Range Finding Device Light Emission Control for Signal Saturation
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Solution Overview
Problem
Range finding devices using the time-of-flight method face challenges in accurately determining distances due to fluctuations in light intensity from reflection, leading to saturation or indistinguishable signals, especially for objects close or far from the camera.
Innovation Solution
A range finding device with a light-emitting unit comprising a two-dimensional array of light-emitting regions and a corresponding light-receiving unit, where the light emission amount is controlled based on preliminary measurements to ensure optimal light reception, allowing for accurate distance calculation through time difference analysis.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If the light emission intensity is increased to improve detection of far objects, then the light receiving level increases, but the sensor output signal becomes saturated and range finding accuracy deteriorates
Solution Approach 1:
The light-emitting unit is divided into multiple light-emitting regions arranged in a two-dimensional array, and the light-receiving unit is divided into multiple light receiving regions. Each region can independently control light emission and reception, allowing for localized intensity adjustment to prevent saturation while maintaining detection capability across different distance ranges.
Solution Approach 2:
The patent applies different light emission intensities to different light-emitting regions based on their corresponding light receiving regions. This allows each region to be optimized for its specific detection needs, with closer regions using lower intensity to avoid saturation and farther regions using higher intensity to ensure sufficient signal strength.
2Object-affected harmful factors
If the light emission intensity is decreased to prevent signal saturation, then the light receiving level is controlled, but the sensor output signal becomes indistinguishable from noise for far objects
Solution Approach 1:
By segmenting the light-emitting and light-receiving units into multiple regions, the system can independently adjust emission intensity for each region. This allows far object regions to receive higher intensity light while near object regions use lower intensity, preventing saturation across the entire field of view.
Solution Approach 2:
Different light emission intensities are applied to different spatial regions based on distance characteristics. Regions corresponding to farther distances receive higher intensity to ensure signal detectability, while regions corresponding to nearer distances use lower intensity to prevent saturation.
3Device complexity
If uniform light emission is used across all light-emitting regions, then the device complexity is reduced, but the light receiving level cannot be optimized for different distances
Solution Approach 1:
The light-emitting unit is segmented into multiple independently controllable light-emitting regions, each corresponding to a light receiving region. This segmentation enables independent intensity control for each region, allowing optimization of light reception for different distances without requiring a completely complex control system.
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 the accuracy of range finding by adjusting light emission amounts for each region, improving detection capabilities for both near and far objects by preventing signal saturation and ensuring sufficient light reception.
Implementation Method 1
calculating a distance to the object using a time difference between a start time when the laser beam is emitted and a time when the light reflected from the object is received. The range finding method is known as the time-of-flight (TOF) method or system.
Implementation Method 2
an optical element configured to guide the light emitted from the light-emitting unit to a range finding area
Implementation Method 3
receiving a reflection light reflected from the object existing in the range finding area
Data Source
AI summary
A range finding device includes a light-emitting unit including light-emitting regions; an optical element to guide light emitted from the light-emitting unit; a light-receiving unit including light receiving regions to receive light reflected from an object; and circuitry to control light emission amount of the light-emitting regions; measure an amount of light received at the light receiving regions; measure a distance to the object by measuring a time difference between a start time when the light is emitted from the light-emitting unit and a time when the light reflected from the object is received by the light receiving regions; cause the light-emitting regions to emit the same light amount as a preliminary light emission stage; control the light emission amount of the light-emitting regions for a main light emission stage based on the amount of light measured at the preliminary light emission stage; and measure the distance to the object.