High dynamic range

About: High dynamic range is a research topic. Over the lifetime, 4280 publications have been published within this topic receiving 76293 citations. The topic is also known as: HDR.

A reassessment of the simultaneous dynamic range of the human visual system

Abstract: The dynamic range of the human visual system should be an important parameter in the design of high dynamic range (HDR) display devices. A good display should at least approximate this range. However, the literature reports a simultaneous dynamic range between 2 and 4 log units of luminance, leaving ambiguity as to what dynamic range HDR display devices should cater for. In this paper we present a sequence of psychophysical experiments, carried out with the aid of a high dynamic range display device, to determine the simultaneous dynamic range of the human visual system under full adaptation to a given background luminance. Our findings show that the human visual system is capable of distinguishing contrasts over a range of 3.7 log units under specific viewing conditions. Further, we show how the dynamic range is affected by stimulus duration, contrast of the stimulus as well as background illumination, thereby accounting for the differences reported in the literature and providing guidance for display design.

Visual-Salience-Based Tone Mapping for High Dynamic Range Images

Abstract: Visual saliency aims to predict the attentional gaze of observers viewing a scene, and it is thus highly demanded for tone mapping of high dynamic range (HDR) images. In this paper, novel saliency-aware weighting and edge-aware weighting are introduced for HDR images. They are incorporated into an existing guided image filter to form a perceptually guided image filter. The saliency-aware weighting and the proposed filter are applied to design a new local tone-mapping algorithm for HDR images such that both extreme light and shadow regions can be reproduced on conventional low dynamic range displays. In particular, the proposed filter is applied to decompose the luminance of the input HDR image into a base layer and a detail layer. The saliency-aware weighting is then adopted to design a saliency-aware global tone mapping for the compression of the base layer. The proposed filter preserves sharp edges in the base layer better than the existing guided filter. Halo artifacts are thus significantly reduced in the tone-mapped image. Moreover, the visual quality of the tone-mapped image, especially attention-salient regions, is improved by the saliency-aware weighting.

Robust high-dynamic-range vector magnetometry with nitrogen-vacancy centers in diamond

Abstract: We demonstrate a robust, scale-factor-free vector magnetometer, which uses a closed-loop frequency-locking scheme to simultaneously track Zeeman-split resonance pairs of nitrogen-vacancy (NV) centers in diamond. This technique offers a three-orders-of-magnitude increase in dynamic range compared to open-loop methodologies; is robust against fluctuations in temperature, resonance linewidth, and contrast; and allows for simultaneous interrogation of multiple transition frequencies. By directly detecting the resonance frequencies of NV centers oriented along each of the diamond's four tetrahedral crystallographic axes, we perform full vector reconstruction of an applied magnetic field.

Display and detail enhancement for high-dynamic-range infrared images

Abstract: Dynamic range reduction and detail enhancement are two important issues for effectively displaying high-dynamic-range images acquired by thermal camera systems. They must be performed in such a way that the high dynamic range image signal output from sensors is compressed in a pleasing manner for display on lower dynamic range monitors without reducing the perceptibility of small details. In this paper, a new method of display and detail enhancement for high dynamic range infrared images is presented. This method effectively maps the raw acquired infrared image to 8-bit domain based on the same architecture of bilateral filter and dynamic range partitioning approach. It includes three main steps: First, a bilateral filter is applied to separate the input image into the base component and detail component. Second, refine the base and detail layer using an adaptive Gaussian filter to avoid unwanted artifacts. Then the base layer is projected to the display range and the detail layer is enhanced using an adaptive gain control approach. Finally, the two parts are recombined and quantized to 8-bit domain. The strength of the proposed method lies in its ability to avoid unwanted artifacts and adaptability in different scenarios. Its great performance is validated by the experimental results tested with two real infrared imagers.

Motion/saturation detection system and method for synthesizing high dynamic range motion blur free images from multiple captures

Abstract: Motion/Saturation detection system and method for synthesizing high dynamic range motion blur free images from multiple captures, the system and method utilizing photocurrent estimation to reduce read noise and enhance dynamic range at the low illumination end, saturation detection to enhance dynamic range at the high illumination end, and motion blur detection to ensure the photocurrent estimation is not corrupted by motion. Motion blur detection also makes it possible to extend exposure time and to capture more images, which can be used to further enhance dynamic range at the low illumination end. The present invention operates completely locally, making it well suited for single chip digital camera implementations.