3D Runs Test for Sonar Randomness Classification

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Solution Overview

Problem

Existing sonar signal processing methods fail to accurately classify data sets with a small number of measurements, often mislabeling nonrandom distributions as random, particularly in naval sonar systems where distinguishing random noise from potential vessel signals is critical.

Innovation Solution

A multistage method involving a three-dimensional runs test is employed, where data points are scored and partitioned into smaller subspaces, with a predefined route passing through each subspace to generate a series of ones and zeros, determining the number of runs and using statistical analysis to assess randomness, including Gaussian statistics and multiple correlation tests to enhance accuracy.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Device complexity

If large sample statistical methods are used to classify small data sets, then the classification process is simplified, but the accuracy deteriorates and nonrandom distributions are mislabeled as random

Engineering Contradiction:
Improveclassification process complexityVSAvoidrandomness classification accuracy
Core Design Contradiction:
Device complexityVSMeasurement precision

Solution Approach 1:

The patent segments the classification process into multiple stages: first applying a runs test for initial classification, then applying additional statistical tests (such as correlation tests, spectral analysis, or higher-order moment tests) to borderline or ambiguous cases. This multi-stage segmentation allows simple classification for clear cases while providing deeper analysis for problematic cases, thereby maintaining both simplicity and accuracy.

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

The patent changes the parameters used for classification by employing multiple different statistical parameters and tests rather than relying on a single large-sample parameter. By using diverse parameters (e.g., run lengths, correlation coefficients, spectral density ratios) that are appropriate for small samples, the classification accuracy improves while the process remains manageable through systematic parameter evaluation.

Inventive Principle:
Principle #35Parameter changes

2Ease of operation

If traditional randomness assessment methods are applied to sparse data, then the analysis is straightforward, but false alarms increase due to incorrect classification

Engineering Contradiction:
Improveanalysis simplicityVSAvoidfalse alarm rate
Core Design Contradiction:
Ease of operationVSReliability

Solution Approach 1:

The patent performs preliminary analysis using the runs test before proceeding to more complex classification. This preliminary action identifies obvious random and nonrandom cases early, allowing straightforward classification for clear cases while triggering more rigorous analysis only for ambiguous cases. This preliminary filtering reduces false alarms without sacrificing analysis simplicity for clear cases.

Inventive Principle:
Principle #10Preliminary action

Solution Approach 2:

The patent incorporates feedback mechanisms where the results of initial classification inform subsequent analysis steps. If the runs test produces ambiguous or borderline results, the system automatically triggers additional statistical tests and re-evaluation. This feedback loop ensures that potentially erroneous classifications are caught and corrected, thereby reducing false alarms while maintaining operational simplicity through automated decision rules.

Inventive Principle:
Principle #23Feedback

3Productivity

If automated classification systems are used for sonar signal processing, then productivity increases, but the ability to detect subtle nonrandom patterns in sparse data decreases

Engineering Contradiction:
Improvesignal processing throughputVSAvoidnonrandom pattern detection capability
Core Design Contradiction:
ProductivityVSMeasurement precision

Solution Approach 1:

The patent implements a dynamic classification system that automatically adjusts the depth and type of analysis based on data characteristics. For clear random patterns, the system uses simple runs test classification for high throughput. For ambiguous or sparse data showing potential nonrandom patterns, the system dynamically activates additional statistical tests and analysis stages. This dynamic adaptation maintains high productivity for straightforward cases while ensuring precise detection of subtle nonrandom patterns when needed.

Inventive Principle:
Principle #15Dynamics

Solution Approach 2:

The patent adds another dimension to the analysis by incorporating multiple types of statistical tests that examine different aspects of the data. Rather than relying on a single throughput-optimized algorithm, the system uses runs tests for speed, correlation tests for pattern detection, spectral analysis for periodicity, and other dimensional approaches. This multi-dimensional analysis ensures subtle nonrandom patterns are detected while maintaining overall productivity through selective application.

Inventive Principle:
Principle #17Another dimension (Dimensionality change)

Data Source

PatentUS7277573B1Enhanced randomness assessment method for three-dimensions
Publication Date: 2007.10.02 THE UNITED STATES OF AMERICA AS REPRESENTED BY THE SECRETARY OF THE NAVY
  • US7277573B1 patent drawing
  • US7277573B1 patent drawing
  • US7277573B1 patent drawing

AI summary

A multi-stage method is provided for automatically characterizing data sets containing data points which are each defined by measurements of three variables as either random or non-random. A three-dimensional Cartesian volume which is sized to contain all of a total number N of data points in the data set which is to be characterized. The Cartesian volume is partitioned into equal sized cubes, wherein each cube may or may not contain a data point. A predetermined route is defined that goes through every cube one time and scores each cube as a one or a zero thereby producing a stream of ones and zeros. The number of runs is counted and utilized to provide a Runs Test which predicts if the N data points in any data set are random or nonrandom. Additional tests are used in conjunction with the Runs Test to increase the accuracy of characterization of each data set as random or nonrandom.