Adaptive ToF Ranging Resolution Under Background Light Noise
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Solution Overview
Problem
Conventional ranging devices face challenges in accurately measuring distance due to noise interference from background light, particularly in bright environments, while in dark environments, they struggle with low-resolution distance images and incorrect detection of reflected light.
Innovation Solution
A ranging device that adjusts the resolution of distance and background light images independently based on background light intensity, using a two-dimensional array of light receiving elements and controlling pixel regions to optimize image resolution according to environmental conditions.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If the same resolution is used for both distance image and background light image, then the device complexity is reduced, but the measurement precision deteriorates in bright environments due to noise interference
Solution Approach 1:
The patent applies dynamics by making the pixel region size adjustable rather than fixed. The controller dynamically changes the pixel region size based on background light intensity conditions - using larger pixel regions in bright environments to reduce noise and smaller pixel regions in dark environments to maintain resolution, thereby resolving the contradiction between measurement precision and device complexity
Solution Approach 2:
The patent changes the parameter of pixel region size according to environmental conditions. By varying this geometric parameter based on background light intensity, the system optimizes the balance between noise suppression in bright conditions and resolution maintenance in dark conditions, improving measurement precision without permanently increasing device complexity
2Measurement precision
If high resolution is used for distance image in bright environments, then the measurement precision is improved, but the reliability deteriorates due to noise interference from background light
Solution Approach 1:
The patent applies local quality by treating the distance image and background light image differently based on local environmental conditions. In bright environments, larger pixel regions are used for the distance image to suppress noise, while in dark environments, smaller pixel regions maintain resolution. This localized adaptation improves both measurement precision and reliability by matching the imaging parameters to the specific lighting conditions
Solution Approach 2:
The system dynamically adjusts pixel region sizes based on real-time background light intensity detection. This dynamic adaptation allows the system to optimize the balance between capturing detailed distance information and suppressing background light noise, thereby improving both measurement precision and the reliability of reflected light detection under varying environmental conditions
3Reliability
If low resolution is used for background light image in dark environments, then the noise suppression is improved, but the measurement precision deteriorates due to incorrect detection of reflected light
Solution Approach 1:
The patent dynamically adjusts pixel region sizes based on background light intensity. In dark environments, smaller pixel regions are used to maintain high resolution and accurate background light detection, while larger pixel regions are used in bright environments for noise suppression. This dynamic adaptation resolves the contradiction by matching the resolution level to the environmental conditions
Solution Approach 2:
The system changes the pixel region size parameter according to ambient lighting conditions. By using smaller pixel regions in dark environments, the system maintains high measurement precision for background light intensity while still achieving effective noise suppression through the adaptive nature of the parameter change, rather than relying on fixed low-resolution settings
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 accurate distance measurement by suppressing noise in bright environments and enhancing detection of background light in dark environments, ensuring precise distance and background light image resolution regardless of lighting conditions.
Implementation Method 1
a light receiving unit (30) that outputs a light reception signal in response to a light reception state
Implementation Method 2
calculate a time of flight (ToF) that is a time from emission of the emitted light to reception of its reflected light
Data Source
AI summary
In a ranging device for measuring a distance to an object, a distance image acquisition unit is configured to, using light reception signal, acquire a distance image that indicates, at each pixel, a distance to the object within a region illuminated with illumination light. A background light image acquisition unit is configured to, using the light reception signals, acquire a background light image that indicates an intensity of background light received at each pixel. An information acquirer is configured to acquire intensity-related information related to the intensity of the background light. A resolution controller is configured to control a resolution of the distance image and a resolution of the background light image by setting a size of pixel regions independently for each of the distance image and the background light image according to the intensity of the background light indicated by the intensity-related information.