Adaptive Signal Averaging for Optical Rangefinders
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Optical rangefinders face limitations in signal-to-noise ratio (SNR) and response time when dealing with moving objects and varying distances, as standard signal averaging techniques fail to account for range-dependent SNR characteristics and object motion, leading to reduced performance and inaccurate range measurements.
Innovation Solution
Implementing a digital processing method that varies the averaging level of signal waveforms based on distance and applies range shifts to compensate for object motion, allowing for improved SNR and faster response times by optimizing the averaging process according to the range-dependent SNR and object velocity.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If standard signal averaging techniques are used to improve SNR, then signal-to-noise ratio is enhanced, but response time increases and accuracy for moving objects deteriorates
Solution Approach 1:
The patent applies dynamics by making the averaging level adaptive rather than fixed. The averaging level is dynamically adjusted based on the range to the target object, allowing the system to optimize between SNR enhancement and response time. For closer objects where SNR is naturally higher, fewer averages are performed, reducing response time. For farther objects requiring more averaging, the system accepts longer response times. This dynamic adaptation resolves the contradiction between improving SNR and maintaining fast response.
Solution Approach 2:
The patent changes the parameter of averaging level based on range distance. By modifying this processing parameter dynamically according to the measured or estimated range to the target, the system optimizes the balance between noise reduction and response speed. The averaging level parameter is adjusted to match the SNR characteristics at different ranges, allowing accurate ranging of moving objects without excessive response delays.
2Device complexity
If fixed averaging level is applied to all ranges, then device complexity is reduced, but measurement precision deteriorates for varying distances
Solution Approach 1:
The patent applies local quality by using different averaging levels for different range zones rather than a uniform approach. Each range interval has its own optimized averaging level tailored to the SNR characteristics at that distance. This allows the system to achieve high measurement precision across varying distances without requiring overly complex adaptive algorithms, as the averaging level is selected based on simple range thresholds.
3Device complexity
If standard averaging is used without range compensation, then device complexity is minimized, but measurement precision deteriorates for moving objects
Solution Approach 1:
The patent applies preliminary action by performing range compensation through waveform shifting before the averaging process. The received waveforms are shifted in the time domain to account for object motion during the measurement interval, aligning them to a common reference point. This preliminary alignment ensures that subsequent averaging accurately enhances the signal without blurring effects from object motion, improving precision for moving targets without requiring complex real-time motion tracking algorithms.
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 enhances the signal-to-noise ratio and reduces response times, enabling accurate ranging of moving objects and maintaining SNR-enhancing capabilities, even when objects are in motion, thereby improving the overall performance of optical rangefinders.
Implementation Method 1
Radiation with wavelength in the optical region of the electromagnetic spectrum... can propagate in the atmosphere in the form of a slowly-diverging optical beam
Implementation Method 2
The TOF principle consists essentially in measuring the time it takes an optical pulse to travel from the rangefinder up to a remote object, and then to return back to the instrument
Implementation Method 3
an optical receiver module for receiving the signal waveforms reflected by the object to be ranged
Data Source
AI summary
Methods and apparatuses for reducing the response time along with increasing the probability of ranging of optical rangefinders that digitize the signal waveforms obtained from the pulse echoes returned from various types of objects to be ranged, the pulse echoes being too weak to allow successful ranging from a single waveform or the objects being possibly in motion during the capture of the pulse echoes. In a first embodiment of the invention, the response time at close range of a digital optical rangefinder is reduced by using a signal averaging process wherein the number of data to be averaged varies with the distance according to a predetermined function. In a second embodiment of the invention, the probability of ranging objects in motion along the line of sight of a digital optical rangefinder is increased and the object velocity measured by performing a range shift of each acquired signal waveform prior to averaging. In a third embodiment of the invention, the signal waveforms acquired in the line of sight of a digital optical rangefinder are scanned over a predetermined zone and range shifted and averaged to allow for early detection and ranging of objects that enter in the zone.