Fuzzy Soft Shadow in Augmented Reality Systems

Realistic soft shadows in Augmented Reality (AR) is a fascinating topic in computer graphics. Many researchers are involved to have a significant improvement on this demand. In this paper, we have presented a new technique to produce soft shadows using one of the well-known methods in mathematics called Fuzzy Logic. Fuzzy logic is taken into account to generate the realistic soft shadows in AR. The wide light source is split into some parts that each of them plays the rule of a single light source. The desired soft shadow is generated by splitting the wide light source into multiple parts and considering each part as a single light source. The method which we called Fuzzy Soft Shadow is employed in AR to enhance the quality of semi-soft shadows and soft shadows

A Fast Silhouette Detection Algorithm for Shadow Volumes in Augmented Reality

Real-time shadow generation in virtual environments and Augmented Reality (AR) was always a hot topic in the last three decades. Lots of calculation for shadow generation among AR needs a fast algorithm to overcome this issue and to be capable of implementing in any real-time rendering. In this paper, a silhouette detection algorithm is presented to generate shadows for AR systems. Δ+algorithm is presented based on extending edges of occluders to recognize which edges are silhouettes in the case of real-time rendering. An accurate comparison between the proposed algorithm and current algorithms in silhouette detection is done to show the reduction calculation by presented algorithm. The algorithm is tested in both virtual environments and AR systems. We think that this algorithm has the potential to be a fundamental algorithm for shadow generation in all complex environments

Soft shadows using sp-line approximation

© 2015 Penerbit UTM Press. All rights reserved. Realistic soft shadows are an important factor to enhance the realism of Augmented Reality systems. Without shadows, virtual objects would look floating over the scene resulting unrealistic rendering of AR environment. Little attention has been directed towards balanced trade-off between shadow quality and computational cost. In this study, a new approach is proposed; Quadratic Sp-line Interpolation (QSI) to soften the outline of the shadow. QSI estimates the border of hard shadow samples. In more details, a reflective hemisphere is used to capture real light then to create an environment map. Implementation of the Median Cut algorithm is performed to locate the direction of real light sources on the environment map. Subsequently, the original hard shadows are retrieved and a sample of multilayer hard shadows is produced. The proposed technique is tested by using three samples of multilayer hard shadows with a varied number of light sources that are generated from the Median Cut algorithm. The experimental results show that the proposed technique has successfully produced realistic soft shadows with low computational costs

Shadow Mapping or Shadow Volume?

In this paper two techniques of shadow generation are described. Volume shadow is geometric base but shadow mapping is image base. Silhouette detection is a most expensive step to create volume shadow. Two algorithms to recognize silhouette are introduced. Stencil buffer and Z- buffer are two other tools for creating shadow by volume shadow technique. Both algorithms are implemented in virtual environment with moveable light source. Triangular method and the Visible-non visible method are introduced. The recent traditional silhouette detection and implementation techniques used in volume shadow algorithm are improved. With introduce flowchart of both algorithms, the last volume shadow algorithm using stencil buffer is rewritten. A very simple algorithm to create volume shadow is proposed. The last shadow mapping algorithm is rewritten. These techniques are poised to bring realism into commercial games. It may be use in virtual reality applications

Real-Time Sky Color with Effect of Sun’s Position

In the rendering of outdoor scenes in virtual environments, the sun's position, sky color, clouds, shadow, trees, grass etc play very important roles in making it realistic. In this paper Sky color and the sun’s position are combined. Specific longitude, latitude, date and time are required parameters to calculate the exact position of the sun. The sun's position is calculated based on Julian dating; the sky’s color is created by Perez modeling. A functional application is designed to show the position of the sun and then sky color in arbitrary location, date and time. It can be possible to use this application in commercial games for outdoor rendering and for teachers to teach some part of physics about earth orbit and effect of the sun on the sky and it can be used in building design

To Combine Silhouette Detection and Stencil Buffer for Generating Real-Time Shadow

This paper describes one of the best methods to generate real-time shadow that called volume shadow. Volume shadow algorithm is possible to implement for virtual environment with moveable illuminated light source. We improve to find silhouette and implementation of the last techniques used in shadow volume algorithms, and limitation of length of volume of each semi-polygon that makes between silhouette's edge and shadow receiver. We rewrite the last volume shadow algorithm using stencil buffer and propose a pseudo code in OpenGl. The best tools that we have used in this algorithm are stencil buffer and Z-buffer.It makes realistic commercial games or it can be use in virtual reality systems

Hybrid Silhouette Detection for Real-Time Shadow Volume

In shadow volume, the most expensive computation is silhouette detection. In this paper, the triangular algorithm (TA) and visible-non-visible (VnV) algorithm that are famous algorithms to detect the outline of occluder are renewed. In this paper, we proposed a hybrid algorithm based on TA and VnV, namely Hybrid Silhouette Detection (HSD) algorithm. HSD is an improved algorithm that can recognize silhouette for generating real-time shadow volume. Our algorithm involves detecting silhouette and decreases the cost of implementation for shadow volume rendering. The last shadow volume algorithm using stencil buffer is rewritten and an algorithm for shadow volume using HSD with respect of culling invisible parts of scene is proposed. An accurate mathematical comparison between TA, VnV and HSD algorithms is undertaken. The obtained results confirm superiority of our proposed algorithm in terms of processing and rendering time. Our algorithm can be used in virtual environment to increase the frame per second and to enhance the realistic of games programming

Real-Time Projection Shadow with Respect to Sun’s Position in Virtual Environments

This paper proposes a real-time software for outdoor rendering to control the shadow’s position with effect of sun's position. The position of sun plays an important rule for outdoor games. Calculation of sun's position, as a result, position and length of shadows require a lot of attention and preciseness. Julian dating is used to calculate the sun's position in the virtual dome. In addition, of computer graphics, building design is another field that this paper contributes on it. To create shadow, projection shadow is proposed. By calculating the sun's position in the specific date, time and location on the earth, shadow is generated. Length and angle of shadow are two parameters measured for building design and both of them are calculated in this real-time application. Therefore, it can be used for teachers to teach some part of physics about earth orbit and it can be used in building design and commercial games in virtual reality systems

Motion deformation style control technique for 3D humanoid character by using MoCap data

Realistic humanoid 3D character movement is very important to apply in the computer games, movies, virtual reality and mixed reality environment. This paper presents a technique to deform motion style using Motion Capture (MoCap) data based on computer animation system. By using MoCap data, natural human action style could be deforming. However, the structure hierarchy of humanoid in MoCap Data is very complex. This method allows humanoid character to respond naturally based on user motion input. Unlike existing 3D humanoid character motion editor, our method produces realistic final result and simulates new dynamic humanoid motion style based on simple user interface control. © 2016 Penerbit UTM Press. All rights reserve

Soft bilateral filtering shadows using multiple image-based algorithms

This study introduces Soft Bilateral Filtering Shadows method of dynamic scenes, which uses multi-matrices of the light sample points due to lack realism in soft shadows generation in real time. While geometry-based shadow algorithm requires one pass per polygon for rendering shadow that requires time-consuming, the adopted shadow map algorithm needs a single rendering pass for each sample point of the light source to generate shadow at low cost. This method renders a complex scenes and accurately eliminating the inherent deficiencies in shadow maps. In order to compute shadow maps, view matrices were used for each sample point of the extended light source. Then penumbra region was used for interpolation based on bilateral filtering to create the soft shadows. They depend on multiple shadow maps which provide antialiasing shadow maps. The method uses fragment shader for rendering multiple shadow maps with penumbra and umbra regions. The main contribution of this article is introducing interpolation bilaterally of image-based shadows. This method makes the most effect of the computation significantly appear at the edges of the penumbra region. Furthermore, the filtering allows to obtain on the soft shadow marvelously at the lowest number possible of the light sample points. The generated soft shadows have good performance and high quality therefore, they are suitable for interactive applications. © 2016 Springer Science+Business Media New Yor