Cross Pixel Optical Flow Similarity for Self-Supervised Learning

We propose a novel method for learning convolutional neural image representations without manual supervision. We use motion cues in the form of optical flow, to supervise representations of static images. The obvious approach of training a network to predict flow from a single image can be needlessly difficult due to intrinsic ambiguities in this prediction task. We instead propose a much simpler learning goal: embed pixels such that the similarity between their embeddings matches that between their optical flow vectors. At test time, the learned deep network can be used without access to video or flow information and transferred to tasks such as image classification, detection, and segmentation. Our method, which significantly simplifies previous attempts at using motion for self-supervision, achieves state-of-the-art results in self-supervision using motion cues, competitive results for self-supervision in general, and is overall state of the art in self-supervised pretraining for semantic image segmentation, as demonstrated on standard benchmarks

Inner Space Preserving Generative Pose Machine

Image-based generative methods, such as generative adversarial networks (GANs) have already been able to generate realistic images with much context control, specially when they are conditioned. However, most successful frameworks share a common procedure which performs an image-to-image translation with pose of figures in the image untouched. When the objective is reposing a figure in an image while preserving the rest of the image, the state-of-the-art mainly assumes a single rigid body with simple background and limited pose shift, which can hardly be extended to the images under normal settings. In this paper, we introduce an image "inner space" preserving model that assigns an interpretable low-dimensional pose descriptor (LDPD) to an articulated figure in the image. Figure reposing is then generated by passing the LDPD and the original image through multi-stage augmented hourglass networks in a conditional GAN structure, called inner space preserving generative pose machine (ISP-GPM). We evaluated ISP-GPM on reposing human figures, which are highly articulated with versatile variations. Test of a state-of-the-art pose estimator on our reposed dataset gave an accuracy over 80% on PCK0.5 metric. The results also elucidated that our ISP-GPM is able to preserve the background with high accuracy while reasonably recovering the area blocked by the figure to be reposed.Comment: http://www.northeastern.edu/ostadabbas/2018/07/23/inner-space-preserving-generative-pose-machine

End-to-end 6-DoF Object Pose Estimation through Differentiable Rasterization

Here we introduce an approximated differentiable renderer to refine a 6-DoF pose prediction using only 2D alignment information. To this end, a two-branched convolutional encoder network is employed to jointly estimate the object class and its 6-DoF pose in the scene. We then propose a new formulation of an approximated differentiable renderer to re-project the 3D object on the image according to its predicted pose; in this way the alignment error between the observed and the re-projected object silhouette can be measured. Since the renderer is differentiable, it is possible to back-propagate through it to correct the estimated pose at test time in an online learning fashion. Eventually we show how to leverage the classification branch to profitably re-project a representative model of the predicted class (i.e. a medoid) instead. Each object in the scene is processed independently and novel viewpoints in which both objects arrangement and mutual pose are preserved can be rendered. Differentiable renderer code is available at:https://github.com/ndrplz/tensorflow-mesh-renderer

AUTO3D: Novel view synthesis through unsupervisely learned variational viewpoint and global 3D representation

This paper targets on learning-based novel view synthesis from a single or limited 2D images without the pose supervision. In the viewer-centered coordinates, we construct an end-to-end trainable conditional variational framework to disentangle the unsupervisely learned relative-pose/rotation and implicit global 3D representation (shape, texture and the origin of viewer-centered coordinates, etc.). The global appearance of the 3D object is given by several appearance-describing images taken from any number of viewpoints. Our spatial correlation module extracts a global 3D representation from the appearance-describing images in a permutation invariant manner. Our system can achieve implicitly 3D understanding without explicitly 3D reconstruction. With an unsupervisely learned viewer-centered relative-pose/rotation code, the decoder can hallucinate the novel view continuously by sampling the relative-pose in a prior distribution. In various applications, we demonstrate that our model can achieve comparable or even better results than pose/3D model-supervised learning-based novel view synthesis (NVS) methods with any number of input views.Comment: ECCV 202

Luminescence Spectroscopy of Quaternary Garnets Doped with Trivalent Rare-Earth Ions

Spectroscopy and energy transport in multi–ion ceramics with garnet structure (GYAGG) doped with rare–earth ions (Ce3+, Tb3+, Eu3+) were studied by photoluminescence (PL), cathodoluminescence (CL) and X–ray luminescence (XRL) methods.The work was partially supported by the Ministry of Science and Higher Education of the Russian Federation (through the basic part of the government mandate, project No. FEUZ-2020-0060)

Towards effective indirect radioisotope energy converters with bright and radiation hard scintillators of (Gd,Y)3Al2Ga3O12 family

Ceramics of quaternary garnets (Gd,Y)3Al2Ga3O12 doped with Ce, Tb have been fabricated and evaluated as prospective materials for indirect energy converters of α-and β-voltaic. Samples were characterized at excitation with an X-ray source and an intense 150 keV electron beam and showed good temperature stability of their emission and tolerance to irradiation. The role of X-rays accompanied the α-particle emitting in the increase of the conversion efficiency is clarified. The garnet-type structure of the matrix in the developed materials allows the production of quality crystalline mass with a light yield exceeding that of the commonly used YAG: Ce scintillator by a factor of two times. © 2022 Korean Nuclear SocietyMinistry of Education and Science of the Russian Federation, Minobrnauka: 075-15-2021-1353, FEUZ-2020-0060; Ministerstwo Edukacji i Nauki, MNiSW: 075-11-2021-070; Ministry of Science and Higher Education of the Russian FederationAuthors with affiliations b, d, e and f acknowledge support from Russian Ministry of Science and Education grant No. 075-15-2021-1353 . The scientific equipment provided by shared research facilities “Scientific Research Analytical Center of National Research Center “Kurchatov Institute” – IREA” was used, with financial support of Russian Federation, represented by the Ministry of Science and Higher Education, agreement No. 075-11-2021-070 dated August 19, 2021. The work was partially supported by the Ministry of Science and Higher Education of the Russian Federation (through the basic part of the government mandate, project No. FEUZ-2020-0060 ) (authors with affiliation “c”).Authors with affiliations b, d, e and f acknowledge support from Russian Ministry of Science and Education grant No. 075-15-2021-1353. The scientific equipment provided by shared research facilities “Scientific Research Analytical Center of National Research Center “Kurchatov Institute” – IREA” was used, with financial support of Russian Federation, represented by the Ministry of Science and Higher Education, agreement No. 075-11-2021-070 dated August 19, 2021. The work was partially supported by the Ministry of Science and Higher Education of the Russian Federation (through the basic part of the government mandate, project No. FEUZ-2020-0060) (authors with affiliation “c”)

Lanthanoid-doped quaternary garnets as phosphors for high brightness cathodoluminescence-based light sources

Gadolinium-yttrium- aluminum-gallium garnets (GYAGG) doped and codoped with Eu, Tb, and Ce were manufactured as ceramics to develop long-wavelength phosphors for high-brightness white light sources based on cathodoluminescence (CL). The CL light yield (LY) of Tb-doped ceramics at high-intensity electron beam excitation is shown to be more than twice as high as that of the conventional phosphor YAG:Ce, whereas codoping with Eu to redshift the chromaticity results in reducing the LY approximately to the level of YAG:Ce. The LY might be substantially improved by using a mix of Tb- and Eu-doped GYGAG powders instead of a single codoped GYGAG to produce ceramic phosphor. The high LY is explained by favorable contribution of Gd sublattice in excitation transfer to activator ions. Chromaticity of phosphors GYGAG:Tb, Eu can be tuned in a wide range by varying the ratio of Tb to Eu concentration. They are radiation resistant and stabile in the temperature range from 300 to 450 K. © 2022 The Author(s)Ministry of Education and Science of the Russian Federation, Minobrnauka: 075-11-2021-070, 075-15-2021-1353, FEUZ-2020-0060This work was supported by the Ministry of Science and Higher Education of the Russian Federation (FEUZ-2020-0060, No. 075-15-2021-1353 & 075-11-2021-070)

A Comparison of Accuracy between A New Commercial ELISA Test, GenediaTM Test and Other Commercial ELISA Tests for Serological Diagnosis of Helicobacter pylori Infection in Korea

Background/Aims : A new commercial enzyme linked immunosorbent assay (ELISA) test using Korean Helicobacter pylori (H. pylori) as an antigen, GenediaTM test, was compared to other serologic tests for H. pylori infection. Methods: Among two hundred seventy three subjects, H. pylori-positive group was consisted of 132 patients (50 peptic ulcer diseases, 52 chronic gastritis, and 30 gastric cancers) and H. pylori-negative group was consisted of 141 patients (121 adults and 20 pediatric patients). Endoscopic antral biopsy specimens were obtained for microscopy and rapid urease test (CLOTM test). We also performed GenediaTM IgG, IgA ELISA, G.A.P IgG, IgA ELISA, and Cobas-core IgG EIA. H. pylori infection was defermined when H. pylori was detected histologically or the results of CLOTM tests were positive. Results : The sensitivities and specificities of the serologic tests were 96.2% and 46.1% in GenediaTM IgG, 91.7% and 52.5% in GenediaTM IgA, 81.8% and 46.8% in G.A.P IgG, 25.0% and 85.1% in G.A.P IgA, 96.9% and 38.6% in Cobas-core test, respectively. In H. pylori-negative pediatric patients, the specificity of the tests was 80% in GenediaTM IgG, 95% in GenediaTM IgA, 60% in G.A.P. IgG, 100% in G.A.P IgA, and 75% in Cobas-core test. Conclusions: In Korea, GenediaTM test was comparable or superior to general serologic tests used for diagnosing H. pylori infection. However, it is necessary to improve the specificity of the GenediaTM test. (Kor J Gastroenterol 2000;36:20 - 28)ope