Image-based appearance acquisition of effect coatings

Filip, Jiřı́; Vávra, Radomír

doi:10.1007/s41095-019-0134-3

Cited by 5 publications

(5 citation statements)

References 39 publications

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“…omits dependency on

φ_{d}

. Although its impact on total energy should be very low [FV19], we cannot guarantee exact energy conservation.…”

Section: Discussion and Method's Limitationsmentioning

confidence: 96%

“…[RSK09] presented extensions towards gonioapparent coatings texture measurement and modelling using bidirectional texture function (BTF) [DvGNK99]. Our work is closely related to work of Filip and Vávra [FV19] comparing several approaches to SVBRDF capturing of effect coatings using half‐difference parameterization.…”

Section: Related Workmentioning

confidence: 99%

“…In the next step, we captured the spatially‐varying appearance of these four samples using the half‐difference parameterization [Rus98]. Due to typically low appearance variation along

φ_{d}

in BRDF and coatings as suggested in [FV19], we fixed the azimuthal angle of illumination direction relative to half‐direction. We fixed

φ_{d} = 90^{\circ}

to obtain the majority of the effective hemisphere around a half‐direction above plane defined by the measured sample normal as reported by [Bur].…”

Section: Measurement Of Anisotropic Effect Coatingsmentioning

confidence: 99%

“…Sampling of all three angles uniformly in step

5^{\circ}

would result to 18

\times 18 \times

72 = 23,328 images, which is inconvenient in practical scenarios. To create a sensible reference data, we considered typically smaller variations along

θ_{d}

and

φ_{h}

and, based on psychophysical thresholds suggested in [FV19], reduced the sampling steps to [

Δ θ_{h}, Δ θ_{d}, Δ φ_{h} false] = false[5^{\circ}, 15^{\circ}, 15^{\circ} false]

. This configuration resulted in

n_{θ_{h}} \times n_{θ_{d}} \times n_{φ_{h}}

= 18

\times 5 \times

24 = 2160 images.…”

Section: Measurement Of Anisotropic Effect Coatingsmentioning

confidence: 99%

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Framework for Capturing and Editing of Anisotropic Effect Coatings

Filip

Vávra

Maile³

et al. 2020

Computer Graphics Forum

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Coatings are used today for products, ranging from automotive production to electronics and everyday use items. Product design is taking on an increasingly important role, where effect pigments come to the fore, offering a coated surface extra optical characteristics. Individual effect pigments have strong anisotropic, azimuthaly‐dependent behaviour, typically suppressed by a coating application process, randomly orienting pigment particles resulting in isotropic appearance. One exception is a pigment that allows control of the azimuthal orientation of flakes using a magnetic field. We investigate visual texture effects due to such an orientation in a framework allowing efficient capturing, modelling and editing of its appearance. We captured spatially‐varying BRDFs of four coatings containing magnetic effect pigments. As per‐pixel non‐linear fitting cannot preserve coating sparkle effects, we suggest a novel method of anisotropy modelling based on images shifting in an angular domain. The model can be utilized for a fast transfer of desired anisotropy to any isotropic effect coating, while preserving important spatially‐varying visual features of the original coating. The anisotropic behaviour was fitted by a parametric model allowing for editing of coating appearance. This framework allows exploration of anisotropic effect coatings and their appearance transfer to standard effect coatings in a virtual environment.

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“…omits dependency on

φ_{d}

. Although its impact on total energy should be very low [FV19], we cannot guarantee exact energy conservation.…”

Section: Discussion and Method's Limitationsmentioning

confidence: 96%

Section: Related Workmentioning

confidence: 99%

“…In the next step, we captured the spatially‐varying appearance of these four samples using the half‐difference parameterization [Rus98]. Due to typically low appearance variation along

φ_{d}

in BRDF and coatings as suggested in [FV19], we fixed the azimuthal angle of illumination direction relative to half‐direction. We fixed

φ_{d} = 90^{\circ}

to obtain the majority of the effective hemisphere around a half‐direction above plane defined by the measured sample normal as reported by [Bur].…”

Section: Measurement Of Anisotropic Effect Coatingsmentioning

confidence: 99%

“…Sampling of all three angles uniformly in step

5^{\circ}

would result to 18

\times 18 \times

72 = 23,328 images, which is inconvenient in practical scenarios. To create a sensible reference data, we considered typically smaller variations along

θ_{d}

and

φ_{h}

and, based on psychophysical thresholds suggested in [FV19], reduced the sampling steps to [

Δ θ_{h}, Δ θ_{d}, Δ φ_{h} false] = false[5^{\circ}, 15^{\circ}, 15^{\circ} false]

. This configuration resulted in

n_{θ_{h}} \times n_{θ_{d}} \times n_{φ_{h}}

= 18

\times 5 \times

24 = 2160 images.…”

Section: Measurement Of Anisotropic Effect Coatingsmentioning

confidence: 99%

See 2 more Smart Citations

Framework for Capturing and Editing of Anisotropic Effect Coatings

Filip

Vávra

Maile³

et al. 2020

Computer Graphics Forum

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show abstract

“…This is inevitable because continuous medium (i.e., LTE) cannot have a texture. Several approaches for obtaining the spatial variation of the luminance are considered in [11]. The basic approach based on a bidirectional texture function is compared with four variants of half-difference parametrization.…”

Section: Related Workmentioning

confidence: 99%

Simulation of Light Scattering in Automotive Paints: Role of Particle Size

2023

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Nowadays, computer simulation is being used to develop new materials. Many of them are dispersed media (e.g., paints, and 3D printer inks). Modern automotive paints are of great interest in research works. They contain colorant particles and thin flat metallic or pearlescent flakes distributed in a clear varnish. There are two main approaches to simulation of light scattering in a dispersed media. The first one is based on the continuous medium model. This model is faster but less accurate. The second approach is the simulation of light propagation through an ensemble of paint flakes and particles represented as an explicit geometry. This model correctly calculates light scattering but is rather time-consuming. In our study, we investigated the dependence of the painted surface luminance on particle size and compared both the approaches. We prove that the effect of coarse particles can emerge even in a model where positions of these particles are not correlated; this is different from the mainstream studies which have only concentrated on the role of these correlations. Then, we suggest a semi-analytical model of dependence on particle size. This model not only allows to more accurately simulate visual appearance but also admits intuitive comprehension of how it is affected by various medium parameters. In case of the divergence between the results of LTE and accurate approaches, we propose a simple approximation that allows to improve the accuracy of the LTE results for coarse particles.

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Rational Design of the Appearance of Complex Industrial Products Based on Visual Communication

Song

Cheng

2020

2019 6th International Conference on Dependable Systems and Their Applications (DSA)

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Image-based appearance acquisition of effect coatings

Cited by 5 publications

References 39 publications

Framework for Capturing and Editing of Anisotropic Effect Coatings

Framework for Capturing and Editing of Anisotropic Effect Coatings

Simulation of Light Scattering in Automotive Paints: Role of Particle Size

Rational Design of the Appearance of Complex Industrial Products Based on Visual Communication

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