Suppose you want to announce or sell something, amuse or persuade someone, explain a complicated system or demonstrate a process.
In other words, you have a message you want to communicate. How do you “send” it? You could tell people one by one or broadcast by radio or loudspeaker. That’s verbal communication.

But if you use any visual medium at all—if you make a poster; type a letter; create
a business logo, a magazine ad, or an album cover; even make a computer printout—you are using a form of visual communication called graphic design.Graphic designers work with drawn, painted, photographed, or computer-generated images (pictures),


but they also design the letterforms that make up various typefaces found in movie credits and TV ads; in books, magazines, and menus; and even on computer screens.

Designers create, choose, and organize these elements—typography, images, and the so-called “white space” around them—to communicate a message.
Graphic design is a part of your daily life. From humble things like gum wrappers to huge things like billboards to the T-shirt you’re wearing, graphic design informs, persuades, organizes, stimulates, locates, identifies, attracts attention and provides pleasure.
Graphic design is a creative process that combines art and technology to communicate ideas.
The designer works with a variety of communication tools in order to convey a message from a client to a particular audience. The main tools are image and typography.

Designers develop images to represent the ideas their clients want to communicate. Images can be incredibly powerful and compelling tools of communication, conveying not only information but also moods and emotions. People respond to images instinctively based on their personalities, associations, and previous experience.
For example, you know that a chili pepper is hot, and this knowledge in combination with the image creates a visual pun.
In the case of image-based design, the images must carry the entire message; there are few if any words to help.
These images may be photographic, painted, drawn, or graphically rendered in many different ways. Image-based design is employed when the designer determines that, in a particular case, a picture is indeed worth a thousand words.

In some cases, designers rely on words to convey a message, but they use words differently from the ways writers do. To designers, what the words look like is as important as their meaning. The visual forms, whether typography (communication designed by means of the printed word) or handmade lettering, perform many communication functions. They can arrest your attention on a poster, identify the product name on a package or a truck, and present running text as the typography in a book does. Designers are experts at presenting information in a visual form in print or on film, packaging, or signs.

When you look at an “ordinary” printed page of running text, what is involved in designing such a seemingly simple page? Think about what you would do if you were asked to redesign the page. Would you change the typeface or type size? Would you divide the text into two narrower columns? What about the margins and the spacing between the paragraphs and lines? Would you indent the paragraphs or begin them with decorative lettering? What other kinds of treatment might you give the page number? Would you change the boldface terms, perhaps using italic or underlining? What other changes might you consider, and how would they affect the way the reader reacts to the content? Designers evaluate the message and the audience for type-based design in order to make these kinds of decisions.

Designers often combine images and typography to communicate a client’s message to an audience. They explore the creative possibilities presented by words (typography) and images (photography, illustration, and fine art). It is up to the designer not only to find or create appropriate letterforms and images but also to establish the best balance between them.

Designers are the link between the client and the audience. On the one hand, a client is often too close to the message to understand various ways in which it can be presented. The audience, on the other hand, is often too broad to have any direct impact on how a communication is presented. What’s more, it is usually difficult to make the audience a part of the creative process. Unlike client and audience, graphic designers learn how to construct a message and how to present it successfully. They work with the client to understand the content and the purpose of the message. They often collaborate with market researchers and other specialists to understand the nature of the audience. Once a design concept is chosen, the designers work with illustrators and photographers as well as with typesetters and printers or other production specialists to create the final design product.

Symbols and logos are special, highly condensed information forms or identifiers. Symbols are abstract representation of a particular idea or identity. The CBS “eye” and the active “television” are symbolic forms, which we learn to recognize as representing a particular concept or company. Logotypes are corporate identifications based on a special typographical word treatment. Some identifiers are hybrid, or combinations of symbol and logotype. In order to create these identifiers, the designer must have a clear vision of the corporation or idea to be represented and of the audience to which the message is directed.

In computer graphics, pictures or graphics objects are presented as o collection of discrete picture elements called pixels. The pixel is the smallest addressable screen element. It is the smallest piece of the display screen which we can control. The control is achieved by setting the intensity and colour of the pixel which compose the screen.

Each pixel on the graphics display does not represent mathematical point. Rather, it represents a region which theoretically can contain a infinite number of points.
The special procedures determine which pixel will the best approximation to the desired picture or graphics object.
The process of determining the appropriate pixels for representing picture or graphics object is known as rasterization, and the process of representing continuous picture or graphics object as a collection of discrete pixels is called scan conversion.
The computer graphics allows rotation, translation, scaling and performing various projections on the picture before displaying it. It also allows to add effects such as hidden surface removal, shading or transparency to the picture before final representation. It provides user the control to modify contents, structure and appearance of pictures or graphics objects using input devices such as a keyboard, mouse, or touch-sensitive panel on the screen. There is a close relationship between the input devices and display devices.
Therefore, graphics devices includes both input devices and display devices.

The computer graphics is a collection, combination and representation of real or imaginary objects from their computer-based models. Thus we can say that computer graphics concerns the pictorial synthesis of real or imaginary objects.
However,the related field image processing or sometimes called picture analysis concerns the analysis of scenes, or the reconstruction of models of 2D or 3D objects from their picture. This is exactly the reverse process.

The image processing can be classified as:
· Image enhancement
· Pattern detection and recognition
· Scene analysis and computer vision

The image enhancement deals with the improvement in the image quality by eliminating noise or increasing image contrast.

Pattern detection and recognition deal with the detection and clarification of standard patterns and finding deviations from these patterns. The optical character recognition (OCR) technology is an practical example of pattern detection and recognition.

Scene analysis and computer vision deals with the

recognition and reconstruction of 3D model of scene from several 2D images.

The above three fields of image processing proved their importance in many area such as finger print detection and recognition, modeling of buildings, ships, automobiles etc., and so on.
We have discussed the two fields : computer graphics and image processing of computer processing of pictures. In the initial stages they were quite separate disciplines. But now a days they use some common features, and overlap between them is growing. They both uses raster displays.

Today, a high quality graphics displays of personal computer provide one of the most natural means of communicating with a computer

It provides tools for producing pictures not only of concrete, ‘real-world’ objects but also of abstract, synthetic objects, such as mathematical surfaces in 4D and of data that have no inherent geometry, such as survey results.
It has an ability to show moving pictures, and thus it is possible to produce animations with interactive graphics.
With interactive graphics use can also control the animation by adjusting the speed, the portion of the total scene in view, the geometric relationship of the objects in the scene to one another, the amount of detail shown and so on.
The interactive graphics provides tool called motion dynamics. with this tool user can move and tumble objects with respect to a stationary observer, or he can make objects stationary and the viewer moving around them. A typical example is walk thorough made by builder to show flat interior and building surroundings. In many case it is also possible to move both objects and view

The interactive graphics also provides facility called update dynamics. With update dynamics it is possible to change the shape, colour or other properties of the objects being viewed. With the recent development of digital signal processing (DSP) and audio synthesis chip the interactive graphics can now provide audio feedback along with the graphical feedbacks to make the simulated environment even more realistic.

In short, interactive graphics permits extensive, high-brand width user-computer interaction. It significantly enhances the ability to understand information, to perceive trends and to visualize real or imaginary objects either moving or stationary in a realistic environment. It also makes it possible to get high quality and more precise result and products with lower analysis and design cost.

The use of computer graphics is wide spread. It is used in various areas such as industry, business, government organizations, education, entertainment and most recently the home. Let us discuss representative uses of computer graphics in brief.

User friendliness is one of the main factors underlying the success and popularity of any system. It is now a well established fact that graphical interfaces provide in attractive and easy interaction between users and computers. The built-in graphics provided with user interfaces use visual control items such as buttons, menus, icons, scroll bar etc, which allows user to interact with computer only by mouse-click. Typing is necessary only to input text to be stored and manipulated.
In industry, business, government and educational organizations, computer graphics is most commonly used to create 2D and 3D graphics of mathematical, physical and economic functions in form of histograms, bars, and pie-chats. These graphs and charts are very useful for decision making.

The desktop publishing on personal computers allow the use of graphics for the creation and dissemination of information. Many organizations does the in-house creation and dissemination of documents. The desktop publishing allows user to create documents which contain text, tables, graphs, and other forms of drawn or scanned images or pictures. This is one approach towards the office automation.

The computer-aided drafting uses graphics to design components and systems electrical, mechanical, electromechanical and electronic devices such as automobile bodies, structures of building, airplane, slips, very large-scale integrated chips, optical systems and computer networks.
Use of graphics in simulation makes mathematic models and mechanical systems more realistic and easy to study. The interactive graphics supported by animation software proved their use in production of animated movies and cartoons films.
There is lot of development in the tools provided by computer graphics. This allows user to create artistic pictures which express messages and attract attentions. Such pictures are very useful in advertising.
By the use of computer now it is possible to control various processes in the industry from a remote control room. In such cases, process systems and processing parameters are shown on the computer with graphic symbols and identification. This makes it easy for operator to monitor and control various processing parameters at a time.
Computer graphics is also used to represent geographic maps, weather maps, oceanographic charts, contour maps, population density maps and so on……….