Contrast in image processing is typically scaled using a power function (gamma) where its exponent specifies the amount of the physical contrast change. While the exponent is normally constant for the whole image, we observe that such scaling leads to perceptual nonuniformity in the context of high dynamic range (HDR) images. This effect is mostly due to lower contrast sensitivity of the human ...

This paper presents a global approach for constructing high dynamic range mosaic from multiple images with large exposure differences. By relating image intensities to scene radiances with a convenient distortion model, we robustly estimated registration parameters for the high dynamic range global mosaic (HDRGM), simultaneously estimating scene radiances and distortion parameters in a single f...

To utilize the full potential of new high dynamic range (HDR) displays, a system for the enhancement of bright luminous objects in video sequences is proposed. The system classifies clipped (saturated) regions as lights, reflections or diffuse surfaces using a semi-automatic classifier and then enhances each class of objects with respect to its relative brightness. The enhancement algorithm can...

The performance of video tone-mapping operators is investigated in a rating experiment using two criteria: overall quality and fidelity to real-world experience. The study includes a tone-curve used in commercial cameras, rarely considered in tone-mapping evaluation studies. The quality is measured for a range of parameter settings, revealing the importance of parameter fine-tuning and often un...

We present a novel algorithm to efficiently generate high quality high dynamic range (HDR) images. Our method is based on the idea of expanding the dynamic range of a reference image at granularity of tiles. In each tile, we use data from a single exposure, but different tiles can come from different exposures. We show that this approach is not only efficient and robust against camera and objec...

Showing high dynamic range images on general displayers whose dynamic ranges are relatively low will result in images with undesirable artifacts such as underexposure or overexposure images. To display images without unwanted artifacts, a Retinex-based tone mapping method is proposed in this paper. We present the weighted edge-preserving smooth filter to estimate a smoother illumination, and a ...

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. While research into ways of rendering images provides us with better and faster methods, we do not necessarily see their full effect due to limitations of the display hardware. The low dynamic range of a standard computer monitor requires some form of mappin...

In this paper, we propose a coding algorithm for High Dynamic Range Images (HDRI). Our encoder applies a tone mapping model based on scaled μ-Law encoding, followed by a conventional Low Dynamic Range Image (LDRI) encoder. The tone mapping model is designed to minimize the difference between the tone-mapped HDRI and its LDR version. By virtue of the nature of the μ-Law model, not only the quali...

Rapid, reliable and objective estimations of Leaf Area Index (LAI) are essential for numerous studies of the atmosphere, as LAI is very often a critical parameter in process-based models of vegetation canopy response to global environmental change. This paper compiles current knowledge concerning the use of direct and indirect methods for LAI determination. The emphasis will be on techniques, t...