Scanning Beam Device Calibration Using Image Pattern Comparison

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Solution Overview

Problem

Scanning beam devices face positional inaccuracies due to environmental, manufacturing, and electronic imperfections, leading to image distortion, especially when operating near resonance frequencies, and existing calibration methods using photosensitive position sensors are costly, limited in field of view, and prone to stray light interference.

Innovation Solution

A method and apparatus for calibrating scanning beam devices by acquiring and comparing images of a calibration pattern with a representation of the expected scan pattern, adjusting drive signals and pixel positions to account for differences between actual and expected positions, without the need for photosensitive position sensors, using a photodetector and image generation logic to generate images at expected positions and calibrate the device.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Measurement precision

If photosensitive position sensors are used for calibration, then measurement precision is improved, but device complexity and cost increase

Engineering Contradiction:
Improveposition measurement precisionVSAvoidcalibration device complexity
Core Design Contradiction:
Measurement precisionVSDevice complexity

Solution Approach 1:

The patent uses a camera to capture an image of the calibration pattern as a copy of the actual beam positions, comparing it with the expected scan pattern representation. This replaces complex photosensitive position sensors with a simpler imaging system that achieves the same calibration objective through image processing rather than direct optical sensing.

Inventive Principle:
Principle #26Copying

Solution Approach 2:

The patent replaces the mechanical/optical photosensitive position sensor system with a digital imaging and image processing system. The camera captures positions visually, and software algorithms compare the captured image with the expected pattern to determine calibration corrections, eliminating the need for specialized photosensitive sensors.

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

2Measurement precision

If photosensitive position sensors are used for calibration, then measurement precision is improved, but manufacturing cost increases

Engineering Contradiction:
Improveposition measurement precisionVSAvoidmanufacturing cost
Core Design Contradiction:
Measurement precisionVSEase of manufacture

Solution Approach 1:

The patent uses a standard camera to capture an image of the calibration pattern, creating a visual copy of beam positions that can be processed digitally. This approach uses off-the-shelf imaging components rather than specialized photosensitive sensors, significantly reducing manufacturing cost while maintaining calibration precision.

Inventive Principle:
Principle #26Copying

Solution Approach 2:

The patent employs a standard camera and digital image processing instead of expensive, specialized photosensitive position sensors. The calibration pattern itself can be a simple, inexpensive physical target that doesn't need to be durable, as it only needs to be visible to the camera for the calibration process.

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

3Measurement precision

If photosensitive position sensors are used for calibration, then measurement precision is improved, but field of view is limited

Engineering Contradiction:
Improveposition measurement precisionVSAvoidfield of view
Core Design Contradiction:
Measurement precisionVSArea of stationary object

Solution Approach 1:

The patent transitions from point-by-point position sensing (1D or limited 2D) to a full 2D image capture approach. The camera captures the entire calibration pattern field of view simultaneously in an image, allowing calibration across a much larger area without being constrained by sensor array limitations.

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

Solution Approach 2:

The camera-based system serves multiple functions: it captures the entire field of view, records beam positions, and provides visual documentation. A single camera component replaces multiple specialized sensors, achieving both wide field of view and precise position measurement through its imaging capability.

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

4Measurement precision

If photosensitive position sensors are used for calibration, then measurement precision is improved, but susceptibility to stray light increases

Engineering Contradiction:
Improveposition measurement precisionVSAvoidstray light interference
Core Design Contradiction:
Measurement precisionVSObject-affected harmful factors

Solution Approach 1:

The patent uses a camera to capture a visual copy of the calibration pattern and beam positions. Standard camera sensors are less susceptible to stray light interference compared to specialized photosensitive position sensors, and the image processing algorithms can filter out stray light effects by looking for the specific calibration pattern features rather than raw optical signals.

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

This approach reduces image distortion by accurately accounting for positional differences, improving image quality without the drawbacks of photosensitive position sensors, such as cost and limited field of view, and simplifies the calibration process.

Implementation Method 1

scanning a cantilevered optical fiber in a scan pattern including moving the cantilevered optical fiber within a Q factor of a resonant frequency of the cantilevered optical fiber

Methodology Applied
Scientific EffectResonance: Resonance

Implementation Method 2

a photodetector to detect light backscattered from the calibration pattern at different times during the scan pattern

Methodology Applied
Scientific EffectBackscattering: Scattering

Data Source

PatentEP2099353B1Scanning beam device calibraton
Publication Date: 2018.09.05 UNIV OF WASHINGTON
  • EP2099353B1 patent drawingFigure 1
  • EP2099353B1 patent drawingFigure 2
  • EP2099353B1 patent drawingFigure 3~4

AI summary

Scanning beam device calibration using a calibration pattern is disclosed. In one aspect, a method may include acquiring an image of a calibration pattern using a scanning beam device. The acquired image may be compared with a representation of the calibration pattern. The scanning beam device may be calibrated based on the comparison. Software and apparatus to perform these and other calibration methods are also disclosed.