Optical Distance Sensor Exposure Control via Intermediate Measurements
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Solution Overview
Problem
Optical distance sensors face challenges in maintaining consistent exposure control, particularly with moving objects, leading to high measurement errors due to varying reflectivity and delayed regulation, which affects signal-to-noise ratio and measurement accuracy.
Innovation Solution
The implementation of intermediate measurements during measurement breaks, where an illuminating light beam is emitted and detected without determining a distance value, allows for real-time adjustment of exposure control, ensuring the received light amount is within a target range, thereby reducing measurement uncertainty and speeding up control stabilization.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If exposure time is adjusted based on object reflectivity, then measurement accuracy is improved, but control stabilization time increases
Solution Approach 1:
The system performs preliminary exposure control adjustments during measurement breaks before actual distance measurement begins. By preparing the exposure settings in advance during idle periods, the system avoids delayed regulation during active measurement, thus reducing control stabilization time while maintaining measurement accuracy.
Solution Approach 2:
The system continuously monitors and adjusts exposure parameters even during measurement breaks, ensuring that exposure control is always active and adapting. This continuous adjustment process prevents delays in stabilization by maintaining readiness to immediately respond to reflectivity changes without waiting for measurement cycles.
2Speed
If intermediate measurements are performed during measurement breaks, then control stabilization speed is improved, but resource consumption increases
Solution Approach 1:
The system uses measurement breaks (idle periods when no distance measurement is occurring) to perform intermediate exposure control measurements. By utilizing otherwise wasted time resources, the system accelerates control stabilization without requiring additional dedicated measurement cycles, thus avoiding excessive resource consumption.
Solution Approach 2:
The system dynamically decides whether to perform intermediate measurements based on current exposure control needs and timing conditions. Rather than performing intermediate measurements at fixed intervals, the system adapts the measurement frequency to actual requirements, optimizing the balance between stabilization speed and resource usage.
3Device complexity
If exposure control is delayed, then device complexity is reduced, but measurement uncertainty increases
Solution Approach 1:
The system performs exposure control adjustments in advance during measurement breaks before actual measurement begins. This preliminary action ensures that exposure settings are optimized before measurement, reducing measurement uncertainty without requiring complex real-time control mechanisms during active measurement.
Solution Approach 2:
The system implements periodic exposure control measurements during measurement breaks at strategically timed intervals. This periodic approach provides regular updates to exposure settings without continuous complex control, balancing simplicity with reduced measurement uncertainty through timely periodic adjustments.
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 approach reduces measurement uncertainty and speeds up control stabilization by allowing for more frequent adjustments without calculating unnecessary distance values, improving signal-to-noise ratio and reducing resource waste.
Implementation Method 1
an illumination beam is generated by a light source and directed onto a target object
Implementation Method 2
This illumination beam causes a measurement beam to be emitted at or near the target object, often through reflection from a surface of the object
Implementation Method 3
The measurement beam is detected by a detector, and the distance between the sensor and the target object is determined from the detector's readings
Data Source
Figure 1~2
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AI summary
An optical distance sensor with closed-loop exposure control is disclosed. The distance sensor (2) comprises a light source (3), a detector (4), a measurement controller (5), an evaluation unit (6) and a closed-loop controller (7). The light source (3) generates an illumination light beam (8) and guides the latter to a measurement object (10). The detector (4) detects a measurement light beam (11) that has been caused by reflection of the illumination light beam (8) at the measurement object (10). The measurement controller (5) controls the detector (4) during detection of the measurement light beam (11) and during a readout of measurement values. In one phase of a measurement operation (14), the evaluation unit (6) is designed to evaluate measurement values of the detector (4) for the purposes of determining a distance (a) between the distance sensor (2) and the measurement object (10). The closed-loop controller (7) drives the light source (3), the detector (4) and/or the measurement controller (5) such that a received amount of light, which is detected during an exposure duration by the detector (4) or a portion of the detector (4), is situated in a target region or approaches said target region. In the process, the distance sensor (2) is designed, both in phases of the measurement operation (14) and in measurement pauses formed between the phases of the measurement operation (14), to emit an illumination light beam (8) and to detect a measurement light beam (11) and evaluate the latter by means of the closed-loop controller (7). Further, a corresponding method of closed-loop control of an optical distance sensor is disclosed.