High-dynamic-range video for photometric measurement of illumination

“…The minimum number of exposures required to accurately capture a scene given an acceptable noise level has also been studied [69,84]. These techniques have also been used for HDR video capture using separate exposures for each frame [103] or rows [205].…”

Section: Exposure Bracketingmentioning

confidence: 99%

“…This can be a major concern in darker scenes, and in general leads to increased image noise. An alternative solution using all the incident light is based on recent (commercial) imaging sensors where the pixel gain can be varied over the sensor, [3,80,205,207]. The analog pixel gain is proportional to the ISO setting found on most cameras.…”

Section: Spatially Varying Sensor Exposurementioning

confidence: 99%

Physically Based Rendering of Synthetic Objects in Real Environments

Kronander¹

2015

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Description of the cover imageRendering of virtual furniture illuminated with spatially varying real world illumination captured in a physical environment at IKEA Communications AB.The virtual scene was modeled by Sören and Per Larsson. Physically based rendering of synthetic objects in real environmentsCopyright © 2015 Joel Kronander (unless otherwise noted) Division of Media and Information TechnologyDepartment of Science and Technology Campus Norrköping, Printed in Sweden by LiU-Tryck, Linköping, 2015 AbstractThis thesis presents methods for photorealistic rendering of virtual objects so that they can be seamlessly composited into images of the real world. To generate predictable and consistent results, we study physically based methods, which simulate how light propagates in a mathematical model of the augmented scene. This computationally challenging problem demands both efficient and accurate simulation of the light transport in the scene, as well as detailed modeling of the geometries, illumination conditions, and material properties. In this thesis, we discuss and formulate the challenges inherent in these steps and present several methods to make the process more efficient.In particular, the material contained in this thesis addresses four closely related areas: HDR imaging, IBL, reflectance modeling, and efficient rendering. The thesis presents a new, statistically motivated algorithm for HDR reconstruction from raw camera data combining demosaicing, denoising, and HDR fusion in a single processing operation. The thesis also presents practical and robust methods for rendering with spatially and temporally varying illumination conditions captured using omnidirectional HDR video. Furthermore, two new parametric BRDF models are proposed for surfaces exhibiting wide angle gloss. Finally, the thesis also presents a physically based light transport algorithm based on Markov Chain Monte Carlo methods that allows approximations to be used in place of exact quantities, while still converging to the exact result. As illustrated in the thesis, the proposed algorithm enables efficient rendering of scenes with glossy transfer and heterogenous participating media.v Populärvetenskaplig SammanfattningEn av de största utmaningarna inom datorgrafik är att syntetisera, eller rendera, fotorealistiska bilder. Fotorealistisk rendering används idag inom många tillämpningsområden såsom specialeffekter i film, datorspel, produktvisualisering och virtuell verklighet. I många praktiska tillämpningar av fotorealistisk rendering är det viktigt att kunna placera in virtuella objekt i fotografier, så att de virtuella objekten ser verkliga ut. IKEA-katalogen, till exempel, produceras i många olika versioner för att passa olika länder och regioner. Grunden till de flesta bilderna i katalogen är oftast densamma, men symboler och standardmått på möbler varierar ofta för olika versioner av katalogen. Istället för att fotografera varje version separat kan man använda ett grundfotografi och lägga in olika virtuella objekt såsom möbler...

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“…We capture panoramic HDR image sequences of incident lighting, using a catadioptric imaging system consisting of an HDR video camera and a mirror sphere. Our hardware solution for HDR video has been presented in detail in Unger et al [20], but a summary is given below.…”

Section: A Real Time Light Probementioning

confidence: 99%

Spatially varying image based lighting by light probe sequences

2007

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We present a novel technique for capturing spatially or temporally resolved light probe sequences, and using them for image based lighting. For this purpose we have designed and built a Real Time Light Probe, a catadioptric imaging system that can capture the full dynamic range of the lighting incident at each point in space at video frame rates, while being moved through a scene. The Real Time Light Probe uses a digital imaging system which we have programmed to capture high quality, photometrically accurate color images of 512x512 pixels with a dynamic range of 10,000,000:1 at 25 frames per second.By tracking the position and orientation of the light probe, it is possible to transform each light probe into a common frame of reference in world coordinates, and map each point and direction in space along the path of motion to a particular frame and pixel in the light probe sequence. We demonstrate our technique by rendering synthetic objects illuminated by complex real world lighting, first by using traditional image based lighting methods and temporally varying light probe illumination, and second an extension to handle spatially varying lighting conditions across large objects and object motion along an extended path.

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High-dynamic-range video for photometric measurement of illumination

Cited by 35 publications

References 7 publications

Evaluation of Tone Mapping Operators for HDR Video

Evaluation of Tone Mapping Operators for HDR Video

Physically Based Rendering of Synthetic Objects in Real Environments

Spatially varying image based lighting by light probe sequences

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