Computer Graphics

The lecture covers main problems in Computer Graphics. The method of presenting images on raster devices is discussed in details. Image rendering algorithms are presented at different level of details. 2D and 3D viewing are presented starting from the set of transformation and ending with stereovision concept. Basic aspects of colorimetry and its application in rendering colour mages is also included. Hardcopy devices both bilevel and colour are briefly presented.
Exercises are devoted to details of mathematics and algorithms.

Lecture contents

1. General information, organization of lecture, references, questionnairy- knowledge level,
   Basic notions, image, computer graphics, image processing, image analysis, image as matrix, computer graphics hardware- output devices, input devices.


2. Comuter graphics survey, areas of application, display devices, CRT tube, magnetic deflection, random scan devices, raster scan devices, interlaced vs noninterlaced, luminescence, persistence, refresh rate


3. CRT colour tubes, delta, PIL, Trinitron, guns arrangement, triads of phosphors, screen resolution, aspect ratio, square pixels, estimation of timing requirements, video signal, composite signal, video dac, raster generator, structures of display controllers Look Up Table, number of bits per pixel


4. Antialiasing, straightforward supersampling, finite width of line, weighted area sampling, filtering, midpoint algorithm, Piteway-Watkinson algorithm,


5. Polygon filling, scan-line fill, inside-outside test, even-odd rule, winding number, directional edge crossing,


6. scan line fill of curved boundary areas, boundary fill algorithm, 4- and 8-neighbourhood, flood fill algorithm, area fill attributes, mapping patterns into area,


7. depth perception, stereovision,


8. Polygon rendering methods, constant intensity flat shading, Mach bands, Gouraud shading, linear interpolation, bilinear interpolation, Phong shading - normal vector interpolation,


9. Illumination, basic notions, photometry units, perfect diffuser - Lambertian surface, basic illumination models, ambient light, perfect diffuse reflection, specular reflection, transparency, refraction, attenuation with distance, aerial perspective, modelling real light sources,


10. Ray-tracing, basic concept, primary and secondary rays, shadows, soft shadows, ray-surface intersection, bounding volumes, visible surface detection, Z-buffer, object representation, analytical, parametric equations, triangular mesh, sweep representation, Constructive Solid Geometry, octree, volume representation- voxels,


11. Input devices, logical vs physical devices, input modes keyboards, mouse, trackball, bat, digitizers, light pen, 3D scanners, mechanical, optical, interactive drawing techniques,


12. Colour in Computer Graphics, properties of human visual system, receptors, receptor response, colorimetry , visual colorimeter, colour space, tristimuli, matching functions, chromaticity coordinates, chromaticity diagram,


13. Transformation between colorimetry systems, RGB EBU, RGB FCC, Colour monitors, number of colours displayed, HSV model, HLS model,


14. Hardcopy devices, monochromatic printers, bilevel printing,grey scale, colour printers, inkjet, thermosublimation, film recorders


15. Animation, basic problems, physically based movements control, morphing techniques




Tutorial contents
Ex.1. 2D coordinate systems, point, line, plane Euclidean distance, Cartesian coordinate system, polar coordinates, transformation between polar and Cartesian systems, orientation of coordinate system,

Ex.2. 3D coordinate system, right hand, left hand orientation, rule of thumb, spherical coordinates, transformation between polar and Cartesian coordinates, cylindrical coordinates, measures of angle, solid angle,

Ex.3. Points and vectors, method of defining vectors, equivalency of points and vectors, vector addition, vectors in 3D space, vector operations, summing, scalar product, vector product,
Ex.4. Vectors and matrices, row vector, column vector, transposition, multiplication, unitary matrix, determinant, matrix inversion,

Ex.5. Test1

Ex.6. Nonlinearities in display channel, gamma correction, equations for rough and precise correction, use of LUTs for correction, saturation, low level signals, method of estimation average gamma value
Ex.7. 2D geometric transformations, sreen coordinates, matrix notation, placement of the origin of coordinate system, detailed disscussion of transformations, translation, rotation, rotation about arbitrary pivot point, scaling, scaling relative to fixed point,

Ex.8. Homogenous coordinates, translation, rotation, scaling, composite transforrmation, concatenation of transformations, translations, rotations, scalings, reflections, shear,
Concatenation properties, computational efficiency of composite transformations,

Ex.9. Transformations between coordinate systems -2D, change of position, change of orientation, versors of new system,, mirroring about arbitrary line,

Ex.10. Basic raster algorithms, line, circle, ellipse, line equations, slope-intercept, axis crosspoint, implicit form,DDA algorithm, Bresenham line algorithm, Bresenham circle algorithm,

Ex.11. Twodimensional viewing, world coordinates, window, viewport, window to viewport transformations, clipping, line clipping, Cohen-Sutherland algorithm, Lian-Barsky algorithm,
Polygon clipping, Sutherland-Hodgeman algorithm, Weiler_Atherton algorithm

Ex.12. Slide session, images from SIGGGRAPH conference

Ex.13. Three dimensional concepts, 3d transformations, homogenous coordinates, object movements vs coordinate system movements, rotation, directional cosines, Euler angles, aeroplane view, roll, pitch, yaw, carousel, cinecamera crane,

Ex.14. Projections, classification, parallel, orthographic, axonometric, isometric, oblique projections cavalier, cabinet, perspective projections, one, two and three vanishing points,
Equivalence of perspective projections and camera obscura view,

Ex.15. Test2

1. D.Hearn, P.Baker "Computer Graphics", Prentice Hall 1994


2. J.D.Foley,A.vanDam,S.Feiner,J.Hughes "Computer Graphics.Principles and practice" 2nd ed. Addison-Wesley 1990


3. J.Dfoley,A.vanDam "Fundamentals of interactive Computer Graphics" Addison-Wesley 1982


4. W.Newman,Rsproul "Principles of interactive Computer Graphics", McGraw Hill 1979


5. D.F.Rogers "Procedural elemets for Computer Graphics" McGraw Hill1985

Knowledge

• Knows graphics hardware
• Knows methods of raster images creation
• Knows basic algorithms

Skills

Social Competence

• Knows the need to continuously raised his/her competention
• Knows the importance of engineer’s ethos