We develop a first-order description of spatio-temporal distortions in ultrashort pulses using normalized parameters that allow for a direct assessment of their severity, and we give intuitive pictures of pulses with different amounts of the various distortions. Also, we provide an experimental example of the use of these parameters in the case of spatial chirp monitored in real-time during the alignment of an amplified laser system.
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http://dx.doi.org/10.1364/oe.15.000242 | DOI Listing |
Entropy (Basel)
January 2025
Faculty of Information Science and Engineering, Ningbo University, Ningbo 315211, China.
Arbitrary translational Six Degrees of Freedom (6DoF) video represents a transitional stage towards immersive terminal videos, allowing users to freely switch viewpoints for a 3D scene experience. However, the increased freedom of movement introduces new distortions that significantly impact human visual perception quality. Therefore, it is crucial to explore quality assessment (QA) to validate its application feasibility.
View Article and Find Full Text PDFPLoS One
July 2024
Faculty of Geography, Yunnan Normal University, Yunnan, China.
Space-time fusion is an economical and efficient way to solve "space-time contradiction". Among all kinds of space-time fusion methods, Fit-FC space-time fusion method based on weight Function is widely used. However, this method is based on the linear model to depict the phase change, but the phase change in the real scene is complicated, and the linear model is difficult to accurately capture the phase change, resulting in the spectral distortion of the fusion image.
View Article and Find Full Text PDFPLoS One
May 2024
School of Engineering, The University of Waikato, Hamilton, New Zealand.
Digital video incurs many distortions during processing, compression, storage, and transmission, which can reduce perceived video quality. Developing adaptive video transmission methods that provide increased bandwidth and reduced storage space while preserving visual quality requires quality metrics that accurately describe how people perceive distortion. A severe problem for developing new video quality metrics is the limited data on how the early human visual system simultaneously processes spatial and temporal information.
View Article and Find Full Text PDFMagn Reson Med
September 2024
School of Biomedical Engineering, Shanghai Jiao Tong University, Shanghai, People's Republic of China.
Purpose: Demonstrate the potential of spatiotemporal encoding (SPEN) MRI to deliver largely undistorted 2D, 3D, and diffusion weighted images on a 110 mT portable system.
Methods: SPEN's quadratic phase modulation was used to subsample the low-bandwidth dimension of echo planar acquisitions, delivering alias-free images with an enhanced immunity to image distortions in a laboratory-built, low-field, portable MRI system lacking multiple receivers.
Results: Healthy brain images with different SPEN time-bandwidth products and subsampling factors were collected.
Sensors (Basel)
November 2023
National Key Laboratory of Optical Field Manipulation Science and Technology, Chinese Academy of Sciences, Chengdu 610209, China.
Adaptive Optics (AO) technology is an effective means to compensate for wavefront distortion, but its inherent delay error will cause the compensation wavefront on the deformable mirror (DM) to lag behind the changes in the distorted wavefront. Especially when the change in the wavefront is higher than the Shack-Hartmann wavefront sensor (SHWS) sampling frequency, the multi-frame delay will seriously limit its correction performance. In this paper, a highly stable AO prediction network based on deep learning is proposed, which only uses 10 frames of prior wavefront information to obtain high-stability and high-precision open-loop predicted slopes for the next six frames.
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