Noise Characterization via Signal Differentiation and Histogram Analysis

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Solution Overview

Problem

Current methods fail to accurately and adaptively separate and characterize noise components from noisy signals in real-time, especially in non-linear systems, without relying on prior knowledge of the pure signal or accumulative information outside a defined window.

Innovation Solution

A method that involves defining a window within a raw signal, numerically differentiating it, finding a histogram that best fits the differentiated signal, determining the probability density function and variance of the noise component, and transforming these properties to obtain the zero-order variance, which can be performed in real-time and is adaptive.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Adaptability or versatility

If conventional noise separation methods are used, then prior knowledge of the pure signal or accumulative information is required, but this increases device complexity and reduces adaptability to new conditions

Engineering Contradiction:
Improveadaptability to different noise conditionsVSAvoidcomplexity of noise characterization system
Core Design Contradiction:
Adaptability or versatilityVSDevice complexity

Solution Approach 1:

The system performs self-characterization of noise by automatically estimating probability density functions and variance from the noisy signal itself, without requiring external prior knowledge or manual calibration. The noise properties are extracted directly from the signal data through statistical analysis, enabling the system to adapt to different noise conditions autonomously

Inventive Principle:
Principle #25Self-service

Solution Approach 2:

The method transforms the noise characterization problem by changing from requiring prior knowledge of signal parameters to estimating noise parameters directly from the noisy signal. By focusing on statistical parameters (PDF, variance) that can be extracted from the signal itself, the system achieves adaptability without increasing complexity

Inventive Principle:
Principle #35Parameter changes

2Measurement precision

If accurate noise characterization is performed using traditional methods, then accumulative information from outside the defined window is required, but this increases loss of time and reduces real-time performance

Engineering Contradiction:
Improveaccuracy of noise property estimationVSAvoidtime delay in noise characterization
Core Design Contradiction:
Measurement precisionVSLoss of time

Solution Approach 1:

The method segments the signal analysis into a defined window, performing noise characterization only on the data within that window. This eliminates the need to accumulate information from outside the window and enables real-time processing, as the noise properties are estimated from the local segment alone

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

The system performs preliminary estimation of noise properties within the defined window before making decisions or adjustments. By having the noise characterization ready within the window bounds, the system avoids time delays associated with accumulating additional external information

Inventive Principle:
Principle #10Preliminary action

3Adaptability or versatility

If non-adaptive noise filtering is used, then the system cannot respond to changing noise conditions, but adding adaptive capabilities increases device complexity

Engineering Contradiction:
Improveability to adapt to changing noise conditionsVSAvoidcomplexity of adaptive noise characterization
Core Design Contradiction:
Adaptability or versatilityVSDevice complexity

Solution Approach 1:

The system implements feedback by continuously estimating noise properties from the incoming signal and using this information to adapt the processing. The estimated PDF and variance feed back into the system to adjust filtering or analysis parameters, enabling automatic adaptation to changing noise conditions

Inventive Principle:
Principle #23Feedback

Solution Approach 2:

The adaptive capability is achieved through self-service, where the system automatically characterizes noise and adjusts its behavior based on the estimated properties. No external control or manual adjustment is needed, as the system serves itself by extracting noise parameters and applying them directly

Inventive Principle:
Principle #25Self-service

Data Source

PatentUS8285764B2System and method for statistically separating and characterizing noise which is added to a signal of a machine or a system
Publication Date: 2012.10.09 MINERAL LASSEN LLC
  • US8285764B2 patent drawing
  • US8285764B2 patent drawing
  • US8285764B2 patent drawing

AI summary

Method for finding the probability density function type and the variance properties of the noise component N of a raw signal S of a machine or a system, said raw signal S being combined of a pure signal component P and said noise component N, the method comprising: (a) defining a window within said raw signal; (b) recording the raw signal S; (c) numerically differentiating the raw signal S within the range of said window at least a number of times m to obtain an m order differentiated signal; (d) finding a histogram that best fits the m order differentiated signal; (e) finding a probability density function type that fits the distribution of the histogram; (f) determining the variance of the histogram, said histogram variance being essentially the m order variance σ2(m) of the noise component N; and (g) knowing the histogram distribution type, and the m order variance σ2(m) of the histogram, transforming the m order variance σ2(m) to the zero order variance σ2(0), σ2(0) being the variance of the pdf of the noise component N, and wherein the histogram type as found in step (e) being the probability density function type of the noise component N.