This landmark book is the first to describe HDRI technology in its entirety and covers a wide-range of topics, from capture devices to tone reproduction and image-based lighting. The techniques described enable you to produce images that have a dynamic range much closer to that found in the real world, leading to an unparalleled visual experience. As both an introduction to the field and an authoritative technical reference, it is essential to anyone working with images, whether in computer graphics, film, video, photography, or lighting design.



New material includes chapters on High Dynamic Range Video Encoding, High Dynamic Range Image Encoding, and High Dynammic Range Display Devices
Written by the inventors and initial implementors of High Dynamic Range Imaging
Covers the basic concepts (including just enough about human vision to explain why HDR images are necessary), image capture, image encoding, file formats, display techniques, tone mapping for lower dynamic range display, and the use of HDR images and calculations in 3D rendering
Range and depth of coverage is good for the knowledgeable researcher as well as those who are just starting to learn about High Dynamic Range imaging


Table of Contents

Introduction; Light and Color; HDR Image Encodings; HDR Video Encodings; HDR Image and Video Capture; Display Devices; The Human Visual System and HDR Tone Mapping; Spatial Tone Reproduction; Frequency Domain and Gradient Domain Tone Reproduction; Inverse Tone Reproduction; Visible Difference Predictors; Image-Based Lighting.

High Dynamic Range Imaging: Acquisition, Display, and Image-Based Lighting (The Morgan Kaufmann Series in Computer Graphics)

New generations of display devices promise to provide significantly improved dynamic range over conventional display technology. In the long run, evolving camera technology and file formats will provide high fidelity content for these display devices. In the near term, however, the vast majority of images and video will only be available in low dynamic range formats. In this paper we describe a method for boosting the dynamic range of legacy video and photographs for viewing on high dynamic range displays. Our emphasis is on real-time processing of video streams, such as web streams or the signal from a DVD player. We place particular emphasis on robustness of the method, and its ability to deal with a wide range of content without user adjusted parameters or visible artifacts. The method can be implemented on both graphics hardware and on signal processors that are directly integrated in the HDR displays.

Ldr2Hdr: on-the-fly reverse tone mapping of legacy video and photographs

The development of high dynamic range (HDR) imagery has brought us to the verge of arguably the largest change in image display technologies since the transition from black-and-white to color television. Novel capture and display hardware will soon enable consumers to enjoy the HDR experience in their own homes. The question remains, however, of what to do with existing images and movies, which are intrinsically low dynamic range (LDR). Can this enormous volume of legacy content also be displayed effectively on HDR displays? We have carried out a series of rigorous psychophysical investigations to determine how LDR images are best displayed on a state-of-the-art HDR monitor, and to identify which stages of the HDR imaging pipeline are perceptually most critical. Our main findings are: (1) As expected, HDR displays outperform LDR ones. (2) Surprisingly, HDR images that are tone-mapped for display on standard monitors are often no better than the best single LDR exposure from a bracketed sequence. (3) Most importantly of all, LDR data does not necessarily require sophisticated treatment to produce a compelling HDR experience. Simply boosting the range of an LDR image linearly to fit the HDR display can equal or even surpass the appearance of a true HDR image. Thus the potentially tricky process of inverse tone mapping can be largely circumvented.

Do HDR displays support LDR content?: a psychophysical evaluation

http://people.csail.mit.edu/pdidyk/papers/ComputationalDisplaysSurvey.pdf

Special Section on Advanced Displays: A survey on computational displays: Pushing the boundaries of optics, computation, and perception

Most existing image content has low dynamic range (LDR), which necessitates effective methods to display such legacy content on high dynamic range (HDR) devices. Reverse tone mapping operators (rTMOs) aim to take LDR content as input and adjust the contrast intelligently to yield output that recreates the HDR experience. In this paper we show that current rTMO approaches fall short when the input image is not exposed properly. More specifically, we report a series of perceptual experiments using a Brightside HDR display and show that, while existing rTMOs perform well for under-exposed input data, the perceived quality degrades substantially with over-exposure, to the extent that in some cases subjects prefer the LDR originals to images that have been treated with rTMOs. We show that, in these cases, a simple rTMO based on gamma expansion avoids the errors introduced by other methods, and propose a method to automatically set a suitable gamma value for each image, based on the image key and empirical data. We validate the results both by means of perceptual experiments and using a recent image quality metric, and show that this approach enhances visible details without causing artifacts in incorrectly-exposed regions. Additionally, we perform another set of experiments which suggest that spatial artifacts introduced by rTMOs are more disturbing than inaccuracies in the expanded intensities. Together, these findings suggest that when the quality of the input data is unknown, reverse tone mapping should be handled with simple, non-aggressive methods to achieve the desired effect.

/pdf/evaluation-of-reverse-tone-mapping-through-varying-exposure-54jp91ny9s.pdf

Evaluation of reverse tone mapping through varying exposure conditions

Recent high dynamic range (HDR) display devices provide significantly greater output brightness and dynamic range compared to conventional display technology. A possible concern for the extended use of HDR displays is the potential to cause visual fatigue. Furthermore, ambient illumination has a significant effect on the perception of the imagery displayed, and its impact on user preferences for brightness and contrast must be understood.In our work we examine these issues by conducting two user studies. In each study, subjects watched video content on an HDR display in several different ambient illumination environments, and were asked to adjust the brightness and black level of the display to their preference. Subjects were also given questionnaires to document their observations and subjective preferences as well as any visual fatigue they may have experienced. We found that subjects experienced minimal visual fatigue, and also found statistically significant differences in preferred display settings under different ambient lighting conditions.

/pdf/video-viewing-preferences-for-hdr-displays-under-varying-2vyz0ghb29.pdf

Video viewing preferences for HDR displays under varying ambient illumination

contrast ratio and amplitude resolution are rapidly growing display specifications. Through a series of human factor studies we have developed simple guidelines for these specifications including viewer preference for luminance, optimal contrast ratio and amplitude resolution under realistic conditions. 1. Introduction past, conventional displays have been largely limited to a dynamic range similar to paper under office lighting conditions - approximately two or three orders of magnitude starting at a grayish black and finishing in the hundreds of cd/m 2 . This paradigm of hundreds-to-one contrast ratio, limited luminance and an amplitude resolution in the hundreds of steps is shifting today. Novel display technologies are emerging with the potential of much higher contrast and brightness. Moreover, even existing display technology is being pushed to the limit with a strong increase in display performance. This trend proceeds unevenly with contrast ratio rising faster than luminance, and amplitude resolution remaining largely static. As a result, many display designs make sub-optimal use of the device capabilities. This paper presents a series of human factor studies that aim to provide a basic framework of luminance, contrast ratio and amplitude resolution and their interaction. The use of a High Dynamic Range (HDR) display (1) as the imaging tool for the study, allows a large enough range for each variable to encompass all current and most near-future display technologies. The results of the study can be used to make design decisions for future displays as well as more realistic comparisons of existing devices. 2. Background Video Electronics Standards Association (VESA) and International Organization for Standardization (ISO) provide common guidelines for display specification including luminance and contrast ratio. Peak luminance is generally easy to measure and reported relatively accurately by the industry. Contrast ratio is significantly more challenging. A proper contrast ratio

25.3: Observations of Luminance, Contrast and Amplitude Resolution of Displays

https://sid.onlinelibrary.wiley.com/doi/pdf/10.1002/j.2637-496X.2009.tb00010.x

Metrics for Local-Dimming Artifacts in High-Dynamic-Range LCDs

Sixty-three participants (range from 18 to 85 years of age) completed 4 data entry tasks on an HP iPAQ 5450 via a touch-screen QWERTY keyboard, as well as a battery of neuro-cognitive tests. Entry errors and assistance required by participants were coded into categories. Multiple regression analyses revealed that episodic memory was the strongest predictor for stand-still errors and commission errors, while sensory abilities was the strongest predictor of omission errors. We suggest that raining sessions that familiarize older adults with the functions of specific keys (e.g. Spacebar and Backspace) and structure of the keyboard, complemented with visual or auditory feedback provided by the keyboard as methods to improve text entry accuracy.

/pdf/cognitive-perceptual-sensory-and-verbal-abilities-as-1loxuei0wv.pdf

Hiroe Li

Papers

Video viewing preferences for HDR displays under varying ambient illumination

25.3: Observations of Luminance, Contrast and Amplitude Resolution of Displays

Metrics for Local-Dimming Artifacts in High-Dynamic-Range LCDs

Cognitive, perceptual, sensory and verbal abilities as predictors of PDA text entry error and instructions across the lifespan