Üç boyutlu canlandırma sisteminde gerçeğe benzetme
Başlık çevirisi mevcut değil.
- Tez No: 39800
- Danışmanlar: DOÇ.DR. FÜSUN TUNALI
- Tez Türü: Yüksek Lisans
- Konular: Bilgisayar Mühendisliği Bilimleri-Bilgisayar ve Kontrol, Computer Engineering and Computer Science and Control
- Anahtar Kelimeler: Bilgisayar destekli benzetim, Bilgisayar yazılımları, Gerçekçi görüntü, Üç boyutlu canlandırma sistemi, Computer aided simulation, Computer softwares, Realistic images, Three dimensional animation system
- Yıl: 1994
- Dil: Türkçe
- Üniversite: İstanbul Teknik Üniversitesi
- Enstitü: Fen Bilimleri Enstitüsü
- Ana Bilim Dalı: Belirtilmemiş.
- Bilim Dalı: Belirtilmemiş.
- Sayfa Sayısı: Belirtilmemiş.
Özet
Özet yok.
Özet (Çeviri)
SUMMARY The hidden line/hidden surface problem is öne of the more difficult in computer graphics. Hidden line/hidden surface algorithms attem.pt to determine the lines edges, surfaces ör volumes that öne visible ör invisible to an observer located at a specific point in space. The complexity of hidden line/hidden surface problem has resulted in a large number of diverse solutions. Many of diverse solutions. Many of these öne för specialised applications. There is no best solution to the hidden line/hidden surface problem. Ali hidden line/hidden surface algorithms involve sorting. The order in which sorting of the geometric co- ordinates occurs is generally immaterial to the efficiency of the algorithms. We used the z-buffer algorithm for the hidden surface algorithm. The technique was originally proposed by Catmull and is an image space algorithm. A frame buffer is used to store the attributes of each pixel in image space. The z buffer is a separate depth buffer used to store the z co-ordinate ör depth of every visible pixel in image space. in use, the depth ör z value of a new pixel to be written to the frame buffer is compared to the depth of that pixel stored in the z buffer. If the comparison indicates that the new pixel is in front of the pixel stored in the frame buffer, then the new pixel is written to the frame buffer and the z buffer updated with the new z value. If not, no action is taken. it handles the hidden surface problem and display of complex surface intersections trivially. Simply defined, rendering is process of producing realistle images ör pictures. Producing realistle images involves both physics and psychology. Light, i.e. electromagnetic energy, reaches the eye after viiiu = AQ / AB Iq = u*Ib + (1-u)*Ia w = BR / BC Ir = w*Ic + (1-w)*Ib t = QP / QR Ip = t*lR + (l-t)*lQ 0=<u,w, t<=l A method due to Bui-Tuong Phong (1975) overcomes some of the disadvantages of Gouraud shading and specular reflection can be successfully incorporated in the scheme. Whereas Gouraud shading interpolates intensity values along a scan line, Phong shading interpolates the normal vector along the scan line. The illumination model is then applied at each pixel, using the interpolated normal to determine the intensity. This technique gives a better local approximation to the surface curvature and hence a better rendering of the surface. Phong shading first approximates the surface curvature at polygonal vertices by approximating the normal at the vertex. A bilinear interpolation is then used to determine the normal at each pixel. Additional difficulties are exhibited by both Gouraud and Phong shading when used in animation sequences. u = AQ / AB no = u*nB + (l-u)*nA w = BR / BC m = w*nc + (l-w)*nB t = QP / QR np = t*m + (l-t)*nQ 0=<u,w, t<=l XISUMMARY The hidden line/hidden surface problem is öne of the more difficult in computer graphics. Hidden line/hidden surface algorithms attem.pt to determine the lines edges, surfaces ör volumes that öne visible ör invisible to an observer located at a specific point in space. The complexity of hidden line/hidden surface problem has resulted in a large number of diverse solutions. Many of diverse solutions. Many of these öne för specialised applications. There is no best solution to the hidden line/hidden surface problem. Ali hidden line/hidden surface algorithms involve sorting. The order in which sorting of the geometric co- ordinates occurs is generally immaterial to the efficiency of the algorithms. We used the z-buffer algorithm for the hidden surface algorithm. The technique was originally proposed by Catmull and is an image space algorithm. A frame buffer is used to store the attributes of each pixel in image space. The z buffer is a separate depth buffer used to store the z co-ordinate ör depth of every visible pixel in image space. in use, the depth ör z value of a new pixel to be written to the frame buffer is compared to the depth of that pixel stored in the z buffer. If the comparison indicates that the new pixel is in front of the pixel stored in the frame buffer, then the new pixel is written to the frame buffer and the z buffer updated with the new z value. If not, no action is taken. it handles the hidden surface problem and display of complex surface intersections trivially. Simply defined, rendering is process of producing realistle images ör pictures. Producing realistle images involves both physics and psychology. Light, i.e. electromagnetic energy, reaches the eye after viiiu = AQ / AB Iq = u*Ib + (1-u)*Ia w = BR / BC Ir = w*Ic + (1-w)*Ib t = QP / QR Ip = t*lR + (l-t)*lQ 0=<u,w, t<=l A method due to Bui-Tuong Phong (1975) overcomes some of the disadvantages of Gouraud shading and specular reflection can be successfully incorporated in the scheme. Whereas Gouraud shading interpolates intensity values along a scan line, Phong shading interpolates the normal vector along the scan line. The illumination model is then applied at each pixel, using the interpolated normal to determine the intensity. This technique gives a better local approximation to the surface curvature and hence a better rendering of the surface. Phong shading first approximates the surface curvature at polygonal vertices by approximating the normal at the vertex. A bilinear interpolation is then used to determine the normal at each pixel. Additional difficulties are exhibited by both Gouraud and Phong shading when used in animation sequences. u = AQ / AB no = u*nB + (l-u)*nA w = BR / BC m = w*nc + (l-w)*nB t = QP / QR np = t*m + (l-t)*nQ 0=<u,w, t<=l XIOrientation interpolation is the most important problem in the key frame method computations. As known, rotation is represented by a matrix of 3x3 (4x4 for homogenous transformations) in traditional method. If an orientation is described by consecutive rotations, the resultant orientation matrix has dependent parameters whose dependency degree is the number of the operations. This shos that there exists more than one parameter to interpolate which causes complicated computations. As interpolation can not be done independently for each parameter, undesired situations will occur. In order to get rid of this problem, quaternions are used in this thesis. Quaternions were defined by Sir William Hamilton, while he had been studying“expansion of complex plane to the tree dimensional space”, in 1843. In this thesis, 3D Rendering techniques, 3D Hidden Line/Surface techniques are examined. 3D Rendering and Animation Software is developed. Developer system provides an interface for 3D rendering, rotation and animation.“Key Frame”technique is used in animation. Hidden line/surface algorithms are examined and compared. Z buffer hidden line/surface algorithm which have more advantages is chosen. Half tone and smooth shading algorithms are examined and compared as a rendering algorithms. Simple, Gouraud and Phong shading algorithms are used in software. Quaternions are used in orientation interpolation. Software uses SVGA256 color graphics. xn
Benzer Tezler
- Şehirsel tasarıma destek veren bir bilgisayar sisteminin oluşturulması, bilgisayar destekli şehirsel tasarım
Başlık çevirisi yok
OSMAN B. ELLİİKİ
Yüksek Lisans
Türkçe
1996
Şehircilik ve Bölge Planlamaİstanbul Teknik ÜniversitesiPROF.DR. CENGİZ GİRİTLİOĞLU
- Algoritma animasyonu sistemleri konusunda inceleme
Başlık çevirisi yok
NAZAN ÇAYRAK
Yüksek Lisans
Türkçe
1998
Bilgisayar Mühendisliği Bilimleri-Bilgisayar ve Kontrolİstanbul Teknik ÜniversitesiKontrol ve Bilgisayar Mühendisliği Ana Bilim Dalı
DOÇ. DR. TAKUHİ NADİA ERDOĞAN
- ADIM: Üç boyutlu canlandırma sistemi
ADIM: A 3D animation system
A.GÖKHAN ERKMAN
Yüksek Lisans
Türkçe
1992
Bilgisayar Mühendisliği Bilimleri-Bilgisayar ve Kontrolİstanbul Teknik ÜniversitesiDOÇ. DR. FÜSUN TUNALI