3D Distance Measurement with Segmented Light Sources
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Solution Overview
Problem
Existing three-dimensional distance measurement apparatuses using the time-of-flight method face challenges in accurately measuring distances due to weak reflected light and interference from unnecessary light sources, such as ceiling reflections, which degrades measurement accuracy, especially when subjects are at different distances.
Innovation Solution
A three-dimensional distance measurement apparatus with multiple light sources that can be individually controlled for emission and adjusted in intensity, allowing for partial overlap of irradiation areas and optimization of light distribution to minimize ambient light interference and ensure adequate light reach for subjects at varying distances.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If a single light source is used to irradiate the subject, then the device structure is simple, but the measurement accuracy degrades due to insufficient light coverage and weak reflected light from distant subjects
Solution Approach 1:
The patent divides a single light source into multiple light sources (first light source and second light source), each irradiating different areas (first irradiation area and second irradiation area). This segmentation allows broader coverage of multiple subjects at different distances while maintaining manageable device complexity through modular configuration.
Solution Approach 2:
The patent extends the irradiation coverage by adding spatial dimension through multiple light sources positioned at different locations. The first and second light sources create overlapping irradiation areas that collectively cover a wider three-dimensional space, enabling accurate measurement of subjects at varying distances.
2Adaptability or versatility
If the irradiation light range is increased to cover multiple subjects, then more subjects can be measured, but unnecessary reflection light from other objects (such as ceiling) increases and acts as disturbance
Solution Approach 1:
The patent assigns different irradiation characteristics to different light sources. The first light source irradiates the first area with first light intensity, while the second light source irradiates the second area with second light intensity. This local quality differentiation allows optimized coverage for specific subject positions while minimizing unnecessary illumination of surrounding objects like ceilings.
Solution Approach 2:
The patent employs partial overlapping of irradiation areas between the first and second light sources. This partial overlap ensures adequate light coverage for subjects at different distances without excessively illuminating unrelated areas, thereby reducing ambient light interference from objects outside the intended measurement zones.
3Measurement precision
If light intensity is increased to improve signal strength, then reflected light detection is improved, but ambient light interference and ghosting effects increase
Solution Approach 1:
The patent segments the total light intensity requirement across multiple light sources. Instead of using one high-intensity light source that causes ghosting, the system uses multiple light sources (first and second) each emitting at optimized intensities. This segmentation reduces individual source intensity while maintaining sufficient total signal for accurate reflected light detection.
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 enhances measurement accuracy by reducing the impact of ambient light and ensuring sufficient light intensity for subjects at different distances, resulting in improved distance imaging and reduced ghosting effects in the distance image.
Implementation Method 1
a distance to a subject on the basis of light transmission time (hereinafter, referred to as a 'time-of-flight (TOF) method')
Implementation Method 2
a light-receiving unit that detects reflection light from the subject
Data Source
AI summary
A three-dimensional distance measurement apparatus include: a plurality of light sources 11 that irradiate light onto the subject; a light emission control unit 12 that controls light emission from a plurality of light sources; a light-receiving unit 13 that detects reflection light from the subject; a distance-calculating unit 14 that calculates a distance to the subject on the basis of a transmission time of reflection light; and an image processing unit 15 that creates a distance image of the subject on the basis of calculated distance data. The plurality of irradiation areas 3 onto which light from the light sources are irradiated are arranged to partially overlap only with the neighboring ones. The light emission control unit 12 individually turns on or off the light sources 11 or individually adjusts the emitted light amounts.