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.

Adaptive-scale wide-field reconstruction for radio synthesis imaging

Abstract: Sky curvature and non-coplanar effects, caused by low frequencies, long baselines, or small apertures in wide field-of-view instruments such as the Square Kilometre Array (SKA), significantly limit the imaging performance of an interferometric array. High dynamic range imaging essentially requires both an excellent sky model and the correction of imaging factors such as non-coplanar effects. New CLEAN deconvolution with adaptive-scale modeling already has the ability to construct significantly better narrow-band sky models. However, the application of wide-field observations based on modern arrays has not yet been jointly explored. We present a new wide-field imager that can model the sky on an adaptive-scale basis, and the sky curvature and the effects of non-coplanar observations with the w-projection method. The degradation caused by the dirty beam due to incomplete spatial frequency sampling is eliminated during sky model construction by our new method, while the w-projection mainly removes distortion of sources far from the image phase center. Applying our imager to simulated SKA data and the real observation data of the Karl G. Jansky Very Large Array (an SKA pathfinder) suggested that our imager can handle the effects of wide-field observations well and can reconstruct more accurate images. This provides a route for high dynamic range imaging of SKA wide-field observations, which is an important step forward in the development of the SKA imaging pipeline.

Ghost removing for HDR real-time video stream generation

Abstract: High dynamic range (HDR) imaging generation from a set of low dynamic range images taken in different exposure times is a low cost and an easy technique. This technique provides a good result for static scenes. Temporal exposure bracketing cannot be applied directly for dynamic scenes, since camera or object motion in bracketed exposures creates ghosts in the resulting HDR image. In this paper we describe a real-time ghost removing hardware implementation on high dynamic range video ow added for our HDR FPGA based smart camera which is able to provide full resolution (1280 x 1024) HDR video stream at 60 fps. We present experimental results to show the efficiency of our implemented method in ghost removing.

21.1: Invited Paper: The Hopeful Future of High Dynamic Range Imaging

Abstract: This paper offers an overview of the challenges and opportunities presented by high dynamic range (HDR) imaging. We examine the length of the imaging pipeline, from creation and storage through image editing and viewing, and discuss how each stage is affected by a move to HDR.

Tone mapping for HDR images with dimidiate luminance and spatial distributions of bright and dark regions

Abstract: This paper proposes a novel tone mapping method in consideration of human's perception for a high dynamic range (HDR) image with dimidiated luminance and spatial distributions of bright and dark regions. In order to represent an HDR image with a low dynamic range (LDR) display, it is necessary to appropriately compress a dynamic range of HDR image by tone mapping.There are some HDR images which cannot represent the real scene precisely by applying conventional tone mapping methods. In this study, we view an HDR image with dimidiated luminance and spatial distributions of bright and dark regions as a target image for our work,we assume that human's perception dose not feel a sense of discomfort even if a magnitude relationship between luminance values of pixels near the boundary of the regions is reversed, when bright and dark regions are definitely divided according to dimidiated luminance and spatial distributions. Under the assumption, we divide HDR image into bright and dark regions and apply a tone mapping method to each region independently. In experiments, we will show that our tone mapping method produces the image represented by utilizing a dynamic range effectively. In addition, we will confirm that our tone mapping method is useful through subjective evaluation and discuss the features of the HDR images which are supposed to be suitable for the proposed method.

A single algorithm combining exposure and focus fusion

Abstract: In scenes of significantly varying lighting conditions, under and over exposed regions can suffer from a loss of information. Similarly, the presence of spatial depth within a scene can cause some image regions to be out of focus. Several methods of addressing these issues exist, including tone mapping for true high dynamic range representation and exposure fusion for combining varied-exposure low dynamic range images, as solutions to the former, and image fusion and segmentation etc. to address the latter. This paper proposes an overhauled method of exposure fusion that solves the exposure and focus problems simultaneously, achieving a well-exposed, all-in-focus result. Smart, scene-based data acquisition techniques for reducing both required input data and computational resources are discussed. A platform for a realtime system implementation is also presented.