Laser Range Finder Parallax Error Correction

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Solution Overview

Problem

Laser removal measuring devices face challenges in accurately determining distance due to parallax errors, especially at closer ranges, which affect the positioning of the target point marking on the device's screen, leading to incorrect alignment and potential misoperation.

Innovation Solution

The device corrects parallax errors by overlaying the marking of the target point with an estimated distance, using trigonometric functions and pixel-level adjustments, ensuring accurate positioning and real-time image updates, even at smaller distances, thereby enhancing operational accuracy and ease of use.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Measurement precision

If a laser range finder is used for distance measurement, then distance can be determined, but parallax errors occur at closer ranges causing incorrect positioning of the target point marking on the screen

Engineering Contradiction:
Improvedistance measurement accuracyVSAvoidtarget point alignment accuracy
Core Design Contradiction:
Measurement precisionVSEase of operation

Solution Approach 1:

The system performs preliminary actions by capturing an image of the target environment before final distance measurement, then uses this image to calculate and apply parallax correction to the target point marking position based on the estimated distance and camera-transmission device geometric relationship

Inventive Principle:
Principle #10Preliminary action

Solution Approach 2:

The system implements feedback by continuously monitoring the target environment through the camera, calculating parallax errors based on the geometric relationship between the camera and transmission device, and adjusting the target point marking position on the screen to compensate for these errors, thereby improving alignment accuracy

Inventive Principle:
Principle #23Feedback

2Ease of operation

If the camera and transmission device are positioned close together in the housing, then the device can be made compact and easier to handle, but parallax errors increase affecting measurement accuracy

Engineering Contradiction:
Improvedevice portabilityVSAvoiddistance measurement accuracy
Core Design Contradiction:
Ease of operationVSMeasurement precision

Solution Approach 1:

The system converts the harmful parallax error caused by close positioning of the camera and transmission device into a calculable geometric relationship. By using the known positions and optical axes of both devices, the system calculates the parallax offset and applies it as a correction to the target point marking, thereby eliminating the measurement error while maintaining compact device design

Inventive Principle:
Principle #22Blessing in disguise (Convert harm into benefit)

3Ease of operation

If parallax correction is applied to the target point marking, then alignment accuracy improves, but computing power requirements and processing time increase

Engineering Contradiction:
Improvetarget point alignment accuracyVSAvoidcomputing power requirements
Core Design Contradiction:
Ease of operationVSDevice complexity

Solution Approach 1:

The system performs preliminary calculations of the parallax correction factors based on the fixed geometric relationship between the camera and transmission device. These correction factors are pre-computed and stored, allowing for rapid application during operation without requiring complex real-time calculations, thus reducing computing power requirements while maintaining alignment accuracy

Inventive Principle:
Principle #10Preliminary action

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 correction method allows for intuitive and precise operation, preventing incorrect targeting and ensuring accurate alignment of the laser beam, with high processing speed and low computing power requirements, enabling efficient and accurate distance measurement.

Implementation Method 1

send time -modulated laser radiation in the form of a laser beam towards a target object

Methodology Applied
Scientific EffectLaser: Laser

Implementation Method 2

A laser radiation, which is reflected by the targeted target object, is at least partially detected by the laser removal measuring device

Methodology Applied
Scientific EffectLight reflection: Reflection

Implementation Method 3

the light term can also be determined from a flight time determination

Methodology Applied
Scientific EffectTime of flight: Time of Flight

Implementation Method 4

a camera for recording at least one image of a target environment of a respective target point

Methodology Applied
Scientific EffectImage recording: Photography

Data Source

PatentEP3679402B1Method for operation of a laser range finder
Publication Date: 2022.10.12 ROBERT BOSCH GMBH
  • EP3679402B1 patent drawingFigure 1
  • EP3679402B1 patent drawingFigure 2(a)~2(c)
  • EP3679402B1 patent drawingFigure 3(a)~3(c)

AI summary

The proposed method for operating a laser distance measuring device (10), in particular a hand-held laser distance measuring device (10), is based on a method in which laser radiation (20) is emitted to a target point (38) by means of an emitter unit, laser radiation (28) reflected back from the target point (38) is detected by a receiver unit (36) with a detection surface (32), at least one image (42,42a,42b) of at least one target environment (44) of the target point (38) is captured by at least one camera (40), and a representation (46,46a,46b) of the image (42,42a,42b), overlaid with a marking (48, 48a, 48b) of the target point (38), is displayed on a screen (14) of the laser distance measuring device (10). According to the invention, a parallax error in the representation (46,46a,46b) of the image (42,42a,42b), overlaid with a marking (48, 48a, 48b) of the target point (38), is corrected according to an estimated distance to the target point (38). The invention also relates to a corresponding laser distance measuring device (10).