Distance Measuring Apparatus Using Time-Division Multiplexed Laser Beams
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Solution Overview
Problem
Conventional optical distance measuring apparatuses face a trade-off between measurement range and resolution, making it complicated to expand the measurement range without reducing resolution, especially when using multiple laser beams for discrimination.
Innovation Solution
The apparatus employs a detection unit with multiple light beam generation optical units and a camera unit that projects and detects multiple laser beams at different angles, using pulse signals and calibration tables to calculate distances across various ranges, allowing expansion of the measurement range without compromising resolution.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Length of stationary object
If multiple laser beams are used to expand measurement range, then measurement range is improved, but device complexity increases
Solution Approach 1:
The patent applies periodic action by using time-division multiplexing where multiple laser beams are emitted in alternating time slots rather than simultaneously. The first laser beam is emitted during a first time period, and the second laser beam is emitted during a second time period. This periodic emission pattern allows the system to expand measurement range while avoiding the complexity of discriminating multiple simultaneous beams, as the camera captures reflections sequentially rather than concurrently.
2Length of stationary object
If measurement range is expanded using multiple laser beams, then measurement range is improved, but discrimination processing becomes complicated
Solution Approach 1:
The system uses periodic action by implementing time-division multiplexing where laser beams are emitted in alternating time slots. The control unit generates a first light emission signal during a first time period and a second light emission signal during a second time period, causing laser beams to reflect off the measurement object at different times. This temporal separation eliminates the need for complex spatial discrimination processing, as the camera naturally captures reflections in sequence corresponding to the emission timing.
Solution Approach 2:
The patent maintains continuity of useful action by ensuring that the alternating emission of multiple laser beams creates a continuous measurement process. While beams are emitted periodically in time slots, the measurement coverage is continuous across the expanded range, with each time period contributing to covering a specific distance range. This continuous measurement approach avoids gaps in measurement capability while managing beam discrimination through temporal rather than spatial separation.
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
Enables easy expansion of the measurement range while maintaining resolution, allowing multiple distance measurement ranges to be covered by a single camera without increasing complexity or reducing accuracy.
Implementation Method 1
a laser light source, and a collimator that shapes the laser beam irradiated from the laser light source
Implementation Method 2
detects a reflection position of the relevant laser beam by a camera
Implementation Method 3
an area scan type CCD camera, and a line scan type CCD camera
Data Source
AI summary
A distance measuring apparatus is characterized in that: a detection unit 1 is provided with a light beam generating unit 12 which is provided with a plurality of light beam generation optical units each of which is provided with a laser light source, and a collimator, and a light beam lighting control unit which generates pulse signals for lighting laser beams as pulse lights in time series, a camera unit 11 which generates position detection information of a plurality of the laser beams, and an optical setting unit 13 which sets the light beam generating unit and the camera unit; and projects the plurality of laser beams, and sets distances of cut lines which are respectively locus lines of the laser beams between intersection points of viewing angle end lines of the camera unit and locus lines of the laser beams, in the vertical direction, as the plurality of distance measurement ranges; and a distance calculation unit 2 obtains a distances from a reference surface, from the position detection information, and discrimination signal, with reference to a calibration table corresponding to the distance measurement range; and thereby the distance measurement range can be expanded by measuring a plurality of different distance measurement ranges by one camera.