Distance Image Sensor Dynamic Charge Distribution for Wide Range Measurement
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Solution Overview
Problem
Conventional distance image capturing apparatuses with fixed electric charge distribution configurations face measurement accuracy issues due to varying subject conditions and environments, leading to limited dynamic range in distance measurement.
Innovation Solution
A distance image capturing apparatus with a light source unit emitting intermittent light pulses and a light receiving unit featuring a distance image sensor with multiple electric charge accumulating units, where the distance image processing unit selects the appropriate electric charge amount for measurement based on a threshold, allowing for dynamic adjustment of charge distribution to widen the measurable distance range.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Device complexity
If the number of times electric charge is divided to the electric charge accumulating parts is fixed to a predetermined number, then the device complexity is reduced, but the measurement precision and dynamic range of distance measurement deteriorate under varying subject conditions
Solution Approach 1:
The patent applies dynamics by making the number of electric charge distribution cycles variable rather than fixed. The control unit dynamically adjusts the distribution cycle count based on feedback from the imaging device's charge accumulation levels, allowing the system to adapt to varying subject conditions (distance, reflectivity, background light) and maintain optimal measurement precision across different scenarios.
Solution Approach 2:
The patent changes the parameter of electric charge distribution cycle count from a fixed value to a variable parameter controlled by the control unit. By adjusting this parameter based on actual measurement conditions, the system optimizes the balance between charge accumulation efficiency and saturation prevention, thereby improving distance measurement accuracy under diverse conditions without significantly increasing device complexity.
2Measurement precision
If the number of times electric charge is divided is increased to improve measurement accuracy in dark environments or for distant subjects, then the measurement precision improves, but the electric charge accumulating parts become saturated in bright environments or for close subjects, causing measurement failure
Solution Approach 1:
The patent implements feedback control where the control unit monitors the electric charge accumulation status from the imaging device and uses this information to adjust the number of distribution cycles. This closed-loop feedback mechanism prevents charge saturation in bright environments while ensuring sufficient charge accumulation in dark environments, thereby maintaining both measurement precision and reliability across varying conditions.
Solution Approach 2:
The system dynamically adjusts the electric charge distribution cycle count based on real-time conditions. By making this parameter adaptive rather than static, the system prevents saturation when subjects are close or environments are bright, while ensuring adequate charge accumulation when subjects are distant or environments are dark, thus improving overall measurement reliability.
3Reliability
If the number of times electric charge is divided is decreased to prevent saturation in bright environments, then the reliability improves, but the measurement precision deteriorates in dark environments or for distant subjects
Solution Approach 1:
The feedback mechanism allows the control unit to determine the appropriate distribution cycle count based on actual charge accumulation levels. This prevents unnecessary reduction of distribution cycles that would harm precision in dark environments, while still preventing saturation in bright environments. The feedback-driven adjustment optimizes measurement precision across all conditions without sacrificing reliability.
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 wider dynamic range in distance measurement by reducing the impact of subject and environmental changes without requiring complex configurations or control, thereby improving measurement accuracy across various conditions.
Implementation Method 1
a photoelectric conversion device generating electric charge corresponding to incident light
Implementation Method 2
distance sensors of a time of flight (hereinafter referred to as 'TOF') system measuring a distance from a subject that is a target object on the basis of a flying time of light using the fact that the speed of light is known
Data Source
AI summary
A distance image capturing apparatus has a light source unit that emits an intermittent light pulse into a space, a light receiving unit that includes a plurality of pixels each having a photoelectric conversion device and electric charge accumulating units, and a distance image processing unit. The distance image processing unit acquires an electric charge amount distributed by a predetermined fixed number of times and accumulated in the accumulating units. The distance image processing unit acquires electric charge amounts accumulated in the accumulating units with different number of times of electric charge distribution as one set and selects one of a first electric charge amount with a larger number of electric charge distribution and a second electric charge amount for acquiring a distance from a subject based on a comparison result with a threshold.