In the past, investigators tend to use multi-channel surface electromyography (sEMG) signal acquisition devices to improve the recognition accuracy for the study of gesture recognition systems based on sEMG. The disadvantages of the method are the increased complexity and the problems such as signal crosstalk. This paper explores a gesture recognition method based on a single-channel sEMG envelope signal feature in the time domain. First, we get the sEMG envelope signal by using a preprocessing circuit. Then, we use the improved method of valid activity segment extraction to find every valid activity segment and extract 15 features from every valid activity segment. Next, we calculate the absolute value of the correlation coefficient between each of the features and target values. After removing the feature with the smaller correlation coefficient, we reserve the 14 features. By the PCA dimensionality reduction algorithm, we transform the 14-dimensional feature into 2-dimensional feature space. Finally, we use the improved KNN algorithm and the soft margin SVM algorithm to complete the classification of five types of gestures. We obtain the gesture recognition rates of 75.8 and 79.4% by using the improved KNN algorithm and the soft margin SVM algorithm.

No abstract

This paper proposes a new image scrambling algorithm based on the periodic characteristics of the Josephus ring. The algorithm composes the pretreatment part of the entire image encryption system and scrambles the rows and columns of the plain image. The Josephus scrambling algorithm is adjustable by using three kinds of parameters: step, m 0 , and n. Different values affect the size of the periodic value of the Josephus ring. In this paper, we focus on the method of determining the period of the Josephus cycle when the parameters are set and the Josephus rule space under arbitrary parameters. Because the Josephus ring is a mathematical problem, we analyze it using the group theory of modern algebra. After the Josephus scrambling, the plain image is encrypted. Because a CA is suitable for image encryption, the encryption part adopts a CA encryption algorithm using a one-dimensional, four-neighbor CA, which has chaotic behavior at the rules of 9d62 (hex). Finally, the number of pixels change rate, the unified averaged changed intensity test, and correlation detection are carried out on the experimental results. The results show that the use of the Josephus scrambling algorithm greatly improves the security of the entire encryption system.