Estimating visual difference between reproduction gamuts: moving our pilot study from the lab to online delivery

Images reproduced for different output devices are known to be limited in the range of colours that can be reproduced. It is accepted that reproductions made with different print processes, and on different substrates, will not match, although the overall reproduction appearance can be optimized using an output rendering. However, the question remains: how different are they visually? This paper reports on a pilot study that tests whether visual difference can be reduced to a single dimensional scale using magnitude estimation. Subject to recent Covid restrictions, the experiment was moved from the lab to an online delivery. We compare the two methods of delivery: in-person under controlled viewing conditions, and online via a web-based interface where viewing conditions are unknown.

Judgements of the Duration of Auditory and Visual Stimuli

Studies of judgements of the durations of filled auditory and visual stimuli were reviewed, and some previously unpublished data were analysed. Data supported several conclusions. Firstly, auditory stimuli have longer subjective durations than visual ones, with visual stimuli commonly being judged as having 80–90% of the duration of auditory ones. Secondly, the effect was multiplicative, with the auditory/visual difference increasing as the intervals became longer. Only a small number of exceptions to both these conclusions were found. Thirdly, differences in variability between judgements of auditory and visual stimuli derived from most procedures were small and sometimes not statistically significant, although differences almost always involved visual stimuli producing more variable judgements. Currently, the most viable explanation of the effects appears to be some sort of pacemaker-counter model with higher pacemaker speed for auditory stimuli, although this approach cannot, in its present form, deal quantitatively with all the findings usually obtained.

Segmentation of Illuminated Areas of Light Using CNN and Large-Scale RGB+D Dataset for Augmented and Mixed Reality Systems

This work is devoted to the problem of restoring realistic rendering for augmented and mixed reality systems. Finding the light sources and restoring the correct distribution of scene brightness is one of the key parameters that allows to solve the problem of correct interaction between the virtual and real worlds. With the advent of such datasets as, "LARGE-SCALE RGB + D," it became possible to train neural networks to recognize the depth map of images, which is a key requirement for working with the environment in real time. Additionally, in this work, convolutional neural networks were trained on the synthesized dataset with realistic lighting. The results of the proposed methods are presented, the accuracy of restoring the position of the light sources is estimated, and the visual difference between the image of the scene with the original light sources and the same scene. The speed allows it to be used in real-time AR/VR systems.

A New Measure to Characterize the Degree of Self-Similarity of a Shape and Its Applicability

We propose a new measure (Γ) to quantify the degree of self-similarity of a shape using branch length similarity (BLS) entropy which is defined on a simple network consisting of a single node and its branches. To investigate the properties of this measure, we computed the Γ values for 70 object groups (20 shapes in each group) in the MPEG-7 shape database and performed grouping on the values. With relatively high Γ values, identical groups had visually similar shapes. On the other hand, the identical groups with low Γ values had visually different shapes. However, the aspect of topological similarity of the shapes also warrants consideration. The shapes of statistically different groups exhibited significant visual difference from each other. Also, in order to show that the Γ can have a wide variety of applicability when properly used with other variables, we showed that the finger gestures in the (Γ, Z) space are successfully classified. Here, the Z means a correlation coefficient value between entropy profiles for gesture shapes. As shown in the applications, Γ has a strong advantage over conventional geometric measures in that it captures the geometrical and topological properties of a shape together. If we could define the BLS entropy for color, Γ could be used to characterize images expressed in RGB. We briefly discussed the problems to be solved before the applicability of Γ can be expanded to various fields.

Optimization of Green Extraction and Purification of PHA Produced by Mixed Microbial Cultures from Sludge

Sludge from municipal wastewater treatment systems can be used as a source of mixed microbial cultures for the production of polyhydroxyalkanoates (PHA). Stored intracellularly, the PHA is accumulated by some species of bacteria as energy stockpile and can be extracted from the cells by reflux extraction. Dimethyl carbonate was tested as a solvent for the PHA extraction at different extraction times and biomass to solvent ratios, and 1-butanol was tested for purifying the obtained PHA at different purification times and PHA to solvent ratios. Overall, only a very small difference was observed in the different extraction scenarios. An average extraction amount of 30.7 ± 1.6 g of PHA per 100 g of biomass was achieved. After purification with 1-butanol, a visual difference was observed in the PHA between the tested scenarios, although the actual purity of the resulting samples did not present a significant difference. The overall purity increased from 91.2 ± 0.1% to 98.0 ± 0.1%.

Robustness Testing of Mesenchymal Stem Cell Monotherapy Following Vascularized Composite Allotransplantation

Background Immunosuppression risks are a major concern with vascularized composite allotransplantation (VCA). As an emerging strategy, the antirejection role played by mesenchymal stem cells (MSCs) is receiving attention. However, the current literature reports are inconclusive regarding the robustness of the MSC monotherapy. Using a rat forelimb VCA model, this study tested the robustness of the immunomodulation efficacy of gingival-derived MSCs (GMSCs) and bone marrow–derived MSCs (BMMSCs). Methods Forelimbs were transplanted on pairs of major histocompatibility complex–incompatible rats (Wistar-Kyoto donor, Lewis [LEW] recipient). Twenty-four LEW rats were randomly divided into four groups, including control (no treatment) and three treatment groups: rapamycin (2 mg/kg/day for 28 days, postoperatively), BMMSC and GMSC, both of which received donor-derived stem cells administered intravenously on postoperative days (PODs) 0, 3, 7, and 14. Rejection was considered as 80% skin necrosis of the allograft. Microcomputed tomography (µCT) was performed to evaluate healing at osteosynthesis site. On POD 14, limbs from each group underwent histological analysis and rejection grading using the Banff system. Results Both BMMSC (15.0 days) and GMSC (14.7 days) treatment failed to prolong VCA survival in comparison with the control group (13.8 days; p > 0.050), while the rapamycin significantly delayed acute VCA rejection (24.5 days; p = 0.003). Micro-CT imaging revealed no gross visual difference across all groups. Histology revealed that the control group was most severely affected (grades III and IV) followed by MSC (grade II) and rapamycin (grade I). Conclusion MSC monotherapy, both BMMSC and GMSC, did not inhibit rejection in our VCA model. Skin immunogenicity is an important issue in promoting rejection, and a concomitant immunosuppression regimen should be considered to prolong allograft survival.

Daltonization by spectral filtering

Observers with a colour vision deficiency usually find it more difficult to discriminate between red and green colours, due to genetic variation in cone spectral sensitivity. Daltonization methods aim to enhance colour stimuli in order to increase the visual difference between them for such observers. In this work we focus on filtering the stimulus in the reflectance domain prior to conversion to colorimetry. This is hypothesized to enable a more precise tuning of the enhancement to the spectral absorptions of the observer with a colour vision deficiency. A spectral sharpening filter was developed and applied to spectral reflectances for a range of colour pairs which observers with a colour vision deficiency would be expected to find difficult to discriminate. The reflectance pairs were converted to colorimetry and presented on a colour display, where the visual difference between the pairs was evaluated by observers in a psychophysical experiment. Results suggest that a suitable filter can lead to an increase in the difference between the red-green pairs.

Neurophysiological and Psychological Consequences of Social Exclusion: The Effects of Cueing In-Group and Out-Group Status

Exclusion by outgroups is often attributed to external factors such as prejudice. Recently, event-related potential studies have demonstrated that subtle cues influence expectations of exclusion, altering the P3b response to inclusion or exclusion. We investigated whether a visual difference between participants and interaction partners could activate expectations of exclusion, indexed by P3b activity, and whether this difference would influence psychological responses to inclusion and exclusion. Participants played a ball-tossing game with two computer-controlled coplayers who were believed to be real. One period involved fair play inclusion while the other involved partial exclusion. Avatars represented participants, with their color matching participant skin tone, and either matching or differing from the color of coplayer avatars. This created the impression that the participant was an ingroup or outgroup member. While ingroup members elicited enhanced P3b activation when receiving the ball during exclusion, outgroup members showed this pattern for both inclusion and exclusion, suggesting that they formed robust a-priori expectations of exclusion. Self-reports indicated that while these expectations were psychologically protective during exclusion, they were detrimental during inclusion. Ultimately, this study reveals that expectations of exclusion can be formed purely based on visual group differences, regardless of the actual minority or majority status of individuals.

Digital Watermarking Image Compression Method Based on Symmetric Encryption Algorithms

A digital watermarking image compression method based on symmetrical encryption algorithm is proposed in this study. First, the original image and scrambled watermarking image are processed by wavelet transform, and then the watermarking image processed by the Arnold replacement method is transformed into a meaningless image in the time domain to achieve the effect of encryption. Watermarking is generated by embedding the watermarking image into the important coefficients of the wavelet transform. As an inverse process of watermarking embedding, watermarking extraction needs to be reconstructed by the wavelet transform. Finally, the watermarking is extracted from the inverse scrambled watermarking image, and a new symmetrically encrypted digital watermarking image is obtained. The compression method compresses the embedded digital watermarking image, so that the volume of the compressed watermarking image is greatly reduced when the visual difference is very small. The experimental results show that the watermarking image encrypted by this method not only has good transparency, but also has strong anti-brightness/contrast attack, anti-shearing, and anti-noise performance. When the volume of the compressed image is greatly reduced, the root mean square error and visual difference measurement of the watermarking image are very small.