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Rahaman, G. M., Norberg, O. & Edström, P. (2015). Experimental analysis for modeling color of halftone images. In: Lecture Notes in Computer Science (including subseries Lecture Notes in Artificial Intelligence and Lecture Notes in Bioinformatics): . Paper presented at 5th International Workshop on Computational Color Imaging, CCIW 2015; Saint Etienne; France; 24 March 2015 through 26 March 2015; Code 114019 (pp. 69-80). Springer, 9016
Open this publication in new window or tab >>Experimental analysis for modeling color of halftone images
2015 (English)In: Lecture Notes in Computer Science (including subseries Lecture Notes in Artificial Intelligence and Lecture Notes in Bioinformatics), Springer, 2015, Vol. 9016, p. 69-80Conference paper, Published paper (Refereed)
Abstract [en]

Reflectance models such as the monochrome Murray–Davies (MD) and the Neugebauer color equations make inaccurate predictions owing to changes in reflectance or tristimulus values (TSVs) of halftone dots and the paper between the dots. In this paper, we characterize the change of micro-TSVs as a function of printed area in spectral halftone image by a power function and compare its prediction efficiency using theoretically and experimentally measured limiting TSVs assuming dots of uniform thickness. We found that experimentally accounting for dot thickness variations as solid and mixed areas more precisely explained the single-model parameter that captured the observed lateral light scattering effect. The results showed that incorporating empirically modeled TSVs of the dots and the paper between dots, as well as introducing a new term addressing mixed area in the MD equation, produced CIE ΔE* ab in the range 1.22–1.76, and the overall gain was more than 1 ΔE* ab.

Place, publisher, year, edition, pages
Springer, 2015
Keywords
Color, Halftone, Light scattering, Murray-Davies, Spectral image
National Category
Electrical Engineering, Electronic Engineering, Information Engineering
Identifiers
urn:nbn:se:miun:diva-24606 (URN)10.1007/978-3-319-15979-9_7 (DOI)000354635100007 ()2-s2.0-84923548278 (Scopus ID)9783319159782 (ISBN)
Conference
5th International Workshop on Computational Color Imaging, CCIW 2015; Saint Etienne; France; 24 March 2015 through 26 March 2015; Code 114019
Note

Export Date: 17 March 2015

Available from: 2015-08-28 Created: 2015-03-17 Last updated: 2015-08-28Bibliographically approved
Edvardsson, S., Neuman, M., Edström, P. & Olin, H. (2015). Solving equations through particle dynamics. Computer Physics Communications, 197, 169-181
Open this publication in new window or tab >>Solving equations through particle dynamics
2015 (English)In: Computer Physics Communications, ISSN 0010-4655, E-ISSN 1879-2944, Vol. 197, p. 169-181Article in journal (Refereed) Published
Abstract [en]

The present work evaluates a recently developed particle method (DFPM). The basic idea behind this method is to utilize a Newtonian system of interacting particles that through dissipation solves mathematical problems. We find that this second order dynamical system results in an algorithm that is among the best methods known. The present work studies large systems of linear equations. Of special interest is the wide eigenvalue spectrum. This case is common as the discretization of the continuous problem becomes dense. The convergence rate of DFPM is shown to be in parity with that of the conjugate gradient method, both analytically and through numerical examples. However, an advantage with DFPM is that it is cheaper per iteration. Another advantage is that it is not restricted to symmetric matrices only, as is the case for the conjugate gradient method. The convergence properties of DFPM are shown to be superior to the closely related approach utilizing only a first order dynamical system, and also to several other iterative methods in numerical linear algebra. The performance properties are understood and optimized by taking advantage of critically damped oscillators in classical mechanics. Just as in the case of the conjugate gradient method, a limitation is that all eigenvalues (spring constants) are required to be of the same sign. DFPM has no other limitation such as matrix structure or a spectral radius as is common among iterative methods. Examples are provided to test the particle algorithm’s merits and also various performance comparisons with existent numerical algorithms are provided.

Place, publisher, year, edition, pages
Elsevier, 2015
Keywords
Particle methods, Computational mechanics, Many-particle dynamics, System of linear equations, Dynamical functional particle method
National Category
Computational Mathematics
Identifiers
urn:nbn:se:miun:diva-26030 (URN)10.1016/j.cpc.2015.08.028 (DOI)000362919500018 ()2-s2.0-84942990585 (Scopus ID)
Available from: 2015-10-05 Created: 2015-10-05 Last updated: 2017-12-01Bibliographically approved
Neuman, M., Edvardsson, S. & Edström, P. (2015). Solving the radiative transfer equation with a mathematical particle method. Optics Letters, 40(18), 4325-4328
Open this publication in new window or tab >>Solving the radiative transfer equation with a mathematical particle method
2015 (English)In: Optics Letters, ISSN 0146-9592, E-ISSN 1539-4794, Vol. 40, no 18, p. 4325-4328Article in journal (Refereed) Published
Abstract [en]

We solve the radiative transfer equation (RTE) using a recently proposed mathematical particle method, originally developed for solving general functional equations. We show that, in the case of the RTE, it gives several advantages, such as handling arbitrary boundary conditions and phase functions and avoiding numerical instability in strongly forward-scattering media. We also solve the RTE, including fluorescence, and an example is shown with a fluorescence cascade where light is absorbed and emitted in several steps. We show that the evaluated particle method is straightforward to implement, which is in contrast with many traditional RTE solvers, but a potential drawback is the tuning of the method parameters.

Place, publisher, year, edition, pages
Optical Society of America, 2015
National Category
Computational Mathematics
Identifiers
urn:nbn:se:miun:diva-26029 (URN)10.1364/OL.40.004325 (DOI)000361556700035 ()26371927 (PubMedID)2-s2.0-84957710820 (Scopus ID)
Available from: 2015-10-05 Created: 2015-10-05 Last updated: 2017-12-01Bibliographically approved
Rahaman, G. M., Norberg, O. & Edström, P. (2014). Extension of Murray-Davies tone reproduction model by adding edge effect of halftone dots. In: Proceedings of SPIE - The International Society for Optical Engineering: . Paper presented at Measuring, Modeling, and Reproducing Material Appearance; San Francisco, CA; United States; 3 February 2014 through 4 February 2014; Code 103465 (pp. Art. no. 90180F). San Francisco, California, United States: SPIE - International Society for Optical Engineering
Open this publication in new window or tab >>Extension of Murray-Davies tone reproduction model by adding edge effect of halftone dots
2014 (English)In: Proceedings of SPIE - The International Society for Optical Engineering, San Francisco, California, United States: SPIE - International Society for Optical Engineering, 2014, p. Art. no. 90180F-Conference paper, Published paper (Refereed)
Abstract [en]

We propose expanding the Murray-Davies formula by adding the effect of edges of solid inks in a halftoned image. The expanded formula takes into account the spectral reflectance of paper white, full tone ink and mixed area scaled by the fractional area coverages. Here, mixed area mainly refers to the edge of an inked dot where the density is very low, and lateral exchange of photons can occur. Also, in such area the paper micro components may have higher scattering power than ink, especially, in uncoated paper. Our methodology uses cyan, magenta and yellow separation ramps printed on different papers by impact and non-impact based printing technologies. The samples include both frequency and amplitude modulation halftoning methods of various print resolutions. Based on pixel values, the captured microscale halftoned image is divided into three categories: solid ink, mixed area, and unprinted paper between the dots. The segmented images are then used to measure the fractional area coverage that the model receives as parameters. We have derived the characteristic reflectance spectrum of mixed area by rearranging the expanded formula and replacing the predicted term with the measured value using half of the maximum colorant coverage. Performance has clearly improved over the Murray-Davies model with and without dot gain compensation, more importantly, preserving the linear additivity of reflectance of the classical physics-based model.

Place, publisher, year, edition, pages
San Francisco, California, United States: SPIE - International Society for Optical Engineering, 2014
Keywords
Printing, color, model, Murray Davies, reflectance, halftoning, segmentation, dot gain, k-means.
National Category
Engineering and Technology
Identifiers
urn:nbn:se:miun:diva-20315 (URN)10.1117/12.2037754 (DOI)000335757500014 ()2-s2.0-84897467351 (Scopus ID)978-081949935-6 (ISBN)
Conference
Measuring, Modeling, and Reproducing Material Appearance; San Francisco, CA; United States; 3 February 2014 through 4 February 2014; Code 103465
Projects
EU Marie Curie Initial Training Networks (ITN) CP7.0
Funder
EU, European Research Council, N-290154
Note

Manuscripts from this conference will appear as Proceedings of SPIE Volume 9018 on SPIE Digital Library within 2-4 weeks after conference.

Available from: 2013-11-26 Created: 2013-11-26 Last updated: 2015-01-02Bibliographically approved
Johansson, N., Neuman, M., Andersson, M. & Edström, P. (2014). Influence of finite-sized detection solid angle on bidirectional reflectance distribution function measurements. Applied Optics, 53(6), 1212-1220
Open this publication in new window or tab >>Influence of finite-sized detection solid angle on bidirectional reflectance distribution function measurements
2014 (English)In: Applied Optics, ISSN 1559-128X, E-ISSN 2155-3165, Vol. 53, no 6, p. 1212-1220Article in journal (Refereed) Published
Abstract [en]

This paper deals with limitations and often overlooked sources of error introduced in compact double-beam goniophotometers. It is shown that relative errors in measured radiance factor, comparable to the total measurement uncertainty, can be introduced if recommended corrections are not carried out. Two different error sources are investigated, both related to the size of the detection solid angle. The first is a geometrical error that occurs when the size of the illuminated area and detector aperture are comparable to the distance between them. The second is a convolution error due to variations in radiant flux over the detector aperture, which is quantified by simulating the full 3D bidirectional reflectance distribution function (BRDF) of a set of samples with different degrees of anisotropic reflectance. The evaluation is performed for a compact double-beam goniophotometer using different detection solid angles, and it is shown that both error sources introduce relative errors of 1%–3%, depending on viewing angle and optical properties of the sample. Commercially available compact goniophotometers, capable of absolute measurements, are becoming more and more common, and the findings in this paper are therefore important for anyone using or planning to use this type of instrument.

Place, publisher, year, edition, pages
Optical Society of America, 2014
Keywords
Reflection, Scattering measurements, BRDF, turbid media
National Category
Natural Sciences
Identifiers
urn:nbn:se:miun:diva-20949 (URN)10.1364/AO.53.001212 (DOI)000331949600027 ()2-s2.0-84942366011 (Scopus ID)
Available from: 2014-01-03 Created: 2014-01-03 Last updated: 2017-12-06Bibliographically approved
Rahaman, G. M., Norberg, O. & Edström, P. (2014). Microscale halftone color image analysis: perspective of spectral color prediction modeling. In: Proceedings of SPIE - The International Society for Optical Engineering: Color Imaging XIX: Displaying, Processing, Hardcopy, and Applications. Paper presented at Color Imaging XIX: Displaying, Processing, Hardcopy, and Applications San Francisco, California, USA, 3 - 5 February 2014 (pp. Art. no. 901506). San Francisco, California, United States: SPIE - International Society for Optical Engineering
Open this publication in new window or tab >>Microscale halftone color image analysis: perspective of spectral color prediction modeling
2014 (English)In: Proceedings of SPIE - The International Society for Optical Engineering: Color Imaging XIX: Displaying, Processing, Hardcopy, and Applications, San Francisco, California, United States: SPIE - International Society for Optical Engineering, 2014, p. Art. no. 901506-Conference paper, Published paper (Refereed)
Abstract [en]

A method has been proposed, whereby k-means clustering technique is applied to segment microscale single color halftone image into three components—solid ink, ink/paper mixed area and unprinted paper. The method has been evaluated using impact (offset) and non-impact (electro-photography) based single color prints halftoned by amplitude modulation (AM) and frequency modulation (FM) technique. The print samples have also included a range of variations in paper substrates. The colors of segmented regions have been analyzed in CIELAB color space to reveal the variations, in particular those present in mixed regions. The statistics of intensity distribution in the segmented areas have been utilized to derive expressions that can be used to calculate simple thresholds. However, the segmented results have been employed to study dot gain in comparison with traditional estimation technique using Murray-Davies formula. The performance of halftone reflectance prediction by spectral Murray-Davies model has been reported using estimated and measured parameters. Finally, a general idea has been proposed to expand the classical Murray-Davies model based on experimetal observations. Hence, the present study primarily presents the outcome of experimental efforts to characterize halftone print media interactions in respect to the color prediction models. Currently, most regression-based color prediction models rely on mathematical optimization to estimate the parameters using measured average reflectance of a large area compared to the dot size. While this general approach has been accepted as a useful tool, experimental investigations can enhance understanding of the physical processes and facilitate exploration of new modeling strategies. Furthermore, reported findings may help reduce the required number of samples that are printed and measured in the process of multichannel printer characterization and calibration.

Place, publisher, year, edition, pages
San Francisco, California, United States: SPIE - International Society for Optical Engineering, 2014
Keywords
Color, modeling, halftoning, segmentation, dot gain, k-means, Murray Davies, CIE LAB
National Category
Engineering and Technology
Identifiers
urn:nbn:se:miun:diva-20314 (URN)10.1117/12.2037256 (DOI)000333196800006 ()2-s2.0-84894564647 (Scopus ID)978-081949932-5 (ISBN)
Conference
Color Imaging XIX: Displaying, Processing, Hardcopy, and Applications San Francisco, California, USA, 3 - 5 February 2014
Projects
EU Marie Curie project (CP7.0)
Funder
EU, European Research Council, N-290154
Note

Manuscripts from this conference will appear as Proceedings of SPIE Volume 9015 on SPIE Digital Library the first day of the meeting.

Available from: 2013-11-26 Created: 2013-11-26 Last updated: 2015-01-02Bibliographically approved
Neuman, M., Edvardsson, S. & Edström, P. (2013). A particle approach to the radiative transfer equation with fluorescence.
Open this publication in new window or tab >>A particle approach to the radiative transfer equation with fluorescence
2013 (English)Article in journal (Refereed) Submitted
National Category
Other Physics Topics
Identifiers
urn:nbn:se:miun:diva-18693 (URN)
Available from: 2013-04-04 Created: 2013-04-04 Last updated: 2016-12-09Bibliographically approved
Namedanian, M., Gustafsson Coppel, L., Neuman, M., Gooran, S., Edström, P., Kolseth, P. & Koh, W. (2013). Analysis of Optical and Physical Dot Gain by Microscale Image Histogram and Modulation Transfer Functions. Journal of Imaging Science and Technology, 57(2), 020504-1-020504-5
Open this publication in new window or tab >>Analysis of Optical and Physical Dot Gain by Microscale Image Histogram and Modulation Transfer Functions
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2013 (English)In: Journal of Imaging Science and Technology, ISSN 1062-3701, E-ISSN 1943-3522, Vol. 57, no 2, p. 020504-1-020504-5Article in journal (Refereed) Published
Abstract [en]

The color of a print is affected by ink spreading and lateral light scattering in the substrate, making printed dots appear larger. Characterization of physical and optical dot gain is crucial for the graphic arts and paper industries. We propose a novel approach to separate physical from optical dot gain by use of a high-resolution camera. This approach is based on the histogram of microscale images captured by the camera. Having determined the actual physical dot shape, we estimate the modulation transfer function (MTF) of the paper substrate. The proposed method is validated by comparing the estimated MTF of 11 offset printed coated papers to the MTF obtained from the unprinted papers using measured and Monte Carlo simulated edge responses.

National Category
Media Engineering
Identifiers
urn:nbn:se:miun:diva-20432 (URN)10.2352/J.ImagingSci.Technol.2013.57.2.020504 (DOI)000344138900004 ()2-s2.0-84886047298 (Scopus ID)
Available from: 2013-12-03 Created: 2013-12-03 Last updated: 2017-12-06Bibliographically approved
Zhang, R., Andersson, H., Andersson, M., Andres, B., Edström, P., Edvardsson, S., . . . Olin, H. (2013). High-speed deposition of multilayer nanofilms using soap-film coating. In: : . Paper presented at 19th International Vacuum Congress (IVC-19), Paris, France, September 9-13 2013.
Open this publication in new window or tab >>High-speed deposition of multilayer nanofilms using soap-film coating
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2013 (English)Conference paper, Oral presentation with published abstract (Refereed)
Abstract [en]

High-speed deposition of multilayer nanofilms using soap-film coating

Renyun Zhang, Henrik A. Andersson, Mattias Andersson, Britta Andres, Per Edström, Sverker Edvardsson, Sven Forsberg, Magnus Hummelgård, Niklas Johansson, Kristoffer Karlsson, Hans-Erik Nilsson, Martin Olsen, Tetsu Uesaka, Thomas Öhlund & Håkan Olin

Department of Applied Science and Design, Mid Sweden University, SE-85170 Sundsvall, Sweden

Email: renyun.zhang@miun.se or hakan.olin@miun.se

Coating1 of thin films is of importance for making functionalized surfaces with applications in many fields from electronics to consumer packaging. To decrease the cost, large scale roll-to-roll2 coating techniques are usually done at high speed, for example, ordinary printing paper is coated at a speed of tens of meters per second by depositing micrometer thick layers of clay. However, nanometer thin films are harder to coat at high speed by wet-chemical methods, requiring special roll-to-roll vacuum techniques3 with the cost of higher complexity.

Here, we report a simple wet chemical method for high-speed coating of films down to molecular thicknesses, called soap-film coating (SFC)4. The technique is based on forcing a substrate through a soap film that contains nanomaterials. In the simplest laboratory version, the films can be deposited by a hand-coating procedure set up in a couple of minutes. The method is quite general molecules or nanomaterials or sub-micrometer materials (Figure 1) with thicknesses ranging from less than a monolayer to several layers at speeds up to meters per second. The applications of soap-film coating is quite wide an we will show solar cells, electrochromic devices, optical nanoparticle crystals, and nano-film devices. We believe that the soap-film coating method is potentially important for industrial-scale nanotechnology.

Fig. 1. Soap film coating of nanoparticles, layered materials, nanowires, and molecules. a sub-monolayer 240 nm silica nanoparticle (scale bar 2 µm) b monolayer c double layer. d monolayer gold nanoparticles. e single layer TiO2 nanoparticles. f sub-monolayer polystyrene (scale 2 µm), g monolayer of polystyrene. h triple-layer of polystyrene. i monolayer of Ferritin.  j AFM image of <1.5 layer GO film (3 µm x 2 µm). k clay on glass (scale 2 µm). l SFC coated nanocellulose. m Absorbance spectra Rhodamine B on a glass slide. AFM of SDS layers n (2 µm x 1.5 µm) and o (20 µm x 15 µm).

References

  1. Tracton, A. A. Coating Technology Handbook (CRC Press, Boca Raton, 2006).

  2. Ohring, M. Materials science of thin films. (Academic press., 2001).

  3. Charles, B. Vacuum deposition onto webs, films and foils. (William Andrew, 2011).

Zhang, R. Y., Andersson, H. A., Andersson, M., Andres, B., Edström, P., Edvardsson, S., Forsberg, S., Hummelgård, M., Johansson, N., Karlsson, K., Nilsson, H.-E., Olsen, M., Uesaka, T., Öhlund, T., Olin H. Soap film coating: High-speed deposition of multilayer nanofilms. Submitted.

National Category
Natural Sciences
Identifiers
urn:nbn:se:miun:diva-20338 (URN)STC (Local ID)STC (Archive number)STC (OAI)
Conference
19th International Vacuum Congress (IVC-19), Paris, France, September 9-13 2013
Available from: 2013-11-27 Created: 2013-11-27 Last updated: 2016-10-20Bibliographically approved
Linder, T., Löfqvist, T., Gustafsson Coppel, L., Neuman, M. & Edström, P. (2013). Lateral light scattering in fibrous media. Optics Express, 21(6), 7835-7840
Open this publication in new window or tab >>Lateral light scattering in fibrous media
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2013 (English)In: Optics Express, ISSN 1094-4087, E-ISSN 1094-4087, Vol. 21, no 6, p. 7835-7840Article in journal (Refereed) Published
Abstract [en]

Lateral light scattering in fibrous media is investigated by computing the modulation transfer function (MTF) of 22 paper samples using a Monte Carlo model. The simulation tool uses phase functions from infinitely long homogenous cylinders and the directional inhomogeneity of paper is achieved by aligning the cylinders in the plane. The inverse frequency at half maximum of the MTF is compared to both measurements and previous simulations with isotropic and strongly forward single scattering phase functions. It is found that the conical scattering by cylinders enhances the lateral scattering and therefore predicts a larger extent of lateral light scattering than models using rotationally invariant single scattering phase functions. However, it does not fully reach the levels of lateral scattering observed in measurements. It is argued that the hollow lumen of a wood fiber or dependent scattering effects must be considered for a complete description of lateral light scattering in paper.

Keywords
Radiative transfer, Halftone image reproduction, Multiple scattering, Turbid media
National Category
Other Physics Topics Paper, Pulp and Fiber Technology
Identifiers
urn:nbn:se:miun:diva-18657 (URN)10.1364/OE.21.007835 (DOI)000316796000119 ()2-s2.0-84875750991 (Scopus ID)
Projects
PaperOpt
Funder
VinnovaThe Knowledge Foundation
Available from: 2013-03-28 Created: 2013-03-28 Last updated: 2017-12-06Bibliographically approved
Organisations
Identifiers
ORCID iD: ORCID iD iconorcid.org/0000-0002-0529-1009

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