Geodesic Measuring Device Microlens Array Depth of Field

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Solution Overview

Problem

Geodetic surveying devices face challenges in quickly, precisely, and reliably aiming at targets due to limitations in focusing optics, which result in inefficiencies and inaccuracies, especially when dealing with objects at different distances or obstructed views.

Innovation Solution

The integration of a microlens array with diffractive and/or refractive optical elements allows for multiple focal lengths on an image sensor, enabling a large depth of field and simultaneous imaging of objects at various distances, eliminating the need for refocusing and reducing mechanical errors.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Measurement precision

If a telescopic sight with focusing optics is used to aim at the target, then the instrument can capture images of the target, but the device requires manual or automated refocusing when dealing with objects at different distances, which reduces productivity and introduces mechanical errors

Engineering Contradiction:
Improvetargeting accuracyVSAvoidmeasurement speed
Core Design Contradiction:
Measurement precisionVSProductivity

Solution Approach 1:

The patent divides the imaging function into multiple focal length channels by integrating a microlens array with individual lenses of different focal lengths. Each lens captures image fragments from different depth ranges simultaneously, eliminating the need for sequential refocusing operations while maintaining accurate targeting across varying distances

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

The patent adds a dimensional aspect to the imaging system by incorporating depth information through multiple focal lengths. Instead of a single two-dimensional image plane, the system captures three-dimensional light field information, enabling simultaneous focus on objects at different distances without mechanical adjustment

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

2Adaptability or versatility

If a telescopic sight with a single focal length is used, then the optical system remains simple, but the depth of field is limited and cannot simultaneously capture sharp images of objects at various distances

Engineering Contradiction:
Improvedepth of field rangeVSAvoidoptical system complexity
Core Design Contradiction:
Adaptability or versatilityVSDevice complexity

Solution Approach 1:

The patent merges multiple optical functions into a single integrated microlens array structure. Individual lenses with different focal lengths are combined in one array, allowing the system to achieve extended depth of field and multi-focal imaging without adding separate optical assemblies or complex mechanical focusing mechanisms

Inventive Principle:
Principle #5Merging (Combining)

Solution Approach 2:

The microlens array serves multiple functions simultaneously: it acts as both the primary imaging element and the depth-multiplexing component. The same optical structure enables capturing images at multiple focal distances, eliminating the need for separate focusing mechanisms while expanding the operational depth range

Inventive Principle:
Principle #6Universality (Multi-functionality)

3Ease of operation

If automated focusing mechanisms are implemented, then the instrument can adjust focus automatically, but the mechanical components introduce potential errors and reduce reliability

Engineering Contradiction:
Improvefocus adjustmentVSAvoidmechanical error susceptibility
Core Design Contradiction:
Ease of operationVSReliability

Solution Approach 1:

The patent replaces the mechanical focusing system with a purely optical solution. Instead of using motors or mechanical actuators to move focusing elements, the system uses a fixed microlens array with multiple focal lengths to achieve automatic focus on different depth planes, eliminating mechanical wear, backlash, and positioning errors

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

Solution Approach 2:

The microlens array automatically directs light from different depth ranges to appropriate image fragments without requiring external control signals or mechanical adjustment. The optical structure itself performs the focusing function passively, improving reliability by removing active mechanical components that could fail

Inventive Principle:
Principle #25Self-service

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

This solution enables rapid and accurate targeting by providing a clear and sharp image of objects at different distances within a large depth range, improving productivity and accuracy by eliminating the need for manual focusing and reducing mechanical errors.

Implementation Method 1

microlens array with a plurality of two-dimensionally defined diffractive and/or refractive optical elements

Methodology Applied
Scientific EffectRefraction: Refraction

Implementation Method 2

microlens array with a plurality of two-dimensionally defined diffractive and/or refractive optical elements

Methodology Applied
Scientific EffectDiffraction: Diffraction

Data Source

PatentEP2835613B1Geodesic measuring device with a microlens array
Publication Date: 2019.01.16 HEXAGON TECH CENT GMBH
  • EP2835613B1 patent drawingFigure 1a~1b
  • EP2835613B1 patent drawingFigure 2a~2b
  • EP2835613B1 patent drawingFigure 3~4

AI summary

The invention relates to a geodetic surveying instrument with a beam source for generating measuring radiation, a base defining a vertical axis, a support carrying a targeting unit and defining a tilting axis, wherein the support is rotatably arranged at the base and relative to the base about the vertical axis, and the targeting unit is rotatably arranged relative to the support about the tilting axis, and an angle and distance measurement function. Furthermore, an image acquisition unit (16) for acquiring images of an object (10) in a field of view defined by the image acquisition unit and a control and processing unit are provided. The image acquisition unit (16) has at least one image sensor (8) and a microlens array (7) with a plurality of two-dimensionally defined diffractive and/or refractive optical elements (7'), wherein, during a measurement process using the image sensor (8), the respective diffractive and/or refractive elements are defined.image pieces generated by refractive optical elements (7') and representing at least parts of the object (10) can be detected and an image data set representing the image pieces can be generated.