Topic
High-dynamic-range imaging
About: High-dynamic-range imaging is a research topic. Over the lifetime, 766 publications have been published within this topic receiving 22577 citations.
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TL;DR: A novel method to map high dynamic range scenes to low dynamic range images for display in standard (low dynamic range) reproduction media is developed and an adaptive conscience learning strategy is employed to ensure that the mappedLow dynamic range displays not only faithfully reproduce the visual features of the original scenes, but also make full use of the available display levels.
25 citations
TL;DR: In this article, a single-mode pupil remapping system was proposed to achieve high dynamic range imaging with a single telescope at a few resolution elements from the central star at a wavelength of 630 nm.
Abstract: The correction of the influence of phase corrugation in the pupil plane is a fundamental issue in achieving high dynamic range imaging. In this paper, we investigate an instrumental set-up which consists of applying interferometric techniques on a single telescope, by filtering and dividing the pupil with an array of single-mode fibres. We developed a new algorithm, which makes use of the fact that we have a redundant interferometric array, to completely disentangle the astronomical object from the atmospheric perturbations (phase and scintillation). This self-calibrating algorithm can also be applied to any - diluted or not - redundant interferometric set-up. On an 8-m telescope observing at a wavelength of 630 nm, our simulations show that a single-mode pupil remapping system could achieve, at a few resolution elements from the central star, a raw dynamic range up to 10 6 , depending on the brightness of the source. The self-calibration algorithm proved to be very efficient, allowing image reconstruction of faint sources (magnitude = 15) even though the signal-to-noise ratios of individual spatial frequencies are of the order of 0.1. We finally note that the instrument could be more sensitive by combining this set-up with an adaptive optics system. The dynamic range would however be limited by the noise of the small, high-frequency displacements of the deformable mirror.
24 citations
TL;DR: The proposed CE algorithm based on high dynamic range (HDR) imaging makes use of different intensity information from multiple images, therefore, the performance of the proposed method is better than that of existing CE algorithms.
Abstract: Video image quality improving technologies produce remarkable achievements as display devices make rapid progress. However, there exist some limitations on intensity representation of display and acquisition devices to reproduce the real world video images. Various contrast enhancement (CE) algorithms have been developed and applied to overcome those limitations but there are many drawbacks such as color information change, loss of the lighting information, and excessive enhancement. This paper proposes a CE algorithm based on high dynamic range (HDR) imaging. First, an input image is determined whether or not it requires CE in a pre-processing step using the proposed auto exposure algorithm. Then, multiple images are generated by applying the intensity mapping function to an input image. At last, an HDR image is constructed with multiple images, in which registration of multiple images is not required. So, the proposed CE algorithm could increase the dynamic range and thus increase the contrast of an input image. The proposed CE method makes use of different intensity information from multiple images, therefore, the performance of the proposed method is better than that of existing CE algorithms. Experiments with three real images show the effectiveness of the proposed CE algorithm
24 citations
12 May 2008
TL;DR: This paper presents an encoding scheme for HDR images, which significantly reduces their storage requirements, with a negligible loss of information, and model an HDR image as a piecewise linear function of its tone-mapped version.
Abstract: With advent of high dynamic range (HDR) imaging techniques, it has been possible to capture natural scenes in larger details. HDR images are tone-mapped to lower dynamic range (LDR) versions for displaying on paper or a screen. Details lost during tone-mapping are important for certain existing and future applications, and need to be preserved. However, the size of HDR images is very large and that gives rise to need of effective encoding techniques. In this paper, we present an encoding scheme for HDR images, which significantly reduces their storage requirements, with a negligible loss of information. We model an HDR image as a piecewise linear function of its tone-mapped version. The tone-mapped image and the error in modeling are stored as LDR images, and these two along with the created model, approximate the HDR image. Comparison with the existing state of the art technique is given to show the effectiveness of our proposed scheme.
24 citations
TL;DR: This paper implements the optical system prototype, analyzes the theory of per-pixel coded exposure for HDRI, and puts forward an adaptive light intensity control algorithm to effectively modulate the different light intensity to recover high dynamic range images.
Abstract: In this paper, we overcome the limited dynamic range of the conventional digital camera, and propose a method of realizing high dynamic range imaging (HDRI) from a novel programmable imaging system called a digital micromirror device (DMD) camera. The unique feature of the proposed new method is that the spatial and temporal information of incident light in our DMD camera can be flexibly modulated, and it enables the camera pixels always to have reasonable exposure intensity by DMD pixel-level modulation. More importantly, it allows different light intensity control algorithms used in our programmable imaging system to achieve HDRI. We implement the optical system prototype, analyze the theory of per-pixel coded exposure for HDRI, and put forward an adaptive light intensity control algorithm to effectively modulate the different light intensity to recover high dynamic range images. Via experiments, we demonstrate the effectiveness of our method and implement the HDRI on different objects.
24 citations