Range Imaging Waveform Distortion Correction
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Solution Overview
Problem
Existing range imaging technologies face inaccuracies in distance measurement due to waveform distortion in rectangular signals, leading to errors in charge accumulation and processing, especially when waveform distortion is significant.
Innovation Solution
A range imaging apparatus and method that includes a light source unit, a light receiver with pixels and a pixel driver circuit, and a range image processor. The processor acquires waveform information indicating distortion, corrects charge amounts based on this information to simulate a non-distorted waveform, and determines the measurement distance using these corrected values.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If waveform distortion correction is not applied, then device complexity is reduced, but measurement precision deteriorates due to errors in distance measurement
Solution Approach 1:
The patent applies preliminary action by pre-calculating and storing correction values for waveform distortion in a lookup table during the design phase. During actual operation, the system simply retrieves the appropriate correction value based on measured waveform parameters, avoiding complex real-time calculations while maintaining high measurement precision
Solution Approach 2:
The patent introduces an intermediary correction mechanism that processes the distorted rectangular waveform through a correction circuit or algorithm. This intermediary step transforms the distorted signal into an equivalent non-distorted signal representation, enabling accurate distance measurement without requiring complete redesign of the signal path
2Measurement precision
If waveform distortion is significant, then charge accumulation errors increase, but processing time increases when correction is applied
Solution Approach 1:
The correction values are pre-calculated and stored in a lookup table during the design phase, allowing the system to quickly retrieve correction factors during operation without performing complex real-time calculations, thus maintaining high charge amount accuracy while minimizing processing time
Solution Approach 2:
The patent uses a simplified correction approach that accepts some approximation in exchange for speed. By using pre-computed correction values rather than exact real-time correction, the system achieves sufficient accuracy for practical applications while dramatically reducing processing time
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 accurately calculates measurement distances even with significant waveform distortion, reducing errors and improving processing efficiency by correcting charge amounts and maintaining accurate distance measurements.
Implementation Method 1
Each of the pixels in the light receiver includes a photoelectric conversion device that generates an electric charge corresponding to incident light
Data Source
AI summary
A range imaging apparatus includes a light source unit that emits light pulse to a measurement space, a light receiver including pixels and a pixel driver circuit, and a range image processor that determines a measurement distance to a subject placed in the space. Each pixel includes a photoelectric conversion device that generates electric charge corresponding to incident light and charge accumulators that store the electric charge, the circuit distributes and stores the charge to each accumulator at a predetermined point in time synchronized with emission of the pulse, the processor acquires waveform information indicating degree of distortion of waveform of rectangular signal having distorted waveform, corrects, based on the information, charge amounts each indicating an amount of the electric charge stored when the waveform has no distortion, and determines the distance using the charge amounts, and the signal is used in signal processing performed until the distance is determined.