Digital Leveling Offset Meter Calibration via Image Processing

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Solution Overview

Problem

Conventional leveling meters provide only visual indications and are not suitable for accurately determining angular offsets in fractions of degrees, while high-cost MEMS inclinometers offer the required accuracy.

Innovation Solution

A computerized digital leveling offset meter that uses an imager to capture images of a bubble and a processor to determine angular offsets by fitting functions to pixel distances and corresponding angular offsets, allowing for precise measurement of pitch and roll offsets to fractions of degrees using relatively low-cost hardware.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Measurement precision

If conventional leveling meters are used, then device cost is low, but measurement precision is insufficient (only visual indication, not suitable for fractions of degrees)

Engineering Contradiction:
Improveangular offset measurement precisionVSAvoiddevice complexity
Core Design Contradiction:
Measurement precisionVSDevice complexity

Solution Approach 1:

The patent replaces the conventional mechanical/optical spirit level system with a digital imaging system. An imager captures images of the bubble, and a processor automatically determines angular offsets by analyzing pixel distances and fitting functions to the data. This substitution of mechanical indication with digital image processing achieves fraction-of-degree precision while maintaining relatively simple device structure.

Inventive Principle:
Principle #28Mechanics substitution (Replace mechanical system)

Solution Approach 2:

The patent creates a digital copy of the bubble position through imaging. Instead of directly reading the physical bubble position visually, the system captures an image of the bubble, extracts its position in pixel coordinates, and uses this digital representation to calculate angular offsets. This copying approach enables precise measurement without complex mechanical sensors.

Inventive Principle:
Principle #26Copying

2Measurement precision

If MEMS inclinometers are used, then measurement precision is high (fractions of degrees), but device cost is high (several thousands of dollars)

Engineering Contradiction:
Improveangular offset measurement precisionVSAvoiddevice complexity
Core Design Contradiction:
Measurement precisionVSDevice complexity

Solution Approach 1:

The patent uses a relatively simple and inexpensive imager (such as a camera module) instead of expensive MEMS inclinometers. The imager captures images of the bubble, and through digital processing, achieves the same measurement precision as high-cost MEMS devices. This approach replaces expensive specialized sensors with cheaper, more common imaging components.

Inventive Principle:
Principle #27Cheap short-living objects (Disposable)

Solution Approach 2:

The patent replaces expensive mechanical/MEMS-based angular sensors with an optical imaging system combined with digital image processing. By capturing bubble position through imaging and calculating angular offsets from pixel distances using function fitting, the system achieves high precision without relying on costly MEMS technology.

Inventive Principle:
Principle #28Mechanics substitution (Replace mechanical system)

3Measurement precision

If visual indication is used, then device complexity is low, but measurement precision is insufficient (cannot determine actual angular offset in fractions of degrees)

Engineering Contradiction:
Improveangular offset measurement precisionVSAvoidautomation level
Core Design Contradiction:
Measurement precisionVSExtent of automation

Solution Approach 1:

The patent replaces manual visual reading with automated digital image processing. The processor automatically captures images of the bubble, determines pixel distances from the center, fits functions to the data, and calculates angular offsets without human intervention. This automation enables fraction-of-degree precision while keeping the overall device structure simple.

Inventive Principle:
Principle #28Mechanics substitution (Replace mechanical system)

Solution Approach 2:

The patent creates a digital record of the bubble position through imaging. Instead of relying on human visual interpretation of the physical bubble position, the system captures an image, extracts precise pixel coordinates, and uses this digital copy for automated calculation of angular offsets, eliminating the need for manual reading while achieving high precision.

Inventive Principle:
Principle #26Copying

Applied Scientific Principles

This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.

Function Achieved in This Case

Accurately measures angular offsets to fractions of degrees with low-cost hardware, overcoming the limitations of conventional leveling meters and high-cost MEMS inclinometers.

Implementation Method 1

an imager configured to image the one or more bubbles and store corresponding image data

Methodology Applied
Scientific EffectLight reflection: Reflection

Data Source

PatentEP3516331B1Method of calibrating a computerized leveling offset meter
Publication Date: 2021.07.21 ISRAEL AEROSPACE IND LTD
  • EP3516331B1 patent drawingFigure 1
  • EP3516331B1 patent drawingFigure 2
  • EP3516331B1 patent drawingFigure 3

AI summary

A method of calibrating a levelling offset meter (LOM) for calculating the angular offset between a plane parallel to the LOM and a predetermined reference plane, the LOM comprises a bull's eye spirit level having a bubble and a processor coupled to an image, comprising: capturing, by the imager, a plurality of images of the spirit level associated with a respective plurality of known angular offsets; calculating in respect of each image a pixel distance from the bubble center to a predetermined zero offset pixel, thereby obtaining a plurality of pixel distances, each pixel distance associated with a known angular offset; fitting a function to a plurality of pairs of values, each pair of values comprising a pixel distance and its associated known angular offset; and storing the function in a memory.