ToF Sensor Depth Calculation Using Multiple Exposure Times
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Solution Overview
Problem
Conventional Time of Flight (ToF) sensors in commercial trailer loading face challenges with measurement accuracy due to high ranges of depths in their field of view, leading to saturation or lack of depth data, particularly when using auto-exposure features.
Innovation Solution
The method involves capturing multiple arrays of point values with different exposure times and quality components, and rendering a 3D point cloud by selecting depth components based on quality thresholds, ensuring accurate depth calculations without relying on single exposure length auto-exposure.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If a single exposure time is used in ToF sensors, then the device complexity is reduced, but measurement precision deteriorates due to saturation or lack of depth data in high depth range scenes
Solution Approach 1:
The patent segments the exposure time into multiple discrete values (first exposure time and second exposure time) that can be selectively applied to different regions of the scene. This segmentation allows the system to capture near-field objects with one exposure time and far-field objects with another, thereby resolving the contradiction between measurement precision and device complexity by dividing the single exposure parameter into multiple specialized exposure settings.
Solution Approach 2:
The patent implements dynamic exposure time selection where the system automatically determines which exposure time to use based on scene characteristics and depth information. This dynamic adjustment allows the ToF sensor to adapt to varying depth ranges in real-time, maintaining high measurement precision across different scene configurations without requiring manual intervention or complex hardware changes.
2Ease of operation
If auto-exposure feature is used to determine optimal exposure time, then ease of operation is improved, but measurement precision deteriorates due to inadequate handling of high depth range scenes
Solution Approach 1:
The patent incorporates a feedback mechanism where the system evaluates the quality of depth data obtained from different exposure times and automatically selects the optimal exposure time based on this feedback. The system monitors depth measurement quality indicators and adjusts the exposure time selection accordingly, ensuring both ease of operation and high measurement precision by letting the system self-optimize based on actual scene conditions.
Solution Approach 2:
The patent changes the exposure time parameter dynamically based on scene requirements rather than using a fixed or简单地 auto-exposed value. By implementing multiple predefined exposure time values and selecting among them based on scene analysis, the system maintains ease of operation while achieving superior measurement precision compared to conventional single-exposure auto-exposure methods.
3Measurement precision
If multiple exposure times are used to capture different depth ranges, then measurement precision is improved, but loss of time increases due to multiple capture cycles
Solution Approach 1:
The patent performs preliminary action by capturing a first set of depth values using a first exposure time before capturing the second set of depth values using a second exposure time. This sequential approach with preliminary capture allows the system to efficiently organize data processing and reduce overall capture time by establishing a capture sequence and reusing processing routines across both exposure time captures.
Solution Approach 2:
The patent merges the results from multiple exposure time captures into a unified depth map. By combining the first set of depth values and the second set of depth values into a single comprehensive depth representation, the system achieves complete depth range coverage without requiring separate processing pipelines, thereby reducing overall processing time and minimizing the time loss associated with using multiple exposure times.
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 effectively handling varying depth ranges within the ToF sensors' field of view, providing robust depth calculations and reducing oversaturation or data loss.
Implementation Method 1
Time of Flight (ToF) sensors are used to determine loading metrics
Data Source
AI summary
A system and method for performing robust depth calculations with time of flight (ToF) sensors using multiple exposure times is disclosed. A three-dimensional (3D) depth sensor assembly captures a first array of n point values, where each point value of the first array has a respective first-array depth component and a respective first-array quality component. The 3D depth sensor assembly then captures a second array of n point values, where each point value of the second array has a respective second-array depth component and a respective second-array quality component. A processor then renders a 3D point cloud comprising a third array of n point values, where each point value of the third array has a respective third-array depth component. The respective third-array depth component for each point value of the third array is based on either the corresponding respective first-array depth component or the corresponding respective second-array depth component.