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The supervised dictionary learning methods have made considerable achievements in the field of pattern recognition. In order to make the learned coefficients have intraclass similarity and interclass incoherence, many dictionary learning methods have been proposed using different structured constraints. However, these constraints often have the disadvantages of complexity, time-consuming, and poor interpretability. More importantly, the existing dictionary learning often ignores the inherent structure of the label matrix. In this paper, we propose a dictionary pair learning based on the structured classifier and perform classifier learning and structured coefficients learning simultaneously. Our main idea is to use the extended label matrix and the invertible constraints on the classification transformation matrix to utilize the structure of the label matrix to impose structured constraints on coefficients. Moreover, the l 21 -norm is added to force the analysis dictionary to focus on more important features. Experimental results on multiple databases prove that our proposed method has better classification performance than several state-of-the-art dictionary learning methods. [ABSTRACT FROM AUTHOR]

Segmentation of dried amnion biomaterial tends to produce invalid (outlier) contour point detections due to texture and colour inhomogeneity of the biomaterial. In this paper, a novel implementation of a non-stationary Bayesian learning process for outlier contour point removal of amnion segmentations is presented. This outlier removal method is independent to algorithms used for the contour detection. The Bayesian process uses a non-stationary kernel to learn a function with complex shape that maps image features in a region-of-interest around each contour point to a discrete output. Based on this output, a contour point can be determined as valid or invalid (outlier). The hyper-parameters of the non-stationary kernel are learned by maximising the marginal likelihood of the combined likelihood of data and the prior of the kernel parameters. Moreover, a novel combination of gradient-ascend and harmonic heuristic search methods is presented to find the optimal hyper-parameters. To validate the method, experiments are conducted to detect and ignore invalid contour points on amnion biomaterial images. A comparison of the proposed method with a logistic regression classification as the baseline is performed. The results show that the proposed method can significantly improve the contour detection by removing outliers and, hence, can reduce waste of uncut biomaterials. [ABSTRACT FROM AUTHOR]