Quaternion non-local means (QNLM) denoising algorithm makes full use of high degree self-similarities inside images to suppress the noise, so similarity metric plays a key role in its performance. In this study, two improvements have been made for QNLM: 1) For low level quaternion quasi-Chebyshev distance is proposed measure image patches and it has used replace Euclidean QNLM algorithm. Since ...

Retrieving relevant text documents on a topic from a large document collection is a challenging task. Different clustering algorithms are developed to retrieve relevant documents of interest. Hierarchical clustering shows quadratic time complexity of O(n 2 ) for n text documents. K-means algorithm has a time complexity of O(n) but it is sensitive to the initial randomly selected cluster centers...