Narrow View Angle Research Articles

SIFT-CNN Pipeline in Livestock Management: A Drone Image Stitching Algorithm

Images taken by drones often must be preprocessed and stitched together due to the inherent noise, narrow imaging breadth, flying height, and angle of view. Conventional UAV feature-based image stitching techniques significantly rely on the quality of feature identification, made possible by image pixels, which frequently fail to stitch together images with few features or low resolution. Furthermore, later approaches were developed to eliminate the issues with conventional methods by using the deep learning-based stitching technique to collect the general attributes of remote sensing images before they were stitched. However, since the images have empty backgrounds classified as stitched points, it is challenging to distinguish livestock in a grazing area. Consequently, less information can be inferred from the surveillance data. This study provides a four-stage object-based image stitching technique that, before stitching, removes the background’s space and classifies images in the grazing field. In the first stage, the drone-based image sequence of the livestock on the grazing field is preprocessed. In the second stage, the images of the cattle on the grazing field are classified to eliminate the empty spaces or backgrounds. The third stage uses the improved SIFT to detect the feature points of the classified images to o8btain the feature point descriptor. Lastly, the stitching area is computed using the image projection transformation.

Development and Prospect of Viewing Angle Switchable Liquid Crystal Devices

As we move from the industrial age to the information age, nowadays, the opportunity to access personal information in public increases as personal computers (PCs), cell phones, automated teller machines (ATM) and other portable display devices have come into wider use, so it is well suited for these liquid crystal displays (LCDs) to switch between wide viewing angle (WVA) (share mode) and narrow viewing angle (NVA) (privacy mode). In this review, we have summarized structures, principles and characteristics of several devices that show great potential application in controllable anti-peeping displays in the eyesight of materials consist of pure liquid crystals (LCs), polymer dispersed LCs (PDLCs), polymer stabilized LCs (PSLCs) or polymer network LCs (PNLCs) and non-LCs, which provides systematic information for next-generation viewing angle-controllable LCDs with lower operating voltage, higher transmittance and good viewing angle controllable characteristics. Because LCs/polymer composite films have the advantages of long life, low power consumption and energy saving, they are regarded as the mainstream technology of next-generation viewing angle controllable displays.

Cooperative People Tracking by Distributed Cameras Network

In the application of video surveillance, reliable people detection and tracking are always challenging tasks. The conventional single-camera surveillance system may encounter difficulties such as narrow-angle of view and dead space. In this paper, we proposed multi-cameras network architecture with an inter-camera hand-off protocol for cooperative people tracking. We use the YOLO model to detect multiple people in the video scene and incorporate the particle swarm optimization algorithm to track the person movement. When a person leaves the area covered by a camera and enters an area covered by another camera, these cameras can exchange relevant information for uninterrupted tracking. The motion smoothness (MS) metrics is proposed for evaluating the tracking quality of multi-camera networking system. We used a three-camera system for two persons tracking in overlapping scene for experimental evaluation. Most tracking person offsets at different frames were lower than 30 pixels. Only 0.15% of the frames showed abrupt increases in offsets pixel. The experiment results reveal that our multi-camera system achieves robust, smooth tracking performance.

32.2: Controllable Viewing Angle Luminance for Super‐Fine‐TFT LCDs

In this letter, A continuously controllable viewing angle liquid crystal display, integrated with two LC cells(display cell and controlling cell), has been demonstrated to display information selectively at one side. The proposed device achieves asymmetric NVA(narrow viewing angle) luminance in private (only right side is visible,) mode, and symmetric WVA(wide viewing angle) luminance in common(left and right) mode by using novel LC and designing inside the viewing angle controlling cell. In NVA mode, Luminance at left side will be eliminated mostly while luminance at the other side remains. This technology meet the requirements of automotive premium CID(Center Information Display) or PID(Passenger Information Display) perfectly well, since it can provide good visual performance for the passenger, while preventing the driver to see any contents on the screen.

Implementation of a crossed-slit system for fast alignment of sealed polycapillary X-ray optics.

A new modification of a table-top laser-driven water-jet plasma X-ray source has been successfully implemented and commissioned at the Extreme Light Infrastructure (ELI) Beamlines user facility. In order to preserve the broadband nature of the source for spectroscopic experiments, a polycapillary lens was initially chosen as the focusing element. Generally, polycapillary X-ray optics have a narrow photon acceptance angle and small field of view, making alignment complicated and time-consuming. This contribution demonstrates a straightforward, reliable and reproducible procedure for aligning polycapillary focusing optics with broadband X-rays. The method involves a pre-alignment step where two X-ray slits are mounted orthogonally on opposite sides of a 3D-printed cylindrical polycapillary holder. This helps to precisely determine the optical axis of the X-ray beam. Subsequent mounting of the polycapillary in the pre-aligned holder with the slits removed allowed for immediate transmission of the X-ray photons through the optics and has provided a good starting point forfine alignment.

A Soft, Biocompatible Magnetic Field Enabled Wireless Surgical Lighting Patty for Neurosurgery

General surgical procedures are subject to low-light conditions or a narrow angle of view, and such limitations in light limit visibility and complicate the given surgical procedure. Conventional lighted surgical tools rely on an external light source, which may be oriented into a cavity or mounted on a surgical instrument such as retractor, endoscopes, or suction tubes. However, such conventional lighted instruments do not provide adequate lighting during various surgical procedures. Here, we present a soft, miniaturized magnetic-enabled wireless surgical lighting patty. Specifically, the proposed surgical lighting patty that can be temporarily implanted into a cavity or surgical corridor provides lighting to the surgical subject and manages fluids in a surgical field. The surgical lighting patty is a multilayer patty, two outer layers of the lighted surgical patty and the center lighted layer. A reed switch in the central layer can activate the power supply in response to a magnet to emit the light from the light source. The result allows a dramatically simplified wireless operation. Moreover, it can provide various wavelengths of light to a surgical field for purposes such as illuminating the surgeon’s field of vision, exciting dyes, and sterilizing surgical fields.

Improvement of off‐axis color shift on hybrid viewing‐angle device using dual γ‐voltage method

AbstractWe have mass production on one kind of liquid crystal display (LCD) device with hybrid viewing‐angle (HVA), which can be switched between the wide viewing‐angle (WVA) and narrow viewing‐angle (NVA) by one button. This device adopts the single cell design that with lower cost, and utilizes the optical properties of electrically tilted LC to achieve the function of NVA display. An issue has received less attention in the past and been indeed found in the production process. It is that the off‐axis color shift will appear in NVA mode. We put forward one method to improve this issue here, which is combined with the concepts of Gray Frame Insertion (GFI) and Impulse‐type driving. By switching the voltage between two different γ values, the color shift will be perfected on the produce.

Characteristics of non-diffractive beam generation related to concentration and propagation distance in highly random media

Laser beam propagation in highly random media can potentially be applied to various optical studies, though the light penetration is often limited to the surface or skin regions of the targets. In free space, it is known that the use of a non-diffractive beam (Bessel beam) is useful for achieving a long-distance propagation by reducing the influence of diffraction. In our previous work [Z. Peng, and T. Shiina, Opt. Commun. 391, 94–99 (2017)], the generation and propagation of such a non-diffractive beam were studied in a scattering medium of colloidal suspension (diluted milk) up to the concentration of 1.2% using cell lengths between 10 and 30 cm. The transformation from an annular beam to a non-diffractive beam was observed using a detector with a narrow view angle of 5.5 mrad. In the present study, experimental results are reported for much higher concentrations using shorter cell lengths of 3 and 5 cm. It is found that a non-diffractive beam is generated as a central peak superposed on widely distributed intensity due to multiple scattering. The polarization property is preserved during the transformation from annular ring to central peak. At the propagation distance of 3 cm, the intensity of non-diffractive beam is maximized with a high media concentration of 22.0% which yields the scattering coefficient of 5 cm−1. Furthermore, it is found that the media concentration range that leads to the generation of the non-diffractive beam becomes wider for such shorter propagation distances.

Fabrication of a controllable anti-peeping device with a laminated structure of microlouver and polymer dispersed liquid crystals film

ABSTRACTDisplay devices with the narrow viewing angle (NVA) and the wide viewing angle (WVA) characteristics can simultaneously meet the demands for privacy protection and information sharing. Herein, we propose a novel method for fabricating a controllable anti-peeping device with a laminated structure of microlouver and polymer dispersed liquid crystals (PDLCs) film, and this device can be reversibly switched between a wider viewing angle range (VAR) for the WVA mode and a narrower viewing angle range (VAR) for the NVA mode at 0 V and 8 V, respectively. Also, the VARs of the controllable anti-peeping device can be dynamically tuned by varying dimensions of the microlouver structures and applying various voltages across the PDLCs film from 0 V to 8 V. The as-fabricated device provides display devices with controllable viewing angle characteristics, which can be applied in the display field with fascinating and practical functions.

Lidar transmitter offers “non-diffracting” property through short distance in highly-dense random media

Non-diffracting beam (NDB) is useful in lidar transmitter because of its high propagation efficiency and high resolution. We aimed to generate NDB in random media such as haze and cloud. The laboratory experiment was conducted with diluted processed milk (fat: 1.8%, 1.1μmφ). Narrow view angle detector of 5.5mrad was used to detect the forward scattering waveform. We obtained the central peak of NDB at the propagation distance of 5cm ~ 30cm in random media by adjusting the concentration of <10%.

Utilizing OCO-2 satellite transect in comparing XCO2 concentrations among administrative regions in Northeast Asia

The principal advantage of OCO-2 satellite transect as a remote sensor is to provide, in a cost-effective manner, information required for narrow and long strip coverage, utilizing narrow view angle. Based on the postulated advantages of OCO-2 satellite transect for multiple nation-wide monitoring, a satellite transect sampling approach has been specifically proposed with focus on administrative region-wide monitoring. This research idea was formulated by incorporating the concept of typical satellite remote sensing into in situ transect techniques. The OCO-2 satellite transect was quite useful in in comparing CO2 concentrations among administrative regions in Northeast Asia and better understanding the nature and extent of carbon intensity that occurs in transect sampling points. This transect sampling survey made it possible to identify area-wide patterns of CO2 concentration changing trends subject to many different influences (e.g. the effects of specific sources of land use), which cannot be acquired by typical GHG monitoring satellite such as GOSAT. The OCO-2 satellite transects break down the usual concept of area-wide mapping established as a typical satellite survey technique. The study concludes that OCO-2 satellite transect is demonstrably suitable as a reliable information source for detecting sufficient ground detail CO2 concentrations, including administrative region monitoring.

Non-diffractive beam in random media

Beam propagation has been given important attention in a variety of applications in medicine, remote sensing and information science. Especially, the beam propagation in highly scattering media, which is called random media, is important. In general, the multiple scattering gets rid of beam characteristics, e.g., intensity distribution, phase front, and polarization. In this study, self-converging effect of annular beam was applied in random media. Diluted milk was used as random media, and the transmitted light was detected with a narrow view angle of 5.5mrad. The collimated annular beam of a few tens millimeters takes a few hundred meters to transform its beam shape into the non-diffractive beam in free space, while this transformation was shorten only to 20cm in random media, that is, the collimated annular beam caused its transformation at only 20cm in random media. The transformed beam kept its optical characteristics of “non-diffractive beam”. Such transformation of the annular beam needs the appropriate condition of random media. Media concentration and propagation distance control the generation of the center peak intensity of the transformed beam. This study indicates the generation of the non-diffractive beam in random media and reveals its appropriate condition.

Viewing-angle-switching device based on array of optical micro-rods incorporated with electrophoretic material systems

We have successfully demonstrated a control device for a viewing angle that enables switching between two states, a wide-viewing angle, and a narrow-viewing angle. It is composed of a light-transmitting portion formed with an array of optical micro-rods and a shielding/transmitting changeable portion of cross stripes designed with electrophoretic material systems consisting of black particles and an optically transparent medium. When the black particles are fully dispersed in the optically transparent medium, the cross stripe portion plays the role of a non-transmitting material as the shielding portion in a similar manner to a conventional viewing angle control film. When the black particles are completely gathered electronically to one side in the optically transparent medium, in contrast, the cross stripe portion filled by the optically transparent medium can transmit incident light. These functions allow us to select electrically either of two modes between a limited viewing angle and a non-limited viewing angle. The optical properties for the limited viewing angle mode were +/−30° of the visible angle and 50% of the transmittance, and the one for the non-limited viewing mode was 58% of the transmittance. The response time from the narrow-viewing angle to wide-viewing angle was 1 s at 20 V of applied voltage.

Emerging Star in Ophthalmic Imaging Technologies – OCT Angiography

Optical Coherence Tomography (OCT) angiography has recently been introduced as a novel non-invasive OCT based technique providing three-dimensional high resolution images of vascular and microvascular ocular structures without the need to use intravenous dyes. A relatively narrow angle of view and a lack of information along the timeline are outweighed by the huge advantages of non-invasiveness and three-dimensional information of the depicted areas of interest, as this technique emerges and becomes the new star among ophthalmic imaging techniques.

The loss cone imager

The Loss Cone Imager (LCI) instrument package on the US Air Force׳s Demonstration and Science eXperiment (DSX) mission is expected to provide in-situ measurements of energetic charged particles in the Earth׳s radiation belts. The LCI comprises an 18-pixel imaging electron spectrometer known as the Fixed Sensor Head (FSH) and a single pixel, narrow view angle, large geometric factor, charged particle telescope known as the High-Sensitivity Telescope (HST). The LCI is anticipated to be flown in a 6000km×12,000km orbit at 42° inclination to allow sampling of the inner and outer radiation belts as well as the slot region.

Simplex based method for compensation films optimization in TN-LCD

The narrow viewing angle (VA) and low contrast ratio (CR) are two of the problems associated with liquid crystal display (LCD). A novel optimization method for the LCD system based on simplex algorithm is demonstrated. A LCD model is constructed using two negative O-plate films, LC cell and one negative C-plate film. The compensator thickness and tilt angel can be successfully used as optimization variables to compensate for narrow VA and low CR. Results show that this approach is faster and more accurate than other approaches. In addition, we show that the oblique leakage light of the dark state is reduced and that high CR, wide VA are obtained.

Viewing angle controllable fringe and in-plane switching vertical alignment LCD

A viewing angle controllable fringe and in-plane switching vertical alignment liquid crystal display (LCD) structure has been proposed. To realise the change from wide viewing angle (WVA) to narrow viewing angle (NVA) in a single LCD panel, the bias voltage is applied on the common electrode, and NVA can decreases with the increasing bias voltage. In WVA mode, the viewing angle cone (contrast ratio larger than 1000:1) is almost 70° and the contrast ratio is larger than 100:1 in arbitrary azimuthal directions. In NVA mode, the viewing angle cone (10:1) can continuously and uniformly change from 40° to 20°.

Continuous viewing angle controllable patterned vertical alignment liquid crystal display

A continuous viewing angle switchable patterned vertical alignment liquid crystal display (PVA-LCD) with circle polarisers is proposed. In wide viewing angle (WVA) mode, the viewing cone with contrast ratio larger than 1000:1 is extended to 50° and the contrast ratio larger than 100:1 is extended to 80°. Meanwhile, the viewing cone with contrast ratio more than 10:1 is limited to 40° in all direction for narrow viewing angle (NVA) mode. The viewing angle of the display can be controlled by applying a bias voltage on the common electrode. With the increasing bias voltage, the viewing angle cone with contrast ratio more than 10:1 can be changed from 40° to 20°. The proposed PVA-LCD has high transmittance (~93%) under the circle polarisers because the dead zone in the normal PVA-LCD with linear polarisers is eliminated.

A miniaturized optical force sensor for tendon-driven mechatronic systems: Design and experimental evaluation

In this paper, an innovative sensor for the control of a tendon-driven mechatronic system is presented. The proposed sensor measures the tendon tension using optoelectronic components properly selected and mounted on a suitably designed compliant frame. This solution presents several advantages mainly in terms of simplicity and compactness with respect to force sensors based on strain-gauge or Bragg-grating. By exploiting the properties of optoelectronic components with a narrow angle of view and by means of a very simple conditioning electronics, the very small deformation of the compliant frame caused by the tendon force can be measured. Moreover, the compliant frame has been designed to allow the sensor to be mounted in any position along the tendon. The sensor working principle, an optimal design procedure and the results of an experimental testbench where two of the proposed sensors are used for the feedback control of a tendon-driven mechatronic system are reported in the paper. The experimental verification of a contact force estimation algorithm useful for grasping and manipulation purposes in which the data collected by the optoelectronic tendon force sensors are exploited is also reported in the paper.

Design and Manufacture of Light Collimator with Narrow View Angle

The use of LED for illumination offers significant advantages, such as lower power consumption, longer lifetime and improved colour management. Sharp gradients in luminous intensity patterns of LED are commonly controlled by the use of secondary optics that are mostly axisymmetric. In the current study, we proposed LED secondary optics forming non-axisymmetric luminous intensity distribution with an extremely narrow view angle. The proposed secondary optics dramatically reduced the view angle of the LED, with a view angle ( 10º) in full width at half maximum (FWHM) in simulations. Afterward, a prototype of the proposed lens was machined by single point diamond turning (SPDT). Luminous intensity distribution of the machined lens was off by about 8º from the optical axis and maintained a view angle of 12º. The peak luminous intensity was folded more than thirty-two times. The proposed lens showed high optical performance and can be used for specialized optical applications.