Alan Chalmers

The University of Warwick · Warwick Manufacturing Group

Food and drink are a key part of our lives. While Virtual Reality has the potential to provide high-fidelity simulation of real experiences in virtual worlds, the incorporation of flavor appreciation within these virtual experiences has largely been ignored. This paper introduces a virtual flavor device to simulate real flavor experiences. The goal...

High-end mobile devices now support displaying video in High Dynamic Range (HDR), delivering a significantly enhanced viewing experience over Standard Dynamic Range (SDR). However, more energy may be required to play HDR, impacting device battery life and reducing overall quality of experience. We present a new methodology for predicting the real-...

High dynamic range (HDR) displays based on liquid crystal panels require local dimming algorithms to reproduce content with high fidelity and HDR. However, most local dimming algorithms are developed by using hand-crafted features and most of them focus on low dynamic range images rather than HDR images. In addition, few local dimming algorithms ca...

Virtual experiences (VEs) have significant potential to enrich emotional interactions, to encourage socialisation and improve communication. In education, VEs offer new approaches for delivering content. In this paper we consider the application of VEs for assisting refugees in Senegal to learn how to navigate the complexities of the UK health syst...

High dynamic range (HDR) displays with dual-panels are one type of displays that can provide HDR content. These are composed of a white backlight panel and a colour LCD panel. Local dimming algorithms are used to control the backlight panel in order to reproduce content with high dynamic range and contrast at a high fidelity. However, existing loca...

Folk dancing is a key aspect of intangible cultural heritage that often reflects the socio-cultural and political influences prevailing in different periods and nations; each dance produces a meaning, a story with the help of music, costumes and dance moves. It has been transmitted from generation to generation, and to different countries, mainly d...

The presence of people plays a key role in how an environment, both now and in the past, is perceived. While there have been numerous computer reconstructions of cultural heritage sites, many, if not most, of these do not contain people. One reason for this is the so called “uncanny valley” affect. Despite huge efforts to create highly realistic lo...

High dynamic range (HDR) technology allows more of the lighting in a specific scene to be captured at a set point in time, and thus is capable of delivering an overall view of the scene that more closely correlates with our visual experience in the real world, compared to standard, or low dynamic range (LDR) technology. Although HDR capabilities of...

Most Convolution Neural Network (CNN) based object detectors, to date, have been optimized for accuracy and/or detection performance on datasets typically comprised of well exposed 8-bits/pixel/channel Standard Dynamic Range (SDR) images. A major existing challenge in this area is to accurately detect objects under extreme/difficult lighting condit...

Dual-panel displays require local dimming algorithms in order to reproduce content with high fidelity and high dynamic range. In this work, a novel deep learning based local dimming method is proposed for rendering HDR images on dual-panel HDR displays. The method uses a Convolutional Neural Network to predict backlight values, using as input the H...

Convolution Neural Network (CNN)-based object detection models have achieved unprecedented accuracy in challenging detection tasks. However, existing detection models (detection heads) trained on 8-bits/pixel/channel low dynamic range (LDR) images are unable to detect relevant objects under lighting conditions where a portion of the image is either...

Accurately identifying cloud types in images has multiple uses from meteorological science to computer graphics, especially as clouds are a major factor influencing atmospheric radiative transport. Understanding which cloud types are present in an image is typically performed on a coarse scale, where cloud types are identified per image, but do not...

In order to enhance viewing experiences, a number of backlight local dimming (BLD) algorithms have been developed to improve the image contrast ratio and provide power efficiency for modern displays. In order to evaluate which BLD algorithm performs best for HDR images rendering on dual-panel displays, this paper presents a comprehensive subjective...

Virtual Environments (VEs) provide the opportunity to simulate a wide range of applications, from training to entertainment, in a safe and controlled manner. For applications which require realistic representations of real world environments, the VEs need to provide multiple, physically accurate sensory stimuli. However, simulating all the senses t...

Serious games are accepted as an effective approach to deliver augmented feedback in motor (re-) learning processes. The multi-modal nature of the conventional computer games (e.g. audiovisual representation) plus the ability to interact via haptic-enabled inputs provides a more immersive experience. Thus, particular disciplines such as medical edu...

Computer-assisted multimodal training is an effective way of learning complex motor skills in various applications. In particular disciplines (eg. healthcare) incompetency in performing dexterous hands-on examinations (clinical palpation) may result in misdiagnosis of symptoms, serious injuries or even death. Furthermore, a high quality clinical ex...

Human facial recognition in the context of surveillance, forensics and photo-ID verification is a task for which accuracy is critical. Quite often limitations in the overall quality of facial images reduces individuals' ability in taking decisions regarding a person's identity. To verify the suitability of advanced imaging techniques to improve ind...

Minna Silver, Gabriele Fangi & Ahmet Denker. Reviving Palmyra in multiple dimensions: images, ruins and cultural memory. 2018. Caithness: Whittles; 978-1-84995-296-5 £30. - Volume 93 Issue 371 - Alan Chalmers

Consumer High Dynamic Range (HDR) displays are appearing on the market. Capable of generating a peak luminance of up to 2000nits, the improved dynamic range they provide can only be perceived when viewed in a dark environment. In this paper, we present a display architecture that is capable of generating a peak luminance of 10,000 nits. We demonstr...

High dynamic range (HDR) displays are capable of displaying a wider dynamic range of values than conventional displays. As HDR content becomes more ubiquitous, the use of these displays is likely to accelerate. As HDR displays can present a wider range of values, traditional strategies for mapping HDR content to low dynamic range (LDR) displays can...

Virtual Environments (VEs) provide the opportunity to simulate a wide range of applications, from training to entertainment, in a safe and controlled manner. For applications which require realistic representations of real world environments, the VEs need to provide multiple, physically accurate sensory stimuli. However, simulating all the senses t...

Recently, there has been significant progress in the research and development of High Dynamic Range (HDR) video technology and state-of-the-art video pipelines are able to offer a higher bit depth support to capture, store, encode and display HDR video content. In this paper, we introduce a novel HDR video compression algorithm which uses a percept...

High dynamic range (HDR) imaging enables the full range of light in a scene to be captured, transmitted and displayed. However, uncompressed 32-bit HDR is four times larger than traditional low dynamic range (LDR) imagery. If HDR is to fulfil its potential for use in live broadcasts and interactive remote gaming, fast, efficient compression is nece...

Head-mounted displays (HMDs) enable a user to view a complete environment as if he/she was there; providing an immersive experience. However, the lighting in a full environment can vary significantly. Panoramic images captured with conventional low dynamic range (LDR) imaging of scenes with a large range of lighting conditions, can include areas of...

An evaluation of a no-reference objective quality metric to accurately measure and compare the increased dynamic range capability of modern image capture systems is presented. The use of commercial off-the-shelf equipment and software allows manufacturers and users to produce results that are both transparent and comparable. The no-reference metric...

High dynamic range (HDR) imaging permits the capture, storage, display, and handling of real world lighting, removing the limitations that traditional imaging has that may lead to over- and underexposed pixels in images. In order to achieve this, HDR imagery requires the storage and manipulation of floating point data, which consumes more space tha...

From relative obscurity just a few years ago, high dynamic range (HDR) has become a powerful marketing tool in the drive to sell “next-generation” televisions. Although higher resolution 4K (3840 × 2160 pixels) televisions have been around for a number of years, they were gaining limited market penetration, as they provide little noticeable differe...

Virtual environments grant the ability to experience real-world scenarios, such as driving, in a virtual, safe and reproducible context. However, in order to achieve their full potential the fidelity of the virtual environment must provide confidence that it replicates the perception of the real-world experience. The computational cost of simulatin...

In the medieval period, Coventry, in the English Midlands was a major centre for tanning as well as for its better-known cloth manufacturing. Heavily damaged during the Second World War, and unsympathetically rebuilt in the 1950s and 1960s, there is little left in modern Coventry to remind visitors of this important period in Coventry's history. Th...

Accurate simulation of all the senses in virtual environments is a computationally expensive task. Visual saliency models have been used to improve computational performance for rendered content, but this is insufficient for multi-modal environments. This paper considers cross-modal perception and, in particular, if and how olfaction affects visual...

HDR video on mobile devices is in its infancy and there are no solutions yet that can achieve full HDR video reproduction due to computational power limitations. In this paper we present a novel and versatile solution that allows the delivery of HDR video on mobile devices by taking into account contextual information and retro-compatibility for de...

This book explores the methods needed for creating and manipulating HDR content. HDR is a step change from traditional imaging; more closely matching what we see with our eyes. In the years since the first edition of this book appeared, HDR has become much more widespread, moving from a research concept to a standard imaging method. This new editio...

Fidelity is of key importance if virtual environments are to be used as authentic representations of real environments. However, simulating the multitude of senses that comprise the human sensory system is computationally challenging. With limited computational resources, it is essential to distribute these carefully in order to simulate the most i...

The world is multisensory. All five major senses, visuals, audio, smell, feel and taste, are important to how we, humans, perceive the world around us. Furthermore, the interaction of the senses—cross-modal effects—can significantly affect our understanding of an environment, with one sensory stimuli even being ignored in the presence of other more...

Serious games are accepted as an effective approach to deliver augmented feedback in motor (re-)learning processes. The multi-modal nature of the conventional computer games (eg. audiovisual representation) plus the ability to interact via haptic enabled inputs provides a more immersive experience. Thus, particular disciplines such as medical educa...

This paper presents the results of a user study which quantifies the relative and absolute quality of example-based texture synthesis algorithms. In order to allow such evaluation, a list of texture properties is compiled, and a minimal representative set of textures is selected to cover these. Six texture synthesis methods are compared against eac...

High Dynamic Range (HDR) video has emerged from research labs around the world and entered the realm of consumer electronics. The dynamic range that a human can see in a scene with minimal eye adaption (approximately 1,000,000: 1) is vastly greater than traditional imaging technology which can only capture about 8 f-stops (256: 1). HDR technology,...

The ability to capture digital engineering imagery during rocket launches in which all of the detail in the scene is present is critical for postlaunch processing and analysis. Rocket launches often present an extreme range of lighting during both day and night missions. Imaging rocket launches has two key challenges: capturing detail of the vehicl...

High Dynamic Range Video: Concepts, Technologies and Applications gives an introduction to a full range of topics within the end-to-end HDR video pipeline, covering the issues around capturing HDR and stereo HDR video, such as ghosting and use of legacy LDR systems, how HDR video can be manipulated, including real-time mixing, the very latest desig...

Mobile devices are now widespread and multimedia consumption on these devices has increased significantly in recent years. More and more high dynamic range (HDR) content is being produced and its imminent adoption by the broadcast community means that there will soon be a demand to visualize HDR content on mobile devices. Mobile devices, however, h...

p class="VARAbstract">The ability of High Dynamic Range (HDR) imaging to capture the full range of lighting in a scene has meant that it is being increasingly used for Cultural Heritage (CH) applications. Photogrammetric techniques allow the semi-automatic production of 3D models from a sequence of images. Current photogrammetric methods are not al...

Rendering textures in real-time environments is a key task in computer graphics. This paper presents a new parallel patch-based method which allows repeatable sampling without cache, and does not create visual repetitions. Interchangeable patches of arbitrary shape are prepared in a preprocessing step, such that patches may lie over the boundary of...

Olfactory displays provide a means to reproduce olfactory stimuli for use in virtual environments. Many of the designs produced by researchers, strive to provide stimuli quickly to users and focus on improving usability and portability, yet concentrate less on providing high levels of accuracy to improve the fidelity of odour delivery. This paper p...

High fidelity rendering systems rely on accurate material representations to produce a realistic visual appearance. However, these accurate models can be slow to evaluate. This work presents an approach for approximating these high accuracy reflectance models with faster, less complicated functions in regions of an image which possess low visual im...

Applying image processing applications under complex or harsh lighting conditions can be a difficult challenge. In particular, face recognition can be prone to such limitations due to the uncontrolled nature of the applications to which it is applied. One of the conventional ways used to resolve this concern is by capturing images under controlled...

In this paper, we present a new technique for displaying High Dynamic Range (HDR) images on Low Dynamic Range (LDR) displays in an efficient way on the GPU. The described process has three stages. First, the input image is segmented into luminance zones. Second, the tone mapping operator (TMO) that performs better in each zone is automatically sele...

A number of High Dynamic Range (HDR) video compression algorithms proposed to date have either been developed in isolation or only-partially compared with each other. Previous evaluations were conducted using quality assessment error metrics, which for the most part were developed for qualitative assessment of Low Dynamic Range (LDR) videos. This p...

From relatively unknown, just 5 years ago, High Dynamic Range (HDR) video is now having a major impact on most aspects of imaging. Although one of the five components of the specification for UHDTV, ITU-R Recommendation BT.2020 in 2012, it is only when it became apparent that HDR could help accelerate the slow penetration of 4K into the TV and home...

A Facial Expression Recognition (FER) study is conducted investigating whether High Dynamic Range (HDR) tone mapped images can improve FER performance under complex lighting conditions. For this purpose, we created a new straightforward facial expression dataset of HDR images, a collection of faces under different lighting contrasts. Our approach a...

The increased interest in high dynamic range (HDR) video over existing low dynamic range (LDR) video during the past decade or so was primarily due to its inherent capability to capture, store and display the full range of real-world lighting visible to the human eye with increased precision. This has led to an inherent assumption that HDR video wo...