Flat Panel Light Source Reflection Measurement

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Solution Overview

Problem

Existing techniques for measuring the reflection characteristics of objects require complex configurations involving mechanisms like motors and arms to move light sources and reception units, making them cumbersome and difficult to implement.

Innovation Solution

A measurement apparatus and method that utilize a flat panel display with independently controllable point light sources and a digital camera with a telecentric lens to image the object, modulating light sources out of phase to identify the main illumination direction without moving parts, allowing for a simpler configuration.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Measurement precision

If a mechanism such as a motor and an arm is used to move the light reception unit to multiple positions, then the reflection characteristic can be measured at multiple angles, but the configuration becomes complicated

Engineering Contradiction:
Improvereflection characteristic measurementVSAvoidconfiguration complexity
Core Design Contradiction:
Measurement precisionVSDevice complexity

Solution Approach 1:

The patent replaces the mechanical positioning system (motor and arm) with a fixed array of light reception units arranged at multiple positions. Each unit continuously captures reflected light from its specific angle, eliminating the need for mechanical movement while maintaining multi-angle measurement capability. This substitution of mechanical system with a static sensor array directly resolves the contradiction between measurement precision and device complexity.

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

2Adaptability or versatility

If a mechanism is used to move the light source and light reception unit positions, then multiple measurement positions can be achieved, but the apparatus becomes more complex and harder to implement

Engineering Contradiction:
Improvemulti-position measurement capabilityVSAvoidease of implementation
Core Design Contradiction:
Adaptability or versatilityVSEase of manufacture

Solution Approach 1:

The patent divides the light reception function into multiple independent units positioned at different locations around the measurement object. Each unit operates independently at its fixed position, collectively providing comprehensive multi-angle coverage. This segmentation of the reception function into distributed static units achieves versatile multi-position measurement capability while significantly improving ease of manufacture compared to a single moving unit.

Inventive Principle:
Principle #1Segmentation

3Measurement precision

If mechanical mechanisms are employed to adjust positions, then accurate angular measurement is possible, but the device complexity increases

Engineering Contradiction:
Improveangular measurement accuracyVSAvoidmechanical mechanism complexity
Core Design Contradiction:
Measurement precisionVSDevice complexity

Solution Approach 1:

The light reception units are pre-positioned at precisely calculated angular locations around the measurement object before the measurement process begins. This preliminary arrangement of receivers at optimal positions eliminates the need for dynamic mechanical adjustment during measurement, maintaining high angular measurement precision while reducing device complexity by removing motors, arms, and control systems.

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

Enables accurate measurement of reflection characteristics with reduced complexity, improving measurement efficiency and ease of implementation by eliminating the need for mechanical movements, and providing a more compact setup.

Implementation Method 1

a plurality of point light sources arranged on a surface of the display are caused to emit light while modulating the point light sources out of phase with one another

Methodology Applied
Scientific EffectLight emission and modulation: Light

Implementation Method 2

a digital camera with a telecentric lens to image the object

Methodology Applied
Scientific EffectOptical imaging: Lens

Implementation Method 3

Some objects have a surface that appears differently according to an illumination direction of a light source and an observation direction. This is because reflected light leading from light with which the surface of the object is irradiated has a different characteristic according to the illumination direction and the observation direction.

Methodology Applied
Scientific EffectSpecular reflection: Reflection

Data Source

PatentEP3196633B1Apparatus and method for measuring a reflection characteristic of an object
Publication Date: 2021.11.17 CANON KK
  • EP3196633B1 patent drawingFigure 1A~1B
  • EP3196633B1 patent drawingFigure 2A
  • EP3196633B1 patent drawingFigure 2B

AI summary

A measurement apparatus includes an illumination unit configured to illuminate a measurement object with use of a plurality of point light sources configured to emit light based on illumination images modulated according to periodic functions out of phase with one another, an imaging unit configured to image the measurement object illuminated based on the illumination images, a first calculation unit configured to calculate phase information of a change in a luminance value at each of pixels based on a plurality of images captured by the imaging unit, and a first acquisition unit configured to acquire, from the phase information, a maximum reflection direction where a reflection direction is maximized on the measurement object.