Random Interval Distance Measuring Apparatus
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Solution Overview
Problem
Existing distance measuring apparatuses using time-of-light sensors face inaccuracies in short distance measurements due to interference from non-distance-measurement objects, where the reflected light from these objects is received after emitting pulsed light beams, leading to incorrect calculation of the distance to the intended object.
Innovation Solution
A distance measuring apparatus that emits multiple pulsed light beams at random intervals, using a time-to-digital converter and histogram-generating-and-distance-calculating unit to differentiate between reflections from the distance-measurement object and non-distance-measurement objects by generating histograms based on the timing differences, ensuring accurate distance calculation.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If multiple pulsed light beams are emitted at regular intervals to improve measurement coverage, then the measurement range is extended, but the reflected light from non-distance-measurement objects is received after the second pulsed light beam is emitted, causing incorrect distance calculation
Solution Approach 1:
The patent applies dynamics by transitioning from regular interval emission to random interval emission of pulsed light beams. The light-emitting portion emits pulsed light beams at randomly determined intervals, which prevents predictable timing patterns that would allow non-distance-measurement objects to be mistakenly measured. This randomization dynamic approach resolves the contradiction by maintaining measurement coverage while preventing incorrect distance calculations from interfering objects.
Solution Approach 2:
The patent changes the timing parameter of light emission from regular intervals to random intervals. By determining emission intervals based on random numbers, the system modifies the temporal distribution of light beams to prevent systematic interference from non-distance-measurement objects, thereby maintaining both measurement range and accuracy.
2Productivity
If the period of emission of multiple pulsed light beams is decreased to improve response speed, then the measurement speed is improved, but the reflected light from non-distance-measurement objects is received after the second pulsed light beam is emitted, causing incorrect distance calculation
Solution Approach 1:
The system maintains high measurement speed by using random interval emission rather than regular interval emission. The randomization prevents the systematic timing issue where non-distance-measurement objects would be measured, while still allowing rapid sequential emission of multiple light beams for fast response.
Solution Approach 2:
The system uses feedback from the histogram analysis of received light to determine whether a measurement is valid. By analyzing the distribution of returned light and comparing it against expected patterns, the system can reject incorrect measurements from non-distance-measurement objects while maintaining fast measurement cycling.
3Device complexity
If the light-emitting portion emits pulsed light beams at regular intervals to simplify control, then the device complexity is reduced, but the reflected light from non-distance-measurement objects is received after the second pulsed light beam is emitted, causing incorrect distance calculation
Solution Approach 1:
The patent introduces dynamic randomization to the emission control mechanism. While this increases control complexity slightly, it fundamentally resolves the interference issue by preventing predictable timing patterns. The random number generator and interval calculation add computational complexity but eliminate the need for complex hardware shielding or physical separation of measurement paths.
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 apparatus effectively inhibits mistaken distance measurements by distinguishing between object and non-object histograms, providing accurate calculations even in cases of short distance measurements and counter differential nonlinearity issues.
Implementation Method 1
a light-emitting portion LE that emits a plurality of pulsed light beams PL and that transmits a plurality of light-emitting pulse signals corresponding to the plurality of pulsed light beams
Implementation Method 2
The distance measuring apparatus calculates a distance from an object by multiplying a time until pulsed light that is emitted from a light-emitting portion is reflected by the object and is received by a light-receiving portion by the speed of light
Implementation Method 3
a time-to-digital converter that converts a light-emitting timing of the plurality of light-emitting pulse signals and an object light-receiving timing of the plurality of object pulse signals into digital values
Implementation Method 4
a histogram-generating-and-distance-calculating unit that generates an object histogram that has a horizontal axis representing a difference between the digital value of the object light-receiving timing and the digital value of the light-emitting timing and that calculates a distance to the distance-measurement object, based on a center of gravity of the object histogram
Data Source
AI summary
A distance measuring apparatus includes: a light-emitting portion that transmits a plurality of light-emitting pulse signals corresponding to a plurality of pulsed light beams; an object light-receiving portion that transmits a plurality of object pulse signals corresponding to a plurality of object pulsed light beams; a time-to-digital converter that converts a light-emitting timing of the plurality of light-emitting pulse signals and an object light-receiving timing of the plurality of object pulse signals into digital values; and a histogram-generating-and-distance-calculating unit that generates an object histogram that has a horizontal axis representing a difference between the digital value of the object light-receiving timing and the digital value of the light-emitting timing and that calculates a distance to the distance-measurement object, based on a center of gravity of the object histogram, wherein the light-emitting portion emits the plurality of pulsed light beams at a random interval corresponding to a uniform random number.