Multi-angle Spectral Imaging for Complex Surface Measurement

Resolve Bottlenecks,
Find Innovative Solutions
Generate Solutions

Solution Overview

Problem

Existing methods for multi-angle spectral imaging struggle with accurate and efficient measurement of complex surface structures, particularly those with interference effect materials, due to limitations in capturing wide color gamut and high dynamic range, and require extensive time and resources for data collection and analysis.

Innovation Solution

A multi-angle spectral imaging method and apparatus using a two-dimensional image sensor with illumination from multiple angles, combined with spectral light sources and band-pass filters, allows for precise measurement of spectral information at each pixel, converting it into color numeric values for analysis in a three-dimensional color space, and incorporates three-dimensional geometry measurement to correct optical geometrical conditions.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Measurement precision

If multi-angle spectral imaging is performed using conventional methods, then spectral information can be acquired, but measurement precision and accuracy are insufficient for complex surface structures with interference effect materials

Engineering Contradiction:
Improvespectral measurement accuracyVSAvoidmeasurement system complexity
Core Design Contradiction:
Measurement precisionVSDevice complexity

Solution Approach 1:

The patent segments the illumination function into multiple independent light sources positioned at different angles (e.g., 0°, 45°, 135°). Each light source illuminates the sample from a specific direction, enabling multi-angle spectral imaging without requiring complex rotating mechanisms. This segmentation approach improves measurement precision for complex surfaces while keeping the device structure relatively simple and stationary.

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

The patent introduces angular dimension by arranging light sources at multiple angles around the sample. Instead of using a single illumination direction, the system captures spectral information from multiple angular perspectives simultaneously, enhancing the ability to characterize complex surface structures with interference effect materials.

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

2Productivity

If conventional single-angle or limited-angle measurement is used, then measurement time is reduced, but the ability to capture wide color gamut and high dynamic range is insufficient

Engineering Contradiction:
Improvemeasurement speedVSAvoidcolor gamut and dynamic range
Core Design Contradiction:
ProductivityVSLoss of information

Solution Approach 1:

The patent merges multiple spectral images acquired under different illumination angles into a comprehensive dataset. By combining information from light sources at various angles, the system captures a wider color gamut and higher dynamic range than single-angle measurement, while maintaining efficient simultaneous acquisition that preserves measurement speed.

Inventive Principle:
Principle #5Merging (Combining)

Solution Approach 2:

The system creates multiple copies of the spectral measurement process at different angles. Instead of sequentially measuring at one angle and moving to another, multiple angular measurements are performed concurrently, effectively copying the measurement process across different illumination geometries to capture complete color information without time loss.

Inventive Principle:
Principle #26Copying

3Device complexity

If illumination from a single angular position greater than 40 degrees is used, then device structure is simplified, but distortion near the rim of the imaging lens increases

Engineering Contradiction:
Improvelighting device structureVSAvoidimage distortion
Core Design Contradiction:
Device complexityVSManufacturing precision

Solution Approach 1:

The patent employs asymmetric arrangement of multiple light sources at specific angles (0°, 45°, 135°) rather than using a single off-center light source. This asymmetric multi-point illumination compensates for lens distortion by providing balanced angular coverage, improving image quality across the entire field of view while maintaining a relatively simple stationary device structure.

Inventive Principle:
Principle #4Asymmetry

4Measurement precision

If extensive data collection and analysis is performed to achieve accurate color evaluation, then measurement precision is improved, but time and resource consumption increase significantly

Engineering Contradiction:
Improvecolor evaluation accuracyVSAvoiddata processing time
Core Design Contradiction:
Measurement precisionVSLoss of time

Solution Approach 1:

The patent performs preliminary organization of multi-angle spectral data during the acquisition phase. By systematically capturing and structuring spectral information from multiple angles simultaneously, the data is prepared in advance for efficient processing, reducing the time and computational resources needed for subsequent analysis while maintaining high measurement precision.

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 approach enables efficient, accurate, and high-resolution measurement of complex surface structures, reducing distortion and allowing for flexible data processing, thereby improving the speed and precision of color evaluation and analysis.

Implementation Method 1

a two-dimensional image sensor which takes an image in a direction perpendicular to the sample surface to be measured

Methodology Applied
Scientific EffectLight reflection: Reflection

Implementation Method 2

spectral light sources and band-pass filters

Methodology Applied
Scientific EffectOptical filtering: Filter (optical)

Implementation Method 3

illumination from multiple angles, combined with spectral light sources

Methodology Applied
Scientific EffectLight emission: Light

Data Source

PatentEP2840368B1Variable angle spectroscopic imaging measurement method and device therefor
Publication Date: 2023.01.18 OFFICE COLOR SCI
  • EP2840368B1 patent drawingFigure 1~2
  • EP2840368B1 patent drawingFigure 3~4
  • EP2840368B1 patent drawingFigure 5

AI summary

A lighting device 10 that emits illumination light from two or more angular directions onto a sample surface 2 to be measured, an imaging optical lens 8, and a monochrome two-dimensional image sensor 4 are provided. This configuration provides a method and an apparatus that take a two-dimensional image of the sample surface 2 to be measured at each measurement wavelength and accurately measure multi-angle and spectral information on each of all pixels in the two-dimensional image in a short time. In particular, a multi-angle spectral imaging measurement method and apparatus that have improved accuracy and usefulness are provided.