Optical Crosstalk Calibration for 3D Ranging Systems
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Solution Overview
Problem
3D ranging systems with active illumination face inaccuracies in distance data due to cross-talk, which current calibration methods fail to adequately address, especially with varying object reflectivity and distances.
Innovation Solution
A calibration method for optoelectronic modules that determines cross-talk calibration parameters by directing modulated light to absorbing targets and deriving parameters from cross-talk signals, allowing for accurate adjustment of measured object distance parameters.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of manufacture
If typical calibration procedures are used to determine offset and gain, then the calibration process is simple, but distance data accuracy deteriorates due to unmitigated cross-talk effects
Solution Approach 1:
The patent applies preliminary action by performing cross-talk calibration before actual distance measurements. The system first determines cross-talk calibration parameters using a substantially absorbing target, then uses these parameters to correct subsequent measurements. This preliminary calibration step eliminates cross-talk effects before they can contaminate the distance data, resolving the contradiction between simple calibration and accurate measurements.
Solution Approach 2:
The patent introduces an intermediary substantially absorbing target as a mediator in the calibration process. This target absorbs emitted light and prevents it from reflecting back to the receiver, allowing the system to isolate and measure only cross-talk signals. This intermediary enables accurate cross-talk characterization without the complexity of multiple reflective targets, maintaining calibration simplicity while improving distance measurement accuracy.
2Ease of operation
If calibration is performed without accounting for cross-talk, then the calibration method is straightforward, but distance measurements become inaccurate especially with varying object reflectivity and distances
Solution Approach 1:
The patent applies parameter changes by introducing cross-talk calibration parameters (offset and gain corrections) that are determined through a specialized calibration procedure. These parameters are then applied to correct distance measurements under varying conditions of object reflectivity and distance. The method maintains operational simplicity by using a straightforward parameter adjustment approach rather than complex real-time corrections, ensuring reliable measurements across different operating conditions.
3Productivity
If cross-talk is not calibrated out, then the system operates without additional calibration steps, but the receiver detects both reflected light and cross-talk light causing measurement errors
Solution Approach 1:
The patent applies the taking out principle by extracting cross-talk signals from the total received signal through separate calibration measurements. By using a substantially absorbing target, the system isolates cross-talk components and determines calibration parameters that represent pure cross-talk effects. These extracted parameters are then removed from subsequent distance measurements, leaving only the accurate reflected light information. This extraction approach maintains operational efficiency while significantly improving measurement precision.
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 method effectively mitigates cross-talk-related inaccuracies, providing accurate distance data by accounting for cross-talk in 3D ranging systems, even with different object reflectivities and distances.
Implementation Method 1
The receiver can collect light reflected from the object or target and produce signals
Implementation Method 2
optoelectronic module having an emitting channel and a receiving channel where the optoelectronic module is operable to demodulate modulated light incident on the receiving channel
Data Source
AI summary
The present disclosure describes calibration methods for optoelectronic modules with active illumination, such as 3D ranging systems. Calibration methods include determining cross-talk calibration parameters for an optoelectronic module having an emitting channel and a receiving channel where the optoelectronic module is operable to demodulate modulated light incident on the receiving channel. Cross-talk calibration parameters are saved to a readable storage medium and recalled during distance measurements to an object or objects in a scene.