Stereo Camera Parallax Calculation Using Dual Phase Difference Distributions

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Solution Overview

Problem

The accuracy of distance measurement between an object and a camera in stereo matching techniques decreases with increasing distance due to camera noise and disturbances, leading to reduced measurement precision.

Innovation Solution

An image processing apparatus and method that generate parallax information using a first phase difference distribution on a pixel-by-pixel basis and a second phase difference distribution on a sub-pixel-by-sub-pixel basis, incorporating edge information and luminance distribution matching to enhance accuracy and robustness against noise.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Measurement precision

If stereo matching is performed using conventional pixel-by-pixel phase difference calculation, then the processing is simple and fast, but the measurement accuracy deteriorates at long distances due to camera noise and disturbances

Engineering Contradiction:
Improvedistance calculation accuracyVSAvoidprocessing complexity
Core Design Contradiction:
Measurement precisionVSDevice complexity

Solution Approach 1:

The patent segments the phase difference calculation into two distinct stages: first calculating pixel-by-pixel phase differences to establish a preliminary distribution, then performing sub-pixel level calculations only in necessary regions based on the first distribution. This segmentation allows the system to maintain high accuracy where needed while avoiding unnecessary complex processing elsewhere, thus resolving the contradiction between measurement precision and processing complexity.

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

The patent applies sub-pixel level processing (excessive action) selectively rather than uniformly across the entire image. By using the first phase difference distribution to identify regions requiring higher precision, the system performs partial excessive action only where camera noise and disturbances significantly impact measurement accuracy, particularly at long distances. This approach improves distance calculation accuracy without incurring the full computational cost of applying sub-pixel processing everywhere.

Inventive Principle:
Principle #16Partial or excessive action

2Measurement precision

If sub-pixel level processing is applied throughout the entire image, then the distance calculation accuracy improves, but the processing time and computational load increase significantly

Engineering Contradiction:
Improvephase difference measurement accuracyVSAvoidprocessing time
Core Design Contradiction:
Measurement precisionVSLoss of time

Solution Approach 1:

The patent divides the image processing into two sequential segments: a first pass using efficient pixel-by-pixel phase difference calculation, and a second pass using computationally intensive sub-pixel processing only in regions identified as needing higher precision. This segmentation dramatically reduces total processing time compared to applying sub-pixel processing uniformly, while still achieving high measurement accuracy in critical areas affected by camera noise and disturbances.

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

The system performs sub-pixel level processing (excessive action) partially rather than completely. By using the first phase difference distribution to identify specific regions where high precision is necessary, the patent applies the computationally expensive sub-pixel processing only to those partial regions, thereby reducing overall processing time while maintaining accuracy where it matters most for distance calculation.

Inventive Principle:
Principle #16Partial or excessive action

Data Source

PatentEP2913793B1Image processing device and image processing method
Publication Date: 2020.06.03 SONY GROUP CORP
  • EP2913793B1 patent drawingFigure 1
  • EP2913793B1 patent drawingFigure 2
  • EP2913793B1 patent drawingFigure 3

AI summary

[Object] To provide an image processing apparatus capable of increasing a distance calculation accuracy. [Solving Means] According to an embodiment of the present technology, there is provided an image processing apparatus including a parallax information generation unit. The parallax information generation unit generates parallax information based on a first phase difference distribution and a second phase difference distribution, the first phase difference distribution being generated on a pixel by pixel basis for the first parallax image and the second parallax image, the second phase difference distribution being generated on a sub-pixel by sub-pixel basis based on the first phase difference distribution.