More Like this

1. On the Ambient Optic Array: James Gibson’s Insights About the Phenomenon of Chiaroscuro

   https://doi.org/10.1177/2041669520952097  

   Todd, James T. (September 2020, i-Perception)

   null (Ed.)

   In 1966, James Gibson first presented his theory of the ambient optic array, and he proposed a new field of ecological optics that he hoped would advance our knowledge on this topic. This study will consider how his ideas have largely come to fruition over the past 50 years. It reviews the research on the visual perception of three-dimensional shape from shading, the effects of ambient light from surface interreflections on observers’ perceptions, the perception of the light field, and the perception of surface materials. Finally, it also considers Gibson’s impact on these developments. 

   more » « less
2. Effect of Illumination on Human Drone Interaction Tasks: An Exploratory Study

   https://doi.org/10.1177/1071181321651123  

   Ozkan Yerebakan, Mustafa; Hao, Shuai; Xu, Kun; Gheisari, Masoud; Jeelani, Idris; Hu, Boyi (September 2021, Proceedings of the Human Factors and Ergonomics Society Annual Meeting)

   With recent changes by the Federal Aviation Administration (FAA) opening the possibility of more areas for drones to be used, such as delivery, there will be increasingly more intera ctions between humans and drones soon. Although current human drone interaction (HDI) investigate what factors are necessary for safe interactions, very few has focused on drone illumination. Therefore, in this study, we explored how illumination affects users’ perception of the drone through a distance perception task. Data analysis did not indicate any significant effects in the normal distance estimation task for illumination or distance conditions. However, most participants underestimated the distance in the normal distance estimation task and indicated that the LED drone was closer when it wa s illuminated during the relative distance estimation task, even though the drones were equidistant. In future studies, factors such as the weather conditions, lighting patterns, and height of the drone will be explored. 

   more » « less
3. Manipulate nanoparticles with a laser-induced microbubble

   https://doi.org/10.1364/BODA.2019.JT4A.2  

   Li, Yuwen; Zhao, Chenglong (April 2019, Optical Manipulation and Its Applications 2019)

   null (Ed.)

   A laser-induced microbubble refers to a bubble that is generated in a liquid solution by CW laser illumination to light absorptive materials. In this study, we use the gold nanoparticles solutions and gold nanoparticle film as the materials to absorb the heat under illumination. Heat transfer from the gold nanoparticles to surroundings induces a sharp increase in temperature, which results the generation of the microbubbles in the solutions. Therefore, the size and position of the surface bubble can be dynamically adjusted by changing the power and position of the laser spots. Convection currents around microbubble can make the gold nanoparticles pinned to the substrate surface, which can generate the Roman ring-shape structure. And then shine the CW laser of different power on the structure, the characteristics of the structure can be changed. These effects can be used for a wide variety of applications including micro/nano-particle manipulation, active microfluidic control, as well as cell stretching and sorting. 

   more » « less
4. Light trapping transparent electrodes with a wide-angle response

   https://doi.org/10.1364/OE.431530  

   Sun, Mengdi; Kik, Pieter_G (July 2021, Optics Express)

   The angle dependent transmission of light trapping transparent electrodes is investigated. The electrodes consist of triangular metallic wire arrays embedded in a dielectric cover layer. Normal incidence illumination of the structure produces light trapping via total internal reflection, virtually eliminating all shadowing losses. It is found that varying the external angle of incidence can affect the light trapping efficiency η_LTdue to partial loss of internal reflection and increased interaction with neighboring wires. Despite these effects, a judicious selection of geometry and materials can reduce shadowing losses by more than 85% over a surprisingly large angular range of 120°. It is demonstrated that the angle-averaged shadowing losses in an encapsulated silicon solar cell under illumination with unpolarized light can be reduced by more than a factor of two for incident angles between −60° and +60° off-normal across the entire AM1.5 solar spectrum. 

   more » « less
5. Freeform Illuminator for Computational Microscopy

   https://doi.org/10.34133/icomputing.0015  

   Song, Pengming; Wang, Tianbo; Jiang, Shaowei; Guo, Chengfei; Wang, Ruihai; Yang, Liming; Zhou, You; Zheng, Guoan (January 2023, Intelligent Computing)

   Programmable illumination control is essential for many computational microscopy techniques. Conventional light source array is often arranged on a fixed grid of a planar surface for providing programmable sample illumination. Here, we report the development of a freeform illuminator that can be arranged at arbitrary 2-dimensional or 3-dimensional (3D) surface structures for computational microscopy. The freeform illuminator can be designed in a small form factor with a dense light source arrangement in 3D. It can be placed closer to the sample for providing angle-varied illumination with higher optical flux and smaller angular increment. With the freeform illuminators, we develop a calibration process using a low-cost Raspberry-Pi image sensor coated with a monolayer of blood cells. By tracking the positional shift of the blood-cell diffraction patterns at 2 distinct regions of the coded sensor, we can infer the 3D positions of the light source elements in a way similar to the stereo vision reconstruction approach. To demonstrate the applications for computational microscopy, we validate the freeform illuminators for Fourier ptychographic microscopy, 3D tomographic imaging, and on-chip microscopy. We also present a longitudinal study by tracking the growth of live bacterial cultures over a large field of view. The reported freeform illuminators and the related calibration process offer flexibilities and extended scope for imaging innovations in computational microscopy. 

   more » « less