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.

High dynamic range mapping of strong radio sources, with application to 3C84

Abstract: A new reduction procedure is described to correct data obtained by the Westerbork Synthesis Radio Telescope. The technique allows very high dynamic range mapping of strong radio sources by also using redundant interferometers. The performance is illustrated with 6-cm and 21-cm continuum maps of 3C84, which have a dynamic range of about 10,000:1.

High dynamic range texture compression for graphics hardware

Abstract: In this paper, we break new ground by presenting algorithms for fixed-rate compression of high dynamic range textures at low bit rates. First, the S3TC low dynamic range texture compression scheme is extended in order to enable compression of HDR data. Second, we introduce a novel robust algorithm that offers superior image quality. Our algorithm can be efficiently implemented in hardware, and supports textures with a dynamic range of over 109:1. At a fixed rate of 8 bits per pixel, we obtain results virtually indistinguishable from uncompressed HDR textures at 48 bits per pixel. Our research can have a big impact on graphics hardware and real-time rendering, since HDR texturing suddenly becomes affordable.

High Dynamic Range Imaging of Natural Scenes.

Abstract: The ability to capture and render high dynamic range scenes limits the quality of current consumer and professional digital cameras. The absence of a well-calibrated high dynamic range color image database of natural scenes is an impediment to developing such rendering algorithms for digital photography. This paper describes our efforts to create such a database. First, we discuss how the image dynamic range is affected by three main components in the imaging pipeline: the optics, the sensor and the color transformation. Second, we describe a calibrated, portable high dynamic range imaging system. Third, we discuss the general properties of seventy calibrated high dynamic range images of natural scenes in the database (http://pdc.stanford.edu/hdri/). We recorded the calibrated RGB values and the spectral power distribution of illumination at different locations for each scene. The scene luminance ranges span two to six orders of magnitude. Within any scene, both the absolute level and the spectral composition of the illumination vary considerably. This suggests that future high dynamic range rendering algorithms need to account jointly for local color adaptation and local illumination level.

Global alignment for high-dynamic range image generation

Abstract: Techniques and tools for high dynamic range (“HDR”) image generation and rendering are described herein. In several described embodiments, images having distinct exposure levels are aligned. In particular embodiments, the alignment of a reference image to a non-reference image is based at least in part on motion vectors that are determined using covariance computations. Furthermore, in certain embodiments, saturated areas, underexposed areas, and/or moving objects are ignored or substantially ignored during the image alignment process. Moreover, in certain embodiments, a hierarchical pyramid block-based scheme is used to perform local motion estimation between the reference image and the non-reference image.

Advanced channelization for RF, microwave, and millimeterwave applications

Abstract: An overview of the channelization function, the parallel signal processing techniques used in channelizers, the signal processing functions, and the critical channelizer parameters is given. Signal processing capabilities that use analog techniques suitable for channelized receivers are compared with those capabilities that can be obtained by using current or foreseen digital techniques. The receiver signal-processing needs are outlined, and the limitations of digital signal processing in terms of the overall receiver signal processing needs are discussed. Options and tradeoffs at the receiver and channelizer technology levels are discussed. Promising channelizer technologies, including components, that have been or potentially may be implemented with small volumes and moderate dynamic range are described. Parallel signal-processing methods, architectural techniques, and hardware for channelized receiver technologies that can be implemented in a small volume (tens of channels per in/sup 3/) with a moderately high dynamic range (>50 dB) are discussed. These include the surface-acoustic-wave (SAW), bulk-acoustic-wave (BAW), magnetostatic-wave (MSW), and acoustooptical (AO) channelizer technologies. The critical signal preprocessing functions required in channelized receivers before the needed information is passed on to the host computer, so that the host computer can be operated at a possible computation rate, are discussed, and the first successful monolithic integrated circuit preprocessor component for channelizers, is presented. >