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.

High dynamic range infrared image detail enhancement based on histogram statistical stretching and gradient filtering

Abstract: In order to improve the image contrast and strengthen the details of high dynamic range (HDR) infrared (IR) image, a detail enhancement method based on histogram statistical stretching (HSS) and gradient filtering (GF) is proposed. First, the outliers in the HDR image are clipped by the proposed histogram statistical strategy and the clipped histogram is then extended to a new grayscale range to acquire a better contrast of view. The details in the HDR image are extracted by using the GF and its result is then adjusted by using the HSS to enhance the low-contrast detail perception. Finally, the GF result is superposed with the HSS result in a proper way to generate the final detail-enhanced image. The contribution and innovation made is threefold. A new technique for visualization of HDR image especially tailored to IR image is proposed. The effectiveness and convenience are shown by analyzing the experimental images that represent the typical and common IR scenes. Last, the performance is quantitatively assessed compared with other well-established methods. The simulation and experimental results approve its low cost, low complexity and promising outlook for real-time processing.

Color high dynamic range imaging: The luminance–chrominance approach: Articles

Abstract: This article presents a novel and efficient approach to color in high dynamic range (HDR) imaging. In contrast to state-of-the-art methods, we propose to move the complete HDR imaging process from RGB to a luminance–chrominance color space. Our aim is to get a computationally efficient technique and to avoid any possible color distortions originating from the three RGB color channels processed separately. To achieve this, we build a camera response function for the luminance channel only and weight and compose the HDR luminance accordingly, while for the chrominance channels we apply weighting in relation with the saturation level. We demonstrate that our technique yields natural and pleasant to perceive tone-mapped images and is also more robust to noise. © 2007 Wiley Periodicals, Inc. Int J Imaging Syst Technol, 17, 152–162, 2007 This paper extends the preliminary work of the authors first introduced in (Pirinen et al.,[2007].

An efficient multiple exposure image fusion in JPEG domain

Abstract: In this paper, we describe a method to fuse multiple images taken with varying exposure times in the JPEG domain. The proposed algorithm finds its application in HDR image acquisition and image stabilization for hand-held devices like mobile phones, music players with cameras, digital cameras etc. Image acquisition at low light typically results in blurry and noisy images for hand-held camera's. Altering camera settings like ISO sensitivity, exposure times and aperture for low light image capture results in noise amplification, motion blur and reduction of depth-of-field respectively. The purpose of fusing multiple exposures is to combine the sharp details of the shorter exposure images with high signal-to-noise-ratio (SNR) of the longer exposure images. The algorithm requires only a single pass over all images, making it efficient. It comprises of - sigmoidal boosting of shorter exposed images, image fusion, artifact removal and saturation detection. Algorithm does not need more memory than a single JPEG macro block to be kept in memory making it feasible to be implemented as the part of a digital cameras hardware image processing engine. The Artifact removal step reuses the JPEGs built-in frequency analysis and hence benefits from the considerable optimization and design experience that is available for JPEG.

Real-Time Biologically-Inspired Image Exposure Correction

Abstract: This chapter presents a real-time FPGA implementation of a biologically-inspired image enhancement algorithm. The algorithm compensates for the under/over-exposed image regions, emerging when High Dynamic Range (HDR) scenes are captured by contemporary imaging devices. The transformations of the original algorithm, which are necessary in order to meet the requirements of an FPGA-based hardware system, are presented in detail. The proposed implementation, which is synthesized in Altera’s Stratix II GX: EP2SGX130GF1508C5 FPGA device, features pipeline architecture, allowing the real-time rendering of color video sequences (25fps) with frame sizes up to 2.5Mpixels.

Radiometric calibration for HDR imaging

Abstract: In this paper we present a method to estimate the radiance map and camera response function for high dynamic range (HDR) imaging which is devoid of free parameters and can reliably recover HDR images with as few as two low-dynamic range (LDR) views acquired at different exposures. To do this, we employ a L1 cost function which lends itself to the use of a Weiszfeld optimisation scheme. We illustrate the utility of the method for computing high-dynamic range images from low-dynamic range imagery. In our experiments, we compare our results with those delivered by alternatives elsewhere in the literature and show that our method can outperform the alternatives with as few as two LDR images. We also apply our method to panorama generation.