Intermittent Light Emission Ranging for Phase Delay Correction
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Solution Overview
Problem
Existing ranging apparatuses using optical Time Of Flight (TOF) technology struggle to accurately measure distances when reflected light experiences delays greater than one cyclic period of modulated light, leading to detection errors and reduced accuracy.
Innovation Solution
A ranging apparatus with an intermittent emission and detection control system that corrects distance calculations based on phase differences between modulated and reflected light, using a corrector unit to adjust measurements even for delayed reflected light, thereby enhancing accuracy.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Area of stationary object
If continuous emission of modulated light is used for distance measurement, then measurement coverage is improved, but detection accuracy deteriorates due to delayed reflected light exceeding one cyclic period
Solution Approach 1:
The patent applies periodic action by intermittently emitting modulated light in cyclic periods and synchronously controlling the image capturing device to detect reflected light only during specific detection periods within each cyclic period. This periodic emission and detection scheme enables the system to distinguish between first reflected light (within one cyclic period) and delayed reflected light (exceeding one cyclic period), thereby maintaining measurement accuracy while preserving comprehensive measurement coverage.
2Productivity
If all pixels are used for distance calculation, then productivity is improved, but reliability deteriorates due to inclusion of pixels detecting delayed reflected light
Solution Approach 1:
The patent applies segmentation by dividing pixels into two categories: first pixels that detect first reflected light (within one cyclic period) and second pixels that detect delayed reflected light (exceeding one cyclic period). The calculating unit selectively uses only first pixels for distance calculation, excluding second pixels. This segmentation ensures reliable distance measurements while maintaining efficiency by utilizing available pixel data without compromising accuracy.
3Measurement precision
If threshold-based pixel selection is used to avoid delayed reflected light, then measurement accuracy is improved, but device complexity increases due to additional control mechanisms
Solution Approach 1:
The patent applies feedback by using the intermittent detection mechanism to identify which pixels detected reflected light during the detection period versus which pixels detected delayed reflected light outside the detection period. The calculating unit receives this feedback information and automatically selects appropriate pixels for distance calculation. This feedback-based approach achieves high measurement accuracy without requiring complex threshold-based filtering or additional control mechanisms.
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 system accurately measures distances by correcting for phase delays in reflected light, improving the overall accuracy of distance measurement and reducing errors caused by delayed light detection.
Implementation Method 1
One known process for measuring the distance up to an object is an optical TOF (Time Of Flight) ranging process
Implementation Method 2
the modulated light as it is detected by the image capturing device 204 has undergone a phase delay of one cycle length
Data Source
AI summary
A first ranging apparatus includes a light emitter for emitting a modulated light which is intensity-modulated, a light detector for detecting a reflected light from an object that is irradiated with the modulated light, a distance calculator for calculating the distance up to the object based on the phase difference between the modulated light and the reflected light, and a gate controller. The gate controller outputs gate pulses to control a light emission controller to intermittently emit the modulated light to the object and also control an electrooptical shutter or an electronic shutter of an image capturing device to intermittently detect the reflected light from the object based on the intermittent emission of the modulated light.