Pulse Distance Measurement with Variable Gain Signal Normalization

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Solution Overview

Problem

Conventional distance measuring instruments face limitations in measurement accuracy, speed, and distance measuring range, as they do not effectively adapt signal gain to varying light pulse intensities, leading to suboptimal analysis of detected signals.

Innovation Solution

A distance measuring instrument employing a variable gain amplifier that adjusts gain based on detected signal intensity, combined with a signal delay module and analyzers to normalize signal intensity, allowing for accurate distance determination independent of original signal intensity.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Measurement precision

If a fixed gain amplifier is used to amplify detected light pulses, then the circuit is simple, but measurement accuracy deteriorates when signal intensity varies

Engineering Contradiction:
Improvedistance measurement accuracyVSAvoidamplifier circuit complexity
Core Design Contradiction:
Measurement precisionVSDevice complexity

Solution Approach 1:

The patent applies dynamics by replacing a fixed gain amplifier with a variable gain amplifier that dynamically adjusts its amplification factor based on the detected signal intensity. The gain is varied inversely with signal intensity, ensuring that weak signals are amplified more while strong signals are amplified less, thereby normalizing the output signal level and improving measurement accuracy across varying distances.

Inventive Principle:
Principle #15Dynamics

Solution Approach 2:

The patent implements feedback by using the detected signal intensity to control the gain of the amplifier. The system measures the intensity of received light pulses and feeds this information back to adjust the amplification level, creating a closed-loop system that automatically compensates for signal strength variations and maintains consistent measurement quality.

Inventive Principle:
Principle #23Feedback

2Measurement precision

If a higher gain is applied to low intensity signals, then measurement accuracy improves, but signal distortion may occur with high intensity signals

Engineering Contradiction:
Improvedetection accuracyVSAvoidsignal integrity
Core Design Contradiction:
Measurement precisionVSReliability

Solution Approach 1:

The variable gain amplifier dynamically adjusts its gain based on the intensity of the input signal. For low intensity signals, the amplifier applies a higher gain to boost the signal level for accurate detection. For high intensity signals, the amplifier automatically reduces the gain to prevent saturation and distortion, thereby maintaining signal integrity across the full dynamic range of detected signals.

Inventive Principle:
Principle #15Dynamics

Solution Approach 2:

The patent changes the amplification parameter (gain) according to the signal intensity parameter. By making the gain a variable parameter rather than a fixed value, the system can optimize the amplification level for each detected signal, ensuring accurate detection of weak signals while avoiding distortion of strong signals through automatic parameter adaptation.

Inventive Principle:
Principle #35Parameter changes

3Productivity

If signal intensity is not normalized, then the analysis must account for intensity variations, but measurement speed decreases

Engineering Contradiction:
Improvemeasurement speedVSAvoidsignal processing complexity
Core Design Contradiction:
ProductivityVSDevice complexity

Solution Approach 1:

The patent performs preliminary action by normalizing the signal intensity through variable gain amplification before the signals are sent to the analysis stage. This preliminary normalization ensures that all subsequent analyses operate on signals of comparable intensity levels, eliminating the need for complex intensity compensation calculations during processing and thereby improving measurement speed without sacrificing accuracy.

Inventive Principle:
Principle #10Preliminary 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

The solution enhances measurement accuracy and range by ensuring consistent signal amplification, enabling more precise distance calculations regardless of signal intensity variations, thus improving the overall performance of distance measuring systems.

Implementation Method 1

a variable gain amplifier for amplifying a detected signal, wherein a higher gain is applied when the detected signal has a low intensity and wherein a relatively lower gain is applied when the detected signal has a relatively higher intensity

Methodology Applied
Scientific EffectVariable gain amplification:

Implementation Method 2

a signal delay module for delaying a first portion of a detected signal, wherein a first analysis of a second portion of the detected signal is performed while the first portion is delayed

Methodology Applied
Scientific EffectSignal delay:

Data Source

PatentEP2193388B1Distance measuring instrument and method
Publication Date: 2016.03.09 TRIMBLE 3D SCANNING
  • EP2193388B1 patent drawingFigure 1
  • EP2193388B1 patent drawingFigure 2~4
  • EP2193388B1 patent drawingFigure 5~7

AI summary

A distance measuring instrument comprises: at least one light source (5); at least one light detector (9); optics (23) to direct measuring light emitted from the at least one light source towards an object (3) and to direct measuring light received back from the object to the at least one detector; a signal delay module (51); a first signal analyzer (42); and a variable gain amplifier (33). A distance measuring method comprises: emitting a pulse of measuring light towards an object; receiving a pulse measuring light from the object and generating a pulse signal corresponding to the pulse of measuring light received from the object; delaying a first portion of the generated pulse signal for a predetermined time; generating an intensity signal indicative of an intensity of the generated pulse signal, while delaying the first portion of the generated pulse signal; amplifying the delayed first portion of the generated pulse signal using a gain dependent on the generated intensity signal; determining a value representing a distance based on the amplified delayed first portion of the generated pulse signal.