Search

Copyright of Journal of Test & Measurement Technology is the property of Publishing Center of North University of China and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

The target tracking by space-based surveillance systems is difficult due to the long distances, weak energies, fast speeds, high false alarm rates, and low algorithmic efficiencies involved in the process. To mitigate the impact of these difficulties, this article proposes a target tracking algorithm based on image processing and Transformer, which employs a two-dimensional Gaussian soft-thresholding method to reduce the image noise, and combines a Laplace operator-weighted fusion method to augment the image, so as to improve the overall quality of the image and increase the accuracy of target tracking. Based on the SiamCAR framework, the Transformer model in the field of natural language processing is introduced, which can be used to enhance the image features extracted from the backbone network by mining the rich temporal information between the initial and dynamic templates. In order to capture the information of the target’s appearance change in the temporal sequence, a template update branch is introduced at the input of the algorithm, which realizes the dynamic update of the templates by constructing a template memory pool, and selecting the best templates for the candidate templates in the memory pool using the cosine similarity-based selection, thus ensuring the robustness of the tracking algorithm. The experimental results that compared with the SiamCAR algorithm and the mainstream algorithms, the TrD-Siam algorithm proposed in this article effectively improves the tracking success rate and accuracy, addressing poor target tracking performance under space-based conditions, and has a good value of application in the field of optoelectronic detection.

Based on infrared absorption spectroscopy technique, a carbon monoxide sensor was developed using the fundamental absorption band of carbon monoxide molecule at the wavelength around 4.6 µm. The developed sensor consists of pulse-modulated wideband incandescence, open ellipsoid light-collector gas-cell, dual-channel detector, and control and signal-processing module. With the prepared standard carbon monoxide gas sample, sensing characteristics on carbon monoxide were investigated using the sensor. Experimental results reveal that the limit of detection is about 10 ppm, the relative error at the limit of detection point is less than 14%, and that is less than 7.8% within the low concentration range of 20∼180 ppm. The maximum absolute errors of 50 min long-term measurement on the 0 and 14 ppm CO gas samples are about 3 and 3.17 ppm, respectively, and the standard deviations are as small as 0.18 and 1.25 ppm, respectively. Compared with the reported carbon monoxide detection systems utilizing quantum cascaded lasers and distributed feedback lasers, the proposed sensor shows potential applications in carbon monoxide detection under the circumstances of coal-mine and environmental protection, by virtue of high performance, low cost, simple optical structure, and so on. [ABSTRACT FROM AUTHOR]

In general flow cytometry enables the characterization of individual cells/microparticles. When a sample is injected into a flow cytometer, the randomly distributed cells are ordered into a stream of single cells. Hence, they can be individually analyzed in the detection system. In this paper, an optoelectronic compact and portable system for bacteria cells detection is described. The system consists of PDMS (polydimethylsiloxane) microfluidic chip, a duralumin holder with microfluidic connectors -- inlets/outlets, as well as optic fiber connectors and waveguides for laser diode and photodetectors (avalanche photodiode BPYP 59 or photomultiplier 9658B). The fluorochrome is excited by light beam of an appropriate wavelength coming from a light source, e.g., the laser diode. The excitation light passes through hydrodynamically focused cells in the middle of the channel. After optical filtering, the light emitted by the fluorochrome is detected by a photodetector. Electrical signals from the selective nanovoltmeter are amplified and collected by the computer electronic system. Since in the real sample bacteria cells are selectively labeled with the fluorophores or antibodies conjugated with fluorochrome, in our experiments to evaluate lower detection limits of the developed detection system, exemplary fluorescent dye solutions of sodium fluorescein were used as testing solutions. [ABSTRACT FROM AUTHOR]

An overview is presented of an experimental search for an ultrawide-band transmission channel with low dispersion and loss. Such a terahertz (THz) interconnect will soon be required by the insatiable demand for higher speed devices and wider bandwidth communication. Starting with the early optoelectronic generation and detection of single-mode, subpicosecond electrical pulses on coplanar transmission lines, their complete characterization by THz time-domain spectroscopy (THz-TDS) is described. The consequent discovery of phase-coherent Cherenkov radiation in the form of an electromagnetic shock wave from these propagating electrical pulses is discussed together with its dominant role in the large measured propagation loss of these pulses. Various techniques to reduce this radiation are presented. The importance of dielectric materials characterization is explained and illustrated by THz-TDS measurements of high Tc substrates. Newly obtained THz waveguide results are presented and compared to the performance of coplanar transmission lines [ABSTRACT FROM PUBLISHER]