Low-cost smartphone-based LIBS combined with deep learning image processing for accurate lithology recognition

A low-cost and multi-channel smartphone-based spectrometer was developed for LIBS. As the CMOS detector is two-dimensional, simultaneous multichannel detection were achieved by coupling a linear array of fibres for light...

Adaptive multichannel detection-resolution of stochastic signals in conditions of parametric prior uncertainty

The purpose of the study is to improve the quality indicators of adaptive multichannel detection-resolution-measurement parameters of stochastic signals under parametric a prior uncertainty.Materials and methods. The methodology for the synthesis of signal detectors of various structures, taking into account various factors, is used to achieve the goal. This makes it possible to exclude from the expression for estimating the signal power the terms due to “colored” internal noises and an uncorrelated background. The tools of correlation analysis, adaptive Bayes approach, criterion of generalized likelihood ratio, methods of calculating its logarithm are also used. Results. In this paper, the problems of synthesis of adaptive multichannel detection-resolution algorithms for stochastic signals of various structures under the influence of intense noise interference are considered. An integral element of the detection task is a joint assessment of the intensity of the useful signal and the correlation matrix of interference. This problem is effectively solved for highintensity signals, and the nonstationarity of the internal noise of the receiving uncorrelated background of the interfering signals is not taken into account. A multi-channel receiving system consisting of a number of independent spatially separated elements that form a linear antenna array is considered. The width of the spectrum of the received signals should be considered sufficiently narrow, so that the delay of the signals at the antenna aperture can be neglected. This provision can significantly improve the performance of detection and resolution of stochastic signals in the background of noise interference. Based on the analysis of a finite discrete sample of complex amplitudes of received oscillations, a detection problem was solved, which is formulated as a problem of checking statistical hypotheses regarding distribution parameters. The detection algorithm is reduced to a comparison with the likelihood ratio threshold, and the threshold level value is determined by the selected optimality criterion and for the Neumann-Pearson criterion remains dependent on the power of interfering oscillations.Conclusion. The presented detector possesses higher characteristics of detection and resolution of stochastic signals in comparison with the known ones. It can be shown that an important property of the obtained statistics is the stabilization of the probability of false detection. This is achieved by normalizing the noise power at the output of the adaptation device. In addition, the resulting algorithm is invariant to the form used for its calculation of the correlation matrix of interference. If we take into account that an uncorrelated background will be added to the internal noise power, with a large number of noise jammers, a significant improvement in the detection performance has been achieved.

Research on the performance of a novel SPR sensor based on graded index multimode fiber

Purpose This paper aims to propose and demonstrate a novel surface plasmon resonance (SPR)-sensing approach by using the fundamental mode beam based on a graded index multimode fiber (GIF). The proposed SPR sensor has high sensitivity and controllable working dynamic range, which expects to solve the two bottlenecks of fiber SPR sensor, including low sensitivity and the difficulty in multichannel detection. Design/methodology/approach The low-order mode of the GIF to SPR sense, which keeps the sensitivity advantage of the single-mode fiber SPR sensor, is used. By using this new SPR sensor, the effect of light incident angle and gold film thickness on working dynamic range was studied. According to the study results, the smaller is the incident angle, the larger is the SPR working dynamic range and the longer is the resonance wavelength with a fixed gold film thickness; the larger is the gold film thickness, the longer is the resonance wavelength with a fixed grinding angle. After the parameter optimization, the sensitivity of these two parameter-adjusting methods reach 4,442 and 3031 nm/RIU. Originality/value When the grinding angle of the GIF increases, the dynamic range of the resonance wavelength increases and has a redshift, sensitivity increases, and the resonance valley becomes more unobvious with a fixed gold film thickness. Similarly, when gold film thickness increases, the dynamic range of the resonance wavelength increases and has a redshift, sensitivity increases, and the resonance valley becomes more unobvious with a fixed grinding angle. These adjusting performance aforementioned lay the foundation for solving of the fiber-based SPR multichannel detection and increasing of the fiber-based SPR sensor sensitivity, which has a good application value.

Combining 12-Lead ECG Information for a Beat Detection Algorithm

This paper proposes a beat detection algorithm specially tailored to be used with 12 channel ECG records. The algorithm first obtains beat positions on each channel, and then combines this information to get an improved estimate. The detection process involves two stages: 1) single-channel detection: implemented by improving one of the most popular methods (Pan-Tompkins) developed to detect beat positions; and 2) multichannel detection: an algorithm that combines the information of the beat positions obtained in each of the 12 channels. In this way, our results clearly improve those obtained with the single-channel detection method, discarding detection errors, false positives, and duplicated beats. Besides, our single-channel method significantly reduces the temporal error when estimating the positions of QRS complexes. In the multichannel detection, the assessment of our algorithm against one-channel based approaches shows a significant improvement in detection outcome (Se = 99.86%, P+ = 99.98%, RMS RR Interval Error = 25.98 ms, F-Score = 0.9992), making it a good starting point for automatic diagnosis of heart conditions.

Paper-based FRET for the direct detection of collagen triple helix

The integration of the GO-based FRET assay with a patterned paper provides a powerful new tool for the detection of collagen molecules with many superior features: tiny volumes of samples, multichannel detection mode, easy operation and low-cost equipment.

Multichannel detection of ionic currents through two nanopores fabricated on integrated Si3N4 membranes

We demonstrated the simultaneous multichannel detections of clear ionic-current blockades without signal crosstalk when poly(dA)60 passed through two nanopores.