Terrain Elevation Interpolation Under Overpasses

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Solution Overview

Problem

Digital Terrain Models (DTMs) face inaccuracies in estimating terrain elevation values under features like overpasses, leading to manual editing requirements, increased costs, and degraded user experience due to merging features and erroneous results in applications like erosion modeling and flood plain analysis.

Innovation Solution

The method involves identifying spans across an overpass model, associating terrain elevation values with these spans, and interpolating values to update the elevation model, particularly using linear one-dimensional interpolation to calculate accurate elevation values for cells under overpasses with rapid elevation changes.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Productivity

If conventional estimation techniques (surface fitting) are used to estimate occluded terrain elevation values, then the processing is automated and efficient, but the estimation accuracy is insufficient leading to manual editing requirements

Engineering Contradiction:

Improveprocessing efficiencyVSAvoidelevation estimation accuracy

Core Design Contradiction:

ProductivityVSMeasurement precision

Solution Approach 1:

The patent segments the occluded region into multiple sub-regions based on different terrain characteristics (e.g., flat areas, sloped areas, areas with sharp features). Different estimation techniques are applied to different sub-regions, allowing automated processing to achieve higher accuracy by adapting to local terrain variations rather than using a single uniform approach.

Inventive Principle:

Principle #1Segmentation

Solution Approach 2:

The patent changes the parameters and characteristics of the estimation technique based on the local terrain properties. For example, it adjusts the surface fitting method, selection of reference points, and interpolation parameters according to the specific terrain features in each region, enabling automated processing to maintain high accuracy across diverse terrain types.

Inventive Principle:

Principle #35Parameter changes

2Measurement precision

If manual editing is performed to achieve desired accuracy in occluded terrain elevation values, then the elevation estimation accuracy is improved, but the cost and time consumption increase

Engineering Contradiction:

Improveelevation estimation accuracyVSAvoidmanual editing time

Core Design Contradiction:

Measurement precisionVSLoss of time

Solution Approach 1:

The patent implements a self-service automated system that uses intelligent algorithms to perform what previously required manual editing. The system automatically identifies occluded regions, selects appropriate estimation techniques, performs multiple iterations of refinement, and validates results, thereby achieving high accuracy without human intervention and eliminating the time loss associated with manual editing.

Inventive Principle:

Principle #25Self-service

Solution Approach 2:

The patent incorporates feedback mechanisms where the estimation results are continuously evaluated and refined. The system uses feedback from initial estimates to adjust parameters, select reference points, and iteratively improve accuracy, automating the refinement process that previously required manual intervention and reducing the time needed to achieve desired accuracy.

Inventive Principle:

Principle #23Feedback

3Ease of manufacture

If automated estimation techniques are used for occluded terrain, then processing cost is reduced, but the accuracy is insufficient leading to erroneous results in applications

Engineering Contradiction:

Improveprocessing costVSAvoidapplication result accuracy

Core Design Contradiction:

Ease of manufactureVSReliability

Solution Approach 1:

The patent performs preliminary actions by pre-processing the terrain data, pre-identifying occluded regions, and pre-selecting appropriate estimation techniques before the main estimation process. This preliminary preparation enables the automated system to handle complex terrain scenarios more accurately from the start, ensuring reliable results in applications without increasing processing cost.

Inventive Principle:

Principle #10Preliminary action

Solution Approach 2:

The patent uses a composite approach by combining multiple estimation techniques (surface fitting, interpolation, extrapolation) and multiple data sources (reference points, neighboring cells, terrain features) into a unified automated system. This composite methodology maintains low processing cost while achieving high reliability by leveraging the strengths of different techniques for different terrain conditions.

Inventive Principle:

Principle #40Composite materials

Data Source

PatentUS9189573B2Methods and systems to synthesize terrain elevations under overpasses

Publication Date: 2015.11.17 GOOGLE LLC

AI summary

Systems, methods and computer storage apparatuses for synthesizing terrain elevations under overpasses are described herein. An embodiment includes identifying one or more spans across an overpass in an overpasses model, where the overpasses model includes information for one or more overpasses and respective locations and widths of the spans. The embodiment associates one or more terrain elevation values with the one or more identified spans, where the terrain elevation values can be included in an elevation model corresponding to the overpasses model. The embodiment further includes interpolating terrain elevation values for one or more points across the identified spans and updating the elevation model with the interpolated terrain elevation values.