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- Abedini, Fereshteh, 1989-
(författare)
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2D and 3D Halftoning for Appearance Reproduction
- 2023
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Doktorsavhandling (övrigt vetenskapligt/konstnärligt)abstract
- The appearance of an object is determined by its chromatic and geometric qualities in its surrounding environment using four optical parameters: color, gloss, translucency, and surface texture. Reconstructing the appearance of objects is of great importance in many applications, including creative industries, packaging, fine-art reproduction, medical simulation, and prosthesis-making. Printers are reproduction devices capable of replicating objects’ appearance in 2D and 3D forms. With the introduction of new printing technologies, new inks and materials, and demands for innovative applications, creating accurate reproduction of the desired visual appearance has become challenging. Thus, the appearance reproduction workflow requires improvements and adaptations. Accurate color reproduction is a critical quality measure in reproducing the desired appearance in any printing process. However, printers are devices with a limited number of inks that can either print a dot or leave it blank at a specific position on a substrate; hence, to reproduce different colors, optimal placement of the available inks is needed. Halftoning is a technique that deals with this challenge by generating a spatial distribution of the available inks that creates an illusion of the target color when viewed from a sufficiently large distance. Halftoning is a fundamental part of the color reproduction task in any full-color printing pipeline, and it is an effective technique to increase the potential of printing realistic and complex appearances. Although halftoning has been used in 2D printing for many decades, it still requires improvements in reproducing fine details and structures of images. Moreover, the emergence of new technologies in 3D printing introduces a higher degree of freedom and more parameters to the field of appearance reproduction. Therefore, there is a critical need for extensive studies to revisit existing halftoning algorithms and develop novel approaches to produce high quality prints that match the target appearance faithfully. This thesis aims at developing halftoning algorithms to improve appearance reproduction in 2D and 3D printing. Contributions of this thesis in the 2D domain is a dynamic sharpness-enhancing halftoning approach, which adaptively varies the local sharpness of the halftone image based on different textures in the original image for realistic appearance printing. The results show improvements in halftone quality in terms of sharpness, preserving structural similarity, and decreasing color reproduction error. The main contribution of this thesis in 3D printing is extending a high quality 2D halftoning algorithm to the 3D domain. The proposed method is then integrated with a multi-layer printing approach, where ink is deposited at variable depths to improve the reproduction of tones and fine details. Results demonstrate that the proposed method accurately reproduces tones and details of the target appearance. Another contribution of this thesis is studying the effect of halftoning on the perceived appearance of 3D printed surfaces. According to the results, changing the dot placement based on the elevation variation of the underlying geometry can potentially control the perception of the 3D printed appearance. It implies that the choice of halftone may prove helpful in eliminating unwanted artifacts, enhancing the object’s geometric features, and producing a more accurate 3D appearance. The proposed methods in this thesis have been evaluated using different printing techniques.
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- Abedini, Fereshteh, et al.
(författare)
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3D Halftoning based on Iterative Method Controlling Dot Placement
- 2020
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Konferensbidrag (refereegranskat)abstract
- Realistic appearance reproduction is of great importance in 3D printing’s applications. Halftoning as a necessary process in printing has a great impact on creating visually pleasant appearance. In this article, we study the aspects of adapting and applying Iterative Method Controlling Dot Placement (IMCDP) to halftone three-dimensional surfaces. Our main goal is to extend the 2D algorithm to a 3D halftoning approach with minor modifications. The results show high-quality reproduction for all gray tones. The 3D halftoning algorithm is not only free of undesirable artifacts, it also produces fully symmetric and wellformed halftone structures even in highlight and shadow regions.
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- Abedini, Fereshteh, et al.
(författare)
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Structure-Aware Halftoning Using the Iterative Method Controlling the Dot Placement
- 2021
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Ingår i: Journal of Imaging Science and Technology. - : I S & T-SOC IMAGING SCIENCE TECHNOLOGY. - 1062-3701 .- 1943-3522. ; 65:6
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Tidskriftsartikel (refereegranskat)abstract
- Many image reproduction devices, such as printers, are limited to only a few numbers of printing inks. Halftoning, which is the process to convert a continuous-tone image into a binary one, is, therefore, an essential part of printing. An iterative halftoning method, called Iterative Halftoning Method Controlling the Dot Placement (IMCDP), which has already been studied by research scholars, generally results in halftones of good quality. In this paper, we propose a structure-based alternative to this algorithm that improves the halftone image quality in terms of sharpness, structural similarity, and tone preservation. By employing appropriate symmetrical and non-symmetrical Gaussian filters inside the proposed halftoning method, it is possible to adaptively change the degree of sharpening in different parts of the continuous-tone image. This is done by identifying a dominant line in the neighborhood of each pixel in the original image, utilizing the Hough Transform, and aligning the dots along the dominant line. The objective and subjective quality assessments verify that the proposed structure-based method not only results in sharper halftones, giving more three-dimensional impression, but also improves the structural similarity and tone preservation. The adaptive nature of the proposed halftoning method makes it an appropriate algorithm to be further developed to a 3D halftoning method, which could be adapted to different parts of a 3D object by exploiting both the structure of the images being mapped and the 3D geometrical structure of the underlying printed surface.
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- Abedini, Fereshteh, et al.
(författare)
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The Effect of Halftoning on the Appearance of 3D Printed Surfaces
- 2021
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Konferensbidrag (refereegranskat)abstract
- Managing the final appearance of 3D surfaces is an interesting and essential topic in 3D printing applications. Knowledge about the parameters which influence the 3D surface reproduction quality enables engineers to achieve the final appearance as accurately as designed. Many studies have been conducted to explore numerous parameters that affect the quality of 3D surface reproduction. This work contributes to verifying the role of halftoning in increasing the 3D surface visual quality and the control over the surface appearance of a 3D printed object. The results show that applying different halftones according to the geometrical characteristics of the 3D surface could emphasize or diminish the perceived 3D geometrical structures of a shape. The experimental results are in line with the simulated outputs reported in previous work. Our findings might introduce a new approach towards having more control over 3D appearance reproduction without changing the material or printer settings.
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- Bäcklund, Christian, et al.
(författare)
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Exploring the relationship between personality and gaming disorder symptoms in a sample of Dota 2 players
- 2024
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Ingår i: Current Psychology. - : Springer. - 1046-1310 .- 1936-4733.
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Tidskriftsartikel (refereegranskat)abstract
- This study explored the relationship between the big five personality traits and gaming disorder symptoms (GDS) in a sample of Dota 2 players. Recent research has indicated that the relationship between personality traits and GDS may depend on the video game genre investigated. However, the association between GDS and personality has yet to be investigated within a specific game, which may be even more relevant to explore as each game offers unique gameplay mechanics that can influence player behavior differently. Thus, the present study investigated the relationship between the big five personality traits and GDS in a sample of video game players from a specific game, DOTA 2 (n = 321, M = 23.25 years, SD = 4.51). Multiple linear regression was used to analyze GDS formatted as a composite score, and multinomial logistic regressions were further conducted for analyses in which gamers were classified into normal gamers (i.e., less than three criteria endorsed), moderate-risk gamers (i.e., four criteria endorsed), and high-risk gamers (i.e., all criteria endorsed). The analysis of the composite score showed a significant relationship between neuroticism, conscientiousness, agreeableness, and GDS. Analyses of the gaming classifications revealed that neuroticism was the most crucial factor concerning differentiating moderate-risk and high-risk from normal gamers. The findings and their practical implications are further discussed.
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- Hulaj, Rame, et al.
(författare)
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A Motivational Model Explaining Performance in Video Games
- 2020
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Ingår i: Frontiers in Psychology. - : Frontiers Media S.A.. - 1664-1078. ; 11
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Tidskriftsartikel (refereegranskat)abstract
- Esports are a rapidly growing phenomenon and understanding of factors underlying game performance are therefore of great interest. The present study investigated the influence of satisfaction of basic psychological needs (competence, autonomy, and relatedness), type of motivation (amotivation, external regulation, introjected regulation, identified regulation, integrated regulation, and intrinsic motivation), and number of matches played (time on task) on individuals’ performance on a matchmaking rating (MMR) in the video game Defence of the Ancients 2 (Dota 2). Collected data from 315 participants was included in the analyses. A web-based questionnaire was used to collect data and structural equation modelling (SEM) was performed to analyze the data. The results show that perceived competence and autonomy were the only significant predictors of MMR performance beyond matches played. Fulfillment of relatedness, as well as motivational factors, were not found to be predictors of MMR scores. The strong effect of matches played, used as proxy of time on task, emphasize the effect of time and practice as a critical aspect of video-game expertise.
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