针对粗糙模糊聚类算法对初值敏感、易陷入局部最优和聚类性能依赖阈值选择等问题, 提出一种混合蛙跳与阴影集优化的粗糙模糊聚类算法(SFLA-SRFCM). 通过设置自适应调节因子, 以增加混合蛙跳算法的局部搜索能力; 利用类簇上、下近似集的模糊类内紧密度和模糊类间分离度构造新的适应度函数; 采用阴影集自适应获取类簇阈值. 实验结果表明, SFLA-SRFCM 算法是有效的, 并且具有更好的聚类精度和有效性指标.
相似文献Image segmentation is a primary task in image processing which is widely used in object detection and recognition. Multilevel thresholding is one of the prominent technique in the field of image segmentation. However, the computational cost of multilevel thresholding increases exponentially as the number of threshold value increases, which leads to use of meta-heuristic optimization to find the optimal number of threshold. To overcome this problem, this paper investigates the ability of two nature-inspired algorithms namely: antlion optimisation (ALO) and multiverse optimization (MVO). ALO is a population-based method and mimics the hunting behaviour of antlions in nature. Whereas, MVO is based on the multiverse theory which depicts that there is over one universe exist. These two metaheuristic algorithms are used to find the optimal threshold values using Kapur’s entropy and Otsu’s between class variance function. They examine the outcomes of the proposed algorithm with other evolutionary algorithms based on cost value, stability analysis, feature similarity index (FSIM), structural similarity index (SSIM), peak signal to noise ratio (PSNR), computational time. We also provide Wilcoxon test which justify the response of these parameters. The experimental results showed that the proposed algorithm gives better results than other existing methods. It is noticed that MVO is faster than other algorithms. The proposed method is also tested on medical images to detect the tumor from MRI T1-weighted contrast-enhanced brain images.
相似文献A feature-weighted Support Vector Machine regression algorithm is introduced in this paper. We note that the classical SVM is based on the assumption that all the features of the sample points supply the same contribution to the target output value. However, this assumption is not always true in real problems. In the proposed new algorithm, we give different weight values to different features of the samples in order to improve the performance of SVM. In our algorithm, firstly, a measure named grey correlation degree is applied to evaluate the correlation between each feature and the target problem, and then the values of the grey correlation degree are used as weight values assigned to the features. The proposed method is tested on sample stock data sets selected from China Shenzhen A-share market. The result shows that the new version of SVM can improve the accuracy of the prediction.
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The mutual information (MI) based on averaged shifted histogram (ASH) probability density estimator is considered as a good indicator of relevance between input variables and output variable. However, it cannot deal with redundant input variables problem. Therefore, a method integrates principal component analysis (PCA) with MI is proposed for radial basis function network (RBFN) to improve the predicting performance of RBFN. Firstly, PCA is employed to characterize the PCs from original variables, among which there is non-correlation. Secondly, MI based on ASH is applied to select the several closest correlation PCs with output variable as the new input variables. Finally, PCA-ASH-RBFN is employed to develop the housing price model based on the Boston housing data set. The result shows that PCA-ASH-RBFN has better prediction and robust performance than PCA-RBFN and RBFN integrating with robust feature selection for input variables.
相似文献Nowadays, the growing population of senior citizens is a challenge for almost all developing countries. New technologies can help monitor elderlies at home by providing an innovative and secure environment and further enhancing their quality of living. Vision-based systems offer promising results in analyzing human posture and detecting abnormal events like falls. Falls appear to possess the most considerable risk for seniors living alone. In this article, a new fall detection method is proposed based on a fusion of motion-based and human shape-based features. Motion History Images (MHI) represent the temporal feature in our approach. Simultaneously, the height-to-width ratio and centroid of the moving person represent the spatial features. A two-channel classification model is designed using a threshold-based and a keyframe-based approach. The two channels are further combined based on any classification disparity for which more information is used to classify between falls and daily activities. Keyframes are selected based on the displacement of the spatial features having a threshold higher than a preset value. Keyframes are subject to a K-NN classification. The proposed algorithm delivers promising results on the UR fall detection dataset’s simulated fall and daily activity sequences. It provides satisfactory performance compared to existing state-of-the-art methods and shows a peak accuracy of 98.6% and recall of 100% in detecting falls. Specificity and precision are over 96%.
相似文献In this paper, we propose a new feature selection method called kernel fisher discriminant analysis and regression learning based algorithm for unsupervised feature selection. The existing feature selection methods are based on either manifold learning or discriminative techniques, each of which has some shortcomings. Although some studies show the advantages of two-steps method benefiting from both manifold learning and discriminative techniques, a joint formulation has been shown to be more efficient. To do so, we construct a global discriminant objective term of a clustering framework based on the kernel method. We add another term of regression learning into the objective function, which can impose the optimization to select a low-dimensional representation of the original dataset. We use L2,1-norm of the features to impose a sparse structure upon features, which can result in more discriminative features. We propose an algorithm to solve the optimization problem introduced in this paper. We further discuss convergence, parameter sensitivity, computational complexity, as well as the clustering and classification accuracy of the proposed algorithm. In order to demonstrate the effectiveness of the proposed algorithm, we perform a set of experiments with different available datasets. The results obtained by the proposed algorithm are compared against the state-of-the-art algorithms. These results show that our method outperforms the existing state-of-the-art methods in many cases on different datasets, but the improved performance comes with the cost of increased time complexity.
相似文献针对锑浮选泡沫图像特征相互耦合、重要度差异显著引起工况难以识别的问题, 提出一种锑浮选工况识别方法. 首先, 在结合敏感性指数与主元分析法选取关键泡沫特征的基础上, 建立物元可拓模型, 通过关联函数计算关键泡沫特征与预设工况类别的关联度; 然后, 引入博弈论, 将层次分析法和熵权法确定的主、客观权重优化融合, 得到泡沫特征的综合权重; 最后, 计算综合关联度, 实现浮选工况的准确识别. 锑浮选工业现场的生产数据验证了所提出方法的有效性.
相似文献基于稀疏表达的跟踪方法通常采用基于固定阈值的模板更新策略, 很难适应不断变化的目标外形; 其次, 稀疏表达缺乏描述目标流行结构的能力, 区分背景和目标的能力差. 针对基于固定阈值的模板更新策略的不足, 提出一种多级分层的目标模板字典. 为了改善对背景和目标的区分能力, 提出一种融合多级稀疏表达和度量学习的目标跟踪方法. 实验结果表明了所提出的方法能有效提高跟踪的鲁棒性和精度.
相似文献针对传统基于稀疏表示的目标跟踪方法中, 当场景中含有与目标相似的背景时容易出现跟踪漂移的问题, 提出一种新的目标跟踪方法. 该方法基于目标的局部二元模式特征, 将目标外观模型同时用原始目标模板与当前帧部分粒子构成的联合模板稀疏表示, 构建一个联合目标函数, 将跟踪问题通过迭代转化为求解最优化问题. 实验结果表明, 所提出跟踪方法在解决遮挡、光照等问题的同时, 对场景中含有与目标相似背景的序列具有较好的跟踪效果.
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