Computer Science. The English Language Perspective - Беликова (1176925), страница 36
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andnatural objects and phenomena, such as the human eye orwater surfaces.A digital image is a representation of a two-dimensional imagein binary format as a sequence of ones and zeros. Digital imagesinclude both vector images and raster images, but raster imagesare more commonly used.PixelIn the enlarged portion of the image individual pixels arerendered as squares and can be easily seen.In digital imaging, a pixel (or picture element) is a single pointin a raster image.
Pixels are normally arranged in a regular 2dimensional grid, and are often represented using dots orsquares. Each pixel is a sample of an original image, wheremore samples typically provide a more accurate representationof the original. The intensity of each pixel is variable; in colorsystems, each pixel has typically three components such as red,green, and blue.GraphicsGraphics are visual presentations on some surface, such as awall, canvas, computer screen, paper, or stone to brand, inform,illustrate, or entertain.
Examples are photographs, drawings,line art, graphs, diagrams, typography, numbers, symbols,geometric designs, maps, engineering drawings, or otherimages. Graphics often combine text, illustration, and color.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 or213effective communication may be the objective, association withother cultural elements may be sought, or merely, the creationof a distinctive style.RenderingRendering is the process of generating an image from a model(or models in what collectively could be called a scene file), bymeans of computer programs.
A scene file contains objects in astrictly defined language or data structure; it would containgeometry, viewpoint, texture, lighting, and shading informationas a description of the virtual scene. The data contained in thescene file is then passed to a rendering program to be processedand output to a digital image or raster graphics image file. Therendering program is usually built into the computer graphicssoftware, though others are available as plug-ins or entirelyseparate programs.
The term "rendering" may be by analogywith an "artist's rendering" of a scene. Though the technicaldetails of rendering methods vary, the general challenges toovercome in producing a 2D image from a 3D representationstored in a scene file are outlined as the graphics pipeline alonga rendering device, such as a GPU. A GPU is a purpose-builtdevice able to assist a CPU in performing complex renderingcalculations. If a scene is to look relatively realistic andpredictable under virtual lighting, the rendering softwareshould solve the rendering equation. The rendering equationdoes not account for all lighting phenomena, but is a generallighting model for computer-generated imagery.
'Rendering' isalso used to describe the process of calculating effects in a videoediting file to produce final video output.3D projection3D projection is a method of mapping three dimensional pointsto a two dimensional plane. As most current methods fordisplaying graphical data are based on planar two dimensionalmedia, the use of this type of projection is widespread,especially in computer graphics, engineering and drafting.214Ray tracingRay tracing is a technique for generating an image by tracingthe path of light through pixels in an image plane.
Thetechnique is capable of producing a very high degree ofphotorealism; usually higher than that of typical scanlinerendering methods, but at a greater computational cost.ShadingShading refers to depicting depth in 3D models or illustrationsby varying levels of darkness. It is a process used in drawingfor depicting levels of darkness on paper by applying mediamore densely or with a darker shade for darker areas, and lessdensely or with a lighter shade for lighter areas. There arevarious techniques of shading including cross hatching whereperpendicular lines of varying closeness are drawn in a gridpattern to shade an area. The closer the lines are together, thedarker the area appears.
Likewise, the farther apart the linesare, the lighter the area appears. The term has been recentlygeneralized to mean that shaders are applied.Texture mappingTexture mapping is a method for adding detail, surface texture,or colour to a computer-generated graphic or 3D model. Itsapplication to 3D graphics was pioneered by Dr. EdwinCatmull in 1974. A texture map is applied (mapped) to thesurface of a shape, or polygon. This process is akin to applyingpatterned paper to a plain white box.
Multitexturing is the useof more than one texture at a time on a polygon. Proceduraltextures (created from adjusting parameters of an underlyingalgorithm that produces an output texture), and bitmaptextures (created in an image editing application or importedfrom a digital camera) are, generally speaking, commonmethods of implementing texture definition on 3D models incomputer graphics software, while intended placement oftextures onto a model's surface often requires a techniqueknown as UV mapping (arbitrary, manual layout of texture215coordinates) for polygon surfaces, while NURBS surfaces havetheir own intrinsic parameterization used as texturecoordinates.3D modeling3D modeling is the process of developing a mathematical,wireframe representation of any three-dimensional object,called a "3D model", via specialized software. Models may becreated automatically or manually; the manual modelingprocess of preparing geometric data for 3D computer graphicsis similar to plastic arts such as sculpting.
3D models may becreated using multiple approaches: use of NURBS curves togenerate accurate and smooth surface patches, polygonal meshmodeling (manipulation of faceted geometry), or polygonalmesh subdivision (advanced tessellation of polygons, resultingin smooth surfaces similar to NURBS models).
A 3D model canbe displayed as a two-dimensional image through a processcalled 3D rendering, used in a computer simulation of physicalphenomena, or animated directly for other purposes. Themodel can also be physically created using 3D Printing devices.Notes:Pixel- Пиксель (пиксел) — наименьший элементизображения или экрана в виде квадратика (квадратнойточки), который может иметь индивидуальные параметры:яркость, цвет и др. Размер пикселя может быть разным взависимости от величины изображения и его разрешения,т. е.
количества пикселов из которых оно состоит.GPU (Graphics Processing Unit) - графический процессор.Он являет собой отдельное устройство игровой приставки,компьютера, фотоаппарата. Отвечает за рендерингграфики, выполняет его.NURBS models - Non-Uniform Rational B-Spline неоднородные рациональные B-сплайны. NURBS-кривые216обладают одной особенностью: они всегда имеют гладкуюформу.Rendering - ре́ндеринг (англ.
rendering — «визуализация»)— термин в компьютерной графике, обозначающийпроцесс получения изображения по модели с помощьюкомпьютерной программы.Assignments1. Translate the sentences from the texts into Russian inwriting paying attention to the underlined words andphrases:1.
A digital image is a representation of a two-dimensionalimage in binary format as a sequence of ones and zeros.2. Digital images include both vector images and rasterimages, but raster images are more commonly used.3. Graphic design may consist of the deliberate selection,creation, or arrangement of typography alone, as in abrochure, flier, poster, web site, or book without anyother element.4.
3D modeling is the process of developing amathematical, wireframe representation of any threedimensional object, called a "3D model", via specializedsoftware.5. Models may be created automatically or manually; themanual modeling process of preparing geometric datafor 3D computer graphics is similar to plastic arts suchas sculpting.2. Answer the following questions:1. What is the pixel`s representation?2. What is the method of 3D projection?3. Who was the pioneer of texture mapping?2174. What are the techniques of shading?5. Give the description of 3D modeling process.3.
Translate into English:Трёхмернаяграфикаобычноимеетделосвиртуальным, воображаемым трёхмерным пространством,которое отображается на плоской, двухмерной поверхностидисплея или листа бумаги. В настоящее время известнонесколько способов отображения трехмерной информациив объемном виде, хотя большинство из них представляетобъёмные характеристики весьма условно, посколькуработают со стереоизображением. Из этой области можноотметить стереоочки, виртуальные шлемы, 3D-дисплеи,способные демонстрировать трехмерное изображение.Несколько производителей продемонстрировали готовые ксерийному производству трёхмерные дисплеи. Однако и3D-дисплеи по-прежнему не позволяют создаватьполноценнойфизической,осязаемойкопииматематическоймодели,создаваемойметодамитрехмерной графики.4.
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