Tone mapping Research Papers - Academia.edu (original) (raw)

In this lecture note, we describe high dynamic range (HDR) imaging systems. Such systems are able to represent luminances of much larger brightness and, typically, a larger range of colors than conventional standard dynamic range (SDR)... more

In this lecture note, we describe high dynamic range (HDR) imaging systems. Such systems are able to represent luminances of much larger brightness and, typically, a larger range of colors than conventional standard dynamic range (SDR) imaging systems. The larger luminance range greatly improves the overall quality of visual content, making it appear much more realistic and appealing to observers. HDR is one of the key technologies in the future imaging pipeline, which will change the way the digital visual content is represented and manipulated today.

The ultimate aim of realistic graphics is the creation of images that provoke the same responses that a viewer would have to a real scene. This STAR addresses two related key problem areas in this effort which are located at opposite ...

In recent years, High Dynamic Range Textures (HDRTs) have been frequently used in real-time applications and video-games to enhance realism. Unfortunately, HDRTs consume a considerable amount of memory, and efficient compression methods... more

In recent years, High Dynamic Range Textures (HDRTs) have been frequently used in real-time applications and video-games to enhance realism. Unfortunately, HDRTs consume a considerable amount of memory, and efficient compression methods are not straightforward to implement on modern GPUs. We propose a framework for efficient HDRT compression using tone mapping and its dual, inverse tone mapping. In our method, encoding is performed by compressing the dynamic range using a tone mapping operator ...

This paper proposes an objective assessment method for perceptual image quality of tone mapped images. Tone mapping algorithms are used to display high dynamic range (HDR) images onto standard display devices that have low dynamic range... more

This paper proposes an objective assessment method for perceptual image quality of tone mapped images. Tone mapping algorithms are used to display high dynamic range (HDR) images onto standard display devices that have low dynamic range (LDR). The proposed method implements visual attention to define perceived structural distortion regions in LDR images, so that a reasonable measurement of distortion between HDR and LDR images can be performed. Since the human visual system is sensitive to structural information, quality metrics that can measure structural similarity between HDR and LDR images are used. Experimental results with a number of HDR and tone mapped image pairs show the effectiveness of the proposed method.

The ability of High Dynamic Range (HDR) imaging to capture the full range of lighting in a scene has prompted an increase in its use for Cultural Heritage (CH) applications. Photogrammetric techniques allow the semi-automatic production... more

The ability of High Dynamic Range (HDR) imaging to capture the full range of lighting in a scene has prompted an increase in its use for Cultural Heritage (CH) applications. Photogrammetric techniques allow the semi-automatic production of three-dimensional (3D) models from a sequence of images. Current photogrammetric methods are not always effective in reconstructing images under harsh lighting conditions, as significant geometric details may not have been captured accurately within under-and overexposed regions of the image. HDR imaging offers the possibility to overcome this limitation, however the HDR images need to be tone-mapped before they can be used within existing photogrammetric algorithms. In this paper we evaluate four different HDR tone-mapping operators (TMOs) that have been used to convert raw HDR images into a format suitable for state-of-the-art algorithms, and in particular keypoint detection techniques. The evaluation criteria used are the number of keypoints, the number of valid matches achieved and the repeatability rate. The comparison considers two local and two global TMOs. HDR data from four CH sites were used: Kaisariani Monastery (Greece), Asinou Church (Cyprus), Château des Baux (France) and Buonconsiglio Castle (Italy). Resumen: Las posibilidades que ofrecen las imágenes de alto rango dinámico (HDR) para registrar la totalidad del rango de iluminación de una escena han propiciado su creciente uso en aplicaciones de patrimonio cultural. Los métodos fotogramétricos actuales permiten la producción semi-automática de modelos tridimensionales (3D) a partir de una secuencia de imágenes. Sin embargo, éstos presentan serias limitaciones en escenas con iluminación dura, resultando en consecuencia la aparición de zonas expuestas o sobreexpuestas. En este tipo de condiciones, el uso de imágenes HDR ofrece la posibilidad de superar este problema. Para evaluar su potencialidad, se presentan en este artículo cuatro operadores diferentes de mapeado tonal (tone-mapping) en imágenes HDR, conocidos como TMOs, cuya misión es convertir las imágenes HDR crudas en un formato adecuado para su uso en algoritmos de vanguardia, y en particular en técnicas de detección de entidades. Los criterios de evaluación que se utilizan para analizar su potencialidad son: el número de entidades detectadas, el número de correspondencias válidas y su índice de repetibilidad. En la comparación se incluyen TMOs, dos locales y dos globales. Se utilizan datos HDR tomados en cuatro sitios patrimoniales: el monasterio de Kaisariani (Grecia), la iglesia de Asinou (Chipre), el castillo de los Baux (Francia) y el castillo de Buonconsiglio (Italia). Palabras clave: toma de imágenes de alto rango dinámico (HDR), mapeado tonal HDR, detección de entidades, reconstrucción 3D basada en imágenes

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... more

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.

Abstract: Tone mapping algorithms are used to adapt captured wide dynamic range (WDR) scenes to the limited dynamic range of available display devices. Although there are several tone mapping algorithms available, most of them require... more

Abstract: Tone mapping algorithms are used to adapt captured wide dynamic range (WDR) scenes to the limited dynamic range of available display devices. Although there are several tone mapping algorithms available, most of them require manual tuning of their rendering parameters. In addition, the high complexities of some of these algorithms make it difficult to implement efficient real-time hardware systems. In this work, a real-time hardware implementation of an exponent-based tone mapping algorithm is presented. The algorithm performs a mixture of both global and local compression on colored WDR images. An automatic parameter selector has been proposed for the tone mapping algorithm in order to achieve good tone-mapped images without manual reconfiguration of the algorithm for each WDR image. Both algorithms are described in Verilog and synthesized for a field programmable gate array (FPGA). The hardware architecture employs a combination of parallelism and system pipelining, so a...

Realistic images can be computed at interactive frame rates for Computer Graphics applications. Meanwhile, High Dynamic Range (HDR) rendering has a growing success in video games and virtual reality applications, as it improves the image... more

Realistic images can be computed at interactive frame rates for Computer Graphics applications. Meanwhile, High Dynamic Range (HDR) rendering has a growing success in video games and virtual reality applications, as it improves the image quality and the player’s immersion feeling. In this paper, we propose a new method, based on a physical lighting model, to compute in real time a HDR illumination in virtual environments. Our method allows to re-use existing virtual environments as input, and computes HDR images in photometric units. Then, from these HDR images, displayable 8-bit images are rendered with a tone mapping operator and displayed on a standard display device. The HDR computation and the tone mapping are implemented in OpenSceneGraph with pixel shaders. The lighting model, together with a perceptual tone mapping, improves the perceptual realism of the rendered images at low cost. The method is illustrated with a practical application where the dynamic range of the virtual environment is a key rendering issue: night-time driving simulation.

ABSTRACT In this paper, we present a solution to the problem of dynamic range compression from multiple exposures called ExpoBlend that operates in the absence of raw format images, relative or absolute exposure values, camera response... more

ABSTRACT In this paper, we present a solution to the problem of dynamic range compression from multiple exposures called ExpoBlend that operates in the absence of raw format images, relative or absolute exposure values, camera response functions, or known irradiance. This is achieved in relatively simplistic fashion by merging image content across provided exposures. The proposed algorithm is directed at making visible any contrast appearing across a dynamic range that exceeds display or printing capabilities through high dynamic range (HDR) compression while preserving the nature of the image structure and detail, lighting, and avoiding introducing discontinuities in illumination or image artifacts. In addition, ExpoBlend allows scaling subject to a single parameter that elicits a trade-off between the impact of illumination and fine detail in the merged result. The strategy applied appeals to an information maximization strategy wherein the local entropy evident in each exposure is computed subject to a logarithmic compression of intensities, and employs cross-exposure normalization of entropy that implies a fusion strategy based on relative entropy across exposures in combination with a soft-maximum operation.

In the last decade, an increasing number of techniques have been developed to reproduce high dynamic range imagery on traditional displays. These techniques, known as Tone Mapping Operators (TMOs), have been compared and ranked in... more

In the last decade, an increasing number of techniques have been developed to reproduce high dynamic range imagery on traditional displays. These techniques, known as Tone Mapping Operators (TMOs), have been compared and ranked in different ways according to several image characteristics. However, none of these algorithms has been developed specifically for small screen devices (SSD). In this paper, we present an evaluation of currently used TMOs to show that SSDs with limited size, resolution and colour depth require specific research to find or create an appropriate solution. The research described in this paper is based on psychophysical experiments; using three different types of displays (CRT, LCD and SSD). The obtained results show that rankings obtained are similar for the LCD and CRT but are significantly different for the SSD. Furthermore, these rankings show additionally that some characteristics of TMOs need to be emphasized to obtain better high-fidelity mapped images fo...