Optical Detection Device Contamination Estimation

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Solution Overview

Problem

Existing methods for estimating the degree of contamination of a front pane in optical detection devices, such as laser scanners, suffer from limited reliability and accuracy due to noise and interference effects, and require additional components and space, making them inefficient and complex.

Innovation Solution

A method that generates an averaged received signal from multiple transmission radiation pulses to suppress noise and interference, allowing for accurate estimation of contamination by evaluating amplitude and peak shape values, without the need for additional LEDs or spatially inclined front panes, thereby reducing complexity and space requirements.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If additional LEDs and photodiodes are used to detect contamination, then contamination detection capability is improved, but device complexity and space requirements increase

Engineering Contradiction:
Improvecontamination detection capabilityVSAvoiddevice complexity
Core Design Contradiction:
ReliabilityVSDevice complexity

Solution Approach 1:

The existing transmission radiation pulses and reception signal processing unit are made to serve dual purposes: both for distance measurement and for contamination detection. The reception signal is processed to extract both distance information and contamination information from the same hardware components, eliminating the need for separate detection systems.

Inventive Principle:
Principle #6Universality (Multi-functionality)

Solution Approach 2:

The front pane itself serves as the detection target for contamination assessment. By analyzing the reflection characteristics of the front pane in the received signal, the system uses the front pane's own optical properties to indicate its contamination state, rather than requiring separate detection components.

Inventive Principle:
Principle #25Self-service

2Reliability

If the front pane is inclined to allow LED light to shine through, then contamination detection is improved, but device complexity and space requirements increase

Engineering Contradiction:
Improvecontamination detection capabilityVSAvoidspace requirements
Core Design Contradiction:
ReliabilityVSVolume of stationary object

Solution Approach 1:

Instead of inclining the front pane to enable detection, the approach is inverted: the front pane maintains its normal position and the detection is achieved by analyzing the reflection characteristics in the received signal. The contamination detection is accomplished by processing the signal reflection patterns rather than by geometric modification.

Inventive Principle:
Principle #13The other way round (Inversion)

3Measurement precision

If multiple received signals are averaged to suppress noise, then measurement precision is improved, but processing time increases

Engineering Contradiction:
Improvecontamination estimation accuracyVSAvoidprocessing time
Core Design Contradiction:
Measurement precisionVSLoss of time

Solution Approach 1:

The system processes multiple received signals by averaging them to achieve noise suppression and improved measurement precision. This partial averaging approach balances the need for accurate contamination detection with acceptable processing time requirements.

Inventive Principle:
Principle #16Partial or excessive action

Applied Scientific Principles

This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.

Function Achieved in This Case

This approach provides reliable and accurate contamination estimation with reduced design effort, eliminating noise interference and avoiding the need for additional components, resulting in a more efficient and compact optical detection device.

Implementation Method 1

the emission of several transmission radiation pulses into a detection area and the generation of a reception signal for each transmission radiation pulse, wherein the reception signal has a plurality of sample values ​​and one sample value in each case the intensity of the received return radiation of the respective transmission radiation pulse

Methodology Applied
Scientific EffectLight reflection: Reflection

Data Source

PatentEP2479586B1Method for estimating the contamination of a front panel of an optical recording device and optical recording device
Publication Date: 2014.03.19 SICK AG
  • EP2479586B1 patent drawingFigure 1a~1c
  • EP2479586B1 patent drawing

AI summary

The present invention relates to a method for estimating the degree of contamination of a front lens of an optical detection device, comprising the steps of: emitting several (p) transmitting pulses into a detection area; for each transmitting pulse, generating a received signal comprising a plurality (q) of samples, wherein each sample represents the intensity of the received back-emission of the respective transmitting pulse at a time at a predetermined time interval from the emission of the transmitting pulse; generating an averaged received signal with a plurality (q) of samples from the several received signals generated from the transmitting pulses, wherein, to determine a sample of the averaged received signal, those samples of the received signals that were determined at corresponding times are added together.and generating at least one windshield contamination value by evaluating an amplitude value and/or a peak shape measurement of the averaged received signal. The invention further relates to a corresponding optical detection device.