共查询到20条相似文献,搜索用时 15 毫秒
1.
利用时间拉伸显微成像系统观察并记录非重复动态随机现象,在其超高成像速度和高空间分辨率下必定会产生大量的数据。一种基于差分检测和游程编码的数据压缩方法,可以有效地解决时间拉伸成像系统的数据存储问题。差分检测可以消除连续相同的信号,只检测出相邻信号的差异,从而提高游程编码算法的有效性。实验中,采用扫描频率为77.76 MHz的时间拉伸显微成像对分辨率板、人红细胞和人乳腺癌细胞线性扫描成像。实验结果表明,数据压缩比可以达到8.47,对比分析发现经过差分检测方法可以获得更高的压缩比。另外,通过计算重建后的图像与原图的结构相似性(SSIM)值发现,经过数据压缩后高质量的图像可以被重建。 相似文献
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Suppression of distortion induced by nonlinearity in a dynamical system (such as an analog optical link) is very challenging, particularly for a wide-bandwidth signal. Conventional compensation techniques are computationally intensive, significantly limiting their realization in real-time applications. Here, we propose and demonstrate an efficient digital postprocessing technique to suppress distortions added to a wideband signal by a nonlinear system with memory effect. Experimentally, digital broadband linearization of the photonic time-stretch analog-to-digital converter (TSADC) is demonstrated. In case of TSADC, a dynamic range improvement of >15 dB compared to conventional memory-less correction method is achieved. 相似文献
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We demonstrate a simple, all-fiber technique for removing nonlinear phase due to self-phase modulation in fiber-based chirped-pulse amplification (CPA) systems. Using a LiNbO3 electro-optic phase modulator to emulate a negative nonlinear index of refraction, we are able to remove 1.0 pi rad of self-phase modulation acquired by pulses during amplification and eliminate nearly all pulse distortion. Our technique is high speed, removes nonlinear phase on a pulse-to-pulse basis, and can be readily integrated into existing CPA systems. 相似文献
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对红外焦平面阵列成像系统而言,基于场景的非均匀校正技术是处理固定图案噪声的关键技术。现有的非均匀校正算法主要被收敛速度和鬼像问题所限制。提出一种新的基于恒定统计算法的自适应场景非均匀校正技术。利用红外图像序列的时域统计信息结合提出的α修正均值滤波来估计探测器的参数,通过减少样本的渐进方差估计,完成成像系统的非均匀性校正。通过模拟和真实的非均匀性图像对算法的性能进行评价。实验结果表明,在继承恒定统计算法快速收敛的同时,图像峰值信噪比较恒定校正法及常系数α校正算法分别有44.5%和32.9%的提升,图像鬼像问题有明显改善。 相似文献
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Multi-hump soliton which consists of plural pulses can propagate in a dispersion-managed optical fiber transmission system
with maintaining the pulse-to-pulse spacings. In this paper, the family members of multi-hump soliton are systematically introduced
using a family tree. The system parameter ranges in which multi-hump soliton can exist are studied by a numerical averaging
scheme. The dependency of pulse energy and pulse-to-pulse spacing on the system parameter is also investigated to show the
robustness of anti-phase bi-soliton against imposed perturbations. 相似文献
7.
Spectral phase ripple associated with novel dispersive devices can distort broadband optical signals. We present a digital postprocessing algorithm to correct for this distortion by exploiting the static deterministic nature of the ripple. This algorithm is demonstrated with empirical data for several systems employing chirped fiber Bragg gratings (CFBGs). We employ this technique in a photonic time-stretch system incorporating CFBGs, improving the signal fidelity by 9 dB. Simulations and experiments show that this algorithm, which can be reduced to a simple interpolation and matrix multiplication, also mitigates additive noise. We see that the act of distortion correction yields signal fidelity superior to that of an ideal dispersive element. 相似文献
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Fard A Yang JY Buckley B Wang J Chitgarha MR Zhang L Willner AE Jalali B 《Optics letters》2011,36(19):3804-3806
Optical performance monitoring of high-capacity networks is one of the enabling technologies of future reconfigurable optical switch networks. In such networks, rapid performance evaluation of data streams becomes challenging due to the use of advanced modulation formats and high data rates. The time-stretch enhanced recording oscilloscope offers a potential solution to monitoring high-rate data in a practical time scale. Here we demonstrate an architecture with a differential detection front end for simultaneous I/Q data monitoring of a 100 gigabits/s return-to-zero differential quadrature phase-shift keying signal. This demonstration shows the potential of this technology for rapid performance monitoring of high-rate optical data streams that employ advanced modulation formats. 相似文献
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四通道实时联合变换相关器 总被引:2,自引:0,他引:2
提出把光学波阵面分割复用器用于单通道实时光电混合联合变换相关系统实现四通道实时相关,使单通道系统扩展为具有多个独立通道的系统,使系统的容量和处理速度提高数倍,使系统的性能得以改善。给出了新系统的设计方案、工作原理和实验结果。 相似文献
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Zhao Min-jie Zou Ying Si Fu-qi Lu Yi-huai Wang Yu Wang Shi-mei Zhou Hai-jin Zeng Yi Liu Wen-qing 《光谱学与光谱分析》2015,(9):2578-2582
Space-borne differential optical absorption spectrometer is a nadir viewing wide field imaging spectrometer, which adopts two-dimensional CCD detector arrays. The pixel response non-uniformity exists in each column of spatial dimension, which will introduce high-frequency instrument-related spectral structures in the measurement data. However, the non-uniformity calibration of space-born imaging spectrometer is difficulty due to two factors: the spectral smile effect and the large field of view. For this reason, a method of non-uniformity calibration is discussed in detail. The result shows that the spectral smile effect and non-uniformity of full FOV image are corrected effectively, and high-frequency instrument-related structures in the measurement data are removed. 相似文献
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利用差分吸收光谱技术原理,设计了相应的差分吸收光谱监测装置,对环境中存在两种主要污染气体SO2和NO2进行了监测。在对所测光谱进行分析时,提出了用傅里叶变换的信号分析方法来解析上述两种气体的吸收光谱。在光谱分析过程中,主要包括光谱信号的去噪处理和慢变化的拟合两大步骤。差分吸收光谱仪所测到的原始光谱经傅里叶变换后,频谱中的低频部分对应的就是原始光谱中的慢变化部分,而噪声谱主要集中在变换后频谱的高频部分,所以可以通过截取一定频率段的频谱后再通过逆傅里叶变换来去除气体吸收光谱中的慢变换部分和噪声部分,进一步处理后可以得到气体的差分吸收光谱,从而反演计算出对应的气体浓度。通过分析比较,该方法是一种新的差分吸收光谱解析方法,可以更好地拟合出原始光谱中的慢变化部分,与此同时,在去除噪声影响,提高信噪比方面有很好的作用。 相似文献
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Wei Zhang Changlun Hou Yu Geng Guoguang Yang 《Optical and Quantum Electronics》2009,41(14-15):981-988
Closely packed optical fiber arrays are used to increase the scanning speed in some laser scanning systems, but standard optical fibers are shown to be unsuitable for these systems. In this paper, a closely packing technique of micro optical fiber arrays is presented. The fabrication and properties of micro fibers, whose diameters range from several hundred nanometers to several microns, are introduced. These micro fibers are arranged side by side in V-shaped grooves, which are fabricated by photolithography and etching techniques on silicon substrate. Comparing to standard optical fiber arrays, such closely packed micro optical fiber arrays can eliminate the dark area among output light spots and can solve the problem of high accuracy demand of exposure location. This closely packing technique is also proved to be a feasible method in practical scanning systems. 相似文献
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激光多普勒超低速测量 总被引:1,自引:0,他引:1
报道激光多普勒超低速测量系统及实验结果,其光学系统为四光路双焦点外差多普勒测速系统,信号处理系统为动态模拟相位计,可测速度范围为1nm/s到300mm/s。 相似文献
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The pattern matching for fingerprints requires a large amount of data and computation time. Practical fingerprint identification systems require minimal errors and ultrafast processing time to perform real-time verification and identification. By utilizing the two-dimensional processing capability, ultrafast processing speed and non-interfering communication of optical processing techniques, fingerprint identification systems can be implemented in real-time. Among the various pattern matching systems, the joint transform correlator (JTC) has been found to be inherently suitable for real-time matching applications. Among the various JTCs, the fringe-adjusted JTC has been found to yield significantly better correlation output compared to alternate JTCs. In this paper, a fingerprint identification system has been developed based on the fringe-adjusted JTC. Since all pattern matching systems suffer from high sensitivity to distortions, the synthetic discriminant function concept has been incorporated in fringe-adjusted JTC to ensure distortion-invariant fingerprint identification. 相似文献
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Yu. N. Kulchin O. B. Vitrik A. V. Dyshlyuk A. M. Shalagin S. A. Babin I. N. Nemov 《Laser Physics》2011,21(2):304-307
The paper presents a reflectometric technique for interrogation of multiple fiber Bragg grating (FBG) sensors based on conventional
optical time domain reflectometry (OTDR). The method proposed rests on the differential measurement of FBGs’ response to a
short probing laser pulse. Implementation of differential measurement principle using several reference FBGs allowed us to
eliminate the susceptibility of the system to intensity fluctuations as well as to increase the measurement range as compared
to the previous developments. The experimental threshold sensitivity amounted to ∼50 microstrain with the measurement range
being defined by the number of reference FBGs and limited only by optical fiber tensile strength. Due to its simplicity, efficiency
and usage of conventional OTDR equipment the proposed FBG interrogation technique can find a wide range of applications dealing
with strain and temperature measurements. 相似文献
19.
An optical sensing technology based on optical coherence tomography is presented for film thickness measurement and defect inspection. In order to improve the imaging quality, a simple interference spectrum processing procedure is proposed to eliminate the DC and the autocorrelation noise. With the proposed method, we obtain high quality one-dimensional depth and two-dimensional cross-sectional images of the films. Then, the thickness and the defect information of the film can be obtained from the acquired images. The experiment result demonstrates that this nondestructive imaging technique is applicable for measuring film thickness and inspecting defects. 相似文献
20.
DSP图像处理技术在空间瞬态光辐射定位探测中的应用 总被引:7,自引:4,他引:3
在分析空间瞬态光辐射信号成像特点的基础上,提出了一种在空间瞬态光辐射信号定位系统中,用高速浮点DSP芯片实现图像处理的方案.图像处理过程为:首先通过阈值分割滤除背景和弱噪音;然后根据目标信号的时空连续性进行目标识别以去除强噪音;最后对识别出的目标像点进行重心位置的提取.实验表明,该硬件图像处理方案具有高的实时处理性和定位准确性,可以很好的满足系统要求. 相似文献