Hidden Surface Removal Algorithm Research Articles

A Space-Optimal Hidden Surface Removal Algorithm for Iso-Oriented Rectangles

We investigate the problem of finding the visible pieces of a scene of objects from a specified viewpoint. In particular, we are interested in the design of an efficient hidden surface removal algorithm for a scene comprised of iso-oriented rectangles. We propose an algorithm where given a set of [Formula: see text] iso-oriented rectangles we report all visible surfaces in [Formula: see text] time and linear space, where [Formula: see text] is the number of surfaces reported. The previous best result by Bern [Journal of Computer and System Sciences 40 (1990) 49–69], has the same time complexity but uses [Formula: see text] space.

A topological-free method for three-axis tool path planning for generalized radiused end milled cutting of a triangular mesh surface

A tool path generation method for a sculptured surface defined by a triangular mesh is presented. Existing tool methods require extensive computer processing power mainly because surface topology for triangular meshes is not provided. The three-axis tool path planning method presented in this paper for generalized radius end mills avoids this problem (and does not need topological information) by offsetting each triangular facet individually. Offsetting a single triangle results in many more triangles, many of which are redundant, increasing the time required for data handling in subsequent steps. To avoid the large number of triangles, the proposed method creates a bounding space to which the offset surface is limited. Applying the boundary space limits the size of the offset surface resulting in a reduction in the number of triangular surfaces generated. The offset surface generation may still result in unwanted intersecting triangles. The tool path planning strategy addresses this issue by applying hidden-surface removal algorithms. Simulation and machining tests are used to validate the tool paths generated using this method.

J121012 固定設置太陽光パネルの受光量最大化に関する検討 : 影による影響の最小化([J121-01]解析・設計の高度化・最適化(1))

Most solar panels are placed statically because of easy construction at various capability of installation locations. Solar panels are installed at roof, wall, ground surface, slope and so on. The amount of light received at fixed panels is affected by the shade of surrounding buildings, seasonal variation of solar orbit, the latitude and the clear sky rate of the installation location and the area. In this study to increase the amount of light received at fixed solar panels, optimization method is applied to determine the optimization parameters relating the installation configuration and the inclined angle of panel. The formulation of the amount of solar light received at solar panels considered shade of obstacles by using ray tracing techniques and hidden surface removal algorithms.

A Fast Hidden Surface Removal Approach for Complex SAR Scene Based on Adaptive Ray-tube Splitting Method

Traditional hidden surface removal algorithm based on hardware Z-Buffer technique cannot give attention to precision or efficiency at the same time when dealing with the non-uniform triangulated SAR (Synthetic Aperture Radar) scene model. A novel high-precision hidden surface removal approach using fast ray-tube splitting algorithm is proposed, where the SAR scene hidden surface removal problem is decomposed into two simple procedures, i.e. a Delaunay triangulator is used to generate the initial ray tubes from the projected point clouds of all incident visible vertices, then an adaptive ray-tube splitting method is adopted to carry out the complex scene shading situations and resultant visible model reconstruction. Simulation results of typical aircraft and T-72 tank show that, the new approach is feasible and effective.

Applying time domain physical optics to acoustic wave backscattering problem

The interest in transient analysis of acoustic waves has been growing in recent years, due to the advance of wide-band sonars. In this paper, a transient analysis method for acoustic backscattering signals is proposed based on the time domain physical optics (TDPO). TDPO is formulated via a theoretical inverse Fourier transform of the conventional physical optics formula used in the frequency domain wave scattering analyses. A hidden surface removal algorithm using an adaptive triangular beam method and a virtual surface concept are adopted to explain shadow effects and multiple reflections among elements, respectively. Numerical analyses are carried out for two kinds of underwater targets: a submarine pressure hull and an idealized submarine, in order to validate the proposed method. The result of the submarine pressure hull shows good agreements between the proposed method and conventional physical optics based on inverse fast Fourier transform. Additionally, the result of the idealized submarine shows that the proposed method is efficient for finding highlights including their contribution to the whole backscattering signal.

An Efficient Output-Size Sensitive Parallel Algorithm for Hidden-Surface Removal for Terrains

We describe an efficient parallel algorithm for hidden-surface removal for terrain maps. The algorithm runs in O(log 4 n) steps on the CREW PRAM model with a work bound of O((n+k) \polylog ( n)) where n and k are the input and output sizes, respectively. In order to achieve the work bound we use a number of techniques, among which our use of persistent data structures is somewhat novel in the context of parallel algorithms.

THE OBJECT COMPLEXITY MODEL FOR HIDDEN-SURFACE REMOVAL

We define a new model of complexity, called object complexity, for measuring the performance of hidden-surface removal algorithms. This model is more appropriate for predicting the performance of these algorithms on current graphics rendering systems than the standard measure of scene complexity used in computational geometry. We also consider the problem of determining the set of visible windows in scenes consisting of n axis-parallel windows in ℝ3. We present an algorithm that runs in optimal Θ(n log n) time. The algorithm solves in the object complexity model the same problem that Bern3 addressed in the scene complexity model.

Polygon-to-Object Boundary Clipping in Object Space for Hidden Surface Removal in Computer-Aided Design

Since techniques for both polygon-to-polygon clipping and polygon-to-object boundary (contour) clipping have been developed, it appears that the visibility problem may exhibit potential for improvement in its time complexity. This paper provides some insight and results concerning the performance of an object-space hidden surface removal algorithm based on polygon-to-object boundary (contour) clipping. The applicability of these results to the graphic rendering of partially visible objects in an incremental computer-aided geometric design system, such as that used in mechanical design, is demonstrated. The polygon-to-object boundary clipping algorithm is compared with the more conventional polygon-to-polygon approach to clipping for hidden surface removal. Examples are included which demonstrate the potential for improving the performance of software-based hidden surface removal algorithms used in computer-aided geometric design applications.

An efficient output-sensitive hidden-surface removal algorithm for polyhedral terrains

In this paper, we present an algorithm for hidden surface removal for a class of polyhedral surfaces which have a property that they can be ordered relatively quickly. For example, our results apply directly to terrain maps. A distinguishing feature of our algorithm is that its running time is sensitive to the actual size of the visible image, rather than the total number of intersections in the image plane which can be much larger than the visible image. The time complexity of this algorithm is O(( k + n) log 2 n) where n and k are, respectively, the input and the output sizes. Thus, in a significant number of situations this will be faster than the worst case optimal algorithms which have running time of Ω(n 2) irrespective of the output size.

An efficient algorithm for hidden surface removal, II

We give an efficient, randomized hidden surface removal algorithm for scenes containing intersecting faces. Randomization is assumed only in the algorithm and not in the input. The algorithm is quasi-output sensitive in the following sense. Project all boundary edges as well as the edges formed by the intersections of scene faces onto the view plane. This gives rise to several junctions in the view plane, visible as well as invisible. Let us define the degree deg( q ) of a junction q as the number of scene faces that give rise to q . Define l ( q ), the obstruction level of q , to be the number of faces in the scene that obscure q with respect to the view point. Thus l ( q )=0 iff q is visible. Then the expected time spent by the algorithm on a junction q is inversely proportional to (1 + l ( q )) deg( q )−1 . Thus the work done on a junction decreases very fast as its obstruction level w.r.t. the view point increases.

A nontraditional computer graphics course for computer science students

The recent theoretical and technological advancement in computer graphics has brought not only exciting changes to the computing field but also new challenges to computer science educators. One of the challenges is effective teaching of computer graphics to computer science students. Several speakers at the SIGGRAPH "91 educators' program addressed various aspects of this theme (Owen, 1991; Schweitzer, 1991; Clevenger, 1991). A SIGGRAPH '92 panel consisting of representatives from academia and industry exchanged ideas and viewpoints on issues ranging from syllabus to the role of graphics in a computer science curriculum. I had the pleasure of being a member of that panel and this paper is a further elaboration of my brief statement in the conference proceedings (Schaller, 1992, 1993).The Department of Computer Science at Queens College offers computer graphics as an elective at the senior level for undergraduate students. The department also offers computer graphics at the graduate level. Since the majority of our graduate students have had no prior training in computer graphics, the two courses do not constitute a one-year sequence and the following considerations are applicable to both cases.The traditional way of teaching computer graphics to computer science students places an emphasis on vector graphics. After some general introduction, discussion typically proceeds to graphical primitives and their attributes, then windowing and geometric transformations, followed by segments and interactive techniques, leading to the use of a standard library such as GKS. Additional 3-D topics may include representation, transformation, projection and hidden surface removal algorithms. Color, and especially shading models, are not discussed until near the end of the semester.While this traditional approach has made invaluable contributions to computer graphics education, it needs to be improved in order to keep up with the rapid growth of the field over the last several years. In the next section, I present a nontraditional syllabus along with a detailed explanation. Sample assignments are in section 3. A comparison of the two syllabi and concluding remarks are in section 4.The computer graphics course described in this paper is quite similar to the course taught by Scott Owen (Owen, 1994).

An improved technique for output-sensitive hidden surface removal

We derive a new output-sensitive algorithm for hidden surface removal in a collection ofn triangles, viewed from a pointz such that they can be ordered in an acyclic fashion according to their nearness toz. Ifk is the combinatorial complexity of the outputvisibility map, then we obtain a sophisticated randomized algorithm that runs in (randomized) timeO(n4/3 log2.89n +k3/5n4/5 + δ for anyδ > 0. The method is based on a new technique for tracing the visible contours using ray shooting.

A Statistical Comparison of Two Hidden Surface Techniques: the Scan‐line and Z‐buffer Algorithms

AbstractThis paper compares two image space hidden surface removal algorithms for polygonal scenes. These are the z‐buffer and scan‐line algorithms. There is first an overview of each algorithm, followed by a simulation experiment, designed to compare the number of polygons per second which can be rendered by each algorithm. The simulation varies the number of polygons in the scene, and the size and distribution of polygons over the display. The results suggest that the z‐buffer is preferred for a large enough number of polygons, however, smaller polygons and uniform distribution of polygons favour the scan‐line approach. The analysis does not take into account the complexity of the shading rule, which is likely also to favour the scan‐line method.

A simple output-sensitive algorithm for hidden surface removal

We derive a simple output-sensitive algorithm for hidden surface removal in a collection of n triangles in space for which a (partial) depth order is known. If k is the combinatorial complexity of the output visibility map , the method runs in time O(n √k log n). The method is extended to work for other classes of objects as well, sometimes with even improved time bounds. For example, we obtain an algorithm that performs hidden surface removal for n (nonintersecting) balls in time O(n 3/2 log n + k).

A systolic algorithm for hidden surface removal

With the advent of VLSI it has become possible to map parallel algorithms for compute-bound problems directly on silicon. Systolic architecture is very good candidate for VLSI implementation because of its regular and simple design, and regular communication pattern. In this paper, a systolic algorithm and corresponding systolic architecture, a linear systolic array, for the scanline-based hidden surface removal problem in three-dimensional computer graphics have been proposed. The algorithm is based on the concept of sample spans or intervals. The worst case time taken by the algorithm is O( n), n being the number of segments in a scanline. The time taken by the algorithm for a given scene depends on the scene itself, and on an average considerable improvement over the worst case behaviour is expected. A pipeline scheme for handling the I/O process has also been proposed which is suitable for VLSI implementation of the algorithm.

Parallel object-space hidden surface removal

A parallel object-space hidden surface removal algorithm for polyhedral scenes is presented. The uniform grid technique is used to achieve parallelism for the hidden line removal. A conflict-detection and back-off strategy is then used to obtain parallelism for the visible region reconstruction from the visible segments. The algorithm has been implemented on a Sequent Balance 21000 shared-memory parallel computer. An average speedup of 10 has been obtained using 15 processors.

An efficient algorithm for hidden surface removal

We give an efficient, randomized hidden surface removal algorithm, with the best time complexity so far. A distinguishing feature of this algorithm is that the expected time spent by this algorithm on junctions which are at the "obstruction level" l , with respect to the viewer, is inversely proportional to l . This provably holds for any input, regardless of the way in which faces are located in the scene, because the expectation is with respect to randomization in the algorithm, and does not depend on the input. In practice, this means that the time complexity is roughly proportional to the size of the actually visible output times logarithm of the average depth complexity of the scene (this logarithm is very small generally).

Worst-case optimal hidden-surface removal

An O( n 2 ) hidden-surface removal algorithm is shown. This is an improvement over the previous best worst-case performance of O( n 2 log n ). It has been established that the hidden-line and hidden-surface problems have an Ω( n 2 ) worst-case lower bound, so the algorithm is optimal. However, the algorithm is not output-size sensitive. Two corollaries to the result are (1) hidden-lines can be removed in optimal O( n 2 ) time, and (2) the portion of a 3-D polyhedron visible from a given interior point is constructible in optimal O( n 2 ) time.

CSIG-a Colour Stress Image Generator

This paper presents details of a postprocessor system designed to improve the graphical presentation of the results of finite-element stress analysis. The CSIG graphics postprocessor accesses the results of finite-element analysis and data from the finite-element model, and uses a modified Wornock hidden-surface removal algorithm for the display of colour stress images of two- and three-dimensional structures.

CSIG—a Colour Stress Image Generator

This paper presents details of a postprocessor system designed to improve the graphical presentation of the results of finite-element stress analysis. The CSIG graphics postprocessor accesses the results of finite-element analysis and data from the finite-element model, and uses a modified Wornock hidden-surface removal algorithm for the display of colour stress images of two- and three-dimensional structures.