Distance Measuring Device Using Convolution Function
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Solution Overview
Problem
Conventional distance measurement methods using optical methods are computationally complex and prone to ambiguity due to periodic light intensity modulation, leading to reduced precision and repetition rates, especially when object reflectivity varies.
Innovation Solution
A distance measuring device that emits short and long light pulses with controlled delays, forming a convolution function to identify the precise delay corresponding to a reference signal, allowing for precise distance calculation while compensating for object reflectivity variations.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If conventional distance measurement methods process light property plots computationally, then distance can be determined, but the processing time increases and repetition rate decreases
Solution Approach 1:
The patent applies preliminary action by pre-defining the integration gate time window [Δs, Δe] based on expected time of flight ranges before measurement begins. This allows the system to directly integrate light properties within predetermined boundaries without requiring complex post-processing algorithms, thereby reducing computation time while maintaining measurement precision and enabling higher repetition rates
2Measurement precision
If light intensity is periodically modulated to measure phase difference, then distance can be measured, but the measurement becomes ambiguous due to periodicity
Solution Approach 1:
The patent uses periodic action by emitting light pulses at regular intervals and measuring the time of flight for each pulse. By using multiple pulse durations (short and long pulses) and comparing their respective time of flight measurements, the system resolves the ambiguity inherent in single-period measurements while maintaining accurate distance determination through the periodic pulse emission pattern
3Adaptability or versatility
If different object reflectivities are measured, then various surface properties can be detected, but the distance measurement precision decreases due to varying plot shapes
Solution Approach 1:
The patent applies parameter changes by measuring light intensity at multiple different time points within the integration gate for both short and long pulses. This creates a time-resolved intensity profile that allows the system to distinguish between variations caused by object reflectivity and variations caused by distance. By analyzing the temporal distribution of reflected light intensity rather than just total energy, the system maintains distance measurement precision while accommodating different reflectivity values
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 method simplifies and enhances the precision of distance measurements by using a convolution function to accurately determine the time of flight, independent of object reflectivity and computational complexity, achieving high precision and accuracy.
Implementation Method 1
the light back-reflected from the object is then captured by a light detector of the device
Data Source
AI summary
A method for determining a distance between a distance measuring device and an object includes the steps of illuminating the object with a short light pulse and long light pulses, outputting a signal value Uref at the end of an integration gate with an invariable delay between the emission start point in time of the short light pulse and integration start point in time Δs, forming a convolution function fc:=U(τ) from the intensity of the light arriving on the photo element and Δs with a respective variable delay τ for each long light pulse between the emission start point in time of the long light pulses and the integration gate, the variable delays being different from each other to form the convolution function, identifying the delay τc in the convolution function which corresponds to Uref, and calculating the distance by using the delay τc in the convolution function.