Design Layer Data Creation for Accurate BRDF Reproduction
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Solution Overview
Problem
Current methods for measuring the bidirectional reflectance distribution function (BRDF) of actual paints struggle to achieve sufficient accuracy, particularly in regular reflection regions, leading to inaccuracies in virtual product appearances and the need for expert tuning or prototype creation.
Innovation Solution
A design layer data creation device that measures and models the reflectance distribution of a paint layer with a clear coat layer, using a reflectance distribution function defined by a linear combination of specular and diffuse reflectance distribution functions, with coupling coefficients obtained to approximate measurement results, reducing measurement error and improving reproducibility.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If a current measuring instrument is used to measure BRDF of actual paint, then the measurement process can be performed, but the measurement accuracy is insufficient in regular reflection regions and substantially horizontal regions
Solution Approach 1:
The reflectance distribution function is segmented into multiple components: a first reflectance distribution function for regular reflection mode, a second reflectance distribution function for specular reflection mode, and a third reflectance distribution function for diffuse reflection mode. Each component models specific reflection characteristics, allowing accurate representation of complex paint appearance including metallic flake effects across different observation angles.
Solution Approach 2:
The reflectance distribution function is constructed as a composite of multiple reflectance distribution functions with different physical meanings. The first function (regular reflection) handles clear coat layer reflection, the second function (specular reflection) handles metallic flake reflection with orientation-dependent characteristics, and the third function (diffuse reflection) handles substrate reflection. This composite approach enables accurate modeling of multi-layer paint systems with metallic pigments.
2Ease of manufacture
If measured BRDF data is used directly to create virtual product appearance, then the process is simple, but the appearance does not reproduce the actual product appearance accurately
Solution Approach 1:
The reflectance distribution function serves as an intermediary between measured reflectance data and virtual product appearance. Instead of using raw measured data directly, the patent fits measurement data to a parametric reflectance distribution function that incorporates physical reflection models. This intermediary representation enables accurate appearance reproduction while maintaining computational efficiency for virtual product visualization.
Solution Approach 2:
The reflectance distribution function uses physical parameters such as metallic flake orientation distribution, flake aspect ratio, and layer thickness to control appearance characteristics. By adjusting these parameters within the reflectance model, the system can accurately reproduce various paint appearances including metallic, pearl, and solid colors without requiring extensive measurement data processing.
3Measurement precision
If expert tuning or prototype creation is performed to improve appearance reproduction, then the accuracy improves, but the time and complexity increase
Solution Approach 1:
The system performs self-service by automatically fitting measurement data to the reflectance distribution function and extracting physical parameters without requiring expert intervention. The automated parameter extraction and model fitting process eliminates the need for manual expert tuning, reducing development time while maintaining high accuracy in virtual product appearance reproduction.
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 allows for the creation of design layer data that accurately represent the BRDF of actual products, enhancing the reproducibility of their appearance without requiring expert tuning or prototype creation, thereby simplifying and shortening the design development process.
Implementation Method 1
measuring instrument which measures reflectance distribution of a design layer configured by a paint color layer having color and formed on the surface of an object, and a transparent clear coat layer superimposed on the paint color layer to cover the paint color layer
Implementation Method 2
a specular reflectance distribution function that represents specular reflectance distribution for defining a specular reflection mode by using, as variables, the incident direction vector and the reflection direction vector of light
Implementation Method 3
a diffuse reflectance distribution function that represents diffuse reflectance distribution for defining a diffuse reflection mode in which the incident direction vector and the reflection direction vector of light at one point of the design layer are used as variables
Data Source
AI summary
There is provided a method and a device, each of which can improve the reproducibility of the appearance of an actual product. A design layer data creation device 100 includes: a measuring instrument 151 which measures a BRDF of a design layer 210 configured by a paint color layer 202 and a clear coat layer 201; and a calculation element 120 which creates design layer data on the basis of an approximate BRDF according to a BRDF model. The calculation element 120 defines the approximate BRDF by respectively obtaining coupling coefficients Ks1, Ks2, and Kd of a specular reflectance distribution function and a diffuse reflectance distribution function so as to approximate measured BRDF data.