Laser Radar Signal Validation for Low Light Accuracy
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Solution Overview
Problem
Existing laser radar devices face accuracy issues in calculating ranges when the light intensity of reflected light is low, leading to increased noise interference and potential errors in cross-correlation values.
Innovation Solution
A laser radar device is designed with a transmission signal generator, light irradiator, reflected light receiver, first and second signal sequence converters, and an acceptance or refusal selecting circuit. The second signal sequence converter outputs pulse signals only when the reception signal exceeds a threshold, and the acceptance or refusal selecting circuit calculates a degree of match between signal sequences to validate the calculated range, preventing errors at low light intensity.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If cross-correlation calculation is used to determine range, then range calculation can be performed, but measurement precision deteriorates when light intensity is low due to noise influence
Solution Approach 1:
The patent applies preliminary action by performing signal sequence conversion and match validation before final range calculation. The reception signal is converted to a pulse signal sequence and compared with the transmission signal sequence in advance, allowing the system to identify and reject ranges with low correlation scores that would otherwise be affected by noise, thereby improving measurement precision before the harmful noise influence can degrade the result.
Solution Approach 2:
The patent implements feedback by calculating a correlation score between transmission and reception signal sequences, then using this score to determine whether to accept or reject the calculated range. This feedback mechanism allows the system to automatically quality-control range measurements, rejecting those with low correlation scores that indicate noise contamination, thus improving measurement precision while filtering out noise-affected results.
2Productivity
If range calculation is performed using low light intensity reflected light, then ranging function is maintained, but reliability decreases due to increased noise and potential errors
Solution Approach 1:
The patent implements feedback by calculating a correlation score between transmission and reception signal sequences, then using this score to determine whether to accept or reject the calculated range. This feedback mechanism allows the system to automatically quality-control range measurements, rejecting those with low correlation scores that indicate noise contamination, thus improving measurement precision while filtering out noise-affected results.
Solution Approach 2:
The patent applies the taking out principle by extracting and evaluating the correlation score as a separate quality metric from the range calculation process. By separating the reliability assessment (correlation score) from the range value itself, the system can identify and exclude unreliable measurements while maintaining the ranging function for valid measurements, thus improving reliability without sacrificing productivity.
3Speed
If signal processing is performed without validation, then processing speed is maintained, but manufacturing precision of range data decreases due to erroneous measurements
Solution Approach 1:
The patent applies preliminary action by performing signal sequence conversion and match validation before final range calculation. The reception signal is converted to a pulse signal sequence and compared with the transmission signal sequence in advance, allowing the system to identify and reject ranges with low correlation scores that would otherwise be affected by noise, thereby improving measurement precision before the harmful noise influence can degrade the result.
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 device effectively prevents the output of ranges likely to include errors when light intensity is low by ensuring accurate signal processing and validation, enhancing the accuracy of range calculations.
Implementation Method 1
a light irradiator to convert the transmission signal generated by the transmission signal generator into transmission light, and irradiate a ranging target with the transmission light
Implementation Method 2
a reflected light receiver to receive, as reflected light, the transmission light reflected by the ranging target, and output a reception signal of the reflected light
Data Source
AI summary
A laser radar device includes a first signal sequence converting unit that converts a transmission signal generated by a transmission signal generating unit into a first pulse signal sequence; a second signal sequence converting unit that converts a reception signal outputted from a reflected light receiving unit into a second pulse signal sequence; and a range calculating unit that calculates a range to a ranging target from a time difference between a time at which transmission light is irradiated by a light irradiating unit and a time at which reflected light is received by the reflected light receiving unit, and an acceptance or refusal selecting unit calculates a degree of match between the first pulse signal sequence and the second pulse signal sequence, and selects or discards the range calculated by the range calculating unit on the basis of the degree of match.