COMPUTER GRAPHICS
Computer graphics have come a long way since their inception in the mid-20th century. From simple line drawings to advanced 3D models, computer graphics have become a vital component of modern technology, used in everything from video games to scientific simulations.
The earliest computer graphics were created in the 1950s and 60s using vector graphics and cathode ray tube displays. These early graphics were often used for scientific or engineering applications, such as creating models of physical systems or displaying data in a visual format.
The 1970s saw the emergence of raster graphics, which allowed for more complex images to be created using pixels rather than lines. This led to the development of early video games and the first digital special effects in movies.
The 1980s and 90s saw the rapid growth of computer graphics technology, with the development of 3D modeling and animation software. This technology was used to create groundbreaking movies such as "Toy Story" and "Jurassic Park", as well as to design cars, buildings, and other products.
Today, computer graphics technology has become even more advanced, with the ability to create photorealistic renderings and virtual reality experiences. Computer graphics are used in everything from entertainment to medicine, allowing doctors to simulate surgical procedures and scientists to visualize complex data sets.
The importance of computer graphics in modern technology cannot be overstated. They allow us to create and interact with digital environments in ways that were previously impossible, and they have revolutionized fields such as architecture, engineering, and medicine.
Furthermore, computer graphics have also become an important tool for artists, allowing them to create digital paintings and sculptures, as well as to design video games and other interactive experiences.
In conclusion, the evolution of computer graphics has been a remarkable journey, with new advancements and applications constantly being developed. As technology continues to advance, it is clear that computer graphics will remain a critical component of our digital world, enabling us to explore, innovate, and create in ways that were once unimaginable.
Types of computer graphics:-
Raster graphics
A raster graphic is essentially a 2D image composed of rows and columns of square pixels. Each pixel contains information about color and hue. When combined, pixels form a coherent image. The more pixels per inch the more high-resolution an image. A high-resolution raster graphic will appear sharper and more true-to-life than one with low resolution.
Vector graphics
A vector graphic is made up of shapes and lines. Mathematical formulas determine how the shapes and lines relate to each other, so that you can scale vector graphics larger or smaller in size without distorting the shape or resolution.
CGI, or computer-generated imagery, turns 2D vector graphics into 3D representations and converts them into raster images. CGI is used in TV, film, or video games to depict characters, scenes, and special effects.
Interactive computer graphics:-
Interactive computer graphics allow a user to tell a computer how to generate an image. Here’s a sampling of what you can do in interactive computer graphics:
Non-interactive computer graphics:-
Concepts and principles:-
Pixel:-
In the enlarged portion of the image individual pixels are rendered as squares and can be easily seen.
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In digital imaging, a pixel (or picture element[24]) is a single point in a raster image. Pixels are placed on a regular 2-dimensional grid, and are often represented using dots or squares. Each pixel is a sample of an original image, where more samples typically provide a more accurate representation of the original. The intensity of each pixel is variable; in color systems, each pixel has typically three components such as red, green, and blue.
Graphics are visual presentations on a surface, such as a computer screen. Examples are photographs, drawing, graphics designs, maps, engineering drawings, or other images. Graphics often combine text and illustration. Graphic design may consist of the deliberate selection, creation, or arrangement of typography alone, as in a brochure, flier, poster, web site, or book without any other element. Clarity or effective communication may be the objective, association with other cultural elements may be sought, or merely, the creation of a distinctive style.
Primitives:-
Primitives are basic units which a graphics system may combine to create more complex images or models. Examples would be sprites and character maps in 2D video games, geometric primitives in CAD, or polygons or triangles in 3D rendering. Primitives may be supported in hardware for efficient rendering, or the building blocks provided by a graphics application.
Rendering:-
Rendering is the generation of a 2D image from a 3D model by means of computer programs. A scene file contains objects in a strictly defined language or data structure; it would contain geometry, viewpoint, texture, lighting, and shading information as a description of the virtual scene.[25] The data contained in the scene file is then passed to a rendering program to be processed and output to a digital image or raster graphics image file. The rendering program is usually built into the computer graphics software, though others are available as plug-ins or entirely separate programs. The term "rendering" may be by analogy with an "artist's rendering" of a scene. Although the technical details of rendering methods vary, the general challenges to overcome in producing a 2D image from a 3D representation stored in a scene file are outlined as the graphics pipeline along a rendering device, such as a GPU. A GPU is a device able to assist the CPU in calculations. If a scene is to look relatively realistic and predictable under virtual lighting, the rendering software should solve the rendering equation. The rendering equation does not account for all lighting phenomena, but is a general lighting model for computer-generated imagery. 'Rendering' is also used to describe the process of calculating effects in a video editing file to produce final video output.
3D projection
3D projection is a method of mapping three dimensional points to a two dimensional plane. As most current methods for displaying graphical data are based on planar two dimensional media, the use of this type of projection is widespread. This method is used in most real-time 3D applications and typically uses rasterization to produce the final image.
Ray tracing
Ray tracing is a technique from the family of image order algorithms for generating an image by tracing the path of light through pixels in an image plane. The technique is capable of producing a high degree of photorealism; usually higher than that of typical scanline rendering methods, but at a greater computational cost.
shading:-
Shading refers to depicting depth in 3D models or illustrations by varying levels of darkness. It is a process used in drawing for depicting levels of darkness on paper by applying media more densely or with a darker shade for darker areas, and less densely or with a lighter shade for lighter areas. There are various techniques of shading including cross hatching where perpendicular lines of varying closeness are drawn in a grid pattern to shade an area. The closer the lines are together, the darker the area appears. Likewise, the farther apart the lines are, the lighter the area appears. The term has been recently generalized to mean that shaders are applied.
Texture mapping:-
Texture mapping is a method for adding detail, surface texture, or colour to a computer-generated graphic or 3D model. Its application to 3D graphics was pioneered by Dr Edwin Catmull in 1974. A texture map is applied (mapped) to the surface of a shape, or polygon. This process is akin to applying patterned paper to a plain white box. Multitexturing is the use of more than one texture at a time on a polygon.[26] Procedural textures (created from adjusting parameters of an underlying algorithm that produces an output texture), and bitmap textures (created in an image editing application or imported from a digital camera) are, generally speaking, common methods of implementing texture definition on 3D models in computer graphics software, while intended placement of textures onto a model's surface often requires a technique known as UV mapping (arbitrary, manual layout of texture coordinates) for polygon surfaces, while non-uniform rational B-spline (NURB) surfaces have their own intrinsic parameterization used as texture coordinates. Texture mapping as a discipline also encompasses techniques for creating normal maps and bump maps that correspond to a texture to simulate height and specular maps to help simulate shine and light reflections, as well as environment mapping to simulate mirror-like reflectivity, also called gloss.
Anti-aliasing:-
Rendering resolution-independent entities (such as 3D models) for viewing on a raster (pixel-based) device such as a liquid-crystal display or CRT television inevitably causes aliasing artifacts mostly along geometric edges and the boundaries of texture details; these artifacts are informally called "jaggies". Anti-aliasing methods rectify such problems, resulting in imagery more pleasing to the viewer, but can be somewhat computationally expensive. Various anti-aliasing algorithms (such as supersampling) are able to be employed, then customized for the most efficient rendering performance versus quality of the resultant imagery; a graphics artist should consider this trade-off if anti-aliasing methods are to be used. A pre-anti-aliased bitmap texture being displayed on a screen (or screen location) at a resolution different than the resolution of the texture itself (such as a textured model in the distance from the virtual camera) will exhibit aliasing artifacts, while any procedurally defined texture will always show aliasing artifacts as they are resolution-independent; techniques such as mipmapping and texture filtering help to solve texture-related aliasing problems.
Volume rendering:-
Volume rendered CT scan of a forearm with different colour schemes for muscle, fat, bone, and blood
Volume rendering is a technique used to display a 2D projection of a 3D discretely sampled data set. A typical 3D data set is a group of 2D slice images acquired by a CT or MRI scanner.
Usually these are acquired in a regular pattern (e.g., one slice every millimeter) and usually have a regular number of image pixels in a regular pattern. This is an example of a regular volumetric grid, with each volume element, or voxel represented by a single value that is obtained by sampling the immediate area surrounding the voxel.
3D modeling:-
3D modeling is the process of developing a mathematical, wireframe representation of any three-dimensional object, called a "3D model", via specialized software. Models may be created automatically or manually; the manual modeling process of preparing geometric data for 3D computer graphics is similar to plastic arts such as sculpting. 3D models may be created using multiple approaches: use of NURBs to generate accurate and smooth surface patches, polygonal mesh modeling (manipulation of faceted geometry), or polygonal mesh subdivision (advanced tessellation of polygons, resulting in smooth surfaces similar to NURB models). A 3D model can be displayed as a two-dimensional image through a process called 3D rendering, used in a computer simulation of physical phenomena, or animated directly for other purposes. The model can also be physically created using 3D Printing devices.