Simultaneous Tracking Of Multiple Targets Research Articles

Prototype development of multi-target tracking system for space multi-node laser communication network

Laser communication network is the future trend, but the disadvantage of a traditional laser communication system is that it can only transmit with a single node. To solve this problem, we propose a multi-target tracking technology to simultaneously establish multiple laser communication links. This study also develops a multi-target detection method based on beacon modulation and code division multiple access, proposes an optical antenna central stabilization method, and enhances the controller of the fast steering mirror (FSM) to improve the tracking performance. To verify the feasibility of our proposed method, we build a prototype system for multi-target laser communication and conduct the corresponding experiment. The experiment simulates the multi-target tracking situation by three beam emitting subsystems, and the dynamic tracking performance of the prototype system is verified by applying perturbations through a shaking table. Results show that the proposed method can effectively extract the position of the target in the mixed beam, with an average detection deviation of 2.95 μrad compared with when only a single beam is incident. The introduction of central stabilization enhances the dynamic tracking performance of the optical antenna. Tracking accuracy of the optical antenna is 24.63 μrad when attitude disturbance is applied. The improved controller enhances the performance of FSM, composite tracking accuracy is 5.69 μrad, and tracking error is reduced by 22.16% compared with the traditional PI controller. Performance also improved by 45.42% compared with when there was no improvement. Experimental results verify the effectiveness of the multi-target tracking system. On the basis of the proposed method, we achieve simultaneous tracking of multiple targets in different directions and significantly improve the dynamic tracking performance.

Trends in hyperspectral imaging: from environmental and health sensing to structure-property and nano-bio interaction studies.

Hyperspectral imaging (HSI) is a technique that allows for the simultaneous acquisition of both spatial and spectral information. While HSI has been known for years in the field of remote sensing, for instance in geology, cultural heritage, or food industries, it recently emerged in the fields of nano- and micromaterials as well as bioimaging and -sensing. Herein, the attractiveness of HSI arises from the suitability for generating knowledge about environment-specific optical properties, such as photoluminescence of optical probes in a biological sample or at a single-crystal/particle level, to be leveraged into better understanding of structure-property relationships and nano-bio interactions, respectively. Moreover, given its excellent spectral resolution, HSI is highly suitable for optical multiplexing in multiple dimensions, as sought after for, e.g., high throughput biological imaging by simultaneous tracking of multiple targets. Overall, HSI is an emerging technique that has the potential to transform analytical approaches from biomedicine to advanced materials research. This Trends Article provides insight into the potential of HSI, highlighting selected examples from well-established fields including environmental monitoring and food quality control to set the stage for the discussion of emerging opportunities at the micro- and nanoscale. Herein, special focus is set on photoluminescent micro- and nanoprobes for health and spectral conversion applications.

Development and Validation of 2D-LiDAR-Based Gait Analysis Instrument and Algorithm.

Acquiring gait parameters from usual walking is important to predict clinical outcomes including life expectancy, risk of fall, and neurocognitive performance in older people. We developed a novel gait analysis tool that is small, less-intrusive and is based on two-dimensional light detection and ranging (2D-LiDAR) technology. Using an object-tracking algorithm, we conducted a validation study of the spatiotemporal tracking of ankle locations of young, healthy participants (n = 4) by comparing our tool and a stereo camera with the motion capture system as a gold standard modality. We also assessed parameters including step length, step width, cadence, and gait speed. The 2D-LiDAR system showed a much better accuracy than that of a stereo camera system, where mean absolute errors were 46.2 ± 17.8 mm and 116.3 ± 69.6 mm, respectively. Gait parameters from the 2D-LiDAR system were in good agreement with those from the motion capture system (r = 0.955 for step length, r = 0.911 for cadence). Simultaneous tracking of multiple targets by the 2D-LiDAR system was also demonstrated. The novel system might be useful in space and resource constrained clinical practice for older adults.

Innovative lens improves imaging for surveillance systems

Historically, the army, border-security agencies, and transportation-security planners have recognized the advantages of panoramic imaging systems that contain fields of view of up to 180◦ in their coverage areas. Such advantages include increased coverage with fewer cameras, simultaneous tracking of multiple targets, full horizon detection, and immersion capability. However, existing panoramic imagers like fisheye, mirror, and PAL (short for panoramic annular imager) have disadvantages related to the number of effective pixels (the basic unit for video screen images) used on their sensors. These disadvantages are due to blind zones and circular or annular (ring-like) image areas that are commonly called footprints. These drawbacks seriously reduce the use of panoramic imagers for surveillance. To solve these problems, we designed a new imager—the Panomorph lens—that incorporates the advantage of full-area coverage (with a 180◦ field of view) and the ability to increase resolution where needed. Thus, the Panomorph lens allows for a larger coverage zone and distributes its image more efficiently on the sensor.1, 2 Two important parameters for the Panomorph lens are the amount and location of the resolution. These parameters, introduced at the optical design stage, allow the Panomorph lens to provide a higher resolution in a defined zone than any other standard panoramic imager. By comparison, a fisheye lens on a standard NTSC camera (i.e. using the accepted television format in North America and Japan) requires up to six times more pixels on its sensor to produce the same resolution.2 For the security and surveillance of buildings such as indoor parking garages, corporate offices, retail stores, shipping ports, storage facilities, airport terminals, and residential homes, a camera is mounted to the ceiling with its lens facing down (see Figure 1, left). The most significant objects are located in the zone at the periphery of the lens, also called the green zone or zone of interest. The green zone is the most important part of the Figure 1. (left) A camera is mounted on the ceiling in an indoor surveillance application. (right) The graph shows the pixel-to-angle coverage, with the dashed line representing a linear pixel coverage.