Research And Realization Of Realistic Images Generating Technology Based On Discrete Points

Using computer to generate realistic images has always been one of the most important subjects in the field of computer graphics. Its major job is to use computer graphics display equipments to simulate, as accurately as possible, those scenes we observe in realities by using planar images with spatial sense. In more specific terms, it is to simulate the effects of being illuminated by various kinds of illuminants. Along with the development of the theories of computer graphics, great accomplishments have been achieved in this field. We have made considerable progress in the technology of surface fa?ade, illumination modeling, visibility, and texture mapping, etc. And now we are able to generate better and more realistic images.This paper has carried on deep research and realization to the generating traditional course of realistic image and has analyzed its shortcoming and insufficient. Then a kind of new method of modeling and drawing on the basis of discrete points is proposed. The thought of this method is very novel and it has simple data construction and the simple procedure of modeling. The content of this text include modeling on the basis of discrete points, transformation of coordinate, realizing of illumination, visibility, image construction, ray tracing, and so on. All have made the good result in a lot of different scenes. Among them the important part are modeling, visibility and image construction. In these parts quantity of work has been done and new algorithm has been proposed, and this algorithm has been verified in practice.At first this text has studied coordinate transformation and illumination in the course of realistic image. In the part of coordinate transformation, we use a new class to define position of viewer, viewer coordinate and the distance between viewer and screen, to transform from world coordinate to eye coordinate, and to project from eye coordinate to screen, etc. This class can be used directly to realize coordinate and projection transformation in other parts of this text. In the part of illumination, we use Phong illumination model,In the part of the modeling on the basis of polygonal meshes, this text studies the procedure of generating realistic images. First, we store all polygons obtained by subdividing the surface of the object into polygons. Second, replace the normal vector of each polygon. after that, calculate the effect of illumination of each polygon by way of illumination modeling. finally, colligate the effects of all the polygons to simulate the whole effect of the scene. In order to get high quality effect, this text has studied furthermore subdivision method on the basis of polygonal meshes, realized Loop scheme based on triangular meshes and Catmull-Clark scheme based on quadrangular meshes. But polygonal meshes there are still some problems left unsolved such as the low efficiency in producing pictures, the difficulty in partially adjusting and modifying the pictures. Besides, polygons can not be used to simulate the surface of the scene precisely, and they are so multifarious in shape that it is difficult to handle them consistently. So after having studied traditional modeling method, this text has realized the modeling on the basis of discrete points. The surface of a 3D object is described by a set of sample points without further topological information such as triangle mesh connectivity or a parameterization. These sample points are stored with color, position and normal information, etc. We define a class CMypoint to denote the discrete point.In the part of rendering on basis of discrete points, this paper has studied visibility and image reconstruction. The ultimate goal of rendering is to display a point set as a smooth surface without holes and without aliasing artifacts. If we rendered each point as a single pixel by coordinate transformation and illumination. We can only display those visible points from the viewer. The task of visibility is to find whether the discrete point is visible or not from the viewer. And in the course...