Contemplation of tone mapping operators in high dynamic range imaging

The technique of tone mapping has found widespread popularity in the modern era owing to its applications in the digital world. There are a considerable number of tone mapping techniques that have been developed so far. One method may be better than the other in some cases which is determined by the requirement of the user. In this paper, some of the techniques for tone mapping/tone reproduction of high dynamic range images have been contemplated. The classification of tone mapping operators has also been given. However, it has been found that these techniques lack in providing quality of service visualization of high dynamic range images. This paper has tried to highlight the drawbacks in the existing traditional methods so that the tone-mapped techniques can be enhanced

Objective and subjective assessment of perceptual factors in HDR content processing

The development of the display and camera technology makes high dynamic range (HDR) image become more and more popular. High dynamic range image give us pleasant image which has more details that makes high dynamic range image has good quality. This paper shows us the some important techniques in HDR images. And it also presents the work the author did. The paper is formed of three parts. The first part is an introduction of HDR image. From this part we can know why HDR image has good quality

A robust patch-based synthesis framework for combining inconsistent images

Current methods for combining different images produce visible artifacts when the sources have very different textures and structures, come from far view points, or capture dynamic scenes with motions. In this thesis, we propose a patch-based synthesis algorithm to plausibly combine different images that have color, texture, structural, and geometric inconsistencies. For some applications such as cloning and stitching where a gradual blend is required, we present a new method for synthesizing a transition region between two source images, such that inconsistent properties change gradually from one source to the other. We call this process image melding. For gradual blending, we generalized patch-based optimization foundation with three key generalizations: First, we enrich the patch search space with additional geometric and photometric transformations. Second, we integrate image gradients into the patch representation and replace the usual color averaging with a screened Poisson equation solver. Third, we propose a new energy based on mixed L2/L0 norms for colors and gradients that produces a gradual transition between sources without sacrificing texture sharpness. Together, all three generalizations enable patch-based solutions to a broad class of image melding problems involving inconsistent sources: object cloning, stitching challenging panoramas, hole filling from multiple photos, and image harmonization. We also demonstrate another application which requires us to address inconsistencies across the images: high dynamic range (HDR) reconstruction using sequential exposures. In this application, the results will suffer from objectionable artifacts for dynamic scenes if the inconsistencies caused by significant scene motions are not handled properly. In this thesis, we propose a new approach to HDR reconstruction that uses information in all exposures while being more robust to motion than previous techniques. Our algorithm is based on a novel patch-based energy-minimization formulation that integrates alignment and reconstruction in a joint optimization through an equation we call the HDR image synthesis equation. This allows us to produce an HDR result that is aligned to one of the exposures yet contains information from all of them. These two applications (image melding and high dynamic range reconstruction) show that patch based methods like the one proposed in this dissertation can address inconsistent images and could open the door to many new image editing applications in the future

Photorealistic physically based render engines: a comparative study

Pérez Roig, F. (2012). Photorealistic physically based render engines: a comparative study. http://hdl.handle.net/10251/14797.Archivo delegad

Interpretacija projektantskih rešenja primenom digitalne grafike

Contemporary design solutions that move the boundaries of creativity include the use of digital graphics, in order to get innovative graphical interpretation which includes interventions in space using various element, materials and plants, which requires the use of a combination of different software packages .This paper analyzes the combination of the available graphical software for interpretation projects in the context of landscape architecture profession. Model 'Garden' was created in the 'SketchUp' software for the purpose of visual questionnaire and detailed research work in programs for visualization: 'Photoshop' , 'Lumion' and '3DMax'. Combining the two research methods: study graphic interpretation, 'learning by doing' method in software for digital graphic and research public opinion questionnaire ('Single stimulus' method) led to the results which give recommendations for the use of a combination of appropriate software packages.Savremena dizajnerska rešenja koja pomeraju granice kreativnosti podrazumevaju upotrebu digitalne grafike, u svrhu dobiijanja inovativnih grafičkih interpretacija. Pejzažna arhitektura je transdisciplinarna struka, koja podrazumeva intervencije u prostoru upotrebom različitih elemenata, materijala i biljaka, što zahteva upotrebu i kombinaciju različitih softverskih paketa. Ovaj rad se bavi istraživanjem kombinacija dostupnih grafičkih softvera za interpretaciju projekata u okviru pejzažnoarhitektonske struke. Model 'Vrt' je izrađen u 'SketchUp' softveru za potrebe izrade vizuelnog upitnika kao i detaljnijeg istraživanja rada u programima za vizuelizaciju: 'Photoshop', 'Lumion' i '3DMax'. Kombinacijom dve istraživačke metode: istraživanjem grafičke interpretacije, učenjem kroz rad ('Learning by doing') u softverima za digitalnu grafiku i istraživanjem mišljenja javnog mnjenja upitnikom ('Single stimulans' metodom) došlo se do rezultata koji daju preporuke za upotrebu kombinacije adekvatnih softverskih paketa

Fully-automatic inverse tone mapping algorithm based on dynamic mid-level tone mapping

High Dynamic Range (HDR) displays can show images with higher color contrast levels and peak luminosities than the common Low Dynamic Range (LDR) displays. However, most existing video content is recorded and/or graded in LDR format. To show LDR content on HDR displays, it needs to be up-scaled using a so-called inverse tone mapping algorithm. Several techniques for inverse tone mapping have been proposed in the last years, going from simple approaches based on global and local operators to more advanced algorithms such as neural networks. Some of the drawbacks of existing techniques for inverse tone mapping are the need for human intervention, the high computation time for more advanced algorithms, limited low peak brightness, and the lack of the preservation of the artistic intentions. In this paper, we propose a fully-automatic inverse tone mapping operator based on mid-level mapping capable of real-time video processing. Our proposed algorithm allows expanding LDR images into HDR images with peak brightness over 1000 nits, preserving the artistic intentions inherent to the HDR domain. We assessed our results using the full-reference objective quality metrics HDR-VDP-2.2 and DRIM, and carrying out a subjective pair-wise comparison experiment. We compared our results with those obtained with the most recent methods found in the literature. Experimental results demonstrate that our proposed method outperforms the current state-of-the-art of simple inverse tone mapping methods and its performance is similar to other more complex and time-consuming advanced techniques

Appearance-based image splitting for HDR display systems

High dynamic range displays that incorporate two optically-coupled image planes have recently been developed. This dual image plane design requires that a given HDR input image be split into two complementary standard dynamic range components that drive the coupled systems, therefore there existing image splitting issue. In this research, two types of HDR display systems (hardcopy and softcopy HDR display) are constructed to facilitate the study of HDR image splitting algorithm for building HDR displays. A new HDR image splitting algorithm which incorporates iCAM06 image appearance model is proposed, seeking to create displayed HDR images that can provide better image quality. The new algorithm has potential to improve image details perception, colorfulness and better gamut utilization. Finally, the performance of the new iCAM06-based HDR image splitting algorithm is evaluated and compared with widely spread luminance square root algorithm through psychophysical studies

Advanced editing methods for image and video sequences

In the context of image and video editing, this thesis proposes methods for modifying the semantic content of a recorded scene. Two different editing problems are approached: First, the removal of ghosting artifacts from high dynamic range (HDR) images recovered from exposure sequences, and second, the removal of objects from video sequences recorded with and without camera motion. These editings need to be performed in a way that the result looks plausible to humans, but without having to recover detailed models about the content of the scene, e.g. its geometry, reflectance, or illumination. The proposed editing methods add new key ingredients, such as camera noise models and global optimization frameworks, that help achieving results that surpass the capabilities of state-of-the-art methods. Using these ingredients, each proposed method defines local visual properties that approximate well the specific editing requirements of each task. These properties are then encoded into a energy function that, when globally minimized, produces the required editing results. The optimization of such energy functions corresponds to Bayesian inference problems that are solved efficiently using graph cuts. The proposed methods are demonstrated to outperform other state-ofthe-art methods. Furthermore, they are demonstrated to work well on complex real-world scenarios that have not been previously addressed in the literature, i.e., highly cluttered scenes for HDR deghosting, and highly dynamic scenes and unconstraint camera motion for object removal from videos.Diese Arbeit schlägt Methoden zur Änderung des semantischen Inhalts einer aufgenommenen Szene im Kontext der Bild-und Videobearbeitung vor. Zwei unterschiedliche Bearbeitungsmethoden werden angesprochen: Erstens, das Entfernen von Ghosting Artifacts (Geist-ähnliche Artefakte) aus High Dynamic Range (HDR) Bildern welche von Belichtungsreihen erstellt wurden und zweitens, das Entfernen von Objekten aus Videosequenzen mit und ohne Kamerabewegung. Das Bearbeiten muss in einer Weise durchgeführt werden, dass das Ergebnis für den Menschen plausibel aussieht, aber ohne das detaillierte Modelle des Szeneninhalts rekonstruiert werden müssen, z.B. die Geometrie, das Reflexionsverhalten, oder Beleuchtungseigenschaften. Die vorgeschlagenen Bearbeitungsmethoden beinhalten neuartige Elemente, etwa Kameralärm-Modelle und globale Optimierungs-Systeme, mit deren Hilfe es möglich ist die Eigenschaften der modernsten existierenden Methoden zu übertreffen. Mit Hilfe dieser Elemente definieren die vorgeschlagenen Methoden lokale visuelle Eigenschaften welche die beschriebenen Bearbeitungsmethoden gut annähern. Diese Eigenschaften werden dann als Energiefunktion codiert, welche, nach globalem minimieren, die gewünschten Bearbeitung liefert. Die Optimierung solcher Energiefunktionen entspricht dem Bayes’schen Inferenz Modell welches effizient mittels Graph-Cut Algorithmen gelöst werden kann. Es wird gezeigt, dass die vorgeschlagenen Methoden den heutigen Stand der Technik übertreffen. Darüber hinaus sind sie nachweislich gut auf komplexe natürliche Szenarien anwendbar, welche in der existierenden Literatur bisher noch nicht angegangen wurden, d.h. sehr unübersichtliche Szenen für HDR Deghosting und sehr dynamische Szenen und unbeschränkte Kamerabewegungen für das Entfernen von Objekten aus Videosequenzen

Defining Reality in Virtual Reality: Exploring Visual Appearance and Spatial Experience Focusing on Colour

Today, different actors in the design process have communication difficulties in visualizing and predictinghow the not yet built environment will be experienced. Visually believable virtual environments (VEs) can make it easier for architects, users and clients to participate in the planning process. This thesis deals with the difficulties of translating reality into digital counterparts, focusing on visual appearance(particularly colour) and spatial experience. The goal is to develop knowledge of how differentaspects of a VE, especially light and colour, affect the spatial experience; and thus to contribute to a better understanding of the prerequisites for visualizing believable spatial VR-models. The main aims are to 1) identify problems and test solutions for simulating realistic spatial colour and light in VR; and 2) develop knowledge of the spatial conditions in VR required to convey believable experiences; and evaluate different ways of visualizing spatial experiences. The studies are conducted from an architecturalperspective; i.e. the whole of the spatial settings is considered, which is a complex task. One important contribution therefore concerns the methodology. Different approaches were used: 1) a literature review of relevant research areas; 2) a comparison between existing studies on colour appearance in 2D vs 3D; 3) a comparison between a real room and different VR-simulations; 4) elaborationswith an algorithm for colour correction; 5) reflections in action on a demonstrator for correct appearance and experience; and 6) an evaluation of texture-styles with non-photorealistic expressions. The results showed various problems related to the translation and comparison of reality to VR. The studies pointed out the significance of inter-reflections; colour variations; perceived colour of light and shadowing for the visual appearance in real rooms. Some differences in VR were connected to arbitrary parameter settings in the software; heavily simplified chromatic information on illumination; and incorrectinter-reflections. The models were experienced differently depending on the application. Various spatial differences between reality and VR could be solved by visual compensation. The study with texture-styles pointed out the significance of varying visual expressions in VR-models