The aim of this paper is two-fold: firstly, to provide an overview of emerging digital practices that support collaborative learning, competency development, and digital literacy for student-centered learning environments in higher education during the rapid digital transition caused by pandemic-related lockdowns across the world, and secondly, to analyze and discuss how systematic reviews of generalized themes and trends can be combined with contextualized experiences and the lessons learned from the Covid-19 crisis to inform the digital transformation of higher education, with a particular focus on bridging the gap between campus-based teaching and online learning and on the identification of the digital competencies that teachers and students must acquire during the continuing shift into a 'new normal' for post-pandemic educational practices. This study was motivated by questions and findings emerging from an early reactive case study conducted by three of this paper's co-authors (Lyngdorf et al., 2021a).
View Article and Find Full Text PDFImaging in poorly illuminated environments using three-dimensional (3D) imaging with passive imaging sensors that operate in the visible spectrum is a formidable task due to the low number of photons detected. 3D integral imaging, which integrates multiple two-dimensional perspectives, is expected to perform well in the presence of noise, as well as statistical fluctuation in the detected number of photons. In this paper, we present an investigation of 3D integral imaging in low-light-level conditions, where as low as a few photons and as high as several tens of photons are detected on average per pixel.
View Article and Find Full Text PDFWe present an approach for optical sensing and detection in turbid water using multidimensional spatial-temporal domain integral imaging and dedicated signal processing algorithms. An optical signal is encoded using pseudorandom sequences, and an image sensor array is used to capture elemental image video sequences of light propagating through turbid water. Using the captured information, multidimensional image reconstruction followed by multi-dimensional correlation to detect the source signal is performed.
View Article and Find Full Text PDFWe present spatial-temporal human gesture recognition in degraded conditions including low light levels and occlusions using passive sensing three-dimensional (3D) integral imaging (InIm) system and 3D correlation filters. The 4D (lateral, longitudinal, and temporal) reconstructed data is processed using a variety of algorithms including linear and non-linear distortion-invariant filters; and compared with previously reported space-time interest points (STIP) feature detector, 3D histogram of oriented gradients (3D HOG) feature descriptor, with a standard bag-of-features support vector machine (SVM) framework, etc. The gesture recognition results with different classification algorithms are compared using a variety of performance metrics such as receiver operating characteristic (ROC) curves, area under the curve (AUC), SNR, the probability of classification errors, and confusion matrix.
View Article and Find Full Text PDFWe present a spatio-temporal analysis of cell membrane fluctuations to distinguish healthy patients from patients with sickle cell disease. A video hologram containing either healthy red blood cells (h-RBCs) or sickle cell disease red blood cells (SCD-RBCs) was recorded using a low-cost, compact, 3D printed shearing interferometer. Reconstructions were created for each hologram frame (time steps), forming a spatio-temporal data cube.
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