Print Data Generation for Anisotropic Surface Scattering Reproduction
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Solution Overview
Problem
Existing techniques for reproducing surface scattering in printed images, such as those described in PTL 1 and NPL 1, face challenges in accurately matching the bidirectional reflectance distribution function (BRDF) of a material using a limited number of color materials, leading to insufficient reproduction of the object's appearance and anisotropic reflection.
Innovation Solution
A print data generating apparatus that obtains a BRDF model group for each color and incident light angle, calculates reflection distribution, and outputs color and form data to accurately reproduce the object's surface scattering, reducing the number of dimensions to be calculated and enabling high-fidelity reproduction.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If optimization is used to match surface scattering in any light source direction and any viewing direction, then the reproduction fidelity is improved, but the calculation complexity and number of dimensions increase greatly
Solution Approach 1:
The patent segments the complex BRDF matching problem by dividing the surface scattering reproduction into discrete angular intervals. Instead of optimizing for all possible incident and viewing directions simultaneously, the method divides the hemisphere into multiple angular bands and processes each band separately, thereby reducing the computational dimensions while maintaining reproduction fidelity.
Solution Approach 2:
The patent transforms the continuous angular parameters of incident light and viewing directions into discrete parameter sets. By defining specific angular intervals and sampling points within these intervals, the method converts an infinite-dimensional optimization problem into a finite-parameter calculation that can be efficiently solved with reduced computational complexity.
2Manufacturing precision
If a three-dimensional structure is used to reproduce surface scattering, then the anisotropic reflection is improved, but the device complexity and manufacturing difficulty increase
Solution Approach 1:
The patent creates a simplified two-dimensional printed copy that reproduces the optical effects of a three-dimensional surface structure. Instead of physically manufacturing complex 3D microstructures, the method calculates and prints color information that optically simulates the appearance of anisotropic reflection, thereby achieving the desired effect without the manufacturing complexity of actual 3D structures.
Solution Approach 2:
The patent replaces the mechanical approach of creating physical three-dimensional microstructures with a computational and optical approach. By using BRDF-based color calculations and printing color information that encodes surface scattering properties, the method substitutes physical 3D fabrication with a 2D printing process that achieves equivalent visual results through optical manipulation.
3Ease of manufacture
If gloss is reproduced based only on intensities in two directions, then the process simplicity is improved, but the reproduction accuracy is insufficient
Solution Approach 1:
The patent adds angular dimensionality to the gloss reproduction process by incorporating multiple viewing directions and incident light angles into the calculation. Instead of relying solely on intensity measurements in two directions, the method integrates reflectance data across multiple angular dimensions, thereby capturing the full complexity of surface scattering while maintaining a systematic processing approach.
Data Source
AI summary
A print data generating apparatus obtains a BRDF model group for each of a plurality of colors and the angle of incident light in the environment where an object to be reproduced is to be viewed. The print data generating apparatus then applies the angle of the incident light thus obtained to each of the models in the BRDF model group to thereby calculate the reflection distribution of the object to be reproduced for which the angle of the incident light is limited. The print data generating apparatus then outputs color data and form data for each of the models in the BRDF model group based on the reflection distribution, the color data indicating a color to be formed on the surface of the object to be reproduced, the form data indicating the form of the object to be reproduced.