GaAs/AlGaAs量子阱红外探测器噪声特性分析

分析了第一激发态在势垒以上的ＧａＡｓ／ＡｌＧａＡｓ量子阱红外探测器中存在的几种基本噪声,讨论了它们对探测器性能的影响。     

一种基于用户关注模型的立体图像舒适度客观评价方法

近年来,立体电视和立体电影的发展掀起了一股“3D”热潮。要让观众享受到高质量的立体内容,首先要解决人们在观看立体视频图像时的不舒适感。本文以立体图像的视差因素为切入点,结合人眼关注模型,设计了并实现了一种立体图像舒适度的客观评价方法。该方法根据人造立体图像的主观实验评价结果,建立了视差——舒适度模型,同时结合图像显著信息,对立体图像的舒适度进行了预测。对比主观评价结果,本文实现的所提出的立体图像舒适度客观评价方法所获取的评价结果与人眼感受具有较好的一致性。     

浅谈室内分布系统WCDMA网络的底噪问题及处理方法

室内分布系统由于直放站、无源器件的引入,多系统合路等原因,易造成WCDMA基站底噪抬升,直接影响室内分布系统的覆盖效果、话务容量及数据业务速率.简要分析了室内分布系统底噪产生的原因,并通过案例讲解几种常见底噪抬升问题的处理,有效降低底噪,提升WCDMA网络服务质量.     

Gradient based adaptive thresholding

For images with poor and non-uniform illumination, adaptive thresholding is required to separate the objects of interest from the background. In this paper a new approach to create an adaptive threshold surface is proposed to segment an image. The technique is inspired by the Yanowitz’s method and is improved upon by the introduction of a simpler and more accurate threshold surface. The method is tested on several images of different patterns with varying illumination and the results are compared to the ones produced by a number of adaptive thresholding algorithms. In order to demonstrate the effectiveness, the proposed method had been implemented in medical and document images. The proposed method compares favorably against those using watershed and morphology in medical image and favorably against variable threshold and adaptive Otsu’s N-thresholding for document image.     

超宽带低噪声放大器的计算机辅助设计

叙述了超宽带低噪声放大器的计算机辅助设计方法，提出了利用普通微带混合集成电路．工艺设计超宽带低噪声放大器的方法和关键技术，并且用带封装的ＢＪＴ和ＦＥＴ实现了两个超宽带低噪声放大器。实验结果和设计结果吻合较好。一个利用２ＳＣ３３５８，放大器为三级，频带为３０ｋＨＺ～１６００ＭＨＺ，增益Ｇ＝２０±１ｄＢ，噪声系数ＮＦ≤３．５ｄＢ；另一个利用ＡＴＦ１０２３５（６），放大器为二级，频带为５００ｋＨＺ～６０００ＭＨＺ，增益Ｇ＝２０±２ｄＢ，噪声系数ＮＦ≤２ｄＢ。     

Direct method for rotation estimation from spherical images using 3D mesh surfaces with SPHARM representation

Since a large field of view obviously bears important advantages, the use of spherical images is becoming increasingly important in various computer vision and image processing applications. This paper presents a novel rotation estimation approach for spherical images based on 3D mesh representation of gray level intensity. Once the 3D meshes of the underlying spherical images are obtained, the 3D rotation can be estimated directly and efficiently, without feature extraction and matching process. Subsequently, we propose a direct method for 3D object rotation estimation using spherical harmonics representation with SVD decomposition and ICP algorithm for estimation refinement. Experimental results validate our approach and prove its suitability and robustness for rotation estimation. Moreover, it performs well against noisy images, brightness changes, image compression and occlusions. A comparative study of our proposed approach with four similar methods for 3D rotation estimation between spherical images, is realized to prove its effectiveness.     

基于参数估计和感知提升的语音增强降噪算法

为了提高单通道语音增强降噪算法的整体质量,该文从噪声消除和语音感知两个角度出发对传统语音增强算法进行改进,通过引入多种处理手段来达到最佳优化效果。首先在参数估计方面,把基于弱语音出现的平滑算法加入到基于固定先验信噪比的软判决方法中来解决噪声谱过估计问题,并根据语音帧存在概率动态调整平滑因子,从而提高先验信噪比的跟踪效果。其次在语音质量感知提升方面,采用谐波恢复的方法重建语音段的高频谐波分量,并采用相位补偿和增益平滑的方法消除静默段和语音段的音乐噪声。实验结果表明,相比传统算法,该文算法通过引入参数估计改进模块和感知质量提升模块,在消噪效果和语音质量两方面均得到了较大的提高,并适用于多类噪声环境和信噪比条件。     

基于生成式对抗网络的遥感图像半监督语义分割

高分辨率遥感图像的语义分割问题是目前遥感图像处理领域中的研究热点之一。传统的有监督分割方法需要大量的标记数据,而标记过程又较为困难和耗时。针对这一问题,提出一种基于生成式对抗网络的半监督高分辨率遥感图像语义分割方法,只需要少量样本标签即可得到较好的分割结果。该方法为分割网络添加全卷积形式的辅助对抗网络,以助于保持高分辨率遥感图像分割结果中的标签连续性;更进一步,提出一种新颖的能够进行注意力选择的对抗损失,以解决分割结果较好时判别器约束的分割网络更新过程中存在的难易样本不均衡问题。在ISPRS Vaihingen 2D语义标记挑战数据集上的实验结果表明,与现有其它语义分割方法相比,所提出方法能够较大幅度地提高遥感图像的语义分割精度。     

A low-complexity low-spurs digital architecture for wideband PLL applications

This paper presents a non-ideality analysis of the wideband frequency synthesizer, and proposes a new digital architecture for signal modulation and quantization. Using error masking strategy, this method can offer smaller routing area and less power consumption without sacrificing any system performance. Simulation results confirm the theoretical predictions. Finally, the design guidelines are derived to fulfill the customized synthesizer specifications.     

Anisotropic diffusion for noise removal of band pass signals

A noise removal method for band pass signals based on the anisotropic diffusion algorithm originally put forward by Perona and Malik is proposed in this paper. The anisotropic smoothing algorithm proposed here is for band pass signals modulated with a constant carrier frequency. A partial differential equation to smooth band pass noisy signals is derived. The propagator of this differential equation is also analytically calculated in this paper. An appropriate linear operator is then considered here for such band pass signals to form an anisotropic diffusion algorithm. The algorithm proposed here demonstrates better performance for band pass noisy signals containing discontinuities in comparison with the traditional Perona-Malik (PM) algorithm and is robust in the presence of excessive noise with SNR less than unity.