Distance-Measuring Device Using Segmented Pulse Detection
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Solution Overview
Problem
Existing time-of-flight (TOF) based distance-measuring methods face challenges in achieving high accuracy due to variations in light detection, particularly in the rise and fall periods of the reflection-light pulse.
Innovation Solution
A distance-measuring device that includes a light source, a light detector, and a circuit controlling both. The circuit generates data indicating distance by detecting reflection-light pulses in specific periods, including parts of the rise and fall periods, to enhance measurement accuracy.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If the light detector detects the entire reflection-light pulse including rise and fall periods, then the measurement coverage is improved, but the measurement precision deteriorates due to variations in light detection during these periods
Solution Approach 1:
The patent segments the reflection-light pulse detection into multiple distinct periods: a first period detecting only the leading edge (rise period), a second period detecting only the trailing edge (fall period), and optionally a third period detecting the middle portion. By dividing the detection process into separate temporal segments, the system captures comprehensive pulse information while excluding the problematic rise and fall periods from the primary distance calculation, thus resolving the contradiction between coverage and precision.
Solution Approach 2:
The patent applies different detection qualities to different parts of the reflection-light pulse. The leading edge detection in the first period and trailing edge detection in the second period use optimized parameters and weighting specifically suited for edge detection, while the middle period (third period) captures the stable central portion. This local optimization of detection quality for different pulse regions improves overall measurement precision while maintaining comprehensive coverage.
2Loss of information
If the detection period includes the rise period and fall period, then the complete pulse information is captured, but the measurement accuracy deteriorates due to light detection variations
Solution Approach 1:
The detection process is segmented into multiple specialized periods: first period for leading edge, second period for trailing edge, and third period for middle portion. Each segment captures specific pulse characteristics, ensuring complete information is gathered across all periods while the final distance calculation uses only the accurate middle period data, excluding the problematic rise and fall period variations.
Solution Approach 2:
The patent extracts and isolates the middle period detection results from the problematic rise and fall period data. By separating the useful middle portion information from the noisy edge portions and using only the extracted middle period data for primary distance calculation, the system achieves high precision while maintaining awareness of complete pulse information through the multi-period detection approach.
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 proposed solution enables more accurate distance measurement compared to traditional methods by effectively capturing components of both the leading and trailing edges of the reflection-light pulse, thereby improving measurement precision.
Implementation Method 1
a light source that outputs a light pulse toward a target object and a light detector that detects a reflection-light pulse returning from the target object due to the light pulse
Implementation Method 2
a light detector that detects a reflection-light pulse returning from the target object due to the light pulse
Data Source
AI summary
A distance-measuring device includes a light source, a light detector, and a circuit. The circuit causes the light source to output a light pulse toward a target object, causes the light detector to detect a reflection-light pulse in a first period and a second period to generate a first signal and a second signal, respectively, and generates and outputs data indicating a distance from the light detector to the target object based on the two signals. The first period includes at least a part of a rise period, from a first point at which an intensity of the reflection-light pulse starts increasing to a second point at which the increase ends, and the first point. The second period includes at least a part of a fall period, from a third point at which the intensity starts decreasing to a fourth point at which the decrease ends, and the fourth point.