# A High-Resolution Texture Mapping Technique for 3D Textured Model
## 2 Problem Statement  
For product presentations in e-commerce, texture quality is the most crucial issue to investigate because it directly affects the visualization effect. Ideally, the texture quality at any view in 3D space should perfectly match that of the corresponding 2D image. Actual texture on the 3D model, however, is usually worse than that of 2D images, mainly because individual texture on the 3D model comes from different image sources. A 3D model reconstructed using multiple images of an object is only an approximation of the object geometry. The camera model and calibration method used to estimate the camera parameters might yield additional errors in the position and orientation of the object images. These errors, combined with errors caused by the texture mapping process, might lead to discrepancy between the texture of the 3D model and the real object. Any defect in the 3D texture could negatively impact perceptions of the product being presented. The following are typical problems involving the 3D texture:  
1. Reduced texture resolution: The texture resolution at any view in 3D space is worse than that of the corresponding object image, primarily because of inappropriate scaling of the pixels between the real image domain and the texture mapping image domain. 2. Missing color on some mesh regions: All 2D meshes on the texture domain should ideally be color-filled, but some may be missed if they are beyond the boundary of the object image, primarily because of insufficient accuracy of the 3D model, especially for those meshes near the image silhouette. 3. Photo inconsistency at the transition of different image sources: Photo inconsistency usually occurs along the boundary of different groups of meshes, with each group textured by different image sources. This problem is the combined effect of insufficient accuracy of the 3D model and the camera parameters. Thus, we develop a texture mapping algorithm that focuses on detecting and removing these problems. The objective of this study is to develop a high-quality texture mapping algorithm that can be combined with a 3D modeling algorithm to generate the 3D textured model of an object for use in e-commerce product presentation. High-quality texture here indicates that the texture at any view in 3D space should be as close as possible to that of the corresponding 2D image, which mainly requires maintenance of the resolution on the texture and elimination of photo-inconsistent errors at the transition of different image sources. A general texture mapping process comprising the following three techniques is proposed: mesh partitioning, mesh parameterization and packing, and texture transferring. Specific efforts are made at each step to initially eliminate problems that might affect the texture of the 3D model. To further reduce the discrepancy of the texture owing to insufficient inaccuracy of the 3D model and camera parameters, a correction and optimization algorithm is presented. The entire texture mapping process is fully automatic and is intended to be used for all kinds of objects. The main contribution of the proposed texture mapping method is as follows. First, we enhance the techniques of converting 3D meshes onto the UV domain so that the shape of most 2D meshes can be preserved and the finest resolution can be obtained in texture transferring. Three main techniques in converting 3D meshes onto the UV domain are mesh partitioning, mesh parameterization and packing. In the proposed mesh partitioning algorithm, a novel chart growth method is proposed to partition 3D meshes iteratively so that each chart of 3D meshes can be as flat (disk type) as possible, which can reduce the error of 2D meshes in mesh parameterization. In the proposed mesh parameterization algorithm, a novel conformal mapping method is proposed to preserve the shape of 2D meshes as close to that of 3D meshes as possible. In the proposed packing method, all regions of 2D meshes are tightly packed in a rectangular area to acquire the finest resolution.