Distance Image Sensor Timing Control for Interference Rejection
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Solution Overview
Problem
Existing distance image capturing devices face challenges in accurately measuring distances due to interference from light pulses emitted by adjacent devices, leading to erroneous measurements and difficulties in integrating measurement results, particularly in environments where multiple sensors are used.
Innovation Solution
The implementation of a distance image capturing device with a light source unit, a light receiving unit, and a timing determining unit that adjusts the accumulation timing to minimize interference by determining the optimal timing for light reception based on electric charge accumulation during inspection intervals, ensuring that interference light is not included in the measurement, thereby maintaining consistent measurement periods.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If multiple distance image capturing devices are used adjacently, then the measurement coverage and application versatility are improved, but interference light from other devices causes erroneous measurements and reduces measurement precision
Solution Approach 1:
The system performs preliminary actions by having each device emit a detection light pulse before the main measurement, and having other devices accumulate electric charge during an inspection time interval to detect the presence of interference light. This preliminary detection allows the system to identify and exclude measurements contaminated by interference light before final distance calculation, thereby maintaining measurement precision while enabling multiple devices to operate adjacently.
2Measurement precision
If the accumulation period length is changed to deviate interference light timing, then interference light influence is reduced, but the measurement time interval changes and integration of measurement results becomes difficult
Solution Approach 1:
The system performs preliminary detection of interference light using a detection light pulse and inspection time interval before the actual measurement. This allows the system to identify interference conditions without changing the main measurement timing, thus maintaining consistent measurement time intervals for result integration while still achieving interference light rejection through the preliminary inspection mechanism.
Solution Approach 2:
The system extracts the interference light detection function into a separate inspection time interval that is distinct from the main measurement time interval. By separating the detection of interference light from the actual distance measurement process, the system can identify and exclude contaminated measurements while maintaining consistent timing for valid measurements, enabling both interference rejection and easy result integration.
3Measurement precision
If interference light detection and exclusion mechanisms are added, then measurement precision is improved, but device complexity increases
Solution Approach 1:
The system achieves multi-functionality by using the same light receiving unit and electric charge accumulating units for both normal distance measurement and interference light detection. The photoelectric conversion device generates electric charge that is accumulated in the same accumulating units regardless of whether the light is from the measurement pulse or interference detection. This universal use of components improves measurement precision through interference detection without significantly increasing device complexity.
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 solution effectively inhibits erroneous distance measurements caused by interference light without degrading the convenience of the measurement process, allowing for accurate and reliable distance measurement even in environments with multiple sensors.
Implementation Method 1
a photoelectric conversion device generating electric charge corresponding to incident light
Data Source
AI summary
A light source unit, a light receiving unit that includes a distance image sensor in which a plurality of pixels each including a photoelectric conversion device generating electric charge corresponding to incident light and a plurality of electric charge accumulating units accumulating the electric charge and dividing and accumulating the electric charge among the electric charge accumulating units at a predetermined accumulation timing are arranged in a two-dimensional matrix pattern, a distance image processing unit that is configured to acquire a distance from a subject present in the space that is an imaging target, and a timing determining unit that is configured to determine the accumulation timing in the measurement time interval on the basis of an electric charge amount in each of the electric charge accumulating units in an inspection time interval in which the light pulse is not emitted at the accumulation timing are provided.