Abstract:The resolution performance of mobile phone camera optics was previously checked only near an infinite point. However, near-field performance is required because of reduced camera pixel sizes. Traditional optics are measured using a resolution chart located at a hyperfocal distance, which can only measure the resolution at a specific distance but not at close distances. We designed a new collimator system that can change the virtual image of the resolution chart from infinity to a short distance. Hence, some le… Show more
“…Furthermore, each sample's images were captured at a sufficiently close distance but exact measurement of camera distance was not observed. This is because the impact of the measurement error due to close-distance variations is statistically insignificant [ 9 , 10 ]. Fig.…”
Section: Experimental Design Materials and Methodsmentioning
“…Furthermore, each sample's images were captured at a sufficiently close distance but exact measurement of camera distance was not observed. This is because the impact of the measurement error due to close-distance variations is statistically insignificant [ 9 , 10 ]. Fig.…”
Section: Experimental Design Materials and Methodsmentioning
“…When combining two optics, the angle of the chief ray passing through the converter and entering the stop should match the field angle of the relay optics [38]. the paraxial layout of a converter in which lenses with negative and positive refractive power values are combined [39]. Therefore, the refractive power of the optical converter should be zero, and the angle of the chief ray decreases from θ to θ 2 .…”
BACKGROUND: Compared to benchtop ultrasound machines, mobile ultrasound machines require portable batteries when acquiring information regarding human tissues during outdoor activities. OBJECTIVE: A novel fisheye lens type was designed to address the charging issue where it is difficult to constantly track the sun. This method does not require the use of a mechanical motor that constantly tracks the sun to charge the portable batteries. METHODS: To obtain an optical solar power system, the numerical aperture (NA) and field angle must be increased. Therefore, we use the fisheye lens with the largest field angle. RESULTS: The NA of the designed fisheye lens system reaches 0.75, allowing light collection of approximately ± 48∘. Additionally, the efficiency ratio of the central and surrounding areas also satisfies more than 80% at a field angle of 85∘ and more than 70% at field angles of 85∘ to 90∘, respectively. CONCLUSIONS: We designed a novel fisheye lens for solar-powered mobile ultrasound machines used outdoors.
“…Producing a collimated beam from a light source is necessary and quintessential in various designs and applications. [1][2][3][4][5] Emitted light from a source, whose optical emission is to be collimated, can exhibit various properties. The quality of collimation requires an understanding of the properties of the optical source such as its spatial coherence and its transverse beam profile.…”
In this paper, we explore the collimation quality of collimated Gaussian beams generated via the deployment of engineered diffusers. Various aspects of beam propagation through engineered diffusers are explored using results from carefully designed experiments. Raw Gaussian beam is incident on a sample engineered diffuser. The beam is then collimated and propagated over several meters to clearly estimate beam divergence for different test cases. These test cases include raw and focused beams incident on engineered diffusers, the effect on collimation with the use of speckle reducers, and the evolution of the collimated beam wavefront during propagation. To measure and document the spatial coherence properties of beam propagation and its spatial coherence properties after propagating through the engineered diffuser, we measure the beam profile with knife-edge measurement, CCD imaging, and Shack-Hartmann sensor-based wavefront measurements along the beam propagation path. We do so for all different type of beam conditioning before incidence at the engineered diffuser – this includes analyzing the effects of a speckle reducer in the system. We present detailed experimental results and parameters of the propagating collimated beam in the paper. We hope that this paper will lay foundations for our understanding of using engineered diffusers for short distance free-space optical links using a beam collimation approach which is several times optically efficient than a pinhole based spatial filtering-based beam collimation approach.
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