Integral Imaging Display System Based on Human Visual Distance Perception Model.

In an integral imaging (II) display system, the self-adjustment ability of the human eye can result in blurry observations when viewing 3D targets outside the focal plane within a specific range. This can impact the overall imaging quality of the II system. This research examines the visual characteristics of the human eye and analyzes the path of light from a point source to the eye in the process of capturing and reconstructing the light field. Then, an overall depth of field (DOF) model of II is derived based on the human visual system (HVS). On this basis, an II system based on the human visual distance (HVD) perception model is proposed, and an interactive II display system is constructed. The experimental results confirm the effectiveness of the proposed method. The display system improves the viewing distance range, enhances spatial resolution and provides better stereoscopic display effects. When comparing our method with three other methods, it is clear that our approach produces better results in optical experiments and objective evaluations: the cumulative probability of blur detection (CPBD) value is 38.73%, the structural similarity index (SSIM) value is 86.56%, and the peak signal-to-noise ratio (PSNR) value is 31.12. These values align with subjective evaluations based on the characteristics of the human visual system.

Integral imaging reconstruction system based on the human eye viewing mechanism.

For integral stereo imaging systems based on lens arrays, the cross-mixing of erroneous light rays between adjacent lenses seriously affects the quality of the reconstructed light field. In this paper, we proposed a light field reconstruction method based on the human eye viewing mechanism, which incorporates simplified human eye imaging into the integral imaging system. First, the light field model for specified viewpoint is established, and the distribution of the light source for each viewpoint is accurately calculated for the EIA generation algorithm of fixed viewpoint. Second, according to the ray tracing algorithm in this paper, non-overlapping EIA based on the human eye viewing mechanism is designed to suppress the amount of crosstalk rays fundamentally. The actual viewing clarity is improved with the same reconstructed resolution. Experimental results verify the effectiveness of the proposed method. The SSIM value is higher than 0.93, which verifies that the viewing angle range is increased to 62°.

Dynamic Analysis and Path Planning of a Turtle-Inspired Amphibious Spherical Robot.

A dynamic path-planning algorithm based on a general constrained optimization problem (GCOP) model and a sequential quadratic programming (SQP) method with sensor input is proposed in this paper. In an unknown underwater space, the turtle-inspired amphibious spherical robot (ASR) can realise the path-planning control movement and achieve collision avoidance. Due to the special underwater environments, thrusters and diamond parallel legs (DPLs) are installed in the lower hemisphere to realise accurate motion control. A propulsion model for a novel water-jet thruster based on experimental analysis and a modified Denavit-Hartenberg (MDH) algorithm are developed for multiple degrees of freedom (MDOF) to realize high-precision and high-speed motion control. Simulations and experiments verify that the effectiveness of the GCOP and SQP algorithms can realize reasonable path planning and make it possible to improve the flexibility of underwater movement with a small estimation error.

Clinical practice guidelines for the nutritional risk screening and assessment of cancer patients: a systematic quality appraisal using the AGREE II instrument.

PURPOSE: To evaluate the quality of published clinical practice guidelines (CPGs) regarding the nutritional risk screening and assessment of cancer patients and to identify high-quality CPGs for clinical healthcare professionals. METHODS: Guidelines for the nutritional risk screening and assessment of cancer patients were comprehensively searched in eight electronic databases, including The Lancet, PubMed, Cochrane Library, Excerpta Medica dataBASE (EMBASE), Web of Science, China National Knowledge Infrastructure (CNKI), China Biology Medicine disc (CBMdisc), and Wan Fang Data, through August 2020. Six relevant guideline databases, including the National Comprehensive Cancer Network (NCCN), the National Guideline Clearinghouse (NGC), the Guideline International Network (GIN), the New Zealand Guidelines Group (NZGG), the China Guideline Clearinghouse (CGC), and Medlive, and relevant nutrition society websites, were also searched through August 2020. The methodological quality of the included CPGs was appraised independently by three assessors using the Appraisal of Guidelines for Research and Evaluation, 2nd edition (AGREE II) tool. RESULTS: Seven CPGs were located, and the domain with the highest percentage was "clarity of presentation" (85.44%), while the domain with the lowest percentage was "applicability" (40.26%). From the AGREE II results, two guidelines were rated as "strongly recommended," three were assessed as "recommended with modifications," and two were deemed as "not recommended." CONCLUSION: Considering that the two "strongly recommended" guidelines were developed within the American and European contexts, translation, validation, and cultural adaptation are recommended prior to implementing these guidelines in other countries or healthcare contexts to improve their effectiveness and sensitivity for local cancer patients. TRIAL REGISTRATION: PROSPERO registration of the study protocol: CRD42020177390 (July 5, 2020).