Electronic Leveling Apparatus with Variable Focus Camera

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Solution Overview

Problem

Conventional electronic leveling apparatuses are time-consuming and inaccurate in aligning the leveling staff with the optical axis, leading to difficulties in measuring height differences due to superimposed light beams and incorrect image analysis.

Innovation Solution

An electronic leveling apparatus with a camera and telescope system, where the camera's optical system has a deeper focus than the telescope's, allowing for automated alignment and accurate identification of the leveling staff through picture analysis, and controlled rotation to ensure precise optical axis alignment.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Productivity

If manual alignment of the leveling staff with the optical axis is used, then the apparatus structure remains simple, but the measurement process becomes time-consuming and accuracy deteriorates

Engineering Contradiction:
Improvemeasurement speedVSAvoidapparatus structure
Core Design Contradiction:
ProductivityVSDevice complexity

Solution Approach 1:

The patent changes the depth of focus parameter of the optical system by introducing a variable focus lens that can switch between two focal states. In the first focal state, the system achieves a deeper depth of focus to capture the entire leveling staff for automated alignment. In the second focal state, it provides a narrower depth of focus for precise height difference measurement, thereby resolving the contradiction between automated alignment speed and measurement precision

Inventive Principle:
Principle #35Parameter changes

Solution Approach 2:

The system enables self-service automated alignment by using the camera to capture images of the leveling staff, processing these images through image analysis algorithms to automatically determine staff position and orientation, and controlling the rotation actuator to align the optical axis with the staff without manual intervention, thus dramatically improving measurement speed

Inventive Principle:
Principle #25Self-service

2Extent of automation

If a reflector and light beam system is used for automated alignment, then alignment automation improves, but the light beam superimposes on the measurement image causing accuracy to deteriorate

Engineering Contradiction:
Improvealignment automationVSAvoidheight difference accuracy
Core Design Contradiction:
Extent of automationVSMeasurement precision

Solution Approach 1:

The patent extracts and removes the reflector and light beam emission/reception means from the leveling apparatus. Instead, it uses a camera to capture images of the leveling staff and processes these images through image analysis to achieve automated alignment. This eliminates the harmful light beam superposition on the measurement image while maintaining alignment automation, thus resolving the contradiction between automation and measurement precision

Inventive Principle:
Principle #2Taking out (Extraction)

Solution Approach 2:

The patent replaces the optical-mechanical light beam alignment system with an image-based computational alignment system. The camera captures the staff position, image processing algorithms analyze the staff location and orientation, and the results guide the rotation actuator for alignment. This substitution eliminates the light beam interference problem while achieving automated alignment through computational methods

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

3Measurement precision

If the optical system uses a narrow depth of focus for precise measurement, then measurement accuracy improves, but the ability to locate and align with the leveling staff automatically deteriorates

Engineering Contradiction:
Improveheight difference precisionVSAvoidstaff location detection
Core Design Contradiction:
Measurement precisionVSDifficulty of detecting and measuring

Solution Approach 1:

The patent introduces a variable focus lens that can dynamically switch between two focal states. In the first focal state, the system provides a deeper depth of focus that allows the entire leveling staff to be captured in focus, enabling easy automated location and alignment. In the second focal state, it provides a narrower depth of focus for precise height difference measurement. This dynamic adjustment resolves the contradiction between detection capability and measurement precision

Inventive Principle:
Principle #15Dynamics

Solution Approach 2:

The patent segments the measurement process into two distinct phases with different focal settings. Phase 1 uses a deeper depth of focus for staff detection, localization, and alignment. Phase 2 switches to a narrower depth of focus for precise height difference measurement. This temporal segmentation allows each phase to optimize for its specific function, resolving the contradiction between detection and measurement requirements

Inventive Principle:
Principle #1Segmentation

Data Source

PatentEP2047212B1Electronic leveling apparatus and method
Publication Date: 2012.04.04 TRIMBLE JENA
  • EP2047212B1 patent drawingFigure 1
  • EP2047212B1 patent drawingFigure 2A~2B
  • EP2047212B1 patent drawingFigure 3~4

AI summary

An electronic leveling apparatus for optically measuring a height difference relative to a leveling staff comprises a telescope, a camera fixed to the telescope, a first actuator for rotating both said telescope and said camera in a horizontal plane about a fixed vertical axis of the apparatus, and a controller. The camera has a depth of focus that is at least twice a depth of focus of the telescope. The controller uses a first output signal from said telescope to output a leveling signal representing a detected height difference. The controller uses a second output signal from said camera to identify a representation of a leveling staff and to control the first actuator based on the identified representation of the leveling staff . Furthermore, a method for optically measuring a height difference of an electronic leveling apparatus relative to a leveling staff is provided.