Height Map Stitching Using Weighted Similarity Measures

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Solution Overview

Problem

Existing methods for combining height maps to create a composite map are inefficient and prone to errors due to the need to choose and align templates, which can lead to incorrect overlap regions and measurement artifacts.

Innovation Solution

A method that directly overlaps and shifts entire height maps to determine overlap regions and similarities, using a weighted similarity measure based on feature classification into sharp and smooth features, to accurately stitch the height maps into a composite map.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If template selection and alignment methods are used to combine height maps, then the combining process can be performed, but the process becomes complex and error-prone due to the need to choose appropriate templates and align them correctly

Engineering Contradiction:

Improveaccuracy of overlap region determinationVSAvoidcomplexity of template selection and alignment process

Core Design Contradiction:

ReliabilityVSDevice complexity

Solution Approach 1:

The patent extracts and removes the template selection step from the height map combining process. Instead of selecting templates from height maps and aligning them, the method directly determines overlap regions between the height maps themselves, eliminating the source of errors related to template choice and alignment.

Inventive Principle:

Principle #2Taking out (Extraction)

Solution Approach 2:

The patent inverts the conventional approach by not trying to match templates to find overlap regions, but rather directly analyzing the height maps to determine where they overlap. The similarity determination is performed directly on the height map data in potential overlap regions without intermediate template processing.

Inventive Principle:

Principle #13The other way round (Inversion)

2Reliability

If multiple templates are tested to prevent incorrect combining, then the reliability of height map combination improves, but the measurement time and processing effort increase significantly

Engineering Contradiction:

Improvecorrectness of height map combinationVSAvoidtime for template testing and validation

Core Design Contradiction:

ReliabilityVSLoss of time

Solution Approach 1:

The patent enables the height maps to self-identify their overlap regions through direct similarity analysis. The method uses similarity measures computed directly from the height map data in potential overlap regions, allowing the system to automatically and correctly identify overlap areas without requiring multiple template tests or external validation.

Inventive Principle:

Principle #25Self-service

3Ease of manufacture

If template-based methods are used, then height map combination can be achieved, but measurement artifacts may be introduced due to incorrect template alignment

Engineering Contradiction:

Improveease of height map combinationVSAvoidmeasurement artifacts from misalignment

Core Design Contradiction:

Ease of manufactureVSObject-generated harmful factors

Solution Approach 1:

The patent introduces similarity measures as an intermediary mechanism to objectively determine overlap regions. By using correlation coefficients or other similarity metrics computed from the actual height map data, the method provides an objective criterion for identifying correct overlap regions, eliminating subjective template alignment decisions that could introduce artifacts.

Inventive Principle:

Principle #24Intermediary (Mediator)

Data Source

PatentUS20250189303A1Method for combining height maps and profilometer for the same

Publication Date: 2025.06.12 MITUTOYO CORP

AI summary

The invention relates to a method for measuring a first height map and a second height map of a sample surface with a profilometer and combining the first and second height maps to a composite height map. The invention further relates to a profilometer configured for measuring a first height map and a second height map and combining the first and second height maps to a composite height map.