This Letter presents a novel, to the best of our knowledge, method to calibrate multi-focus microscopic structured-light three-dimensional (3D) imaging systems with an electrically adjustable camera focal length. We first leverage the conventional method to calibrate the system with a reference focal length
Optimizing retrieval spaces of bio-optical models for remote sensing of ocean color
We investigated the optimal number of independent parameters required to accurately represent spectral remote sensing reflectances (
- PAR ID:
- 10408361
- Publisher / Repository:
- Optical Society of America
- Date Published:
- Journal Name:
- Applied Optics
- Volume:
- 62
- Issue:
- 13
- ISSN:
- 1559-128X; APOPAI
- Format(s):
- Medium: X Size: Article No. 3299
- Size(s):
- Article No. 3299
- Sponsoring Org:
- National Science Foundation
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f 0. Then we calibrate the system with other discrete focal lengthsf i by determining virtual features on a reconstructed white plane usingf 0. Finally, we fit the polynomial function model using the discrete calibration results forf i . Experimental results demonstrate that our proposed method can calibrate the system consistently and accurately. -
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There has been a long-term endeavor in the light-scattering research community to develop a Lorenz-Mie theory-type method for simulating light scattering by spheroidal particles with small-to-large sizes. A spheroid is a very important nonspherical shape in modeling the optical properties of many natural particles. For the first time, we develop a computationally feasible separation of variables method (SVM) in spheroidal coordinates to compute optical properties of spheroids with small-to-large sizes compared to the wavelength of the incident light (
λ ). The method is applicable to spheroids with size parameters (2π /λ times the major semiaxis) up to at least 600, and is not restricted by particle aspect ratios. Therefore, the work reported here represents a breakthrough in solving the optical properties of a nonspherical particle in an analytical form. -
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A new lens capability for three-dimensional (3D) focal control is presented using an optofluidic system consisting of
n × n arrayed liquid prisms. Each prism module contains two immiscible liquids in a rectangular cuvette. Using the electrowetting effect, the shape of the fluidic interface can be rapidly adjusted to create its straight profile with the prism’s apex angle. Consequently, an incoming ray is steered at the tilted interface due to the refractive index difference between two liquids. To achieve 3D focal control, individual prisms in the arrayed system are simultaneously modulated, allowing incoming light rays to be spatially manipulated and converged on a focal point located atP focal(f x,f y,f z) in 3D space. Analytical studies were conducted to precisely predict the prism operation required for 3D focal control. Using three liquid prisms positioned on thex -,y -, and 45°-diagonal axes, we experimentally demonstrated 3D focal tunability of the arrayed optofluidic system, achieving focal tuning along lateral, longitudinal, and axial directions as wide as 0 ≤f x ≤ 30 mm, 0 ≤f y ≤ 30 mm, and 500 mm ≤f z ≤ ∞. This focal tunability of the arrayed system allows for 3D control of the lens’s focusing power, which could not be attained by solid-type optics without the use of bulky and complex mechanical moving components. This innovative lens capability for 3D focal control has potential applications in eye-movement tracking for smart displays, autofocusing of smartphone cameras, or solar tracking for smart photovoltaic systems. -
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ABSTRACT Objective Neighborhood perceptions are associated with physical and mental health outcomes; however, the biological associates of this relationship remain to be fully understood. Here, we evaluate the relationship between neighborhood perceptions and amygdala activity and connectivity with salience network (i.e., insula, anterior cingulate, thalamus) nodes.
Methods Forty-eight older adults (mean age = 68 [7] years, 52% female, 47% non-Hispanic Black, 2% Hispanic) without dementia or depression completed the Perceptions of Neighborhood Environment Scale. Lower scores indicated less favorable perceptions of aesthetic quality, walking environment, availability of healthy food, safety, violence (i.e., more perceived violence), social cohesion, and participation in activities with neighbors. Participants separately underwent resting-state functional magnetic resonance imaging.
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β = −0.33,p FDR= .04) and participation in activities with neighbors (β = −0.35,p FDR= .02) were associated with higher left amygdala activity, independent of covariates including psychosocial factors. Less favorable safety perceptions were also associated with enhanced left amygdala functional connectivity with the bilateral insular cortices and the left anterior insula (β = −0.34,p FDR= .04). Less favorable perceived social cohesion was associated with enhanced left amygdala functional connectivity with the right thalamus (β = −0.42,p FDR= .04), and less favorable perceptions about healthy food availability were associated with enhanced left amygdala functional connectivity with the bilateral anterior insula (right:β = −0.39,p FDR= .04; left:β = −0.42,p FDR= .02) and anterior cingulate gyrus (β = −0.37,p FDR= .04).Conclusions Taken together, our findings document relationships between select neighborhood perceptions and amygdala activity as well as connectivity with salience network nodes; if confirmed, targeted community-level interventions and existing community strengths may promote brain-behavior relationships.
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N ) of phase shifters, instead of the generalN (phase shifters) toN (emitters) control, the PCU can enable anN to 2N –1 control, which efficiently suppresses the aliasing effect. The theoretical analysis, numerical simulation, and experimental proof-of-concept have been completed in this work. The results show that a maximum suppression of 92.54% can be achieved for the grating lobes in simulation, and an average 53.76% is tested for one grating lobe in the experiment. In conclusion, the PCU can be used as a universal aliasing suppression unit on many types of integrated OPA devices.
