in much the same way that it did back in the Disney studios of the 1920s. In those days, artists, called master animators, would refine the storyboard into detailed frames, called key frames, that established the appearance of the characters and scenery at regular intervals of the animation.

Multimedia Fundamentals Assistant animators would then draw additional frames that would fill the gaps between the key frames so that the animation would appear continuous and smooth. This fill- in-the-gap process was called in-betweening.

Multimedia Fundamentals to be continue…