280 likes | 376 Views
Explore the fundamentals of computer graphics, including theory, algorithms, and hardware components. Learn about graphics software packages and color models such as RGB and CMY, essential for creating vivid visuals in various applications.
E N D
Computer Graphicschapter 1 Dr. Jehad Q. O. Alnihoud Email: jehad@aabu.edu.jo Phone: 3354
Books • F.S. Hill, Computer Graphics Using OpenGL, Prentice-Hall (2001). • Mason Woo, OpenGL Programming Guide, Addison Wesley (2000). • Hearn and Baker, Computer Graphics, Prentice-Hall (1997).
Books (Supplementary reference) • Foley, V. Dam, Feiner, Hughes, Computer Graphics Principles and Practice, 2/e, Addison Wesley, 1997. • Edward Angel, Interactive Computer Graphics, Addison Wesley, 1997. • Zhigang Xiang, Schaum’s Outlines: Computer Graphics, McGrawHill, 2001. • Shreiner D, OpenGL Reference Manual, Addison-Wesley, 2000.
Course Assessment • Coursework 50% • First Exam 15% • Second Exam 15% • Group Project 10% • Lab 10% • Final Exam 50% Attendance in both lecture and lab sessions is compulsory.
Graphics Applications • Art and Entertainment • Animations • Movies • Commercials • Special Effects
Graphics Applications • Image Processing • Analysis, Reconstruction • Medical Imaging • Movies
Graphics Applications • Simulation • Modeling and Analysis • Virtual Environments
Graphics Applications • Scientific Visualization • Data Representation and Plotting • 3D Views
Graphics Applications • CAD/CAM • Industrial Design • Structural Design • Surface Modeling
Graphics Software Packages • Early graphics libraries: • GKS (Graphical Kernel System) • PHIGS • OpenGL (Silicon Graphics) • Java2D (Sun Microsystems) • Java3D (Sun Microsystems) • VRML (Silicon Graphics)
Graphics: Main Components • Theory • Analytical Geometry • Vectors and Matrices • Algorithms • Eg: Line drawing, Filling etc. • Implementation • Programming (OpenGL)
Graphics Hardware • Line Drawing Devices: • Eg. Pen Plotters • Advantages: Perfect lines, Sharp Diagrams • Disadvantages: Not suitable for filled regions.
Graphics Hardware • Raster Devices: Create pictures by displaying dots • Eg: Video monitor, dot-matrix printer, laser printer, ink-jet printer, film recorder • Advantages: Filled, shaded regions are easily displayed • Disadvantages: Jaggies Pixel
Pixel Depth • Pixel depth refers to the number of bits used to represent a pixel value. 1 bit/pixel: 0 2 Levels (Bi-level image) 1 2 bits/pixel: 0 0 4 Levels 0 1 1 0 1 1
Pixel Depth • 1 bit per pixel produce 2 levels (bi-level image). • 2 bits per pixel produce 4 levels. • 8 bits per pixel produce 256 levels. • In general, if the pixel depth is n, then it is possible to have 2n levels.
Raster Display • Most display used for computer graphics nowadays are raster displays. • Image presented in display surface that contains certain number of pixels. Eg. 480 x 640 (r x c). • Frame buffer is a region of memory sufficiently large to hold all the pixel values for display.
Frame Buffer • System with 64 color (3 DACs): • Each DAC uses 2 bits/pixel. • Total color: 4 x 4 x 4 = 64 • If the display surface is 1024 x 1280, then the memory required for frame buffer is 0.9375 MB • Monochrome Video display: • Only one DAC required. 6 planes of memory in frame buffer gives 26 = 64 level of gray.
Frame Buffer • System with 24 bit color (3 DACs): • Each DAC uses 8 bits/pixel. (Total 24 bits/pixel) • Total color: 28 x 28 x 28 = 224 • If the display surface is 1024 x 1280, then the memory required for frame buffer is 3.75MB
Color Models: RGB Diagram • RGB Model is used for colored light sources • RGB Model is additive Basis colors: R, G, B R: Red=[1, 0, 0] G: Green=[0, 1, 0] B: Blue=[0, 0, 1] C: Cyan=[0, 1, 1] M: Magenta=[1, 0, 1] Y:Yellow=[1, 1, 0] W:White=[1,1,1] K: Black=[0,0,0]
Color Models: RGB Cube Complementary Colors: Two colors that combine to form White. Eg. Red, Cyan. Gray Values: Every point on the primary diagonal has equal values for all the components.
Color Models: CMY Diagram • CMY Model is used for colored pigments • CMY Model is subtractive Basis colors: C, M, Y C: Cyan=[1, 0, 0] M: Magenta=[0, 1, 0] Y: Yellow=[0, 0, 1] R: Red=[0, 1, 1] G: Green=[1, 0, 1] B: Blue=[1, 1, 0] W:White=[0,0,0] K: Black=[1,1,1]
Color Models: RGB <-> CMY (r, g, b)RGB = (1,1,1) (c, m, y)CMY Light A red colored surface absorbs cyan from a white light
Color Models: HSV H (Hue): 0 to 360 degrees 0: Red, 60: Yellow …. S (Saturation): 0 to 1 0: Axis, 1: Boundary V (Value): 0 to 1 0: Vertex, 1: Base Examples: Eg. Yellow: [60, 1.0, 1.0] Black: [ -, -, 0.0] White: [-, 0.0, 1.0]