Distance Imaging Sensor Timing for Wide-Range Accurate Measurement
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Conventional distance-measuring techniques face challenges in achieving both high accuracy and a wide measurement range due to the inverse relationship between distance measurement range and accuracy, which is limited by the pulse width of the light source.
Innovation Solution
A distance-measuring imaging device that uses a solid-state imager with multiple signal accumulation regions to accumulate signals at different exposure times, allowing for the determination of signal magnitude relationships and calculation of object distance without exclusive background light accumulation, thereby increasing the measurement range without widening the light source pulse width.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Length of stationary object
If the pulse width of the light source is increased to widen distance measurement range, then distance measurement range is improved, but distance measurement accuracy deteriorates
Solution Approach 1:
The imaging device divides the imaging period into multiple distinct intervals (first imaging interval, second imaging interval, third imaging interval) with different exposure timings. Each interval captures reflected light from the object at different time points, allowing the system to measure both close and far distances accurately without increasing pulse width. This temporal segmentation enables multi-range measurement while maintaining high precision.
Solution Approach 2:
The system dynamically adjusts exposure timings across multiple imaging intervals rather than using a single static exposure period. By varying the exposure timing in each interval and comparing signal amounts across these dynamic measurements, the device can determine distances with high accuracy across a wide range, from near to far objects, without being constrained by pulse width limitations.
2Measurement precision
If the pulse width of the light source is decreased to improve distance measurement accuracy, then distance measurement accuracy is improved, but distance measurement range deteriorates
Solution Approach 1:
The imaging period is segmented into multiple intervals with different exposure timings. The first imaging interval captures early-arriving reflected light from closer objects, while subsequent intervals capture later-arriving light from farther objects. This segmentation allows the system to maintain high accuracy with a narrow pulse width while effectively extending the measurable distance range through multi-interval detection.
Solution Approach 2:
The system performs periodic imaging across multiple intervals, with each interval having specific exposure timings. By repeating the measurement process across these periodic intervals and comparing signal amounts, the device can accurately determine distances to both near and far objects, effectively extending the measurement range without compromising accuracy.
3Measurement precision
If multiple signal accumulation regions are used to accumulate signals at different exposure times, then distance measurement range and accuracy are both improved, but device complexity increases
Solution Approach 1:
Multiple signal accumulation regions within the imaging element serve multiple functions: they accumulate reflected light signals at different exposure timings, enable background light removal through dedicated regions, and provide the data necessary for distance calculation. This multi-functionality allows the system to achieve wide measurement range and high accuracy without proportionally increasing overall device complexity, as the same structural elements perform multiple critical roles.
Solution Approach 2:
The patent combines background light removal functionality with the distance measurement function by using specific signal accumulation regions (such as the third imaging interval) dedicated to capturing background light. This merging of functions allows the system to eliminate background light interference while simultaneously performing accurate distance measurements, reducing the need for separate dedicated components and thereby controlling device complexity.
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 enables high accuracy and a wider distance measurement range by extending the exposure period for reflected light capture, preventing the need for increased light source pulse width, and allowing for more precise distance calculations.
Implementation Method 1
a solid-state imaging element that performs, for an area including an object OB, exposure to light a plurality of times according to timing indicated by an exposure signal, and generates a signal corresponding to a total exposure amount of the exposure
Data Source
AI summary
A distance-measuring imaging device includes a light source that applies light according to timing of a light emission signal; a solid-state imager that performs, for an object, exposure according to timing of an exposure signal, and generates raw data corresponding to an exposure amount of the exposure; a signal amount comparator that determines a magnitude relationship in signal amount in the raw data; and a distance calculator that generates and outputs a distance signal based on a determination result. The solid-state imager accumulates, in each of different signal accumulation regions for accumulating signals detected in a same pixel, a signal by exposure in an exposure period that differs in exposure signal timing. The signal amount comparator determines the magnitude relationship between the signals accumulated in the signal accumulation regions. The distance calculator calculates the distance to the object using an arithmetic expression selected depending on the determination result.