Point Cloud Matching via Logical Arrays and Multi-Resolution Pyramids

Resolve Bottlenecks,
Find Innovative Solutions
Generate Solutions

Solution Overview

Problem

Current point cloud comparison and matching algorithms are computationally intensive and complex, requiring large data structures like octrees and relying on computer vision techniques, which are inefficient and processor-intensive, especially when dealing with varying point densities and orientations.

Innovation Solution

The use of logical arrays for comparing and matching point clouds, involving multi-resolution comparison through voxelization, angular and translation alignment, and logical operations to generate compact and efficient comparison results, allowing for faster processing and reduced memory usage.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Measurement precision

If computer vision-based approaches with octree data structures are used for point cloud comparison, then spatial information accuracy is maintained, but processing time and computational complexity increase significantly

Engineering Contradiction:
Improvespatial information accuracyVSAvoidprocessing time
Core Design Contradiction:
Measurement precisionVSLoss of time

Solution Approach 1:

The point cloud data is segmented into multiple resolution levels using a pyramid structure, where each level represents the same spatial information at different granularities. This allows the algorithm to perform comparisons at coarse resolutions first for quick matching, then refine at finer resolutions only where needed, dramatically reducing overall processing time while preserving spatial accuracy.

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

The invention dynamically selects the appropriate resolution level for comparison based on the required accuracy and computational resources. The multi-resolution pyramid allows the system to adaptively choose between fast coarse matching and accurate fine matching, optimizing the trade-off between processing speed and spatial information accuracy for different application scenarios.

Inventive Principle:
Principle #15Dynamics

2Reliability

If feature-based matching with normal vector calculation is used, then matching accuracy is improved, but processor intensity and computational load increase

Engineering Contradiction:
Improvematching accuracyVSAvoidprocessor intensity
Core Design Contradiction:
ReliabilityVSPower

Solution Approach 1:

The invention extracts only the essential spatial occupancy information from point clouds, representing each point cloud as a binary occupancy grid that indicates which spatial locations are occupied. This extracted representation captures the fundamental geometric structure needed for matching while eliminating computationally expensive features like normal vectors, surface curvature, and other detailed geometric properties.

Inventive Principle:
Principle #2Taking out (Extraction)

Solution Approach 2:

The invention changes the parameter representation from continuous geometric features (normal vectors, curvature) to discrete occupancy states (occupied/not occupied). This parameter transformation simplifies the data structure and enables efficient bitwise operations for comparison, reducing processor intensity while maintaining matching reliability through the multi-resolution pyramid approach.

Inventive Principle:
Principle #35Parameter changes

3Measurement precision

If detailed feature derivation and statistical distance calculation are performed, then matching precision is enhanced, but device complexity and memory requirements increase

Engineering Contradiction:
Improvematching precisionVSAvoiddata structure complexity
Core Design Contradiction:
Measurement precisionVSDevice complexity

Solution Approach 1:

The invention creates simplified binary copies of the point cloud data in the form of occupancy grids at multiple resolution levels. These binary representations serve as lightweight proxies for the original detailed point clouds, enabling fast comparison operations using simple bitwise logic while preserving the essential spatial structure needed for accurate matching.

Inventive Principle:
Principle #26Copying

Solution Approach 2:

The invention transforms the problem from comparing complex multi-dimensional feature vectors to comparing simple binary occupancy grids. By changing the dimensional representation from continuous feature space to discrete spatial occupancy space, the algorithm achieves matching precision through the multi-resolution pyramid structure while dramatically reducing data structure complexity and memory requirements.

Inventive Principle:
Principle #17Another dimension (Dimensionality change)

4Measurement precision

If high-resolution point cloud comparison is performed, then spatial detail accuracy is maintained, but data size and memory consumption increase

Engineering Contradiction:
Improvespatial detail accuracyVSAvoiddata size
Core Design Contradiction:
Measurement precisionVSQuantity of substance

Solution Approach 1:

The invention implements a nested multi-resolution pyramid structure where coarse-resolution occupancy grids are embedded within finer-resolution grids. Each level of the pyramid contains the essential spatial information of the level below it at a reduced scale, allowing the system to store and process data at multiple resolutions efficiently without duplicating all information at each level.

Inventive Principle:
Principle #7Nested doll (Nesting)

Solution Approach 2:

The invention applies different levels of spatial detail (quality) to different regions and resolution levels based on the comparison needs. Coarse regions use lower-resolution representations that consume less memory, while critical regions require higher-resolution details. This local quality adjustment optimizes the balance between spatial detail accuracy and data size through the multi-resolution pyramid structure.

Inventive Principle:
Principle #3Local quality

Data Source

PatentUS11106936B2Object point cloud comparison and matching
Publication Date: 2021.08.31 GENERAL ATOMICS CO
  • US11106936B2 patent drawing
  • US11106936B2 patent drawing
  • US11106936B2 patent drawing

AI summary

Point clouds of objects are compared and matched using logical arrays based on the point clouds. The point clouds are azimuth aligned and translation aligned. The point clouds are converted into logical arrays for ease of processing. Then the logical arrays are compared (e.g. using the AND function and counting matches between the two logical arrays). The comparison is done at various quantization levels to determine which quantization level is likely to give the best object comparison result. Then the object comparison is made. More than two objects may be compared and the best match found.