1,721,012 research outputs found
Hologram Domain Data Compression: Performance of Standard Codecs and Image Quality Assessment at Different Distances and Perspectives
No full textComputer generated holograms represent a novel digital media that with adequate processing tools and the advance of holographic display technologies will foster the development of true immersive video technologies applications. A digital hologram typically conveys a considerable amount of data making compression and image quality evaluation tools necessary for the development of practical applications. This paper proposes an objective evaluation of the performances of state-of-the-art compression techniques applied to digital holographic data. The experimental analysis takes into account several holographic images reconstructing the holograms from different perspectives and distances. The results of the exploratory study are reported, discussed and complemented with a statistical analysis of the hologram data under test, providing insights for computer-generated holography compression techniques design
3D point cloud reconstruction from single plenoptic image
No full textNovel plenoptic cameras sample the light field crossing the main camera lens. The information available in a plenoptic image must be processed, in order to create the depth map of the scene from a single camera shot. In this paper a novel algorithm, for the reconstruction of 3D point cloud of the scene from a single plenoptic image, taken with a consumer plenoptic camera, is proposed. Experimental analysis is conducted on several test images, and results are compared with state of the art methodologies. The results are very promising, as the quality of the 3D point cloud from plenoptic image, is comparable with the quality obtained with current non-plenoptic methodologies, that necessitate more than one image
Effect on dental stain occurrence by chewing gum containing sodium tripolyphosphate--a double-blind six-week trial
No full textObjective: A six-week controlled double-blind clinical study was conducted to assess and to measure the efficacy of a sugar-free chewing gum containing sodium tripolyphosphate (1%) on dental stain occurrence versus a placebo sugar-free chewing gum. Methods: One-hundred and eleven subjects who had a Lobene Modified Index for stain extent score between 0.33 and 1.5 in their frontal teeth joined this study. Each subject entered in the test or the control group using a random table which allowed for an equal distribution of smokers and habitual tea users. Participants agreed to chew two gums (two grams each) three times per day, after meals, for ten minutes over six weeks. All received the same dentifrice containing only fluoride as the active agent. After six weeks, participants were scored for dental stain with the Lobene Modified Index. Data were scored by the same blinded operator for all measurements. Comparisons between the groups with respect to baseline scores were performed using an unpaired t-test, and inside the groups with a paired t-test (α = 0.05). Results: One-hundred and eight subjects completed the trial; three left, but none reported problems linked to sodium tripolyphosphate. The mean difference for stain extent index after the six-week trial was 0.04 (± 0.08) in the control group, and-0.05 (± 0.08) in the test group (p < 0.001). A statistically significant reduction was also reported for intensity and composite indexes. The initial mean for stain extent index in the test group was 0.8 (± 0.34), and at six weeks was 0.74 (± 0.33; p < 0.001). The initial mean for extent index in the control group was 0.78 (± 0.3), and at six weeks was 0.81 (± 0.32; p < 0.005). Conclusion: This trial showed a reduction in dental stain by a chewing gum containing sodium tripolyphosphate after six weeks
Objective Image Quality Analysis of Convolutional Neural Network Light Field Coding
No full textLight field digital images are novel image modalities for capturing a sampled representation of the plenoptic function. A large amount of data is typically associated to a single sample of a scene, and data compression tools are required in order to develop systems and applications for light field communications. This paper presents the study of the performance of a convolutional neural network autoencoder as a tool for digital light field image compression. Testing conditions and a framework for the experimental evaluation are proposed for this study. Different encoders and coding conditions are taken into consideration, obtained results are reported and critically discussed
Whitening Optical Effect of New Chewing Gums
Full text linkBackground: Today, many treatments are available to enhance the color of teeth, but they require a few days to weeks to deliver this effect. Objective: To evaluate the instantaneous optical whitening effect of two new sugar-free chewing gums and one dentifrice of proven efficacy versus one placebo chewing gum. Methods: This was a single-blind, parallel trial. 424 participants entered the study and were randomly allocated to four groups. They received a personal silicone mask with a calibrated hole at one upper incisor to apply a dental colorimeter. The tools tested were chewing-gum containing indigotine (E132-FD&C Blue 2) and spirulina, chewing-gum containing only spirulina, chewing-gum placebo, and dentifrice containing Blue Covarine. Vita® Easyshade scored the tooth color, and the WIO and WID whiteness indexes were calculated. For chewing gums, the color of the teeth was scored before the assumption and after 2’30” of mastication. For dentifrice, participants brushed for 1’30”, then rinsed, and the color was scored before brushing and after 2’30”. Statistical analysis was performed by ANOVA and Tukey post-hoc. Results: The two experimental whitening chewing gums and the dentifrice significantly increased the WIO and the WID indexes from the baselines (p<0.001). Moreover, their effects were statistically greater than those reported for the placebo chewing gum (p<0.05) but not significatively different among them (p=NS). Conclusion: All the tested whitening tools showed an instant optical whitening perception. Further studies are required to assess the intensity of the effect over a prolonged time to meet the people's request for fast whitening tools
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