• Title/Summary/Keyword: luminance mapping

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Methodological study on the High Dynamic Range Imaging Processing (채광·조명설비시스템의 광학 분석을 위한 이미지 프로세싱 기법에 관한 연구)

  • Lim, Hong Soo;Kim, Gon
    • KIEAE Journal
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    • v.10 no.4
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    • pp.3-8
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    • 2010
  • Recently, various daylight evaluation methods for visual environment have been developed; simulation analysis methods, numerical calculation, and data monitoring methods. However, it is impossible for simulation analysis to make real scenes and visualize real images exactly. Also, a numerical calculation is considered as an out of date and time-consuming mean. Therefore, for acquisition of accurate results, many studies often use the monitoring data methods. Especially, most studies regarding discomfort glare are evaluated by measuring the physical quantity of luminance through traditional measuring Minolta Luminance meters as an instrument. But, this method has a difficulty in measuring several points at the same time because of the limitation of spaces and time when mapping. So, this study focused on the potential usefulness of High Dynamic Range photography technique as a luminance mapping tool. In order to evaluate the accuracy of proposed programs such as webHDR, Photomatix and PHOTOLUX, this paper has conducted an experiment by using Canon EOS 5D and NICON Coolpix8400 digital camera.

Logarithmic Tone Mapping for High Dynamic Range Imaging

  • Lee, Joo-Hyun;Jeon, Gwang-Gil;Jeong, Je-Chang
    • Proceedings of the Korean Society of Broadcast Engineers Conference
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    • 2009.01a
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    • pp.154-157
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    • 2009
  • High dynamic range image can describe the real world scenes that have a wide range of luminance intensity. To display high dynamic range (HDR) image into conventional displayable devices such as monitors and printers, we proposed the logarithmic based global mapping algorithm that consider the features of image using mapping parameters. Based on characteristics of image, we first modify input luminance values for reproducing perceptually tuned images and then displayable output values are obtained directly. The experimental results show that the proposed algorithm achieves good subjective results while preserving details of image, furthermore proposed algorithm has fast simple and practical structure for implementation.

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Gamut Mapping Using Variable Anchor Points for Continuous Color Reproduction between Devices (장치간 연속 색 재현을 위한 가변 닻점 방식의 색역 사상)

  • 이채수;윤태진;한찬호
    • Proceedings of the Korea Society for Industrial Systems Conference
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    • 2001.05a
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    • pp.300-310
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    • 2001
  • In this paper, new gamut-mapping algorithm (GMA) that utilizes variable anchor points (center of gravity on the luminance axis) is proposed. The proposed algorithm increases luminance range, which is reduced from conventional gamut mapping toward an anchor point. In this process, this algorithm utilizes multiple anchor points with constant slopes to both reduce a sudden color change on the gamut boundary of the printer and to maintain a uniform color change during the mapping process. Accordingly, the proposed algorithm can reproduce high quality images with low-cost color devices.

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Image-Based Relighting - Luminance Mapping Based on Lighting Functions

  • Manabe, Tomohisa;Raytchev, Bisser;Tamaki, Toru;Kaneda, Kazufumi
    • International Journal of CAD/CAM
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    • v.12 no.1
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    • pp.38-47
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    • 2012
  • The paper proposes a method for generating a sequence of images with smooth transition of illumination from two input images with different lighting conditions. Our relighting approach is image-based, such as the light field rendering. We store the luminances (pixel RGB values) into "lighting functions" consisting of a couple of parameters related to normal vectors. Images with different light positions are rendered by interpolating the luminances retrieved from the lighting functions. The proposed method is a promising technique for many applications requiring a scene with variety of lighting effects, such as movies, TV games, and so on.

Gamut Mapping Using Variable Multiple Anchor Points for Continuous-Tone Color Reproduction (연속계조 칼라재현을 위한 가변 다중 닻점을 이용한 색역 사상)

  • Lee, Chae-Su;Lee, Cheol-Hui;Ha, Yeong-Ho
    • Journal of the Korean Institute of Telematics and Electronics S
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    • v.36S no.8
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    • pp.55-64
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    • 1999
  • In this paper, new gamut-mapping algorithm (GMA) that utilizes variable anchor points (center of gravity on the luminance axis) is proposed. The proposed algorithm increases luminance range, which is reduced from conventional gamut mapping toward an anchor point. In this process, this algorithm utilizes multiple anchor points with constant slopes to both reduce a sudden color change on the gamut boundary of the printer and to maintain a uniform color change during the mapping process. Accordingly, the proposed algorithm can reproduce high quality images with low-cost color devices.

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Enhanced High Contrast Image Rendering Method Using Visual Properties for Sharpness Perception (시각 선명도 감각 특성을 이용한 개선된 고명암 대비 영상 렌더링 기법)

  • Lee, Geun-Young;Lee, Sung-Hak;Kwon, Hyuk-Ju;Sohng, Kyu-Ik
    • The Journal of Korean Institute of Communications and Information Sciences
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    • v.38A no.8
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    • pp.669-679
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    • 2013
  • When an image is converted from HDR (high dynamic range) to LDR (low dynamic range), a tone mapping process is the essential component. Many TMOs (tone mapping operators) have been motivated by human vision which has lower physical luminance range than that in real scene. The representative of human vision properties which motivate TMOs is the local adaptation. However, TMOs are ultimately compressing image information such as contrast, saturation, etc. and the compression causes defects in image quality. In this paper, in order to compensate the degradation of the image which is caused by TMOs, the visual acuity-based edge stop function is proposed for applying the property of human vision to base-detail separation. In addition, using CSF (contrast sensitivity function) which represents the relationship among spatial frequency, contrast sensitivity, and luminance, the sharpness filter is designed and adaptively applied to the detail layer in regard to surround luminance.

Lightness and Chroma Mapping Consider the Device Characteristic (장치 특성을 고려한 밝기 사상 및 색역 사상)

  • 박양우;이채수;엄태억;장주석
    • Proceedings of the IEEK Conference
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    • 2000.11d
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    • pp.143-146
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    • 2000
  • In this paper, luminance mapping for uniform color distribution and gamut mapping for maximum chroma reproduction are proposed. In the conventional lightness mapping, the average lightness difference between the two gamut is increased and different color changes in bright and dark regions are also increased. To solve these problems, a lightness mapping is proposed that minimizes the lightness difference of the cusps at each hue angle and produces same color changes in bright and dark regions. Also, chroma mapping that utilize variable anchor point and an anchor point are proposed for maximum chroma reproduction and uniform color change. The proposed algorithm reduce a sudden color change on the gamut boundary of the printer and to maintain a uniform color change during the mapping process. Accordingly, the proposed algorithm can reproduce high quality images with low-cost color devices.

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Improved Algorithm of Sectional Tone Mapping for HDR Images (HDR 이미지를 위한 단면 톤 매핑 개선 알고리즘 구현)

  • Lee, Yong-Hwan;Kim, Heung-Jun
    • Journal of the Semiconductor & Display Technology
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    • v.20 no.2
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    • pp.137-140
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    • 2021
  • High dynamic range (HDR) technology has been drawing attention in the field of imaging and consumer entertainment. As tools for capturing and creating HDR contents, encoding, and transmission evolve to support HDR formats, various display capabilities are being developed and increased. Hence, there is need for remapping native HDR imagery for display on lower quality legacy standard dynamic range (SDR) displays. This operation is referred to as tone mapping. In this paper, we present a sectional tone mapping method by Lenzen, and expand upon a tone mapping approach to improve temporal stability while maintaining picture quality. Compared to the existing block-based sectional tone mapping, our method uses the edge awareness-based tone mapping. We estimate the performance of the objective metric on temporal flickering. The experimental result shows that the algorithm maintains a smoother relationship between the output luminance values, and this reveals success in reducing halos and improving temporal stability with adopted edge aware filtering.

Improvement of Efficient Tone-Mapping Curve using Adaptive Depth Range Coefficient (적응적 깊이 영역 변수를 활용한 효율적인 톤 매핑 커브 개선)

  • Lee, Yong-Hwan;Kim, Youngseop;Ahn, Byoung-Man
    • Journal of the Semiconductor & Display Technology
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    • v.14 no.4
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    • pp.92-97
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    • 2015
  • The purpose of this work is to support a solution of optimizing TMO (tone mapping operator). JPEG XT Profile A and C utilize Erik Reinhard TMO that works well in most cases, however, detailed information of a scene is lost in some cases. Reinhard TMO only calculates its coefficient to have tone-mapping curve from log-average luminance, and this lead to lose details of bright and dark area of scenes in turn. Thus, this paper proposes an enhancement of the default TMO for JPEG XT Profile C to optimize tone-mapping curve. Main idea is that we divide tone mapping curve into several ranges, and set reasonable parameters for each range. By the experimental results, the proposed scheme shows and obtains better performance within a dark scene, compared to the default Reinhard TMO.

Tone Mapping Method using Non-linear Dynamic Range Normalization for High Dynamic Range Images (HDR 영상을 위한 비선형 동적영역 정규화를 이용한 톤 매핑 기법)

  • Kim, Beom-Yong;Hwang, Bo-Hyun;Yun, Jong-Ho;Choi, Myung-Ryul
    • Proceedings of the IEEK Conference
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    • 2008.06a
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    • pp.851-852
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    • 2008
  • In this paper, we propose a tone mapping method using Non-linear Dynamic Range Normalization (NDRN) for High Dynamic Range (HDR) images. HDR images are not suitable for commercial display devices because dynamic range of HDR images do not match with one of Low Dynamic Range (LDR) display devices. To reproduce a tone of HDR images for LDR displays, tone mapping methods have been proposed such as local and global tone mapping. We introduce NDRN to locate mean of HDR images at the center of LDR. NDRN preserves the details for highlight and shadow. By suppressing the significant luminance change in tone mapping, naturalness of original image can be also preserved. The experimental results show that the proposed method preserves details and naturalness of original images.

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