3-boyutlu modellerin imge sıkıştırma yöntemleriyle sıkıştırılması

A Connectivity-Guided Adaptive Wavelet Transform (CGAWT) based mesh compres-sion algorithm is proposed. On the contrary to previous work, the proposed methoduses 2D image processing tools for compressing the mesh models. The 3D models arefirst transformed to 2D images on a regular grid structure by performing orthogonalprojections onto the image plane. This operation is computationally simpler than pa-rameterization. The neighborhood concept in projection images is different from 2Dimages because two connected vertex can be projected to isolated pixels. Connectiv-ity data of the 3D model defines the interpixel correlations in the projection image.Thus the wavelet transforms used in image processing do not give good results onthis representation. CGAWT is defined to take advantage of interpixel correlations inthe image-like representation. Using the proposed transform the pixels in the detailsubbands are predicted from their connected neighbors in the low-pass subbands ofthe wavelet transform. The resulting wavelet data is encoded using either ?Set Parti-tioning In Hierarchical Trees? (SPIHT) or JPEG2000. SPIHT approach is progressivebecause different resolutions of the mesh can be reconstructed from different partitionsof SPIHT bitstream. On the other hand, JPEG2000 approach is a single rate coder.The quantization of the wavelet coefficients determines the quality of the reconstructediiimodel in JPEG2000 approach. Simulations using different basis functions show thatlazy wavelet basis gives better results. The results are improved using the CGAWTwith lazy wavelet filterbanks. SPIHT based algorithm is observed to be superior toJPEG2000 based mesh coder and MPEG-3DGC in rate-distortion.Keywords: 3D Model Compression, Image-like mesh representation, Connectivity-Guided Adaptive Wavelet Transformiv