Category Archives: Publications and Academic Research

A Computer Aided Color Appearance Design System for Metallic Car Paint

Ryan Abellera's Concept Design for CCS Class
Ryan Abellera's Concept Design for CCS Class. Paint formulated on site using Dupont ColorNet and Spectramaster.

Abstract: A computer aided design system for determining the color appearance of metallic automotive coatings has been developed. A sketch based bidirectional reflectance distribution function design interface allows simple concept art to be used to style new metallic car colors. The final design is specified using industrial measurement standards for metallic color appearance, and paint formulations are determined by employing an automotive refinish system. A virtual collection of existing automotive paints, specified using the measurement standard, is provided, and tools for searching this database, for both design and manufacturing purposes, are described. The system is assessed by using it in industrial and educational design studios.

Title: A Computer Aided Color Appearance Design System for Metallic Car Paint
Authors: Clement Shimizu and Gary W. Meyer
Published in Journal of Imaging Science and Technology, 59(3): 030403-1–030403-10, 2015.
Society for Imaging Science and Technology 2015
Presented at 23th Color and Imaging Conference 2015 (CIC23)

 BIBTEX CITATION
@inproceedings{shimizu2015,
author = {Clement Shimizu and Gary W. Meyer},
title = {A Computer Aided Color Appearance Design System for Metallic Car Paint},
year = {2015},
booktitle = {Journal of Imaging Science and Technology}
}

Computerised Colour

BRDF Design software developed by Clement Shimizu while at the University Of Minnesota
BRDF Design software developed by Clement Shimizu while at the University Of Minnesota
Abstract: Cynthia Challener discusses the use of Colour Rendering by way of computers to define a popular trend and to speed up colour design. Color Design software by Clement Shimizu, Ph.D. and Gary W. Meyer’s computer graphics lab are discussed.

Title: Computerised Color
Authors: Cynthia Challener
Published in Polymers Paint Color Journal Vol 202 no 4573 June 2012 pages 10-11.

BIBTEX CITATION
@inproceedings{Challener2012,
author = {Cynthia Challener},
title = {Computerised Color},
date = {June 2012},
booktitle = {Polymers Paint Color Journal Vol 202 no 4573}
}

PhD. Thesis: Computer Aided Design for Color Appearance

Computer Aided Design of Automotive Color at Ford
By: Clement Shimizu
Adviser: Gary W. Meyer

This research documents the creation and application of the first complete computer aided design system for color appearance. In this thesis, the fundamental components of computer aided geometric design (CAD) are applied to computer aided color appearance design (CACAD) including visualization, design, analysis/optimization, and scanning/prototyping tools. A series of experiments demonstrate the CACAD system’s maturity by showing that it is effective at designing, visualizing, and formulating paints in a wide variety of real world situations.
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Color Styling Tools


Authors: Clement Shimizu and Gary W. Meyer

Creative tools are proposed that allow color stylists to take advantage of their training in the art and design fields. A simple reflection model is employed that has the minimum number of free parameters required to design solid and metallic color finishes from conceptualization to fabrication. The parameters correspond to color specification terms familiar to designers such as face color, flop color, travel, and gloss. We demonstrate how the reflection model can also be used to develop effective interfaces for color stylists. We create a virtual mood board that allows direct selection of the reflection model parameters from pictures. We also develop an image based BRDF tweaker for adjusting color appearance directly on a 3D object. Continue reading

A Computer Graphics System for Examining Paint Color Collections

Benjamin More Paint Selector
Authors: Seth Berrier, Gary W. Meyer, and Clement Shimizu

A computer graphic program for organizing and displaying the colors in a paint collection is presented. A virtual representation for the traditional color card fan deck is described. This interactive program provides a lightness, chroma and hue interface for selecting a color from the collection. Software for visualizing a paint color on a three dimensional surface is also discussed. This tool allows the user to evaluate the sheen of a solid paint color and the travel of a metallic or pearlescent paint color. Continue reading

Predicting and Fixing Geometric Color Mismatches

Illustration of a color mismatch due to geometric misalignment of a car bumper
Why do car bumpers often look like they are painted the wrong color, even if the paint is a perfect match? Small geometric misalignment (labeled angle β) can cause significant perceived color mismatches especially in metallic automotive paints.

Authors: Clement Shimizu and Gary W. Meyer

Color mismatches that result from geometric misalignment are studied. Differences in color can result when adjacent parts of an object are coated with the same paint but are not aligned to create a continuous geometric surface. The color difference that results due to shading can be accentuated by the use of metallic and pearlescent paints with goniochromatic properties. A metric is developed for determining when the color difference is large enough for the misalignment to become apparent. A technique is also presented for selecting a paint that matches the adjacent part and creates the illusion of geometric continuity even though the two parts are misaligned. Continue reading

Automotive Spray Paint Simulation


Authors: Jonathan Konieczny, John Heckman, Gary W. Meyer, Marty Manyen, Marty Rabens, and Clement Shimizu

A system is introduced for the simulation of spray painting. Head mounted display goggles are combined with a tracking system to allow users to paint a virtual surface with a spray gun. Ray tracing is used to simulate droplets landing on the surface of the object, allowing arbitrary shapes and spray gun patterns to be used. This system is combined with previous research on spray gun characteristics to provide a realistic simulation of the spray paint including the effects of viscosity, air pressure, and paint pressure. The simulation provides two different output modes: a non-photorealistic display that gives a visual representation of how much paint has landed on the surface, and a photorealistic simulation of how the paint would actually look on the object once it has dried. Useful feedback values such as overspray are given. Experiments were performed to validate the system. Continue reading

OmniMap: Projective Perspective Mapping API for Non-planar Immersive Display Surfaces

Fisheye Projection Mapping
Authors: Clement Shimizu, Jim Terhorst, and David McConville (done under D’nardo Colucci for the Elumenati)

Typical video projection systems display rectangular images on flat screens. Optical and perspective correction techniques must be employed to produce undistorted output on non-planar display surfaces. A two-pass algorithm, called projective perspective mapping, is a solution well suited for use with commodity graphics hardware. This algorithm is implemented in the OmniMap API providing an extensible, reusable C++ interface for porting 3D engines to wide field-of-view, non-planar displays. This API is shown to be easily integrated into a wide variety of 3D applications. Continue reading

VR Spray Painting for Training and Design

The end result of using the system to spray paint a car hood. Both directionally diffuse and gloss layers have been applied. In this case, a photorealistic image of how the paint would look when dry is displayed to the user. Useful information such as overspray, and percentage covererage is given to the user. This makes the system ideal for training, as both visual and numeric feedback is given to the trainee.

Authors: Jonathan Konieczny, Gary W. Meyer, Clement Shimizu, John Heckman, Marty Manyen, and Marty Rabens

A system is introduced for the simulation of spray painting. Head mounted display goggles are combined with a tracking system to allow users to paint a virtual surface with a spray gun. Ray tracing is used to simulate droplets landing on the surface of the object, allowing arbitrary shapes and spray gun patterns to be used. This system is combined with previous research on spray gun characteristics to provide a realistic simulation of the spray paint including the effects of viscosity, air pressure, and paint pressure. The simulation provides two different output modes: a non-photorealistic display that gives a visual representation of how much paint has landed on the surface, and a photorealistic simulation of how the paint would actually look on the object once it dried. Useful feedback values such as overspray are given. Experiments were performed to validate the system. Continue reading

Creating Metallic Color Sequences for an Architectural Wall

Architectural Exhibit at the Goldstein Museum

Authors: Seth Berrier, Gary Meyer, and Clement Shimizu

A metallic paint scheme for an architectural wall is created using computer aided color appearance design techniques. New computer graphic hardware that allows real-time rendering of complex reflectance functions is employed to produce photo-realistic images of the metallic paint applied to the surface of the wall. An interpolation scheme is developed that permits one and two dimensional metallic shade sequences to be determined between individual bricks in a single row of the wall and between the complete rows of bricks that compose the wall. Paint formulation software, originally developed for auto refinish applications, is used to determine the paint mixtures necessary to realize the metallic colors in the design. A prototype of the wall is constructed and exhibited in a museum gallery. Continue reading

The Wall of Inspiration: A Computer Aided Color Selection System


Authors: Seth Berrier, Clement Shimizu, Patrick Chong, D’nardo Colucci, and Gary Meyer

Computer graphics hardware and software is used to create a new set of tools for selecting a household paint color. Important surface reflection effects, such as gloss and pearlescence, are rendered in real time using pixel shading hardware. Unlike traditional paint chips, this feature permits colors to be evaluated on three dimensional shapes and in different surface finishes. A novel set of color navigation tools is provided to allow the user to visualize the color collection supplied by the manufacturer, to select subsets of the collection for consideration, and to match or modify an existing color sample. This interface is easier to use and less expensive to produce than the fan deck found in most paint stores. The pictures produced by the software are displayed on a four panel video wall. The large size of the wall allows the user to evaluate the appearance of the color at a scale similar to its final dimension once it has been applied to a surface. Continue reading

A Handheld Flexible Display System

Projection mapping a brain onto a flexible rear projection screen.
Authors: Jonathan Konieczny, Clement Shimizu, Gary Meyer, and D’nardo Colucci

A new close range virtual reality system is introduced that allows intuitive and immersive user interaction with computer generated objects. A projector with a special spherical lens is combined with a flexible, tracked rear projection screen that users hold in their hands. Unlike normal projectors, the spherical lens allows for a 180 degree field of view and nearly infinite depth of focus. This allows the user to move the screen around the environment and use it as a virtual “slice” to examine the interior of 3D volumes. This provides a concrete correspondence between the virtual representation of the 3D volume and how that volume would actually appear if its real counterpart was sliced open. The screen can also be used as a “magic window” to view the mesh of the volume from different angles prior to taking cross sections of it. Real time rendering of the desired 3D volume or mesh is accomplished using current graphics hardware. Additional applications of the system are also discussed. Continue reading

Computer aided design of automotive finishes

Standards for measuring metallic automotive paints

Authors: Gary W. Meyer, Clement Shimizu, Alan Eggly, David Fischer, Jim King, and Allan Rodriguez

The principles of computer aided design were applied to the creation of new automotive finishes. A computer graphic program was written that allows the user to interactively adjust the surface reflection properties of an automotive paint and visualize the appearance of that paint on a three dimensional surface. The program gives a designer intuitive controls over a second order polynomial that defines the color of the paint at a series of aspecular angles. An automotive stylist was permitted to use the program and design three new automotive paints that had never been manufactured. Formulations for the designed paints were determined by inputting the desired aspecular measurements into an automotive refinish system. The new paints were mixed and sprayed on metal panels. Comparisons between the actual and simulated finishes were judged to be adequate by those involved in the experiment. Continue reading

Computational Automotive Color Appearance

Controlled Lighting for Comparison between Computer Display and manufactured paint prototypes used a SpectraLight Color temperate and spectrum controlled lamp

Authors: Gary W. Meyer and Clement Shimizu

A computer graphic system has been developed that permits the interactive design of new automotive finishes. The software makes use of a reflection model for car paint that is based on industry standards for measuring the appearance characteristics of the paint. These measurements include gloss for the clearcoat and three aspecular measurements for the metallic basecoat. The program interface provides a means for altering the reflectance properties of the paint and for visualizing the effect of those changes on the color appearance of the car. The desired aspecular measurements for the new paint can be input to a paint formulation system so that the paint can be manufactured. A test of the system shows good correspondence between the designed and the fabricated paint. Continue reading

Computer Aided Color Appearance Design Using Environment Map Based Lighting

Material Design in Environment Map Based Lighting
Material Design in Environment Map Based Lighting
Authors: Clement Shimizu and Gary W. Meyer

A BRDF approximation is developed that is suitable for interactive color appearance design in direct lighting provided by environment maps. The BRDFs are approximated as a linear combination of cosine lobes with a fixed set of specular exponents. A nonlinear optimization routine is used to fit the cosine lobes to BRDFs appropriate for a specific color appearance design application: automotive paint. Modification and rendering of the BRDF is made possible by linearly combining prefiltered environment maps for each cosine lobe in real time. Continue reading

Interactive Goniochromatic Color Design

BRDF Designer

Authors: Clement Shimizu, Gary W. Meyer, and Joseph P. Wingard

An interactive program has been developed to assist in the design of new goniochromatic colors. The program gives the user a unique set of controls over a second order polynomial that defines these color families at a sequence of aspecular reflection angles. One approach, based on traditional metallic colors, allows the user to adjust the average hue, saturation, and brightness of all of the colors interpolated by the polynomial. Another method, appropriate for the newer effect colors, permits the designer to establish face and flop colors to be reached at either end of the interpolation. In a final technique, variations produced by adjusting model parameters can be evaluated and selected. Continue reading

Hardware Accelerated Motion Blur Generation


Authors: Clement Shimizu, Amit Shesh, and Baoquan Chen

Motion blur occurs in photography by the motion of objects during the finite exposure time that the camera shutter remains open for to record the image on film. The traditional method of rendering a motion blur with a computer is to render the scene at many discrete time instances in every frame. In this paper, we present an efficient motion blur generation method that leverages modern commodity graphics hardware. Our method avoids rendering the entire complex scene many times per frame. It first renders the scene into a texture, next renders the optic flow, created based on object transformation, to a vector field texture. The scene texture is finally efficiently blurred according to the vector field using texture mapping hardware to do a piecewise iterative line integral convolution. Though our method uses vertex velocities to calculate image pixel velocities, the line integral convolution is performed on an image, making our method largely independent of scene complexity. Continue reading