• Transactions of Materials Processing
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• v.18 no.2
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• pp.128-134
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• 2009

The present study covers an integrated simulation method to evaluate optical performance of an aspheric plastic lens by connecting an injection molding analysis with a ray tracing simulation. Traditional ray tracing methods have based on the assumption that the optical properties of a lens are homogeneous throughout the entire volume. This assumption is to a certain extent unrealistic for injection-molded plastic lenses because material properties vary at every point due to the injection molding effects. To take into account the effects of the inhomogeneous optical properties of the molded lens, a numerical scheme is developed to calculate the distribution of refractive index induced from the injection molding process. This index distribution is then reflected onto CODE $V^{(R)}$ simulation and used to calculate ray paths in inhomogeneous media. The proposed tracing scheme is implemented on the tracing of an aspheric lens for a mobile phone camera module.

• Journal of the Korea Computer Graphics Society
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• v.28 no.3
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• pp.113-123
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• 2022

Ray tracing-based rendering creates by far more realistic images than the traditional rasterization-based rendering. However, it is still burdensome when implemented for a Head-Mounted Display (HMD) system that demands a wide field of view and a high display refresh rate. Furthermore, for presenting high-quality images on the HMD screen, a sufficient number of ray sampling should be carried out per pixel to alleviate visually annoying spatial and temporal aliases. In this paper, we extend the recent selective foveated ray tracing technique by Kim et al. [1], and propose an improved real-time rendering technique that realizes the rendering effect of the classic Whitted-style ray tracing on the HMD system. In particular, by combining the ray tracing hardware-based acceleration technique and time-constrained rendering scheme, we show that fast HMD ray tracing is possible that is well suited to human visual systems.

• Proceedings of the KSR Conference
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• 1998.11a
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• pp.388-397
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• 1998

This paper gives the way of analyzing internal noise of rolling stocks which is urgently required by civilians. Triangular beam method among ray tracing techniques is utilized to compute noise distribution of rolling stocks. Noise source and transmisstion loss of several sections from experimental work are included in this calculation. Ray tracing technique is found useful to compute big structures like rolling stocks.

• Proceedings of the KSME Conference
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• 2003.04a
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• pp.992-997
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• 2003

Aspherical lens design method named ray reverse tracing method is introduced. Differently from the traditional design method, the ray reverse tracing method traces the shape and location of a real object by use of its virtual image. From the result, it was convinced that spherical aberration free aspherical lens could be designed by use of the ray reverse tracing method. Furthermore, it could reduce the degree of dependence of optical characteristics on designer's ability, because deformation terms and optimization can be eliminated, which has been performed in conventional lens design process.

• Journal of the Korean Society of Manufacturing Process Engineers
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• v.6 no.1
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• pp.7-12
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• 2007

The optic industry is a high value-added advanced technology industry combined with the precision machine industry and the digital electronics industry. The aspheric lens, one of optic parts, is a key technology having a significant influence on the performance of optic equipment. So this study relates to designing an aspheric lens to which a ray-tracing method is applied. In the ray-tracing method, a refractive index of material is used, which take an advantage that the location of a light source and incident angle can be fixed, unlike the ray back-tracing scheme.

• IEIE Transactions on Smart Processing and Computing
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• v.5 no.4
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• pp.289-293
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• 2016

As more mobile devices are equipped with multi-core CPUs and are required to execute many compute-intensive multimedia applications, it is important to optimize the systems, considering the underlying parallel hardware architecture. In this paper, we implement and optimize ray-tracing application tailored to a given mobile computing platform with multiple heterogeneous processing elements. In this paper, a lightweight ray-tracing application is specified and implemented in Kahn process network (KPN) model-of-computation, which is known to be suitable for the description of real-time applications. We take an open-source C/C++ implementation of ray-tracing and adapt it to KPN description in the Distributed Application Layer framework. Then, several possible configurations are evaluated in the target mobile computing platform (Exynos 5422), where eight heterogeneous ARM cores are integrated. We derive the optimal degree of parallelism and a suitable distribution of the replicated tasks tailored to the target architecture.

• Journal of the Korean Society for Precision Engineering
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• v.32 no.1
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• pp.75-81
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• 2015

Modeling and analysis using a ray tracing method for internal defects were described. Reflection and refraction of rays on the interface of defects were modeled using the Harvey model and the Lambertian model. The diffraction on the interface of defects affected the incoming signals and it could evaluate any defects in the matter and its signal would be analyzed with the ray tracing simulation. The simulation results were compared with actual detecting signals and the ray tracing model was shown in good agreement with experimental data. This method has a possibility to be used as wave propagation modeling in non-destructive testing.

• Journal of the Korean Society for Precision Engineering
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• v.20 no.10
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• pp.191-198
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• 2003

In this study, aberration free aspherical lens design method named ray reverse tracing method is introduced. Differently from the traditional design method, the ray reverse tracing method traces the shape and location of a real object by use of its virtual image. From the result, especially spherical aberration free aspherical lens could be designed by use of the ray reverse tracing method. Furthermore, it could reduce the degree of dependence of optical characteristics on designer's ability, because deformation terms and optimization can be eliminated, which has been performed in conventional lens design process.

• The Transactions of the Korea Information Processing Society
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• v.6 no.5
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• pp.1362-1372
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• 1999

Ray-tracing algorithm can synthesize photo-realistic image, but its computational cost is high. Fast image synthesis based on ray-tracing is one of the most important topics in computer graphics. There are two methods for high speed ray-tracing. First this paper discusses various load distribution and scheduling of multiprocessor for high sped ray-tracing. Then this paper proposes load distribution strategies based on them, implements and evaluates it on multiprocessor. The experiment results show that the proposed method can solve the unbalanced load problem of dynamic load distribution, and scan line method and dot method among a kind of static load distribution strategies disperse the load efficiently.

• The Journal of Korean Institute of Electromagnetic Engineering and Science
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• v.20 no.5
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• pp.471-479
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• 2009

In this paper, we proposed an improved ray tracing method with an amelioration of visible tree structure, a visible face determination method, and non-uniform random test point method. In a proposed visible tree structure, it reduces tree nodes by means of merging similar nodes. In a visible face determination method, it shows that a ray hit test with a packet ray method can reduce a test time. A ray tracing method involving with a packet ray hit test method can improve a tree construction time up to 3.3 times than a ray tracing method with a single ray hit test method. Furthermore, by seeding a non-uniform and random test point on a face, tree construction time is improved up to 1.11 times. Received powers from the proposed ray tracing results and measured results have good agreement with 1.9 dB RMS error.