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[IEEE 2018 IEEE Avionics and Vehicle Fiber-Optics and Photonics Conference (AVFOP) - Portland, OR, USA (2018.11.13-2018.11.14)] 2018 IEEE Avionics and Vehicle Fiber-Optics and Photonics Conference (AVFOP) - Linear Ring Modulators with DC Kerr Phase Shifters
摘要： We demonstrate a silicon ring modulator with linear phase shift versus voltage, derived from the interplay between plasma dispersion effect and DC Kerr effect. The dynamic range is 103.6 dB. Hz2/3 at a 1.2 GHz carrier.
关键词： silicon ring modulator,plasma dispersion effect,linear phase shift,dynamic range,DC Kerr effect
更新于2025-09-09 09:28:46
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High Dynamic Range Video || An Application of HDR in Medical Imaging
摘要： The “slow revolution” that brought the field of diagnostic radiology from analog film to digital imaging paved the way to important benefits that were progressively achieved in the last few decades: above all, the possibility for medical personnel to rapidly share huge amounts of patient-related information. However, some of the consequences of the analog-to-digital shift were problematic. One issue, whose importance is often underestimated, was the visual quality of the images presented to the physician. As will be described in detail herein, the requirements of the different specialties with regard to medical images span a wide range; the weakest link in the processing chain, which determines the overall quality, is frequently the display equipment. In particular, the dynamic range of the luminance that the device can emit and its relation to the typical illumination of the environment in which the device operates should be considered with care. Old analog films placed on a lightbox could yield peaks of 4000 cd/m2, and could span a luminance range of several log units: this made details well visible even in a highly illuminated room. The best medical CRT displays at the time of the digital transition, instead, had a maximum luminance in the several hundred candelas per square meter (cd/m2) range. Only later did LCDs reach 1000 cd/m2, at the price of an undesired higher luminance for “black” pixels. In this chapter we will describe a solution aimed at overcoming dynamic range problems in the visualization of medical images. We will first analyze the specific requirements for a high dynamic range (HDR) display that should operate in the medical (diagnostic) context, and the procedures that are followed in a laboratory of the US Food and Drug Administration to evaluate such a display. We will then describe in some detail an LCD composed of two stacked liquid crystal panels, a prototype of which is presently being developed at Barco.
关键词： Visualization,LCD,Dual-Layer,Medical Imaging,High Dynamic Range
更新于2025-09-09 09:28:46
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Ghost and Noise Removal in Exposure Fusion for High Dynamic Range Imaging
摘要： For producing a single high dynamic range image (HDRI), multiple low dynamic range images (LDRIs) are captured with different exposures and combined. In high dynamic range (HDR) imaging, local motion of objects and noise in a set of LDRIs can influence a final HDRI: local motion of objects causes the ghost artifact and LDRIs, especially captured with under-exposure, make the final HDRI noisy. In this paper, we propose a ghost and noise removal method for HDRI using exposure fusion with subband architecture, in which Haar wavelet filter is used. The proposed method blends weight map of exposure fusion in the subband pyramid, where the weight map is produced for ghost artifact removal as well as exposure fusion. Then, the noise is removed using multi-resolution bilateral filtering. After removing the ghost artifact and noise in subband images, details of the images are enhanced using a gain control map. Experimental results with various sets of LDRIs show that the proposed method effectively removes the ghost artifact and noise, enhancing the contrast in a final HDRI.
关键词： Ghost Removal,High Dynamic Range Imaging,Exposure Fusion,Noise Removal
更新于2025-09-09 09:28:46
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Quantitative measurement of contrast, texture, color, and noise for digital photography of high dynamic range scenes
摘要： Today, most advanced mobile phone cameras integrate multi-image technologies such as high dynamic range (HDR) imaging. The objective of HDR imaging is to overcome some of the limitations imposed by the sensor physics, which limit the performance of small camera sensors used in mobile phones compared to larger sensors used in digital single-lens reflex (DSLR) cameras. In this context, it becomes more and more important to establish new image quality measurement protocols and test scenes that can differentiate the image quality performance of these devices. In this work, we describe image quality measurements for HDR scenes covering local contrast preservation, texture preservation, color consistency, and noise stability. By monitoring these four attributes in both the bright and dark parts of the image, over different dynamic ranges, we benchmarked four leading smartphone cameras using different technologies and contrasted the results with subjective evaluations.
关键词： image quality,texture preservation,color consistency,high dynamic range,noise stability,contrast preservation,HDR
更新于2025-09-04 15:30:14
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Research on the performance of a novel SPR sensor based on graded index multimode fiber
摘要： Purpose – This paper aims to propose and demonstrate a novel surface plasmon resonance (SPR)-sensing approach by using the fundamental mode beam based on a graded index multimode fiber (GIF). The proposed SPR sensor has high sensitivity and controllable working dynamic range, which expects to solve the two bottlenecks of fiber SPR sensor, including low sensitivity and the difficulty in multichannel detection. Design/methodology/approach – The low-order mode of the GIF to SPR sense, which keeps the sensitivity advantage of the single-mode fiber SPR sensor, is used. By using this new SPR sensor, the effect of light incident angle and gold film thickness on working dynamic range was studied. According to the study results, the smaller is the incident angle, the larger is the SPR working dynamic range and the longer is the resonance wavelength with a fixed gold film thickness; the larger is the gold film thickness, the longer is the resonance wavelength with a fixed grinding angle. After the parameter optimization, the sensitivity of these two parameter-adjusting methods reach 4,442 and 3031 nm/RIU. Originality/value – When the grinding angle of the GIF increases, the dynamic range of the resonance wavelength increases and has a redshift, sensitivity increases, and the resonance valley becomes more unobvious with a fixed gold film thickness. Similarly, when gold film thickness increases, the dynamic range of the resonance wavelength increases and has a redshift, sensitivity increases, and the resonance valley becomes more unobvious with a fixed grinding angle. These adjusting performance aforementioned lay the foundation for solving of the fiber-based SPR multichannel detection and increasing of the fiber-based SPR sensor sensitivity, which has a good application value.
关键词： Dynamic range,Sensitivity,GIF,SPR sensor
更新于2025-09-04 15:30:14
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Combining Global and Local Feature Analyses for Quality Evaluation of Tone-Mapped HDR Images
摘要： In existing literature, many tone mapping operators have been designed to convert high dynamic range (HDR) images to low dynamic range (LDR) images for visualization on the standard LDR displays. However, it inevitably causes distortions and artifacts due to the dynamic range compression, resulting in an unpleasant visual experience. In this paper, we propose a no reference (NR) quality evaluation method for tone-mapped (TM) HDR images based on global and local feature analyses. The key strategy of the proposed method lies in measuring the abnormal exposure both globally and locally as well as the halo effects. To be speci?c, given that the abnormal exposure usually induces the color and brightness changes, the global colorfulness and distribution of brightness are ?rst extracted to quantify the abnormal degree of exposure. Then, since abnormal exposure has diverse in?uences on local regions, the local features are further extracted from the statistical perspective on the discrete cosine transform domain. Finally, the edge strength is computed locally to measure the halo effects. All extracted quality-sensitive features are combined and trained together with subjective ratings to form a regression model using support vector regression. With extensive experiments, we have shown that the proposed method outmatches several mainstream NR image quality assessment methods designed for both natural scene images and TM HDR images.
关键词： halo effects,High dynamic range (HDR),quality evaluation,no reference,tone mapping
更新于2025-09-04 15:30:14
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[IEEE 2018 13th European Microwave Integrated Circuits Conference (EuMIC) - Madrid, Spain (2018.9.23-2018.9.25)] 2018 13th European Microwave Integrated Circuits Conference (EuMIC) - GaAs Balanced Amplifier for Ka-Band Space Communications System
摘要： The paper deals with the development of a state-of-the-art medium level amplifier able to combine good noise performance with a high P1dB compression point. The MMIC is realized with a balanced structure and making use of the PH25 GaAs pHEMT process provided by UMS. The balanced structure allows to achieve a gain of 19 dB with a P1dB compression point greater than 15 dBm and a noise figure of about 3 dB in a large bandwidth spanning from 26.5 GHz to 31.5 GHz. The chip has a single bias pad; the input and output bond wires are directly matched on chip, so easingenhancing the mechanical integration in the front-end.
关键词： Ka-band,GaAs technology,Balanced amplifier,Space technology,dynamic range
更新于2025-09-04 15:30:14
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Quarter Video Graphics Array Digital Pixel Image Sensing With a Linear and Wide-Dynamic-Range Response by Using Pixel-Wise 3-D Integration
摘要： We have developed a quarter video graphics array (QVGA) digital pixel image sensor by using the 3-D integration technology. The pulse-frequency modulation (PFM) analog-to-digital converter (ADC) operates as a digital pixel, which overcomes the signal saturation due to the full well capacity of the photodiode (PD). We have also newly designed a PFM-ADC for pixels with a pinned PD and a floating diffusion to comply with the CMOS image sensor process used to attain high sensitivity and low noise. PDs, comparators, logic circuits, and counters are integrated into two silicon-on-insulator layers by pixel-wise 3-D integration with gold electrodes with a 5 μm diameter, thereby achieving a QVGA resolution for a 20-mm square chip in the 0.18- and 0.2-μm process nodes. The developed sensor exhibits both the excellent linearity and a wide-dynamic range of more than 96 dB. Video images with a high bit depth of 16 bit are also obtained to demonstrate the superior image sensing, capable of capturing the real world at high fidelity.
关键词： analog-to-digital converters (ADCs),dynamic range,image sensors,3-D integrated circuits,integrated circuit interconnections,pulse generation,silicon on insulator (SOI)
更新于2025-09-04 15:30:14