• Journal of Korea Multimedia Society
• /
• v.7 no.11
• /
• pp.1550-1555
• /
• 2004

Shadows increase the visual realism of computer-generated images and they are good hint for spatial relationships between objects. Previous methods to produce a shadow texture for an object are to render all objects between the object and light source. Consequently entire time for generating shadow textures between all objects is Ο(Ν$^2$), where Ν is the number of objects. We propose a novel shadow texture generation method with constant processing time for each object using shadow depth buffet. In addition, we also present method to achieve further speed-up using temporal coherence. If the transition between dynamic and static state is not frequent, depth values of static objects does not vary significantly. So we can reuse the depth value for static objects and render only dynamic objects.

• Proceedings of the Korean Information Science Society Conference
• /
• 2005.11a
• /
• pp.748-750
• /
• 2005

본 논문은 오목한 물체의 그림자 표현이 가능한 그림자 텍스처를 생성하기 위해, 기존의 그림자 맵 (shadow MaP) 방법으로 그림자 정보를 생성하고 아틀라스 텍스처 (atlas texture)에 저장하는 방법을 제안한다. 기존 그림자 텍스처 방법은 그림자 정보를 이미지 텍스처에 저장하므로 그래픽스 하드웨어의 색상 처리 기능을 사용하여 고품질의 그림자를 효율적으로 표현하는 장점이 있지만 오목한 물체의 그림자를 표현하지 못하고 그림자 텍스처 생성에 많은 시간이 소요되는 문제점을 가지고 있다. 실험 결과, 새로운 방법은 그림자 텍스처의 문제점을 해결하고 고품질의 그림자를 표현하는 것을 알 수 있다.

• Proceedings of the Korea Contents Association Conference
• /
• 2006.11a
• /
• pp.806-810
• /
• 2006

The research of computer graphics is divided into two parts of photorealistic rendering and non-photorealistic rendering. The purpose of non-photo realistic rendering is to make image like cartoon, water-color, hatching etc. In this paper, we study for real-time hatching rendering and shadow techniques and we combine two techniques to make real-time hatching shadow. In shadow techniques we apply projected texture shadow to hatching rendering. Eventually, we introduce natural real-time hatching shadow through comparison and analysis.

• International Journal of Contents
• /
• v.12 no.2
• /
• pp.1-5
• /
• 2016

Extensible 3D (X3D) is the ISO standard for defining 3D interactive web- and broadcast-based 3D content integrated with multimedia. With the advent of this integration of interactive 3D graphics into the web, users can easily produce 3D scenes within web contents. Even though there are diverse texture nodes in X3D, projective textures are not provided. We enable X3D to provide SingularProjectiveTexture and MultiProjectiveTexture nodes by materializing independent nodes of projector nodes for a singular projector and multi-projector. Our approach takes the creation of an independent projective texture node instead of Kamburelis's method, which requires inconvenient and duplicated specifications of two nodes, ImageTexture and Texture Coordinate.

• The KIPS Transactions:PartB
• /
• v.12B no.4 s.100
• /
• pp.395-402
• /
• 2005

Object extraction is needed to track objects in color traffic image sequence. To extract objects, we use background differencing method based on MOG(Mixture of Gaussians). In extracted objects, shadows may be included. Due to shadows, we may not find exact location of objects and sometimes we find adjacent objects are glued together. Many methods have been proposed to remove shadows. Conventional methods usually assume that color and texture information are preserved under the shadow. Thus these methods do not work well if these assumptions do not hold. In this paper, we propose a new robust shadow removal method which works well in those situations. First we extract shadow pixel candidates by analysing color information and compute the ratio of shadow pixel candidates over the total number of Pixels. W the ratio is reasonable, we remove shadow candidate Pixels and if not, we use data in history array containing Previous removal records. We applied the method to real color traffic image sequences and obtained good results.

• Journal of KIISE:Computer Systems and Theory
• /
• v.29 no.5
• /
• pp.245-256
• /
• 2002

Shadows are important elements in producing a realistic image. Generation of exact shapes and positions of shadows is essential in rendering since it provides users with visual cues on the scene. It is also very important to be able to create soft shadows resulted from area light sources since they increase the visual realism drastically. In spite of their importance. the existing shadow generation algorithms still have some problems in producing realistic shadows in real-time. While image-based rendering techniques can often be effective1y applied to real-time shadow generation, such techniques usually demand so large memory space for storing preprocessed shadow maps. An effective compression method can help in reducing memory requirement, only at the additional decoding costs. In this paper, we propose a new image-barred shadow generation method based on image warping. With this method, it is possible to generate realistic shadows using only small sizes of pre-generated shadow maps, and is easy to extend to soft shadow generation. Our method will be efficiently used for generating realistic scenes in many real-time applications such as 3D games and virtual reality systems.

• International Journal of Fuzzy Logic and Intelligent Systems
• /
• v.10 no.3
• /
• pp.178-183
• /
• 2010

In this study we augmented a virtual object to an image of a flexible surface such as a paper, which is acquired from a web camera. To get more presence feeling, we consider realistic illumination on augmenting. To get the geometric relation between the camera and the flexible surface, we use markers that are printed on the surface. Using marker information in prior, three dimensional coordinates of the surface can be calculated. After the marker is removed from the input image, we attach a two dimensional texture and shadow to the flexible surface by considering realistic illumination.

• KSII Transactions on Internet and Information Systems (TIIS)
• /
• v.11 no.11
• /
• pp.5436-5458
• /
• 2017

Automatic Video Surveillance System (AVSS) has become important to computer vision researchers as crime has increased in the twenty-first century. As a new branch of AVSS, baggage detection has a wide area of security applications. Some of them are, detecting baggage in baggage restricted super shop, detecting unclaimed baggage in public space etc. However, in this paper, a detection & classification framework of baggage is proposed. Initially, background subtraction is performed instead of sliding window approach to speed up the system and HSI model is used to deal with different illumination conditions. Then, a model is introduced to overcome shadow effect. Then, occlusion of objects is detected using proposed mirroring algorithm to track individual objects. Extraction of rotational signal descriptor (SP-RSD-HOG) with support plane from Region of Interest (ROI) add rotation invariance nature in HOG. Finally, dynamic human body parameter setting approach enables the system to detect & classify single or multiple pieces of carried baggage even if some portions of human are absent. In baggage detection, a strong classifier is generated by boosting similarity measure based multi layer Support Vector Machine (SVM)s into HOG based SVM. This boosting technique has been used to deal with various texture patterns of baggage. Experimental results have discovered the system satisfactorily accurate and faster comparative to other alternatives.

• Journal of the Semiconductor & Display Technology
• /
• v.10 no.2
• /
• pp.31-38
• /
• 2011

This paper introduces a video based traffic monitoring system for detecting vehicles and obstacles on the road. To segment moving objects from image sequence, we adopt the background subtraction algorithm based on the local binary patterns (LBP). Recently, LBP based texture analysis techniques are becoming popular tools for various machine vision applications such as face recognition, object classification and so on. In this paper, we adopt an extension of LBP, called the Diagonal LBP (DLBP), to handle the background subtraction problem arise in vision-based autonomous parking systems. It reduces the code length of LBP by half and improves the computation complexity drastically. An edge based shadow removal and blob merging procedure are also applied to the foreground blobs, and a pose estimation technique is utilized for calculating the position and heading angle of the moving object precisely. Experimental results revealed that our system works well for real-time vehicle localization and tracking applications.

• Journal of the Korean Vacuum Society
• /
• v.8 no.2
• /
• pp.116-120
• /
• 1999

Fe-Ni alloy thin films with about 3.5 $\mu\textrm{m}$ thickness were successfully grown on Al-killed steel substrates employing DC magnetron sputtering method, and then the4 film properties were characterized. The deposited film exhibited a fibre texture structure with the relationship of ${110}_\textrm{film}//{111}_\textrm{substrate}$. We found that the adhesion between the film and the substrate was fairly good considering no debonding behavior after the thermal cyclic test of 5,000 times from room temperature to $200^{\circ}C$. Also we found that the Fe-Ni alloy deposition induced a significant decrease of thermal expansion in the film processing, a new material system with much lower thermal expansion coefficient which can be applied more as shadow mask materials than an Al-killed steel sheet.