An L0 regularized cartoon-texture decomposition model for restoring images corrupted by blur and impulse noise

In this paper, we address the image restoration case that includes both blurring and impulse noise. To recover an image with abundant features, we propose an L0 regularized cartoon-texture model for the simultaneous deblurring and impulse noise removal problem. We propose an L0 regularized framelet-based sparse representation and L0 regularized discrete cosine transform (DCT)-based sparse approximation to model the cartoon and texture of images, respectively. Unlike other cartoon-texture decomposition based-restoration approaches, our method does not depend on local features but globally controls the important non-zero components of the cartoon and texture in the framelet and DCT domain. Furthermore, we develop an alternating half-quadratic splitting method to solve the proposed L0 regularized cartoon-texture deblurring and impulse noise removal model (L0_RCTDINR) by introducing an alternating algorithm into the half-quadratic method. Experiments show the effectiveness of L0_RCTDINR on deblurring and impulse noise removal compared with existing state-of-the-art methods.     

W-Mo合金CMP工艺参数的影响与优化研究

简述了金属化学机械抛光的机理。将半导体制造工艺中的化学机械抛光技术拓展并应用到W-Mo合金表面加工中,在实现W-Mo合金材料表面高平坦度、低粗糙度的前提下,提高W-Mo合金去除速率。针对W-Mo合金的性质,选用碱性抛光液,并采用田口方法对抛光液pH值、抛光压力和抛光盘转速三个重要因素进行了优化设计,得到以去除速率为评价条件的综合最优抛光参数。实验分析表明,当抛光液pH值为11,抛光压力为80 kPa,抛光盘转速60 r/min时,可以获得较高的去除速率。     

基于FCM的雨天视频图像复原

恶劣天气条件下图像退化的复原方法,对提高户外视觉系统的稳定性和实用性极为重要。雨作为其中一种场景,影响了户外图像或视频进行可靠目标检测、物体识别和跟踪、特征提取等基本操作,极易造成处理偏差,因此有必要对去雨方法进行研究,复原该类图像,消除降雨对图像质量的影响,以保证图像的清晰度。基于视频中雨滴的时域特性和像素直方图的全局特性,借助FCM(模糊C均值)聚类算法,提出了检测与去除视频中雨滴的方法。通过视频中4种不同场景的实验,验证了该方法的有效性。同时,该算法也可应用于其它类似雨的场景检测中。     

碱性条件下铝CMP的机理分析及实验优化

依据铝的电化学腐蚀特性,阐明了碱性条件下铝化学机械抛光(CMP)的机理。由于铝的硬度较低,在抛光过程中容易产生微划伤等缺陷,因此首先探索出适宜铝化学机械抛光的低压条件(4 psi,1 psi=6.895 kPa)。此外,提出两步抛光的方法,在抛光初期采用压力4 psi,抛光液由质量分数为40%的纳米级硅溶胶与去离子水(DIW)以体积比1∶1配制,氧化剂(H2O2)体积分数为1.5%,FA/O I型表面活性剂体积分数为1%,调节FA/OⅡ型螯合剂pH值为11.0,获得了较高的铝去除速率(341 nm/min)。在抛光后期采用低压1.45 psi,抛光液主要成分为体积分数5%的FA/O表面活性剂,并在较大体积流量(300 mL/min)的条件下进行抛光,充分利用表面活性剂的作用,对实验方案进行优化。采用优化后的实验方案,铝表面的划伤和缺陷显著减少。     

抛光液组成对LiNbO3 CMP去除速率的影响

影响LiNbO3化学机械抛光速率的因素很多,如抛光液组成、抛光垫质量、抛光工艺参数等.主要研究了抛光液对去除速率的影响,采用磨料 碱 活性剂的配方,首先分析了抛光液各成分对去除速率的影响机理,然后结合各因素的部分相关实验,从机械、化学角度分析其性质特点,对LiNbO3晶片的去除速率进行了研究.结果表明,在保证获得较好抛光表面的前提下,采用的磨料质量分数越高越好,但活性剂体积分数不宜过高,溶液pH值采用无机碱进行调节,即可获得较高的去除速率.     

Accurate segmentation of land regions in historical cadastral maps

Historical cadastral maps are valuable sources for historians to study social and economic background of changes in land uses or ownerships. In order to conduct large-scale historical research, it is essential to digitize the cadastral maps. As being established in antiquity, however, they suffer from significant noise artifacts attributed to hand-drawn cartography. In this paper, we propose a novel method of extracting land regions automatically in historical cadastral maps. First, we remove grid reference lines based on the density of the black pixel with the help of the jittering. Then, we remove land owner labels by considering morphological and geometrical characteristics of thinned image. We subsequently reconstruct land boundaries. Finally, the land regions of a user’s interest are modeled by their polygonal approximations. Our segmentation results were compared with manually segmented results and showed that the proposed method extracted the land regions accurately for assisting cadastral mapping in historical research.     

暗原色先验图像去雾算法研究

为了减小有雾天气对户外成像系统尤其是航拍视觉系统成像的影响,提出了一种新颖快速的基于暗原色先验和雾天图像退化模型的图像去雾方法.结合航拍图像特点,对原暗原色先验去雾箅法做了优化和改进.选取一系列户外带雾图像进行大量实验,结果表明,该方法能从物理特性上快速明显的去除雾的干扰,提高图像的清晰度,增强图像色彩和细节,复原得到...     

Random-valued impulse noise removal using adaptive dual threshold median filter

Noise detection and its removal is very important in the image processing. Detection of noise is very crucial and significant in random valued impulse noise because it does not hamper the image pixels uniformly. This paper presents a novel and unique concept of adaptive dual threshold for the detection of random valued impulse noise along with simple median filter at noise removal stage. Simulation results shows that an efficient noise detection leads to a superior quality of de-noised image as compared to existing adaptive threshold based image de-noising techniques. Proposed threshold computation is based on averaging of pixel values of window which enhances the PSNR of our system as compared to existing median filter based image de-noising methods.     

Digital canvas removal in paintings

The periodic structure of the underlying support of paintings on canvas can become quite prominent and disturbing in high resolution digital recordings. In this paper, we construct a new model and method for the digital removal of canvas which is considered as a noise component superimposed on the painting artwork. The high resolution of the images prohibits the efficient application of existing adaptive denoising filters. Hence, a two-step approach is proposed. First a (smoothing) Wiener filter is applied to the complete image. The second step consists of a spatially adaptive extension with low-complexity to obtain a generic digital canvas removal filter.     

基于FRFT的风廓线雷达间歇杂波抑制

风廓线雷达回波信号中的间歇强杂波严重干扰了大气湍流回波信号的识别和频谱估计。为了抑制该类杂波,提出了基于分数阶Fourier变换（FRFT）的杂波抑制方法,该方法利用间歇强杂波在分数阶Fourier频率域的能量聚集特性,通过窄带带阻滤波器在分数阶Fourier频率域滤除杂波,且对杂波滤除后的信号进行时域重构进而得到杂波抑制后回波信号的频谱图。与未进行杂波抑制回波信号的频谱图相比,间歇杂波部分被抑制明显。理论及仿真实验结果证明了该方法的有效性。