采用改进Canny算子分割尿沉渣图像

作为尿沉渣自动识别的关键一部分,尿沉渣图像的准确分割具有非常重要的意义。用Canny算子检测尿沉渣图像的过程中存在双阈值的选取不能自适应、检测出的边缘不闭合等不足。为改进这些不足,先对经过非最大值抑制后得到的候选边缘点用一个小的结构元素进行一次形态学膨胀,为提取闭合的边缘打下基础,然后提出了利用梯度图像的最高梯度来确定高阈值和利用梯度图像的局部梯度信息来确定低阈值的方法,该双阈值的选取方法自适应性强。实验结果表明,改进的Canny算子能够自动地分割尿沉渣图像,分割精度高,抗噪声干扰性强。     

一种基于Canny理论的自适应边缘检测方法

基于Canny算子，提出了一种Canny自适应的边缘检测方法。Canny自适应算法在保持了Canny算子原有的定位准确，单边响应和信噪比高等优点的基础上，提高了Canny算子在提取图像边缘细节信息和抑制假边缘噪声方面的性能。Canny自适应算法将整幅图像分割为若干子图像，并根据各子图像的边缘梯度信息，结合全局边缘梯度特征信息自适应地生成动态阈值，提高了边缘检测的自动化程度，在实际的应用中获得了很好的效果。通过数学分析和试验结果证明了Canny自适应算法是一种有效的边缘检测改善方法。     

改进的Sobel算子彩色图像边缘检测

为了解决传统灰度图像边缘检测中容易出现的边缘定位偏差、边缘丢失以及边缘不连续等问题,结合传统的Sobel梯度边缘检测方法和图像阈值分割技术,提出了一种改进的Sobel算子彩色图像边缘检测方法。通过对比试验结果表明,该方法可以有效地降低色彩边缘的误检率,一定程度上提高了边缘检测器的性能。     

基于局部期望阈值分割的图像边缘检测算法

传统图像边缘特征检测通过梯度算子卷积计算获取梯度图,并根据梯度变化情况设定阈值得到边缘信息,但图像的各局部区域梯度变化不均匀,采用统一阈值分割边缘信息往往会造成获取的边缘信息不准确。本文提出一种基于图像局部区域期望的自适应阈值方法,首先采用Sobel算子获取图像梯度矩阵,然后将梯度矩阵分割为多个子区域,并计算每个子区域的局部期望作为该区域阈值,进行边缘特征提取。实验表明,提出的方法提高了图像主要目标物边缘特征的识别度,区域边缘信息划分准确。     

一种精确的自适应图像边缘提取方法

针对传统Canny算子需要人为指定参数和阈值等问题,提出一种自适应图像边缘提取方法。该方法使用改进的自适应中值滤波对图像去噪;用8点邻域梯度计算方法自适应计算滤波后图像梯度的幅值;根据图像的梯度信息特征,用梯度的熵和标准差自适应地调整高低阈值。实验结果表明,与传统Canny算子相比,该算法在滤除图像噪声、保留细节边缘和保持边缘连通性方面都获得了不错的效果,提高了边缘检测的自动化程度,更具有实用性。     

自适应Canny算子电池极片瑕疵边缘检测

瑕疵边缘是极片图像的最主要特征, 本文研究了Canny算子提取极片瑕疵的边缘特征,并针对传统Canny算子进行电池极片瑕疵边缘检测存在假边缘的同时还丢失了灰度变化缓慢的局部边缘问题,利用像素8邻域计算图像梯度,并根据图像边缘梯度特征信息,用二维最大熵来自适应确定Canny算子的高、低阈值.试验结果表明:自适应Canny算子是一种十分有效的方法,适合于计算机视觉的电池极片瑕疵检测过程.     

改进Canny边缘检测的遥感影像分割

基于边缘特征的图像分割算法中,能够准确地检测出边缘是进行图像分割的前提和关键。针对目前遥感图像分割算法普遍存在鲁棒性差、易发生边缘信息缺失以及适用范围较窄的缺点,提出了一种基于改进Canny边缘检测的遥感影像分割算法。针对传统Canny高斯滤波在平滑图像的同时也模糊了边缘,改用具有保边特性的引导滤波对图像进行平滑;针对噪声对求导敏感这一问题,增加45°和135°方向梯度模板来计算图像梯度和方向;针对传统Canny算子人为设定高、低阈值的局限性问题,改用大律法自适应地根据图像灰度选取高、低阈值。为充分利用多光谱图像的优点,在进行边缘检测时采用波段分解,逐波段进行处理,随后将边缘综合成一幅结果图,最后进行区域生长。实验结果表明,与其他和传统边缘检测的分割方法相比,该方法在遥感影像分割中取得了较好的结果。     

结合Canny算子的图像二值化方法

用Robert、Sobel、Prewitt、Laplacian、LoG和Canny算子,对图像进行了边缘检测实验,分析了边缘检测的结果,得出Canny边缘检测算子,是图像边缘检测的一种十分有效的方法。然后,根据图像的Canny算子边缘信息,将最佳全局阈值法与局部阈值自适应法在边缘信息的基础上融合起来,对图像进行了二值化处理。实验表明此算法在二值化图像时,能很好的保留图像的边缘信息。     

基于轮廓矩的热敏电阻封装质量检测研究

针对热敏电阻封装质量检测问题,设计了基于阈值分割及轮廓矩识别的自动检测方法.该方法首先对封装热敏电阻进行灰度化处理,再利用最大类间方差法对图像进行阈值分割,进一步通过形态学运算得到不合噪声的目标二值图像,并采用Canny算子提取到封装热敏电阻的连续轮廓,然后根据轮廓矩理论提取了封装热敏电阻边缘图像的前三阶轮廓矩,最后得到与模板的欧氏距离,通过阈值比对实现了封装质量识别.实验验证表明该方法对几种封装不合格产品的固定样本检测准确率都在90％以上,对随机样本的检测准确率接近人工检测的准确率,且单根检测耗时220 ms远远小于单根平均5 s的人工检测耗时.     

一种改进的Canny边缘检测算法

针对噪声对图像边缘检测的影响,为抑制虚假边缘,提出了一种改进的Canny边缘检测算法。该算法首先采用分数阶差分方法来计算梯度,同时利用相邻像素的梯度及其梯度差两种信息来改进非极大值抑制过程,最后通过迭代计算的方法,自适应确定梯度图像的分割阈值。试验结果表明,改进算法的抗噪声性能与传统的Canny边缘检测算法相比有明显优势,提高了图像边缘检测的准确度。     

Simultaneous unidirectional and bidirectional chaos-based optical communication using hybrid coupling semiconductor lasers

A simultaneous unidirectional and bidirectional chaos-based optical communication scheme based on a hybrid coupling semiconductor laser system that consists of one center semiconductor laser(CSL)and multiple side semiconductor lasers(SSLs)is proposed numerically.In this scheme,the SSLs oriented in a linear chain mutually couple with the adjacent SSLs and they are subjected to identical unidirectional injections from the CSL which is a chaotic external cavity semiconductor laser.We theoretically analyze the conditions for diferent types of chaos synchronization based on the symmetry operation mechanism and injection-locking mechanism,and numerically investigate the influences of operation parameters,parameter mismatch robustness,chaos pass filtering efects and communication performance of the hybrid coupling semiconductor laser system.The simulation results demonstrate that with proper selection of the unidirectional and mutual coupling conditions,the SSLs can synchronize with each other isochronally and simultaneously synchronize to the CSL completely or laggardly,which enables the proposed system to achieve a unidirectional broadcasting communication from the CSL to the SSLs and a bidirectional communication among the SSLs simultaneously.The proposed scheme is beneficial to the implementation of optical chaos communication networks.     

Contour detection improved by frequency domain filtering of gradient image

We propose an intermediate computational step,frequency domain filtering of gradient image,to improve contour detection performance of gradient-based edge detectors.This step is inspired by analyzing the spectrum distribution of object contours and texture edges in the frequency domain of gradient image.We illustrate the principle and efect of this step by adding it to the Canny edge detector.The resulting operator can selectively retain object contours and region boundaries,and meanwhile can dramatically reduce non-meaningful elements caused by textured background.We use several types of images to compare the proposed method and other related methods qualitatively and quantitatively.Experimental results show that the proposed method can efectively enhance the contour detection of Canny edge detector and achieves similar detection performance to two other related methods but runs faster.     

Solving the process of hysteresis without determining the optimal thresholds

Hysteresis is an important edge detection technique, but the unsupervised determination of hysteresis thresholds is a difficult problem. Thus, hysteresis has limited practical applicability. Unimodal thresholding techniques are another edge detection method. They are useful, because the histogram of a feature image (usually the feature image is an approximation of the gradient image) is unimodal, and there are many unsupervised methods to solve this problem. But such techniques do not use spatial information to detect edge points, so their performance is worse than that of the hysteresis.In this paper, we show how to formulate the hysteresis process as a unimodal thresholding problem without determining the optimal hysteresis thresholds. Using similar steps of the Canny edge detector to obtain an approximation of the gradient image we compare the performance of our method against that of a method that determines the best parameters of an edge detector and show that our method performs relatively well. Additionally, our method can adjust its sensitivity by using different unimodal thresholding techniques.     

新颖的物体轮廓提取：基于双边滤波的多级边缘检测*

提出了一种新颖的物体轮廓提取方法,即通过多级边缘检测来提取物体的主要边界。双边滤波器用来建立多级,同时Canny边缘算子相应地产生边缘图,组合边缘图构造出一幅多级图。次段被定义为边缘像素的连接结构,提取并连接这些次段可以构成闭合轮廓。最终图像中最相关的闭合轮廓被判定为真实的物体轮廓。实验结果表明,该物体轮廓提取方法具有较高的可靠性并且受噪声影响较小。     

A novel histogram transformation to improve the performance of thresholding methods in edge detection

The gradient image is used to detect edge points, and the gradient histogram is a typical case of a unimodal histogram. It is well-documented that bi-modal thresholding methods (such as the Otsu method) detect edges poorly. Therefore, specific unimodal thresholding methods are used to detect edge points. However, unimodal thresholding methods (such as the Rosin method) sometimes obtain very noisy results. In this paper, we propose a histogram transformation to improve the performance of some thresholding methods. Using the Berkeley Segmentation Dataset, we present quantitative performance results in an edge detection task to show that our transformation improves the performance of the Otsu and Rosin methods. Our histogram transformation can be used by any histogram thresholding method, but the performance of the method, using the transformed histogram, will depend of the criterion used by this method.     

Accurate object contour tracking based on boundary edge selection

In this paper, a novel method for accurate subject tracking, by selecting only tracked subject boundary edges in a video stream with a changing background and moving camera, is proposed. This boundary edge selection is achieved in two steps: (1) removing background edges using edge motion, and from the output of the previous step, (2) selecting boundary edges using a normal direction derivative of the tracked contour. Accurate tracking is based on reduction of the effects of irrelevant edges, by only selecting boundary edge pixels. In order to remove background edges using edge motion, the tracked subject motion is computed and edge motions and edges having different motion directions from the subjects are removed. In selecting boundary edges using the normal contour direction, the image gradient values on every edge pixel are computed, and edge pixels with large gradient values are selected. Multi-level Canny edge maps are used to obtain proper details of a scene. Multi-level edge maps allow tracking, even though the tracked object boundary has complex edges, since the detail level of an edge map for the scene can be adjusted. A process of final routing is deployed in order to obtain a detailed contour. The computed contour is improved by checking against a strong Canny edge map and hiring strong Canny edge pixels around the computed contour using Dijkstra's minimum cost routing. The experimental results demonstrate that the proposed tracking approach is robust enough to handle a complex-textured scene in a mobile camera environment.     

基于递归滤波的边缘检测算法

针对包含不同程度噪声数字图像的边缘检测问题,提出了两种建立在房顶型模糊边缘模型基础上的平滑和边缘检测滤波器。首先用这些滤波算子以三阶递归的形式实现图像的平滑及梯度计算,再进行非极大值抑制及双阈值的边缘检测连接。实验结果表明,该方法得到的梯度图像均比Canny和Deriche滤波算子清晰,所得边缘图像也更加完整,检测时间也少于其他方法。     

Logarithmic dyadic wavelet transform with its applications in edge detection and reconstruction

In this paper, based on the logarithmic image processing model and the dyadic wavelet transform (DWT), we introduce a logarithmic DWT (LDWT) that is a mathematical transform. It can be used in image edge detection, signal and image reconstruction. Comparative study of this proposed LDWT-based method is done with the edge detection Canny and Sobel methods using Pratt's Figure of Merit, and the comparative results show that the LDWT-based method is better and more robust in detecting low contrast edges than the other two methods. The gradient maps of images are detected by using the DWT- and LDWT-based methods, and the experimental results demonstrate that the gradient maps obtained by the LDWT-based method are more adequate and precisely located. Finally, we use the DWT- and LDWT-based methods to reconstruct one-dimensional signals and two-dimensional images, and the reconstruction results show that the LDWT-based reconstruction method is more effective.     

基于改进Live-Wire算法的无人机遥感影像标注

标签的制作是深度学习应用的关键步骤,为了克服无人机平台的复杂运动、光照条件不足、地物轮廓复杂等导致遥感影像的地物轮廓提取和标注的难点,文中提出一种改进的Live-wire算法并用于无人机遥感影像的典型地物的标签标注;通过改进模糊隶属度函数克服了Pal-King隶属函数灰度覆盖空间不足的缺陷并结合双阈值方法实现边缘点的提取,以改进的Pal-King的模糊边缘检测方法替代Live-Wire算法的拉普拉斯边缘提取方法;通过增加节点之间梯度幅值的变化特征优化代价函数,以提高Live-Wire算法的轮廓跟踪的连续性;大量的对比实验证明,相较于传统方法,改进的Live-Wire方法的轮廓提取和跟踪的稳健性、效率更高.     

Robust image corner detection through curvature scale space

This paper describes a novel method for image corner detection based on the curvature scale-space (CSS) representation. The first step is to extract edges from the original image using a Canny detector (1986). The corner points of an image are defined as points where image edges have their maxima of absolute curvature. The corner points are detected at a high scale of the CSS and tracked through multiple lower scales to improve localization. This method is very robust to noise, and we believe that it performs better than the existing corner detectors An improvement to Canny edge detector's response to 45° and 135° edges is also proposed. Furthermore, the CSS detector can provide additional point features (curvature zero-crossings of image edge contours) in addition to the traditional corners