Turning water into rock: The inverted waves effect

Humans perceive shape in two-dimensional shaded images, and turning such an image upside down can result in inversion of the relief of this image. Previous research indicates that this inversion is caused by assumptions related to overhead illumination, global convexity and viewpoint above the surface. In our article, we describe the inverted waves effect, in which turning an image of waves upside down changes its relief and also its perceived material properties.Peer reviewe

A method for Measuring Contact Points in Human–Object Interaction Utilizing Infrared Cameras

This article presents a novel method for measuring contact points in human-object interaction. Research in multiple prehension-related fields, e.g., action planning, affordance, motor function, ergonomics, and robotic grasping, benefits from accurate and precise measurements of contact points between a subject's hands and objects. During interaction, the subject's hands occlude the contact points, which poses a major challenge for direct optical measurement methods. Our method solves the occlusion problem by exploiting thermal energy transfer from the subject's hand to the object surface during interaction. After the interaction, we measure the heat emitted by the object surface with four high-resolution infrared cameras surrounding the object. A computer-vision algorithm detects the areas in the infrared images where the subject's fingers have touched the object. A structured light 3D scanner produces a point cloud of the scene, which enables the localization of the object in relation to the infrared cameras. We then use the localization result to project the detected contact points from the infrared camera images to the surface of the 3D model of the object. Data collection with this method is fast, unobtrusive, contactless, markerless, and automated. The method enables accurate measurement of contact points in non-trivially complex objects. Furthermore, the method is extendable to measuring surface contact areas, or patches, instead of contact points. In this article, we present the method and sample grasp measurement results with publicly available objects.Peer reviewe

Reading e-books on a near-to-eye display: Comparison between a small-sized multimedia display and a hard copy

Peer reviewe

Underlying elements of image quality assessment: : Preference and terminology for communicating image quality characteristics

Image quality markedly affects the evaluation of images, and its control is crucial in studies using natural visual scenes as stimuli. Various image elements, such as sharpness or naturalness, can impact how observers view images and more directly how they evaluate their quality. To gain a better understanding of the types of interactions between these various elements, we conducted a study with a large set of images with multiple overlapping distortions, covering a wide range of quality variation. Observers assigned a quality rating on a 0-10 scale plus a verbal description of the images, explaining the elements on which their rating was based. Regression model predicting image quality ratings using 68 attributes uncovered the link between verbal descriptions and quality ratings and the importance of the image quality rating for each of the 68 image attributes. Brightness, naturalness, and good colors seem to be related to the highest image quality preference. However, the most important elements for predicting good image quality were related to image fidelity such as graininess and sharpness. This indicates that a certain level of image fidelity must be achieved before more subjective associations with, for instance, naturalness can emerge. Of the attributes, 72% had a negative impact on the preference judgment. This negative bias may be due to the fact that there are more ways that observers can perceive an image to fail than to excel when they are asked to evaluate image quality.Image quality markedly affects the evaluation of images, and its control is crucial in studies using natural visual scenes as stimuli. Various image elements, such as sharpness or naturalness, can impact how observers view images and, more directly, how they evaluate their quality. To gain a better understanding of the types of interactions between these various elements, we conducted a study with a large set of images with multiple overlapping distortions, covering a wide range of quality variation. Observers assigned a quality rating of the images on a 0–10 scale and gave a verbal description explaining the elements on which their rating was based. A regression model predicting image quality ratings using 68 attributes uncovered the link between verbal descriptions and quality ratings and the importance of the image quality rating for each of the 68 image attributes. Brightness, naturalness, and good colors seem to be related to the highest image quality preference. However, the most important elements for predicting good image quality were related to image fidelity such as graininess and sharpness. This indicates that a certain level of image fidelity must be achieved before more subjective associations with, for instance, naturalness can emerge. Of the attributes, 72% had a negative impact on the preference judgment. This negative bias may be due to the fact that there are more ways that observers can perceive an image to fail than to excel when they are asked to evaluate image quality.Peer reviewe

The impact of the display type and content to a game adaptation

This study examines the impact of the display type (form) and content (game) to the PC-game adaptation. An ordinary table-top display (cathode ray tube; CRT) and a near-eye display (NED) suitable for mobile gaming are compared in two different driving games. A measurement model based on a large dataset (n=2182) is applied to study psychological aspects of the game adaptation. This model integrates two constructs considered important for the game adaptation: involvement and presence. The results show that the content affected the subjective sense of presence. However, the form did not have an effect on the pres-ence. These results indicate that NED’s are capable of support-ing similar adaptation to the game worlds as compared to CRT’s. However, the results also weakly indicate that playing with a CRT increases the evaluations of interaction. The study shows the advantages of using multidimensional measures in studying a rich human-computer interaction

Upper Nasal Hemifield Location and Nonspatial Auditory Tones Accelerate Visual Detection during Dichoptic Viewing

Visual performance is asymmetric across the visual field, but locational biases that occur during dichoptic viewing are not well understood. In this study, we characterized horizontal, vertical and naso-temporal biases in visual target detection during dichoptic stimulation and explored whether the detection was facilitated by non-spatial auditory tones associated with the target's location. The detection time for single monocular targets that were suppressed from view with a 10 Hz dynamic noise mask presented to the other eye was measured at the 4 degrees intercardinal location of each eye with the breaking Continuous Flash Suppression (b-CFS) technique. Each target was either combined with a sound (i.e., high or low pitch tone) that was congruent or incongruent with its vertical location (i.e., upper or lower visual field) or presented without a sound. The results indicated faster detection of targets in the upper rather than lower visual field and faster detection of targets in the nasal than temporal hemifield of each eye. Sounds generally accelerated target detection, but the tone pitch-elevation congruency did not further enhance performance. These findings suggest that visual detection during dichoptic viewing differs from standard viewing conditions with respect to location-related perceptual biases and crossmodal modulation of visual perception. These differences should be carefully considered in experimental designs employing dichoptic stimulation techniques and in display applications that utilize dichoptic viewing.Peer reviewe

An effective method for measuring text legibility in XR devices reveals clear differences between three devices

Reading is a crucial aspect of the extended reality (XR) experience across various professional and recreational contexts. Legibility, which is defined as the ease with which a character can be recognized, is an essential determinant of readability. As legibility on a specific device cannot be deduced from technical specifications alone, an efficient perceptual method for measuring legibility is needed to measure the legibility of text presented in XR. In this study, we present a method for comparing the legibility limits of XR devices, where single letter legibility is measured with fast and precise psychophysical methods. We applied the method to compare the legibility in three commercial XR headsets (Varjo VR-2, HTC Vive Pro Eye, Oculus Quest 2) in experiments with human observers. Our results show that the single letter legibility methods presented here provide an effect size approximately ten times higher compared to the widely used method of reading speed. This allows for the use of fewer observers and the detection of smaller differences, making it a more efficient and effective approach for comparing the legibility limits of XR devices

Differential Regulation of Decorin and Biglycan Gene Expression by Dexamethasone and Retinoic Acid in Cultured Human Skin Fibroblasts

Proteoglycans participate in the assembly of extracellular matrix, directly by interacting with other matrix components and indirectly by regulating cellular growth-factor responses. We have studied the regulation of gene expression of two small extracellular matrix chondroitin/dermatan sulfate proteoglycans, decorin and biglycan, by dexamethasone and retinoic acid In cultured human skin fibroblasts. Dexamethasone increased decorin production, maximally 4,8- fold, and decorin mRNA levels up to 2.3-fold, but had no effect on biglycan production or mRNA levels. Dexamethasone also prevented transforming growth factor-β-elicited down-regulation of decorin mRNA levels and production by dermal fibroblasts. In addition, dexamethasone potently inhibited enhancement of biglycan production and mRNA levels by transforming growth factor-β. Retinoic acid dose dependently reduced decorin mRNA levels (by 51%) and production (by 72%), but had no effect on biglycan gene expression. Retinoic acid did not alter the effect of transforming growth factor-β on decorin or biglycan production or mRNA levels. These results provide evidence that tile effects of glucocorticoids and retinoids on dermal connective tissue are partially mediated via altered expression of decorin and biglycan, which both in turn regulate the activity of transforming growth factor-β, the most potent stimulator of connective tissue deposition

Evaluation of subjective video quality of mobile devices,”

ABSTRACT Subjectively perceived video quality is a critical factor when adopting new mobile video applications. When video is used in mobile networks the most important requirements are related to low bitrates, framerates and the screen size of mobile device. In two tests we investigated the effects of codecs and combinations of audio and video streams with low bitrates and different contents on the perceived video quality of mobile devices. The first test showed that the codec H.264 produced the most satisfying video quality, but the quality was not high enough for the presentation of textual information. In the second test, the audio-video ratio 32/128kbps was found to be the most pleasant, but there were content dependent variations