Perspective (geometry)

About: Perspective (geometry) is a research topic. Over the lifetime, 277 publications have been published within this topic receiving 5795 citations. The topic is also known as: perspective (geometry).

How much teaching aids that mechanical drawing used

Abstract: (B, ) the utility model discloses a how much teaching aids that mechanical drawing used. It includes mutual perpendicular to each other H perspective plane (1), V perspective plane (2) and W perspective plane (3), is equipped with lamp pearl (4) of arranging with the dot matrix form on H perspective plane (1), V perspective plane (2) and W perspective plane (3), being provided with support (5) in the top on H perspective plane (1), being equipped with projection thing (7) that comprise lamp strip (6) on support (5), lamp strip (6) and lamp pearl (4) warp way is connected with controller (8). The utility model has the characteristics of the transform rapidly, the knowledge point show is efficient, the demonstration feels strong etc, and the utility model discloses can increase student's enthusiasm and interest in learning. (B, )

Point process and graph cut applied to 2D and 3D object extraction

Abstract: The topic of this thesis is to develop a novel approach for 3D object detection from a 2D image. This approach takes into consideration the occlusions and the perspective effects. This work has been embedded in a marked point process framework, proved to be efficient for solving many challenging problems dealing with high resolution images. The accomplished work during the thesis can be presented in two parts. First part: we propose a novel probabilistic approach to handle occlusions and perspective effects. The proposed method is based on 3D scene simulation on the GPU using OpenGL. It is an object based method embedded in a marked point process framework. We apply it for the size estimation of a penguin colony, where we model a penguin colony as an unknown number of 3D objects. The main idea of the proposed approach is to sample some candidate configurations consisting of 3D objects lying on the real plane. A Gibbs energy is define on the configuration space, which takes into account both prior and data information. The proposed configurations are projected onto the image plane, and the configurations are modified until convergence. To evaluate a proposed configuration, we measure the similarity between the projected image of the proposed configuration and the real image, by defining a data term and a prior term which penalize objects overlapping. We introduced modifications to the optimization algorithm to take into account new dependencies that exists in our 3D model. Second part: we propose a new optimization method which we call "Multiple Births and Cut" (MBC). It combines the recently developed optimization algorithm Multiple Births and Deaths (MBD) and the Graph-Cut. MBD and MBC optimization methods are applied for the optimization of a marked point process. We compared the MBC to the MBD algorithms showing that the main advantage of our newly proposed algorithm is the reduction of the number of parameters, the speed of convergence and the quality of the obtained results. We validated our algorithm on the counting problem of flamingos in a colony.

Smooth projective stacks : ample bundles and D-affinity

Abstract: This thesis is on the study of sheaves of O-modules and D-modules on projective stacks. In chapter 1, a historical perspective is given on the main fidings that have shaped and influenced the study carried out and exposed in this thesis. In chapter 2, the principal definitions and results used in the forthcoming sections are recalled. An appendix is added at the end of this chapter exposing self-containedly why quotient singularities and orbifolds are two equivalent notions. In chapter 3, the property of ampleness of vector bundles on projective stacks is generalised and studied. Basic properties are given; in particular it is proved that weighted projective stacks have ample tangent vector bundle. In chapter 4, D-modules on projective stacks are studied. General conditions on the weights and the shift guaranteeing a weighted projective stack to be D-affine are given. Thus, proving a version of the Beilinson-Bernstein Localisation Theorem. In particular, a weighted projective stack is D-affine if and only if the greatest common divisor of its weights is one. A theorem of Kashiwara is extended to smooth projective stacks, it is shown that the category of D-modules on a smooth closed projective substack [X] is equivalent to the category of D-modules on the ambient smooth projective stack [Y ] supported on [X].

A real time three-dimensional color animation system

Abstract: A system is described for the generation of real time quasi three-dimensional animated television images. The technique utilized is a composite of the "multi-plane" cartoon animation technique and three-dimensional object projection techniques using polygonal patch representations of objects. The hardware environment consists of a hierarchical memory structure utilizing shift register "background" planes and a fast random access main image "foreground" plane. The foreground plane has a variable "depth" with respect to the background planes. Perspective relations in the image structure are maintained in real time with only infrequent updating of the background data.