Signal Processing Device Noise Reduction Response Time

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Solution Overview

Problem

Laser displacement sensor devices face a trade-off between noise reduction performance and response time, as increasing the number of data points for moving average calculation improves noise reduction but significantly lengthens calculation time.

Innovation Solution

A signal processing device that combines a moving-average calculating unit with an infinite impulse response filter, where the filter coefficient is determined based on the difference between moving-average and infinite impulse response filter outputs, to reduce noise without increasing response time.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Measurement precision

If the number of data points for moving average calculation is increased, then noise reduction performance is improved, but response time increases

Engineering Contradiction:

Improvenoise reduction performanceVSAvoidresponse time

Core Design Contradiction:

Measurement precisionVSLoss of time

Solution Approach 1:

The patent combines moving average calculation and infinite impulse response filter into a single signal processing device. The moving-average calculating unit computes moving average of the input signal, and the infinite impulse response filter processes this result to reduce noise. This merging allows the system to achieve effective noise reduction without requiring a large number of data points, thus maintaining fast response time while improving measurement precision.

Inventive Principle:

Principle #5Merging (Combining)

Solution Approach 2:

The infinite impulse response filter acts as an intermediary between the moving average calculation and the final output. It takes the moving average result and further processes it to reduce noise components. This intermediary approach allows the system to achieve superior noise reduction performance without directly relying on increasing the number of data points for moving average calculation, thereby preventing response time increase.

Inventive Principle:

Principle #24Intermediary (Mediator)

2Measurement precision

If moving average calculation is used to reduce noise, then measurement precision is improved, but calculation time increases

Engineering Contradiction:

Improvenoise reduction performanceVSAvoidcalculation speed

Core Design Contradiction:

Measurement precisionVSProductivity

Solution Approach 1:

The signal processing device merges moving average calculation with infinite impulse response filter processing. The moving-average calculating unit performs moving average on the input signal, and the infinite impulse response filter unit further processes this result. This combination achieves effective noise reduction with efficient calculation speed, as the infinite impulse response filter can reduce noise without requiring extensive data point accumulation.

Inventive Principle:

Principle #5Merging (Combining)

Solution Approach 2:

The system changes the approach from relying solely on increasing the number of data points for moving average to using an infinite impulse response filter with appropriately designed filter coefficients. This parameter change in the signal processing methodology allows the system to maintain high calculation speed while achieving superior noise reduction performance.

Inventive Principle:

Principle #35Parameter changes

3Measurement precision

If the length of the section for moving average calculation is increased, then noise reduction performance is improved, but response time increases

Engineering Contradiction:

Improvenoise reduction performanceVSAvoidresponse time

Core Design Contradiction:

Measurement precisionVSDuration of action of moving object

Solution Approach 1:

The infinite impulse response filter serves as an intermediary that processes the moving average result to further reduce noise. This intermediary processing allows the system to achieve effective noise reduction without increasing the length of the moving average section, thereby maintaining fast response time while improving measurement precision.

Inventive Principle:

Principle #24Intermediary (Mediator)

Solution Approach 2:

The patent replaces the mechanical approach of increasing data point accumulation for noise reduction with a digital signal processing approach using an infinite impulse response filter. This substitution allows the system to achieve superior noise reduction performance without the time penalty associated with extending the moving average section length.

Inventive Principle:

Principle #28Mechanics substitution (Replace mechanical system)

Data Source

PatentUS10458789B2Signal processing device, sensor device, and signal processing method

Publication Date: 2019.10.29 MITSUBISHI ELECTRIC CORP

AI summary

A signal processing device for performing processing for reducing noise in a displacement amount measured on a basis of light reflected from a detection object includes a moving-average calculating unit that performs moving average calculation for an input signal to reduce a noise component included in the input signal and an infinite impulse response filter that reduces a noise component included in an input signal by digital signal processing. A filter coefficient of the infinite impulse response filter is determined on a basis of a difference between a first calculation result output by the moving-average calculating unit and a second calculation result output by the infinite impulse response filter when a same signal is input to the moving-average calculating unit and the infinite impulse response filter.