- 标题
- 摘要
- 关键词
- 实验方案
- 产品
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Robust Noisiness Measure Based Improved Generalized Fuzzy Peer Group for Removal of Mixed Noise From Color Image
摘要： In this letter, a novel method has been proposed to estimate noisiness of a pixel in an image. The proposed noisiness is based on a robust noisiness measure, which is evaluated using noise and edge information of locality of the pixel. Furthermore, this noisiness is used to develop a fuzzy peer group for removing mixed Gaussian and impulse noises from color images. Also, an iterative approach to the proposed method is presented. The proposed approach is then compared with the state-of-the-art algorithms. Results shows that the proposed method outperform existing algorithms significantly.
关键词： fuzzy peer group,robust noisiness measure,Mixed noise removal
更新于2025-09-23 15:22:29
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Speckle Noise Reduction of Medical Imaging via Logistic Density in Redundant Wavelet Domain
摘要： In the digital world, artificial intelligence tools and machine learning algorithms are widely applied in analysis of medical images for identifying diseases and make diagnoses; for example, to make recognition and classification. Speckle noises affect all medical imaging systems. Therefore, reduction in corrupting speckle noises is very important, since it deteriorates the quality of the medical images and makes tasks such as recognition and classification difficult. Most existing denoising algorithms have been developed for the additive white Gaussian noise (AWGN). However, AWGN is not a speckle noise. Therefore, this work presents a novel speckle noise removal algorithm within the framework of Bayesian estimation and wavelet analysis. This research focuses on noise reduction by the Bayesian with wavelet-based method because it provides good efficiency in noise reduction and spends short time in processing. The subband decomposition of a logarithmically transformed image is best described by a family of heavy-tailed densities such as Logistic distribution. Then, this research proposes the maximum a posteriori (MAP) estimator assuming Logistic random vectors for each parent-child wavelet coefficient of noise-free log-transformed data and log-normal density for speckle noises. Moreover, a redundant wavelet transform, i.e., the cycle-spinning method, is applied in our proposed methods. In our experiments, our proposed methods give promising denoising results.
关键词： wavelet transforms.,Bayesian estimation,speckle noise,non-Gaussian model
更新于2025-09-23 15:22:29
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A Compact X-Band Vector Network Analyzer for Microwave Image Sensing
摘要： This work develops a compact and portable X-band vector network analyzer (VNA) for low-cost microwave image sensing applications. Since significant local oscillator (LO) injection pulling and poor LO phase noise performance may reduce the accuracy of measurement, the developed VNA uses the single-conversion technique and the phase noise cancellation technique to suppress the injection pulling effect and the LO phase noise, respectively. A hybrid phase detection algorithm that includes arctangent, arcsine and arccosine functions is proposed to overcome the bottleneck of the distortion of conventional quadrature phase detection in some phase regions. Experimental results demonstrate that the X-band microwave image sensing system that uses the developed VNA, which is highly compact and portable, can effectively yield a contour image of bones in a chicken wing and pork ribs.
关键词： transceiver,microwave image sensing,vector network analyzer,phase noise,frequency synthesizer
更新于2025-09-23 15:22:29
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[IEEE 2018 OCEANS - MTS/IEEE Kobe Techno-Ocean (OTO) - Kobe (2018.5.28-2018.5.31)] 2018 OCEANS - MTS/IEEE Kobe Techno-Oceans (OTO) - Underwater Image Denoising Based on Non-Local Methods
摘要： Due to the medium scattering and light absorption, the acquired underwater optical images suffer from poor visibility. Absorption and scattering effects are caused not only by the water itself but also by other floating particles. Moreover, backscattering is strengthened during the light is reflected and deflected multiple times by the suspended particles before reaching the camera. The backscattering gives rise to specific strong correlated noise together with a constant level degrading the image contrast. Although there are many effective dehazing methods to remove the veil background, they have ignored the influence of backscattering noise, which still exists in the dehazed images. In addition, because of the special characteristics of backscattering noise, the traditional image denoising methods are difficult to make sense, even cause distortion. Accordingly, this paper employed the non-local denoising methods which are referred to Non-Local Means algorithm and Block-Matching 3D collaborative filtering to suppress the backscattering noise. The experimental results show that they can effectively remove the backscattering noise of underwater image and achieve better image quality.
关键词： backscattering noise,BM3D,NLM,underwater image
更新于2025-09-23 15:22:29
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[IEEE 2018 20th International Conference on Transparent Optical Networks (ICTON) - Bucharest (2018.7.1-2018.7.5)] 2018 20th International Conference on Transparent Optical Networks (ICTON) - Mitigation of Amplitude and Phase Distortions by Using Conjugate-NOLM Regenerator
摘要： In this paper we propose a conjugate nonlinear optical loop mirror scheme (Conj-NOLM) by cascading two NOLMs with an intermediate optical phase conjugator stage (OPC). This new configuration utilizes mid-span spectral inversion to cancel out the nonlinear phase distortion that is introduced by the two NOLM units. Moreover, numerical investigation has been carried out for 16-QAM signals demonstrating increased robustness against accumulated amplitude and phase distortions in the transmission links.
关键词： conjugate nonlinear optical loop mirror,all-optical regenerator,multilevel amplitude and phase noise suppression
更新于2025-09-23 15:22:29
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Nonlinear multimodal interference for ytterbium-doped all-fiber mode-locking noise-like pulse generation
摘要： This work demonstrates the generation of the noise-like pulse (NLP) in an all-normal-dispersion passively mode-locked ytterbium-doped ring laser cavity with nonlinear multimodal interference as an equivalent all-fiber saturable absorber, for the first time to the best of our knowledge. Depending on the appropriate optimization of the intra-cavity birefringence and reasonable control of the curving curvature of the multimode fiber, self-started NLP operation can be built and maintained within a wide pump range. Additionally, the effect of the multimode fiber length on the NLP mode-locking performance and the generation of the high power NLP have also been experimentally studied.
关键词： ytterbium-doped fiber,all-fiber laser,nonlinear multimodal interference,noise-like pulse,mode-locking
更新于2025-09-23 15:22:29
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Trap and 1/f-noise effects at the surface and core of GaN nanowire gate-all-around FET structure
摘要： Using capacitance, conductance and noise measurements, we investigate the trapping behavior at the surface and in the core of triangular-shaped one-dimensional (1D) array of GaN nanowire gate-all-around field effect transistor (GAA FET), fabricated via a top-down process. The surface traps in such a low dimensional device play a crucial role in determining the device performance. The estimated surface trap density rapidly decreases with increasing frequency, ranging from 6.07 × 1012 cm?2·eV?1 at 1 kHz to 1.90 × 1011 cm?2·eV?1 at 1 MHz, respectively. The noise results reveal that the power spectral density increases with gate voltage and clearly exhibits 1/f-noise signature in the accumulation region (Vgs > Vth = 3.4 V) for all frquencies. In the surface depletion region (1.5 V < Vgs < Vth), the device is governed by 1/f at lower frequencies and 1/f 2 noise at frequencies higher than ~ 5 kHz. The 1/f 2 noise characteristics is attributed to additional generation–recombination (G–R), mostly caused by the electron trapping/detrapping process through deep traps located in the surface depletion region of the nanowire. The cutoff frequency for the 1/f 2 noise characteristics further shifts to lower frequency of 102–103 Hz when the device operates in deep-subthreshold region (Vgs < 1.5 V). In this regime, the electron trapping/detrapping process through deep traps expands into the totally depleted nanowire core and the G–R noise prevails in the entire nanowire channel.
关键词： gate-all-around field effect transistor (FET),trap,nanowire,GaN,1/f-noise
更新于2025-09-23 15:22:29
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[IEEE 2018 IEEE Asian Solid-State Circuits Conference (A-SSCC) - Tainan, Taiwan (2018.11.5-2018.11.7)] 2018 IEEE Asian Solid-State Circuits Conference (A-SSCC) - A Sub-Picosecond Hybrid DLL for Large-Scale Phased Array Synchronization
摘要： A large-scale timing synchronization scheme for scalable phased arrays is presented. This approach utilizes a DLL co-designed with a subsequent 2.5GHz PLL. The DLL employs a low noise, fine/coarse delay tuning to reduce the in-band rms jitter to 323fs, an order of magnitude improvement over previous works at similar frequencies. The DLL was fabricated in a 65nm bulk CMOS process and was characterized from 27MHz to 270MHz. It consumes up to 3.3mW from a 1V power supply and has a small footprint of 0.036mm2.
关键词： phase noise,tracking loops,CMOS integrated circuits,radio frequency,phase locked loops,phased-arrays,delay-lines
更新于2025-09-23 15:22:29
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[IEEE 2018 IEEE 3rd International Conference on Integrated Circuits and Microsystems (ICICM) - Shanghai, China (2018.11.24-2018.11.26)] 2018 IEEE 3rd International Conference on Integrated Circuits and Microsystems (ICICM) - A Novel LC VCO with High Output Power and Low Phase Noise Using Differential Active Inductor
摘要： This paper presents a novel LC voltage-controlled-oscillator (VCO) based on active inductor (AI). Taking advantage of equivalent RLC model of the AI, a novel tunable differential AI (DAI) is designed and used to act as the LC tank of the VCO. First, a tunable DAI with cascode-structure and current-mirror feedback networks is designed to achieve high quality factor (Q) and high equivalent parallel resistance (Rp). Then, the DAI is used to replace LC in VCO to realize good comprehensive performance of VCO such as low phase noise, low power consumption and high output power. Based on TSMC 0.18μm RF CMOS process, the novel VCO is verified by Agilent’s Advanced Design System (ADS). The results show that under the supply voltage of 1.8V, the output power reaches up to -4.2 dBm, a frequency tuning range is in 1.126-2.713 GHz, and the phase noise at 1-MHz offset is -117.2 dBc/Hz. A power of only 13.6 mW is consumed.
关键词： power consumption,output power,phase noise,LC voltage-controlled-oscillator,active inductor
更新于2025-09-23 15:22:29
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[IEEE 2018 IEEE International Conference on Imaging Systems and Techniques (IST) - Krakow (2018.10.16-2018.10.18)] 2018 IEEE International Conference on Imaging Systems and Techniques (IST) - Noise-filtering method for large-scale holographic 3D display
摘要： In a digital holographic display, it is not desirable to observe the conjugate image and zeroth-order diffracted light in the reconstructed image. To remove noise, various methods have been proposed to limit the noise bandwidth in the Fraunhofer region using optics. In general, a 4-F relay optic-based noise-filtering system is used in these noise-filtering methods. However, in the case of a holographic display configuration, where a conventional 4-F relay optics-based noise-filtering optical system is applied, the optical performance at a critical level is required because the diffraction angle and display area become larger. Here, we propose parallel noise filtering as a new method to remove the optical noise in a holographic display. The proposed parallel noise-filtering method can be achieved by applying a new noise-filtering optical system based on 2-F relay optics. The proposed technique significantly reduces the burden on the holographic display optics configuration and dramatically reduces the optical path to enable a holographic display with a commercially available form factor.
关键词： Noise filtering,Holography,3D display
更新于2025-09-23 15:22:29