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Pedersen M.,Gjøvik University College | Bonnier N.,Oce Print Logic Technologies | Hardeberg J.Y.,Gjøvik University College | Albregtsen F.,University of Oslo
Journal of Electronic Imaging | Year: 2010

The evaluation of perceived image quality in color prints is a complex task due to its subjectivity and dimensionality. The perceived quality of an image is influenced by a number of different quality attributes. It is difficult and complicated to evaluate the influence of all attributes on overall image quality, and their influence on other attributes. Because of this difficulty, the most important attributes of a color image should be identified to achieve a more efficient and manageable evaluation of the image's quality. Based on a survey of the existing literature and a psychophysical experiment, we identify and categorize existing image quality attributes to propose a refined selection of meaningful ones for the evaluation of color prints. © 2010 SPIE and IS&T.

Baar T.,Oce Print Logic Technologies | Baar T.,Telecom ParisTech | Samadzadegan S.,TU Darmstadt | Brettel H.,Telecom ParisTech | And 2 more authors.
Proceedings of SPIE - The International Society for Optical Engineering | Year: 2014

An important aspect for print quality assessment is the perceived gloss level across the printout. There exists a strong relationship between the surface roughness of a printout and the amount of specular reflection which is perceived as gloss variations. Different print parameters influence the surface roughness of the printouts such as the paper substrate, the type of inks and the print method. The lack of control over the print's surface roughness may result in artefacts such as bronzing and differential gloss. Employing a 2.5D or relief printing system, we are able to control the printout roughness by manipulating the way the ink is deposited in a layer-by-layer basis. By changing the deposition time in between two layers of white ink and the order on which the pixels are printed, we achieve different gloss levels from a matte to a glossy appearance that can be controlled locally. Understanding the relationship between different printing parameters and the resulting gloss level allows us: to solve differential gloss artefacts (to obtain a print with a full gloss or matte finish) and to use the local gloss variations to create reflection effects in the printouts. Applications related to security printing have also been explored. Our results showed a reduced level of gloss toward a matte appearance as the ink deposition time between the layers was increased, allowing more time for the ink to dry between passes. We measured the gloss levels using a gloss meter and a psychophysical experiment was conducted to validate our measurements and observations. © 2014 SPIE-IS & T.

Lindner A.,Ecole Polytechnique Federale de Lausanne | Bonnier N.,Oce Print Logic Technologies | Susstrunk S.,Ecole Polytechnique Federale de Lausanne
Proceedings of SPIE - The International Society for Optical Engineering | Year: 2011

We present a novel framework for automatically determining whether or not to apply black point compensation (BPC) in image reproduction. Visually salient objects have a larger influence on determining image quality than the number of dark pixels in an image, and thus should drive the use of BPC. We propose a simple and efficient algorithmic implementation to determine when to apply BPC based on low-level saliency estimation. We evaluate our algorithm with a psychophysical experiment on an image data set printed with or without BPC on a Canon printer. We find that our algorithm is correctly able to predict the observers' preferences in all cases when the saliency maps are unambiguous and accurate. © 2010 Copyright SPIE - The International Society for Optical Engineering.

Lindner A.,Ecole Polytechnique Federale de Lausanne | Shaji A.,Ecole Polytechnique Federale de Lausanne | Bonnier N.,Oce Print Logic Technologies | Susstrunk S.,Ecole Polytechnique Federale de Lausanne
MM 2012 - Proceedings of the 20th ACM International Conference on Multimedia | Year: 2012

With the advent of social image-sharing communities, millions of images with associated semantic tags are now available online for free and allow us to exploit this abundant data in new ways. We present a fast non-parametric statistical framework designed to analyze a large data corpus of images and semantic tag pairs and find correspondences between image characteristics and semantic concepts. We learn the relevance of different image characteristics for thousands of keywords from one million annotated images. We demonstrate the framework's effectiveness with three different examples of semantic image enhancement: we adapt the gray-level tone-mapping, emphasize semantically relevant colors, and perform a defocus magnification for an image based on its semantic context. The performance of our algorithms is validated with psychophysical experiments. © 2012 ACM.

Shadkami P.,Oce Print Logic Technologies | Bonnier N.,Oce Print Logic Technologies
Lecture Notes in Computer Science (including subseries Lecture Notes in Artificial Intelligence and Lecture Notes in Bioinformatics) | Year: 2010

Document image analysis is used to segment and classify regions of a document image into categories such as text, graphic and background. In this paper we first review existing document image analysis approaches and discuss their limits. Then we adapt the well-known watershed segmentation in order to obtain a very fast and efficient classification. Finally, we compare our algorithm with three others, by running all the algorithms on a set of document images and comparing their results with a ground-truth segmentation designed by hand. Results show that the proposed algorithm is the fastest and obtains the best quality scores. © 2010 Springer-Verlag.

Bonnier N.,Oce Print Logic Technologies | Lindner A.J.,Telecom ParisTech
Journal of Electronic Imaging | Year: 2010

The capacity of a printing system to accurately reproduce details has an impact on the quality of printed images. The ability of a system to reproduce details is captured in its modulation transfer function (MTF). In the first part of this work, we compare three existing methods to measure the MTF of a printing system. After a thorough investigation, we select the method from Jang and Allebach and propose to modify it. We demonstrate that our proposed modification improves the measurement precision and the simplicity of implementation. Then we discuss the advantages and drawbacks of the different methods depending on the intended usage of the MTF and why Jang and Allebach's method best matches our needs. In the second part, we propose to improve the quality of printed images by compensating for the MTF of the printing system. The MTF is adaptively compensated in the Fourier domain, depending both on frequency and local mean values. Results of a category judgment experiment show significant improvement as the printed MTF-compensated images obtain the best scores. © 2010 SPIE and IS&T.

Ortiz Segovia M.V.,Purdue University | Bonnier N.,Oce Print Logic Technologies | Allebach J.P.,Purdue University
Proceedings of SPIE - The International Society for Optical Engineering | Year: 2012

Ink-saving strategies for CMYK printers have evolved from their earlier stages where the 'draft' print mode was the main option available to control ink usage. The savings were achieved by printing alternate dots in an image at the expense of reducing print quality considerably. Nowadays, customers are not only unwilling to compromise quality but have higher expectations regarding both visual print quality and ink reduction solutions. Therefore, the need for more intricate ink-saving solutions with lower impact on print quality is evident. Printing-related factors such as the way the printer places the dots on the paper and the ink-substrate interaction play important and complex roles in the characterization and modeling of the printing process that make the ink reduction topic a challenging problem. In our study, we are interested in benchmarking ink-saving algorithms to find the connections between different ink reduction levels of a given ink-saving method and a set of print quality attributes. This study is mostly related to CMYK printers that use dispersed dot halftoning algorithms. The results of our efforts to develop such an evaluation scheme are presented in this paper. © 2012 SPIE-IS&T.

Felhi M.,CNRS Lorraine Research Laboratory in Informatics and its Applications | Bonnier N.,Oce Print Logic Technologies | Tabbone S.,CNRS Lorraine Research Laboratory in Informatics and its Applications
Proceedings - International Conference on Image Processing, ICIP | Year: 2011

In this paper we study the detection of skewed text lines in scanned document images. The aim of our work is to develop a new automatic approach able to estimate precisely the skew angle of text in document images. Our new method is based on Maximum Gradient Difference (MGD) and R-signature. It detects zones that have high variations of gray values in different directions using the MGD transform. We consider these zones as being text regions. R-signature which is a shape descriptor based on Radon transform is then applied in order to approximate the skew angle. The accuracy of the proposed algorithm is evaluated on an open dataset by comparing error rates. © 2011 IEEE.

Ortiz Segovia M.V.,Purdue University | Bonnier N.,Oce Print Logic Technologies | Allebach J.P.,Purdue University
Proceedings of SPIE - The International Society for Optical Engineering | Year: 2012

Common ink-saving techniques usually restrict the ink consumption when printing a document by replacing a percentage of cyan, magenta, and yellow, by black ink. Even though such methods achieve a considerable reduction in the amount of ink used in a page, the visual quality of the print is affected and unpleasing effects in pastels and skin tones are observed. On the other hand, the quality of the print is not only affected by the ink-saving algorithm, but also by the way the color halftoning algorithm arranges the dots in the print. Therefore, the relationship between the contents of the document to be printed and the printing process needs to be addressed by the ink-saving strategy. A color direct binary search halftoning method that strives to minimize both the ink usage and the perceived error between the continuous-tone color image and the color halftone image is proposed. Our goals are to estimate the effects of the ink-saving module of a printing workflow in individual regions of the document, and to determine the dot arrangement and ink combination that consumes the least amount of ink while preserving printing quality. © 2011 Copyright Society of Photo-Optical Instrumentation Engineers (SPIE).

Baar T.,Telecom ParisTech | Brettel H.,Telecom ParisTech | Segovia M.V.O.,OCE Print Logic Technologies
Proceedings of SPIE - The International Society for Optical Engineering | Year: 2015

The studies regarding fine art reproduction mainly focus on the accuracy of colour and the recreation of surface texture properties. Since reflection properties other than colour are neglected, important details of the artwork are lost. For instance, gloss properties, often characteristic to painters and particular movements in the history of art, are not well reproduced. The inadequate reproduction of the different gloss levels of a piece of fine art leads to a specular reflection mismatch in printed copies with respect to the original works that affects the perceptual quality of the printout. We used different print parameters of a 3D high resolution printing setup to control the gloss level on a printout locally. Our method can be used to control gloss automatically and in crucial applications such as fine art reproduction. © 2015 SPIE-IS&T.

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