Multi-threshold recurrence plot calculation method and device

Abstract

The invention discloses a multi-threshold recurrence plot calculation method and device, and is characterized in that recursion points are inquired by a nearest neighbor point search method based on a data query tree, a multi-threshold recurrence plot is stored in a compressed format, and diagonals in different threshold recurrence plots can be recurred and searched from the multi-threshold recurrence plot. The method comprises the following specific steps: (1) establishing and initializing a recurrence plot data structure; (2) carrying out recurrence update on the data query tree; (3) searching all nearest neighbor points in a neighbourhood which takes a current point as the center and a maximum threshold value Epsilon Q as a radius in the query tree as the recurrence points, taking a formula as a reference threshold value to quantize the recurrence points, wherein a quantization distance is used for forming the matrix elements of the multi-threshold recurrence plot; (4) recording all recurrence points into the recurrence plot record; repeating the step (2) to the step (4) to search all the recurrence points; and (5) in a multi-threshold recurrence plot data record, inquiring and recording the diagonals in the different threshold recurrence plots. When only a recurrence unit in an area (TL is greater than or equal to 1 and smaller than or equal to i-j, and TH is greater than or equal to i-j and smaller than N-1) is required, the length of the query tree is not greater than NW=TH-TL+1.

Description

technical field [0001] The invention relates to a calculation method of a recursive graph, which is mainly used for processing non-stationary and nonlinear signals. Background technique [0002] The recursive state of the system means that some states of the system are similar at a specific time. Recursive phenomena are a fundamental feature of deterministic dynamical systems. Eckmann et al. proposed a tool that can observe the recursive characteristics of the state on a two-dimensional graph - Recurrence Plot (RP), which enables us to analyze and process non-stationary nonlinear signals on a two-dimensional recurrence graph. [0003] For a set of d-dimensional space vectors its recursive graph Depend on [0004] R i，j =Θ(ε-||x i -x j ||), i, j=0, 1, ..., N-1 [0005] Composition, where ε is the threshold value, ||·|| is the norm operation, which can be ||·|| 2 (Euclidean distance), Θ(·) is the Heaviside function. due to R i，i ≡0 and R i，j =R j，i , in fact onl...

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Problems solved by technology

If ε is too large, there will be too many wrong adjacent points, and the density of black points in the recursive graph is too high; if ε is too small, many normal adjacent points will not be described, and the white area of ​​the recursive graph will become larger

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