喷墨打印纸印刷斑纹研究

目的将扫描仪和STFI-Mottling Expert斑纹测试软件相结合,研究喷墨打印纸的印刷斑纹。方法从数字图像处理的角度,用STFI印刷斑纹预测模型的斑纹测试软件,选取2种涂布纸和2种双胶纸,测试单色实地印刷样张的印刷斑纹,探究不同喷墨打印纸的印刷斑纹情况。结果空白双胶纸的斑纹较空白涂布纸严重,对青、品红、黄的单色实地印刷时,4种纸的印刷斑纹严重程度与空白纸张斑纹的测试结果吻合,而黑色实地印刷的斑纹情况较特殊。人眼对波长2~16 mm的印刷墨斑非常敏感,用STFI-斑纹专家软件测试的斑纹数值与视觉判定结果的相关系数为0.90,具有良好的相关性。结论用STFI印刷斑纹预测模型探究喷墨打印纸的印刷斑纹情况,对实际生产具有一定的指导价值。     

纸张印刷墨斑检测方法研究

目的基于扫描仪和STFI-Mottling Expert斑纹测试软件,提出一种使用改进型变异系数Mod Co V表征纸张印刷墨斑的新方法。方法纸张表面的印刷墨斑图像通过扫描仪获取,再经过软件分析,从数字图像处理的角度研究印刷斑纹;实验选用新闻纸、双胶纸、铜版纸和喷墨纸等4种纸张,分析不同波长范围和不同方向的印刷墨斑情况。结果使用改进型变异系数Mod Co V表征印刷墨斑,其视觉判定的相关性比使用变异系数Co V表征印刷墨斑的传统方法更好,在研究不同波长的墨斑水平和墨斑取向问题方面也表现出一定的优越性。结论该方法操作简单,能更加客观地对印刷墨斑进行度量,更加方便地解决印刷墨斑所引起的问题,提高了印品质量。     

避免胶卷在冲洗过程中产生网状斑纹的措施

通常冲洗后的胶卷上常有网状斑纹出现,这种网状斑纹的产生缘于明胶的膨胀。胶卷产生网状斑纹后,使胶卷的成象质量大幅度下降,甚至使成象遭到破坏。所以必须分析明胶膨胀的原因,在此基础上寻求防止胶卷上产生网状斑纹的办法。明胶膨胀的主要原因大致有以下四种:     

如何防止静电斑纹

静电斑纹是指在显影后的底片上,出现像照片那样的树枝状斑纹和中心密度大并向四周扩散的圆形斑点斑纹,它们往往作为一种灰雾密度出现。由于某种原因带有静电荷的胶片,如果与带有相反静电荷的物体接触时放电、发光,使胶片感光产生了灰雾。静电斑纹的发生,决定于引起胶片的带电与放电的机会,根据摩擦带静电的物质的带电分类,静电的电性可分为正电和负电,对于胶片就产生了带正电荷和带负电荷二种静电斑纹。出现上述的树枝状斑纹,说明胶     

面板堆石坝基础开挖及处理设计

在坝基开挖处理中,针对不同的地质缺陷采取相应的处理设计以满足面板堆石坝的地基要求。斑纹针对面板堆石坝基础开挖及处理设计进行了阐述。     

纹理防伪技术原理及优势透视

一、防伪原理纹理防伪是以包装材料本身固有的斑纹记号为防伪识别标记的一种防伪技术。自然界的斑纹总是千差万别的,如指纹、木纹,石纹、斑马纹、冰纹、干裂的地面等纹理都是随机的。唯一的,不可能有两个完全一样的。利用这一原理,选用纹理清晰的包装材料制成防伪标签,对每一枚标签材料的斑纹记号进行拍摄、编号、建档、存入防伪数据库中。消费者可通过互联网、传真、电话查询档案、辨别真伪。     

激光大气传输光斑统计概率接收孔径效应

本文综合考虑湍流大气对激光斑纹强度、光束传输方向的调制作用和有限接收孔径的光强起伏、相位起伏平滑作用等因素,从理论上研究了激光斑纹强度、相位起伏概率密度函数和孔径平滑作用,求得了高阶强度矩的孔径平滑因子。     

高性能医学图像三维中值滤波去斑算法与实现

为了满足实时实现三维医学图像去斑应用的需要,本文提出一种新的实现三维中值滤波器的快速算法及其高性能VLSI结构.该方法根据二维数组部分排序结果的分布特征,采用一种三维部分排序技术,有效减少三维中值滤波算法的实现复杂度.理论分析和实验结果表明,该方法可减少约33%的计算复杂度和/或硬件资源需求,从而能有效减少三维中值滤波器软件实现的系统延时和硬件实现的系统成本和功耗.     

“马可波罗”地砖一年后现黑斑

装修新房时购买了"马可波罗"地砖,但一年后发现地砖出现黑色斑纹。商家承认是质量问题,但就赔偿问题双方一直没有达成一致意见,导致至今还没解决。地砖竟出现黑色斑纹近日,市民罗先生向本报投诉,称他2010年装修新房时,于当年10月2日在位于抚生路的"马可     

彭泽鲫

彭泽鲫，因其常栖于湖中的芦苇丛中，体侧有5～7条灰黑色的芦苇似的斑纹（池塘中饲养一段时间后，斑纹会逐渐消失）而被称为芦花鲫。它以个体大（已知一尾最大个体体重6．5千克）著称，所以称它为彭泽大鲫。彭泽鲫原产于江西省彭泽县丁家湖、     

用斑点成像消除光学系统像差的影响

在详细分析用斑点成像消除目标图像中随机扰动影响的基础上,提出了在有像差光学系统中,应用斑点成像消除图像中像差影响的方法。通过在光学系统的光路中引入随机相位屏,采集物的短曝光像,用斑点成像处理,恢复目标图像的功率谱和相位谱,可以得到目标近衍射极限的图像。实验结果表明,这种方法可以消除图像中光学系统像差的影响。     

数字散斑干涉测量流体温度场中的图象处理方法

本文介绍了一种适用于数字散斑干涉测量流体温度场的计算机图象处理方法，主要介绍了以傅立叶变换为基础的低通滤波法在去除散斑图象噪声中的应用，从而提高了散斑干涉图的信噪比，获得了与光学干涉相似的干涉图象。将此法运用于酒精灯火焰散斑干涉图的后续处理上，取得了较好的效果，具有较高的运行效率。     

Strain compounding: a new approach for speckle reduction

A new compounding technique for reducing speckle brightness variations is proposed. This method exploits the decorrelation between signals under different strain states. The different strain states can be created using externally applied forces such as the ones used in sonoelastography. Such forces produce three-dimensional tissue motion. By correcting only the in-plane (i.e., axial and lateral) motion, the images under different strain states have similar characteristics except for speckle appearance caused by the uncorrected out-of-plane (i.e., elevational) motion. Additional speckle decorrelation is also introduced through tissue motion correction caused by the change of effective in-plane sample volume geometry. Therefore, these images can be combined for speckle reduction with less degradation in in-plane spatial resolution than conventional approaches. In this paper, three-dimensional tissue motion under various strain conditions were simulated. It was found that significant speckle decorrelation existed at strains achievable in some clinical situations. Experiments were also conducted to test efficacy of this approach. Pulse-echo data from a gelatin-based phantom were acquired using a 5-MHz, single crystal transducer, and both conventional and compound B-mode images were formed. Results indicated that speckle brightness variations were reduced, and detectability of low contrast objects was enhanced. Performance limitations and fundamental differences between the proposed technique and existing techniques are discussed     

基于自适应形态滤波的医学超声图像降噪

针对医学超声图像上的斑点噪声,本文提出一种基于自适应形态滤波的降噪方法.首先构造一组检测图像中不同像素值突变的结构因子;再对每个结构因子构造相应的形态滤波结构元;最后对每个像素点邻域进行结构检测,找到该点处最可能存在的突变结构,以相应的结构元完成该点的形态滤波.对不同信噪比的仿真图像和实际图像分别采用本文方法和各向异性扩散滤波,不同尺度传统形态滤波进行了:比较实验,结果表明:采用本方法可将超声图像的信噪比、对比度噪声比和图像优度分别平均提高15%、37%和69%,优于其它方法.     

A New Hybrid Model for Segmentation of the Skin Lesion Based on Residual Attention U-Net

Skin segmentation participates significantly in various biomedical applications, such as skin cancer identification and skin lesion detection. This paper presents a novel framework for segmenting the skin. The framework contains two main stages: The first stage is for removing different types of noises from the dermoscopic images, such as hair, speckle, and impulse noise, and the second stage is for segmentation of the dermoscopic images using an attention residual U-shaped Network (U-Net). The framework uses variational Autoencoders (VAEs) for removing the hair noises, the Generative Adversarial Denoising Network (DGAN-Net), the Denoising U-shaped U-Net (D-U-NET), and Batch Renormalization U-Net (Br-U-NET) for removing the speckle noise, and the Laplacian Vector Median Filter (MLVMF) for removing the impulse noise. In the second main stage, the residual attention u-net was used for segmentation. The framework achieves (35.11, 31.26, 27.01, and 26.16), (36.34, 33.23, 31.32, and 28.65), and (36.33, 32.21, 28.54, and 27.11) for removing hair, speckle, and impulse noise, respectively, based on Peak Signal Noise Ratio (PSNR) at the level of (0.1, 0.25, 0.5, and 0.75) of noise. The framework also achieves an accuracy of nearly 94.26 in the dice score in the process of segmentation before removing noise and 95.22 after removing different types of noise. The experiments have shown the efficiency of the used model in removing noise according to the structural similarity index measure (SSIM) and PSNR and in the segmentation process as well.     

Adaptive correction to the speckle correlation fringes by using a twisted-nematic liquid-crystal display

An innovative technique for reducing speckle noise and improving the intensity profile of the speckle correlation fringes is presented. The method is based on reducing the range of the modulation intensity values of the speckle interference pattern. After the fringe pattern is corrected adaptively at each pixel, a simple morphological filtering of the fringes is sufficient to obtain smoothed fringes. The concept is presented both analytically and by simulation by using computer-generated speckle patterns. The experimental verification is performed by using an amplitude-only spatial light modulator (SLM) in a conventional electronic speckle pattern interferometry setup. The optical arrangement for tuning a commercially available LCD array for amplitude-only behavior is described. The method of feedback to the LCD SLM to modulate the intensity of the reference beam in order to reduce the modulation intensity values is explained, and the resulting fringe pattern and increase in the signal-to-noise ratio are discussed.     

Speckle reduction in optical coherence tomography by adaptive total variation method

An adaptive total variation method based on the combination of speckle statistics and total variation restoration is proposed and developed for reducing speckle noise in optical coherence tomography (OCT) images. The statistical distribution of the speckle noise in OCT image is investigated and measured. With the measured parameters such as the mean value and variance of the speckle noise, the OCT image is restored by the adaptive total variation restoration method. The adaptive total variation restoration algorithm was applied to the OCT images of a volunteer’s hand skin, which showed effective speckle noise reduction and image quality improvement. For image quality comparison, the commonly used median filtering method was also applied to the same images to reduce the speckle noise. The measured results demonstrate the superior performance of the adaptive total variation restoration method in terms of image signal-to-noise ratio, equivalent number of looks, contrast-to-noise ratio, and mean square error.     

Completely passive method of speckle reduction utilizing static multimode optical fibre and two-dimensional diffractive optical element

ABSTRACT

In this paper, we present experimental results on speckle noise suppression using a completely passive method. The passivity of the method is achieved owing to the absence of any mechanical, electronic, or other dynamic influences on the optical scheme elements. In the experiment, a multimode semiconductor 520?±?5-nm laser with a spectral bandwidth of 2?nm, static two-dimensional (2D) and 2?×?1D diffractive optical elements (DOEs), as well as multimode single-core optical fibre and multimode optical fibre bundle were used. The dependence of the speckle reduction efficiency as a function of the optical fibre type and optical fibre length was measured for different DOEs. A speckle contrast of 0.148 and speckle reduction coefficient of 2.38 were obtained for a 2.5-m-long multimode optical fibre bundle. The experimental results confirmed that it is possible to construct completely passive optical circuits with reduced speckle noises using static multimode optical fibres and diffraction optical elements.     

Bayesian neural-networks-based evaluation of binary speckle data

We present a new method using Bayesian probability theory and neural networks for the evaluation of speckle interference patterns for an automated analysis of deformation and erosion measurements. The method is applied to the fringe pattern reconstruction of speckle measurements with a Twyman-Green interferometer. Given a binary speckle image, the method returns the fringe pattern without noise, thus removing the need for smoothing and allowing a straightforward unwrapping procedure and determination of the surface shape. Because no parameters have to be adjusted, the method is especially suited for continuous and automated monitoring of surface changes.     

基于字典算法的OCT图像散斑稀疏降噪

光学相干层析扫描(OCT)作为一种新型无创高分辨率扫描方式,在临床上得到广泛应用,但是OCT图像本身存在严重的散斑噪声,这大大影响了疾病的诊断。本文针对OCT图像中的乘性散斑噪声,改进了两种原始字典降噪算法。该算法首先对OCT图像进行对数变换,采用正交匹配追踪算法进行稀疏编码,以及K奇异值分解学习算法进行自适应字典的更新,最后通过加权平均以及指数变换回到空域。实验结果表明,本文改进的两种字典算法能有效降低OCT图像中的散斑噪声,获得良好的视觉效果。并通过均方误差(MSE)、峰值信噪比(PSNR)、结构相似性(SSIM)以及边缘保持指数(EPI)四个指标评价降噪效果,与两种原始字典降噪算法和传统滤波算法相比,两种改进字典算法降噪效果优于其他算法,其中自适应字典算法表现更好。