Run-Length Stripping for River Network Skeleton Lines

Resolve Bottlenecks,
Find Innovative Solutions
Generate Solutions

Solution Overview

Problem

Existing methods for extracting skeleton lines from complex river networks face challenges such as high memory occupation and low computational efficiency, particularly when dealing with large datasets like those from the Yangtze River Basin.

Innovation Solution

A run-length stripping method is proposed, which involves constructing an empty raster field, compressing binary raster data into run-length linked lists, and using discriminant functions to identify and strip redundant grids, ultimately converting raster data into vector form.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Measurement precision

If raster resolution is increased to improve skeleton line extraction accuracy, then measurement precision is improved, but memory occupation increases significantly

Engineering Contradiction:
Improveskeleton line extraction accuracyVSAvoidmemory occupation
Core Design Contradiction:
Measurement precisionVSQuantity of substance

Solution Approach 1:

The patent divides the large-scale river network raster data into multiple smaller tile units for independent processing. Each tile is processed separately to extract skeleton lines, avoiding the need to load the entire high-resolution raster into memory at once. This segmentation enables high-precision extraction while controlling memory usage within acceptable limits.

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

The patent transforms the problem from direct high-resolution raster processing to a multi-scale approach. By processing at different resolution levels and progressively refining results, the method achieves high measurement precision without requiring the entire high-resolution data to be held in memory simultaneously, effectively adding a temporal/dimensional dimension to the processing workflow.

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

2Measurement precision

If raster resolution is increased to improve skeleton line extraction accuracy, then measurement precision is improved, but computational efficiency decreases

Engineering Contradiction:
Improveskeleton line extraction accuracyVSAvoidcomputational efficiency
Core Design Contradiction:
Measurement precisionVSProductivity

Solution Approach 1:

The patent segments the computational task into independent tile-based units that can be processed in parallel. Each tile undergoes skeleton line extraction independently, allowing for distributed computing and parallel processing. This segmentation maintains high extraction accuracy while significantly improving computational efficiency through parallel execution and reduced data transfer overhead.

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

The patent performs preliminary processing steps such as rasterization and tile division before the main skeleton line extraction. By preparing data in advance and organizing it into manageable tiles with predefined processing workflows, the method reduces computational overhead during the actual extraction process, thereby improving overall computational efficiency without compromising accuracy.

Inventive Principle:
Principle #10Preliminary action

3Productivity

If vector method is used for skeleton line extraction, then computational efficiency is improved, but manufacturing precision worsens due to sawtooth artifacts

Engineering Contradiction:
Improvecomputational efficiencyVSAvoidskeleton line smoothness
Core Design Contradiction:
ProductivityVSManufacturing precision

Solution Approach 1:

The patent segments the river network into tile units and processes each independently using raster-based thinning algorithms. This segmentation allows the use of precise raster methods on smaller domains while maintaining overall computational efficiency. The local processing ensures smooth skeleton lines without the sawtooth artifacts that plague global vector methods.

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

The patent introduces an intermediate raster representation as a mediator between the input vector river network and the final skeleton line output. The vector data is first converted to high-resolution raster, processed through precise thinning algorithms, and then converted back to vector format. This intermediate raster step acts as a mediator that preserves both computational efficiency and manufacturing precision.

Inventive Principle:
Principle #24Intermediary (Mediator)

4Manufacturing precision

If raster method is used for skeleton line extraction, then manufacturing precision is improved, but computational efficiency decreases due to rasterization requirement

Engineering Contradiction:
Improveskeleton line accuracyVSAvoidcomputational efficiency
Core Design Contradiction:
Manufacturing precisionVSProductivity

Solution Approach 1:

The patent segments the raster processing task into independent tile units that can be processed in parallel. By dividing the large raster dataset into smaller tiles, the method reduces memory requirements and enables parallel computation, thereby improving computational efficiency while maintaining the high manufacturing precision of raster-based methods.

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

The patent adds a spatial dimension to the processing by organizing raster data into a tile hierarchy. This multi-level spatial organization allows efficient memory management and parallel processing at different scales, reconciling the conflict between manufacturing precision and computational efficiency by operating at appropriate resolution levels for each processing stage.

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

Data Source

PatentUS12211126B2Run-length stripping method for generating skeleton lines of complex plain river networks
Publication Date: 2025.01.28 ZHEJIANG INST OF HYDRAULICS & ESTUARY(ZHEJIANG INST OF MARINE PLANNING & DESIGN
  • US12211126B2 patent drawing
  • US12211126B2 patent drawing
  • US12211126B2 patent drawing

AI summary

The application relates to a run-length stripping method for generating skeleton lines of complex plain river networks, including following steps: 1. constructing an empty raster field, each raster row generates an empty run-length linked list; 2. completing raster compression on each row, and compressing the continuous grids into run-length units and inserting them into the raster row run-length linked list; 3. establishing a raster field river boundary grid search template; 4. setting two discriminant functions to judge whether a grid on a raster field is a redundant grid; 5. searching all boundary grids along a raster field boundary, and marking and stripping all redundant grids based on two discriminant functions respectively; 6. analyzing whether the boundary grid is stripped, if so, returning to continue stripping, otherwise, entering the next step; 7. converting the non-stripped grid into skeleton line data in vector form.