Adaptive Bin-Width Time-of-Flight Ranging for Distance Resolution
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Solution Overview
Problem
Existing time-of-flight ranging devices face challenges in achieving accurate distance measurement while balancing integration time and storage requirements, leading to increased costs and errors when objects approach each other.
Innovation Solution
A time-of-flight ranging device and method that dynamically adjusts bin widths in histogram data by varying integration periods, allowing for high-resolution sensing without increasing storage space or total sensing time.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If the integration time of the time-to-digital converter decreases, then the distance resolution increases and ranging error decreases, but the number of bins in the histogram increases requiring increased storage space and chip area
Solution Approach 1:
The patent applies dynamics by making the bin width configuration adaptive and variable rather than fixed. The system dynamically adjusts bin widths based on detected target distance, using narrow bins for close targets and wide bins for distant targets. This dynamic adaptation resolves the contradiction by optimizing both distance resolution and storage efficiency according to actual sensing conditions.
Solution Approach 2:
The patent changes the parameter of bin width from a fixed value to a variable parameter that adapts to different ranging scenarios. By modifying the bin width parameter based on detected distance, the system achieves high distance resolution when needed while maintaining storage efficiency, thus resolving the contradiction between measurement precision and chip area.
2Area of stationary object
If the integration time of the time-to-digital converter increases to reduce chip area, then the number of bins decreases and storage space is reduced, but the distance resolution drops and ranging error increases
Solution Approach 1:
The system dynamically adjusts bin widths based on detected target distance, making the histogram structure adaptive rather than static. This dynamic approach allows the system to maintain high distance resolution for close targets using narrow bins while using wider bins for distant targets, optimizing both chip area and measurement precision.
Solution Approach 2:
The patent applies local quality by using different bin widths for different distance ranges within the histogram. Instead of using a uniform bin width throughout, the system employs narrow bins in regions where high resolution is needed (close distances) and wider bins where less resolution is required (distant targets), thus optimizing both storage and precision locally.
3Measurement precision
If the number of bins in the histogram increases to improve distance resolution, then the storage space and processing chip costs increase considerably
Solution Approach 1:
The patent changes the bin width parameter from fixed to variable, allowing the system to use fewer bins with adaptive widths instead of many fixed-width bins. This parameter change reduces storage space requirements while maintaining the ability to achieve high distance resolution when needed, resolving the contradiction between measurement precision and storage space.
Solution Approach 2:
By making bin widths dynamic and adaptive to target distance, the system reduces the total number of bins required in the histogram. This dynamic approach optimizes storage space by only using the resolution necessary for each specific ranging scenario, rather than provisioning for maximum resolution in all cases.
4Measurement precision
If the bin widths are uniformly reduced to improve sensing accuracy for close objects, then the storage space requirements and processing complexity increase
Solution Approach 1:
The patent applies local quality by using different bin widths for different regions of the histogram corresponding to different distance ranges. Narrow bins are used only in the regions where close targets are detected, while wider bins are used for distant targets, thereby reducing overall processing complexity while maintaining high sensing accuracy where needed.
Solution Approach 2:
The system dynamically adjusts bin widths based on detected target distance, making the histogram structure adaptive rather than uniformly fine-grained. This dynamic adaptation reduces processing complexity by avoiding the need to process uniformly narrow bins across the entire distance range, while still achieving high sensing accuracy for close objects when required.
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 solution provides accurate distance measurements with improved sensing accuracy and reduced errors by adaptively adjusting integration periods, maintaining consistent storage requirements.
Implementation Method 1
time-of-flight ranging device and time-of-flight ranging method
Data Source
AI summary
A time-of-flight ranging device and a time-of-flight ranging method are provided. The time-of-flight ranging device includes a light source, a sensing array, and a time-to-digital converter. The light source emits a laser pulse signal towards a sensing target. The sensing array includes a plurality of sensing units. The sensing array is configured to sense reflected pulse light generated when the sensing target reflects the laser pulse signal. The time-to-digital converter is coupled to the sensing array. The time-to-digital converter performs an integration operation on a plurality of sensing results of the sensing units during a plurality of consecutive integration periods to generate histogram data. At least part of the integration periods have different time lengths, such that at least part of a plurality of bins in the histogram data have different bin widths.