• Journal of Korea Multimedia Society
• /
• v.7 no.1
• /
• pp.44-53
• /
• 2004

This paper aims at presenting high quality at low resolution apply by a new antialiasing method for voxelized implicit surfaces. Implicit surfaces create a unique type of 3D-modeling. Some use of implicit surfaces are scientific and medical visualization, animation, medical simulation and interactive modeling. One of previous antialiasing methods for implicit surfaces presented by raytracing or texture mapping is making use of a stochastic sampling. But this method requires more calculation time and costs which is caused by complicated and difficult implicit functions. In the meanwhile, voxelized implicit surfaces generally use high resolution for good quality images but it costs to generate. In order to this problem, this paper suggests a shifted double Z-buffer which is very simple, more efficient and easy. Tn addition, there are applied box-filter and tent-filter to the double Z-buffer antialiasing method for better images. For results this method generate high quality image and it is easy to apply to various filters and is able to extend to multi Z-buffer.

• Proceedings of the Korean Information Science Society Conference
• /
• 2000.04b
• /
• pp.661-663
• /
• 2000

자연에 존재하는 연속량의 데이터는 디지털화 될 때 숫자로 변환된다. 이때 부딪치는 일반적인 문제는 완전히 통합되지 않았거나 잘못 통합된 표본 추출의 결과로 정보를 잃어버리는 앨리어싱(Aliasing) 현상이 일어나게 된다. 현재 일반 사용자가 사용하는 PC기반의 모니터 해상도는 96PPI(Pixel ZPer Inch)밖에 제공하지 못한다. 이러한 저해상도에서 컴퓨터 그래픽 이미지 객체를 디스플레이 할 때 앨리어싱 현상이 자주 발생한다. 현재 PC 기반의 그래픽 하드웨어 구조의 변형없이 저해상도 모니터상에서 앨리어싱 현상이 발생하는 이미지를 기존의 계산 방법을 감소시키면서 앨리어싱 현상을 제거하는 기법이 필요하다. 본 연구에서는 이와 같이 앨리어싱 현상을 감소시켜 이미지 데이터의 품질을 향상시킬 수 있는 개선된 Anti-Aliasing 알고리즘을 제안한다.

• Journal of Korea Multimedia Society
• /
• v.8 no.2
• /
• pp.249-257
• /
• 2005

This paper aims at reducing aliasing in pixel-based rendering for 3D implicit surfaces by shifted multi Z-buffers. The voxelized implicit surfaces with high resolution take so much time in generating high Quality image without aliasing. So in rendering a voxelized implicit surfaces, a new antialiasing method which can generate a high quality image at a lower resolution is required. Therefore, this paper suggests that a method which get various sampling values by shifting several z-buffers in each voxel and average them, The advantages are effective memory, simple calculation and easy convergence with various filters. But, the increase of number of z-buffer also increase the consuming time rapidly. Therefore, the research for representing the relation the degree of image quality with the consumption of time as a number is required.

• Journal of Digital Contents Society
• /
• v.8 no.1
• /
• pp.85-91
• /
• 2007

This paper proposes a new hybrid anti-aliasing method for reducing aliasing appearing on an implicit surface using the point sampling. The hybrid anti-aliasing method is a method that finds differences in the values of pixel shown in Z-buffers for an implicit surface and thereby uses each of three types of Z-buffer. After determining the level of differences, it expresses a 3 dimensional object by using a multi Z-buffer if the level is severe, a double Z-buffer for a middle level, and only the original Z-buffer for a negligible difference. In comparison with the existing method in which multi Z-buffers have been entirely used for enhancing the anti-aliasing effect, the hybrid anti-aliasing method is an efficient method demonstrating an effect similar to the one using a multi Z-buffer while reducing the number of Z-buffers to be used.

• Proceedings of the Korea Multimedia Society Conference
• /
• 2002.11b
• /
• pp.497-502
• /
• 2002

레이 트레이싱이나 텍스쳐 맵핑에 의한 Implicit 곡면에서의 앤티 앨리어싱을 위한 방법으로 일반적으로 stochastic 샘플링 방법이 많이 사용되고 있다. 하지만 이 방법은 복잡한 함수로 표현된 Implicit 곡면에 더 많은 복잡한 계산을 요구하며 이에 따라 처리 시간과 비용이 많이 든다. 본 논문에서는 복셀(voxel)로 표현되는 Implicit 곡면에서 효율적인 방법 및 계산으로 앨리어싱을 감소시키기 위하여 shifted 더블 Z-버퍼를 이용하였으며, 또한 box-filter와 tent-filter를 적용함으로써 양질의 Implicit 곡면 이미지를 표현하였다.

• Proceedings of the Korea Information Processing Society Conference
• /
• 2007.05a
• /
• pp.357-360
• /
• 2007

초해상도 영상 복원은 저해상도 이미지를 고해상도 이미지로 변환하는 기술이다. 저해상도를 고해상도로 변환 시 정보가 없는 화소에 대한 정확한 화소값을 예측하는 보간법을 이용하게 되며 영상의 스케일링에 따른 앨리어싱 (aliasing) 이 발생하는 문제를 해결해야 한다. 본 논문에서는 Sobel 연산자를 통해 구한 에지 성분의 크기와 방향성을 이용하여, 초해상도 영상의 앨리어싱과 블러링(blurring) 을 줄이는 기법을 제안한다.

• Proceedings of the Korean Institute of Information and Commucation Sciences Conference
• /
• v.9 no.1
• /
• pp.651-654
• /
• 2005

Shadows are important elements for realistic rendering of the 3D scene. Image based methods which are techniques to generate shadows are widely used because of fast calculation time. However, this algorithm has aliasing problems. PCF is a method to solve the aliasing problem. Using PCF technique, antialiased shadow boundary can be generated. However, PCF with large filter size requires more time to calculate antialiased shadow boundary. This paper introduces an improved PCF technique which generates antialiased shadow boundary similar to that of PCF. Compared with PCF, this technique can generate antialiased shadows in less time.

• Journal of the Korea Institute of Information and Communication Engineering
• /
• v.11 no.8
• /
• pp.1442-1449
• /
• 2007

Shadows are important elements for realistic rendering of the 3D scene. We cannot recognize the distance of objects in the 3D scene without shadows. Two methods, image-based medthods and object-based methods, are largely used for the rendering of shadows. Object based methods can generate accurate shadow boundaries. However, it cannot be used to generate the realtime shadows because the time complexity defends on the complexity of the 3D scene. Image based methods which are techniques to generate shadows are widely used because of fast calculation time. However, this algorithm has aliasing problems. PCF is a method to solve the aliasing problem. Using PCF technique, antialiased shadow boundaries can be generated. However, PCF with large filter size requires more time to calculate antialiased shadow boundaries. This paper proposes an improved PCF technique which generates antialiased shadow boundaries similar to that of PCF. Compared with PCF, this technique can generate antialiased shadows in less time.

• The Journal of Korean Institute of Electromagnetic Engineering and Science
• /
• v.30 no.2
• /
• pp.124-131
• /
• 2019

This study presents an imaging algorithm that can provide an image of a moving target in a multiple-input-multiple-output radar environment where multiple transmitting and receiving radars are fixed on the ground. The proposed algorithm, which is based on polar format processing using plane wave approximation, is shown to provide an unaliased image by using multiple transmitting radars even when the distances between the receiving radars are relatively large. We derive the conditions necessary to deploy the transmitting radars by which the resolution of the reconstructed image can be improved, while simultaneously reducing aliasing artifacts. Moreover, we offer a means of separating out each transmitting radar target echo. Finally, the performance of the proposed system is verified through a simulation.

• Proceedings of the Korean Society of Precision Engineering Conference
• /
• 2004.10a
• /
• pp.422-425
• /
• 2004

This paper develops an octree-based algorithm for machining simulation. Most commercial machining simulators are based on the Z map model, which has several limitations in terms of achieving a high level of precision in five-axis machining simulation. Octree representation being a three-dimensional (3D) decomposition method, an octree-based algorithm is expected to be able to overcome such limitations. With the octree model, storage requirement is reduced. Moreover, recursive subdivision is processed in the boundaries, which reduces useless computations. The supersampling method is the most common form of antialiasing and is typically used with polygon mesh rendering in computer graphics. The supersampling technique is being used to advance the efficiency of the octree algorithm..