Image-based Rendering

This paper gives an overview of computer graphics representations of trees commonly used for the rendering of complex scene of vegetation. Looking for the right compromise between realism and efficiency has lead researchers to consider various types of geometrical plant models with different types of complexity. To achieve realist plant model, a complex structure of plant with full details is generally considered. In contrast, to promote efficiency, other approaches summarize plant geometry with few primitives allowing rapid rendering. Finally, to find a good compromise, structures with adaptive complexity are defined. Theses different types of representations and the ways to use them are presented, classified and discussed. The proposed classification principles rely on the type of structural details used in the plants representations. Characterization of all these methods is completed with various additional criteria including rendering primitive type, distance validity, interacti...

This paper presents a new hybrid Kinect-variety based synthesis scheme that renders artifacts-free multiple views for autostereoscopic/ auto-multiscopic displays. The proposed approach does not explicitly require dense scene depth information for synthesizing novel views from arbitrary viewpoints. Instead, the integrated framework first constructs a consistent minimal image-space parameterization of the underlying 3D scene. The compact representation of scene structure is formed using only implicit sparse depth information of few reference scene points extracted from raw RGB-D data. The views from arbitrary positions can be inferred by moving the novel camera in parameterized space by enforcing Euclidean constraints on reference scene images under a full-perspective projection model. Unlike state-of-the-art DIBR methods, where input depth map accuracy is crucial for high quality output, our proposed algorithm does not depend on precise per-pixel geometry information. Therefore, it simply sidesteps to recover and refine the incomplete or noisy depth estimates with advanced filling or upscaling techniques. Our approach performs fairly well in unconstrained indoor/outdoor environments, where the performance of range sensors or dense depth-based algorithms could be seriously affected due to scene complex geometric conditions. We demonstrate that the proposed hybrid scheme provides guarantees on the completeness, optimality with respect to the inter-view consistency of the algorithm. In the experimental validation, we performed a quantitative evaluation as well as subjective assessment on scene with complex geometric or surface properties. Comparison with latest representative DIBR methods is additionally performed to demonstrate the superior performance of the proposed scheme.

The purpose of this project was to create several methods for achieving non-photorealistic appearance of the objects or, in other words, the goal was to create several different implementations of the cartoonish shader, which can sometimes be referred to as a cel-shader or just toon-shader.

Este documento es un ejercicio elaborado durante el seminario de área impartido por el Dr. Peter Krieger en la Maestría en Arquitectura de la UNAM, en donde se abordan temas de interés actual que son parte de la producción arquitectónica y de ciudad así como los modos de difusión de ellas, como lo son las imágenes virtuales, y las consecuencias tangibles que tiene esta difusión sobre la ciudad, explicado a partir de un centro comercial en proceso de construcción como caso de estudio, siendo una tipología de edificación que ha tomado fuerza en Ciudad de México y en otras del mundo.

This paper presents a novel solution for approximations to some large convolution kernels by leveraging a weighted box-filtered image pyramid set. Convolution filters are widely used, but still compute-intensive for real-time rendering when the kernel size is large. Our algorithm approximates the convolution kernels, such as Gaussian and cosine filters, by two phases of down and up sampling on a GPU. The computational complexity only depends on the input image resolution and is independent of the kernel size. Therefore, our method can be applied to nonuniform blurs, irradiance probe generations, and ray-traced glossy global illuminations in real time, and runs in effective and efficient performance.

Automatic attendance system is one of the significant issues of today's research. Among other methods, human face recognition is highly used technique for attendance automation. Many systems have been proposed in literature using face recognition. Most of the systems are using fixed camera and desktop computers. We propose a system using mobile phones where an image is captured of group of peoples and face detection is done automatically. While considering computational and storage power of mobile devices, extracted local binary features for detected faces are then transferred to server machine using firebase database. Matching is done on server side, if face recognized than attendance is marked and feedback is sent back to client side. Experiments show effectiveness of proposed techniques with 95% correct recognition rate.

Il lavoro proposto vuole ottimizzare una metodologia di documentazione dell’architettura che, a partire dalle fotografie panoramiche, si misura di volta in volta con gli strumenti e le tecnologie a disposizione per proporre una soluzione integrata, speditiva e low-cost di Virtual Architecture.
La tecnica sviluppata nasce in un contesto di ricerca più ampio che da anni studia la possibilità di usare le immagini panoramiche sferiche per il rilievo metrico dell’architettura (Fangi, 2007-2012). I dati a disposizione (panoramiche orientate), l’affidabilità raggiunta e metodi di Image-based Modeling (d’Annibale, 2009-2011) sono alla base della proposta di una tipo di ricostruzione 3D integrata ed estremamente flessibile: dal rilievo professionale del patrimonio culturale alla sua comunicazione nei musei virtuali.
La soluzione proposta si sviluppa tramite l’integrazione e implementazione di diverse tecniche (Fotogrammetria Sferica, Structure From Motion, Image-based Modeling) e si pone l’obiettivo di raggiungere alti livelli di precisione metrica del rilievo e resa fotorealistica dei modelli ricostruiti. L’intera procedura risulta essere accessibile grazie alla scelta di utilizzare strumenti low-cost e adattabile allo scopo finale.
Diversi sono i livelli di documentazione possibili all’interno dell’unico processo proposto: dalla navigazione virtuale di panorami sferici a complessi sistemi di simulazione e ricostruzione virtuale.
Tools VR permettono l’integrazione delle tecnologie e lo sviluppo di nuove soluzioni per la navigazione virtuale.
Affinate tecniche di Image-based Modeling permettono la costruzione di modelli con texture fotorealistiche ad alta risoluzione.
L’alta risoluzione delle fotografie panoramiche, lo sviluppo di tools per la creazione di affidabili algoritmi di orientamento dei panorami e restituzione fotogrammetrica garantiscono precisioni centimetriche e texture ad alta risoluzione.
Tecniche automatizzate sono oggetto di indagine, successiva implementazione ed integrazione tramite tool ad hoc che sfruttano tutte le potenzialità delle fotografie panoramiche.
Il workflow di lavoro permette diversi tipi di output che vanno dalla fedele restituzione di punti tramite fotogrammetria sferica a dense nuvole di punti ottenuti da restituzione automatizzata. I dati opportunamente trattati ed integrati possono fornire diversi livelli di analisi e ricostruzione virtuale che uniscono la precisione della fotogrammetria alla resa foto realistica delle superfici modellate.
E’ stata infine testata una nuova soluzione di navigazione virtuale che all’interno dello stesso ambiente propone la possibilità di interagire contemporaneamente con i panorami sferici ad alta risoluzione orientati nello spazio e con il modello 3D ricostruito.

Special relativistic visualization offers the possibility of experiencing the optical effects of traveling near the speed of light, including apparent geometric distortions as well as Doppler and searchlight effects. Early high-quality computer graphics images of relativistic scenes were created using offline, computationally expensive CPU-side 4D ray tracing. Alternate approaches such as image-based rendering and polygon-distortion methods are able to achieve interactivity, but exhibit inferior visual quality due to sampling artifacts. In this paper, we introduce a hybrid rendering technique based on polygon distortion and local ray tracing that facilitates interactive high-quality visualization of multiple objects moving at relativistic speeds in arbitrary directions. The method starts by calculating tight image-space footprints for the apparent triangles of the 3D scene objects. The final image is generated using a single image-space ray tracing step incorporating Doppler and searchlight effects. Our implementation uses GPU shader programming and hardware texture filtering to achieve high rendering speed.

This paper demonstrates the use of High Dynamic Range (HDR) fisheye images of the sky dome in lighting simulations. The objective is to improve the accuracy of simulations with site specific sky conditions. The luminance information stored at a pixel level in an ...