Topic
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.
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19 Mar 2015
TL;DR: A TDC architecture is presented which combines the two step iterated TCSPC process of time-code generation, followed by memory lookup, increment and write, into one parallel direct-to-histogram conversion.
Abstract: Time-correlated single photon counting (TCSPC) is a photon-efficient technique to record ultra-fast optical waveforms found in numerous applications such as time-of-flight (ToF) range measurement (LIDAR) [1], ToF 3D imaging [2], scanning optical microscopy [3], diffuse optical tomography (DOT) and Raman sensing [4]. Typical instrumentation consists of a pulsed laser source, a discrete detector such as an avalanche photodiode (APD) or photomultiplier tube (PMT), time-to-digital converter (TDC) card and a FPGA or PC to assemble and compute histograms of photon time stamps. Cost and size restrict the number of channels of TCSPC hardware. Having few detection and conversion channels, the technique is limited to processing optical waveforms with low intensity, with less than one returned photon per laser pulse, to avoid pile-up distortion [4]. However, many ultra-fast optical waveforms exhibit high dynamic range in the number of photons emitted per laser pulse. Examples are signals observed at close range in ToF with multiple reflections, diffuse reflected photons in DOT or local variations in fluorescent dye concentration in microscopy. This paper provides a single integrated chip that reduces conventional TCSPC pile-up mechanisms by an order of magnitude through ultra-parallel realizations of both photon detection and time-resolving hardware. A TDC architecture is presented which combines the two step iterated TCSPC process of time-code generation, followed by memory lookup, increment and write, into one parallel direct-to-histogram conversion. The sensor achieves 71.4ps resolution, over 18.85ns dynamic range, with 14GS/s throughput. The sensor can process 1.7Gphoton/s and generate 21k histograms/s (with 4.6μs readout time), each capturing a total of 1.7kphotons in a 1μs exposure.
79 citations
TL;DR: This paper revisits the digitization journey of the traditional charge-pump PLL that has resulted in an all-digital frequency synthesizer with the best-in-class RF performance while occupying only a fraction of the silicon area and consuming only a fractions of the power.
Abstract: The past several years have successfully brought all-digital techniques to the RF frequency synthesis, which could arguably be considered one of the last strong bastions of the traditionally-analog design approaches. With their high sensitivity and high dynamic range requirements, the RF circuits have long had a good excuse to avoid any possible source of digital switching activity. With the constant scaling of CMOS feature size and the merciless push for integration, the existence of almost free and powerful digital logic could not go unnoticed. Hence, the environment was ripe to transform the RF functions into digital realizations, as well as to apply digital assistance to help with the performance of RF circuits. This paper revisits the digitization journey of the traditional charge-pump PLL that has resulted in an all-digital frequency synthesizer with the best-in-class RF performance while occupying only a fraction of the silicon area and consuming a fraction of the power. The paper also offers a few novel techniques to further improve area, current consumption, testability, and reliability of frequency synthesizers.
79 citations
Patent•
30 Sep 2011
TL;DR: The range of embodiments includes systems, methods, and apparatus for defect compensation that may be applied to displays having multiple imaging layers, such as high dynamic range displays, and/or to stereoscopic displays such as autostereoscopic displays as mentioned in this paper.
Abstract: The range of embodiments includes systems, methods, and apparatus for defect compensation that may be applied to displays having multiple imaging layers, such as high dynamic range displays, and/or to stereoscopic displays, such as autostereoscopic displays.
79 citations
TL;DR: It is argued that high dynamic range representation can encode images regardless of the technology used to create and display them, with the accuracy that is only constrained by the limitations of the human eye and not a particular output medium.
Abstract: The advances in high dynamic range (HDR) imaging, especially in the display and camera technology, have a significant
impact on the existing imaging systems. The assumptions of the traditional low-dynamic range imaging, designed for
paper print as a major output medium, are ill suited for the range of visual material that is shown on modern displays. For
example, the common assumption that the brightest color in an image is white can be hardly justified for high contrast
LCD displays, not to mention next generation HDR displays, that can easily create bright highlights and the impression
of self-luminous colors. We argue that high dynamic range representation can encode images regardless of the technology
used to create and display them, with the accuracy that is only constrained by the limitations of the human eye and
not a particular output medium. To facilitate the research on high dynamic range imaging, we have created a software
package (http://pfstools.sourceforge.net/) capable of handling HDR data on all stages of image and video processing. The
software package is available as open source under the General Public License and includes solutions for high quality
image acquisition from multiple exposures, a range of tone mapping algorithms and a visual difference predictor for HDR
images. Examples of shell scripts demonstrate how the software can be used for processing single images as well as video
sequences.
79 citations
TL;DR: This paper proposes a comprehensive approach that can be used to improve the demodulation linearity of microwave DRSs, such that detailed time-domain motion information ranging from micro-scale to large scale can be accurately reconstructed.
Abstract: Miniaturized Doppler radar sensor (DRS) for noncontact motion detection is a hot topic in the microwave community. Previously, small-scale physiological signals such as human respiration and heartbeat rates are the primary interest of study. In this paper, we propose a comprehensive approach that can be used to improve the demodulation linearity of microwave DRSs, such that detailed time-domain motion information ranging from micro-scale to large scale can be accurately reconstructed. Experiments show that based on a digital-IF receiver architecture, dynamic dc offset tracking, and the extended differentiate and cross-multiply arctangent algorithm, the displacement and velocity of both micrometer-scale vibration of a tuning fork and meter-scale human walking can be accurately recovered. Our work confirms that substantial time-domain motion information is carried by the signals backscattered from moving objects. Retrieval of such information using DRSs can be potentially used in a wide range of healthcare and biomedical applications, such as motion pattern recognition and bio-signal measurements.
79 citations