Stereo Matching Disparity Derivation for Weak Texture Objects

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Solution Overview

Problem

Conventional stereo matching methods fail to accurately derive disparity values for objects with weak texture, as costs are affected by surrounding features with strong texture, leading to inaccurate distance measurements.

Innovation Solution

A disparity value deriving device that calculates costs for candidates on an epipolar line, changes costs exceeding a threshold to a higher value, synthesizes costs for corresponding regions, and derives disparity values based on the smallest synthesized cost, effectively isolating the impact of weak texture objects from strong texture surroundings.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Quantity of substance

If costs of all pixels including surrounding strong texture regions are aggregated to derive disparity for weak texture objects, then more disparity information is available, but the costs for weak texture objects are contaminated by costs from strong texture surroundings

Engineering Contradiction:
Improvequantity of cost informationVSAvoiddisparity measurement accuracy
Core Design Contradiction:
Quantity of substanceVSMeasurement precision

Solution Approach 1:

The patent segments the cost information by introducing a confidence map that divides pixels into reliable (strong texture) and unreliable (weak texture) regions. This segmentation allows the system to selectively aggregate costs only from reliable regions when calculating disparity for weak texture objects, preventing contamination from strong texture surroundings while maintaining sufficient cost information for accurate disparity derivation.

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

The patent applies local quality by making the cost aggregation process adaptive to local image characteristics. The confidence map evaluates texture strength locally for each pixel, and the cost synthesis selectively weights or excludes costs from neighboring pixels based on their local texture quality. This ensures that weak texture regions receive cost information only from other weak texture regions with similar characteristics, improving measurement precision.

Inventive Principle:
Principle #3Local quality

2Device complexity

If conventional stereo matching is used for weak texture regions, then processing is simple, but sufficient effect cannot be obtained and accurate disparity cannot be derived

Engineering Contradiction:
Improveprocessing complexityVSAvoiddisparity measurement accuracy
Core Design Contradiction:
Device complexityVSMeasurement precision

Solution Approach 1:

The patent performs preliminary action by generating a confidence map before the disparity calculation process. This confidence map pre-identifies which pixels have strong texture (reliable) and which have weak texture (unreliable). By preparing this classification in advance, the system can then efficiently aggregate costs only from appropriate regions during the disparity calculation, achieving accurate results for weak texture objects without excessive processing complexity.

Inventive Principle:
Principle #10Preliminary action

Solution Approach 2:

The patent introduces a confidence map as an intermediary element that mediates between the raw image data and the disparity calculation process. This intermediary structure stores texture quality information and guides the cost aggregation process, enabling the system to handle weak texture regions accurately while maintaining overall processing efficiency. The confidence map acts as a bridge that translates local texture characteristics into global disparity calculation decisions.

Inventive Principle:
Principle #24Intermediary (Mediator)

Data Source

PatentUS10104359B2Disparity value deriving device, movable apparatus, robot, disparity value producing method, and computer program
Publication Date: 2018.10.16 RICOH CO LTD
  • US10104359B2 patent drawing
  • US10104359B2 patent drawing
  • US10104359B2 patent drawing

AI summary

A disparity value deriving device includes a calculator configured to calculate costs of candidates for a corresponding region in a comparison image that corresponds to a reference region in a reference image, based on luminance values of the regions. The device also includes a changer configured to change a cost exceeding a threshold to a value higher than the threshold; a synthesizer configured to synthesize a cost of a candidate for a corresponding region for one reference region after the change and a cost of a candidate for a corresponding region for another reference region after the change; and a deriving unit configured to derive a disparity value based on a position of the one reference region and a position of the corresponding region in the comparison image for which the cost after the synthesis is smallest.