35 results about "Spectral signal-to-noise ratio" patented technology

The invention discloses a method for processing dynamic spectral data based on single-edge extraction, and relates to the field of spectral analysis technology. The method comprises the following steps of: acquiring the all-band photoplethysmographic pulse wave; acquiring an all-band photoplethysmographic pulse wave template by using the all-band photoplethysmographic pulse wave and correcting the waveform of the photoplethysmographic pulse wave with each wavelength so as to eliminate the error introduced by the instability of the waveform of the photoplethysmographic pulse wave with each wavelength; removing single-edge dynamic spectrum comprising gross error by using the average effect of single-edge dynamic spectrums corresponding to a front edge and a rear edge of each pulse period according to a 3sigma rule; and superposing the remaining single-edge dynamic spectrums after the removal of the gross error to obtain dynamic spectral output. The method fully utilizes the acquired spectral data, improves the accuracy of the waveform of the photoplethysmographic pulse wave within each wavelength and each period, has higher accuracy, obviously improves the measurement speed, effectively improves the dynamic spectral signal-to-noise ratio and improves the accuracy of dynamic spectral method-based noninvasive blood component detection.

The invention relates to a method and apparatus of infrared modulation photo-induced luminous spectrum based on step scan. The apparatus comprises a Fourier transform infrared spectrograph measuring system, a laser used as active light source, a lock-in amplifier which connects the Fourier transform infrared spectrograph detector and the circuit controlling plate and a circuit-breaker on the light path between the sample and the laser, so that it can transfer the constant active light into the modulated active light and feedback it in the reference end of the lock-in amplifier to control the lock-in.

The invention relates to an indirect coupling conic fiber grating ultrasonic sensor. According to the indirect coupling conic fiber grating ultrasonic sensor, an upper end of a casing is provided with a sealing cover for processing a center hole, a sealing cover noise abatement pad is arranged between the sealing cover and the casing, a lower end of the casing is provided with a sound coupling cone, a sound coupling noise abatement pad is arranged between the sound coupling cone and the lower end of the casing, the top portion of the sound coupling cone is provided with a light guide fiber mounting hole through processing, one end of a light guide fiber is arranged in the light guide fiber mounting hole, the other end of the light guide fiber penetrates through the center hole of the sealing cover, the light guide fiber is provided with a grating, grating zone length of the grating is 1-10mm, and wavelength is 1540-1560nm. Based on tests, the sensor has excellent response performance, stability and sensitivity for 300KHz wave band ultrasonic signals, under the real-time acquisition mode, the spectrum signal to noise ratio is high, the ultrasonic signals reflected on upper and lower surfaces of organic glass can be intelligibly identified, the ultrasonic signals are suitable for dynamic scanning acquisition in an earthquake physics model, ultrasonic multi-layer imaging can be realized, and the sensor can be applied to the nondestructive structure test, oil and gas field physics model imaging, elastic wave speed modeling and biologic and medical technology fields.

The invention provides a wide band environment air infrared telemetering and monitoring system and method, wherein the system is mainly composed of an infrared monitor, a cloud head and an upper computer; the infrared monitor comprises an infrared window, a visible light window, a blackbody radiation calibration device, a front telescope, an interferometer, an infrared detector, a signal control and communication interface, an intelligent discriminator and a CCD camera. According to the invention, the system has the advantages of high spectral resolution and high luminous flux, can achieve theidentification and alarm of multi-component air, can fully utilize the built-in blackbody to carry out high-precision calibration, and can achieve on-line spectral calibration and radiation calibration requirements, the application advantage is obvious, particularly, a high level can be achieved in the aspect of spectral signal-to-noise ratio.

The invention relates to a method and apparatus of infrared modulation photo-induced luminous spectrum based on step scan. The apparatus comprises a Fourier transform infrared spectrograph measuring system, a laser used as active light source, a lock-in amplifier which connects the Fourier transform infrared spectrograph detector and the circuit controlling plate and a circuit-breaker on the light path between the sample and the laser, so that it can transfer the constant active light into the modulated active light and feedback it in the reference end of the lock-in amplifier to control the lock-in.

The invention discloses an active and passive dual-mode spectrometer, which is composed of two parts inside and outside a fuselage. Among them, there are two-in-one optical fiber, interface, slit and main controller outside the fuselage; the inside of the fuselage contains electric stage, active converging mirror, prism, active collimating mirror, active blazed grating, passive blazed grating, grating bracket, column Converging lens, linear variable filter, back-illuminated array detector, array drive circuit, passive converging mirror, passive collimating mirror, exit slit, shading screen, photomultiplier tube, motorized scanning table, scanning controller, working circuit. The beneficial effect of the present invention is that, by adopting ingenious electromechanical switching and grating area splitting, the internal structure of the spectrometer can be optimized, and the compactness and convenience of the system can be improved; the same spectrometer and the same optical fiber inlet can realize the composite detection of active and passive spectra, and improve the detection efficiency. Efficiency: According to the different characteristics of active and passive spectra, different designs are adopted at the sensor end to achieve targeted spectral detection, improve active spectral resolution and passive spectral signal-to-noise ratio.

The invention relates to a near infrared spectrum denoising method combining lifting wavelet and SG filtering, and belongs to the technical field of near infrared spectrum signal preprocessing. The method includes: carrying out lifting wavelet decomposition on the noisy near infrared spectrum signal to obtain a multilayer wavelet coefficient; performing hard threshold de-noising on the high-frequency coefficient of each layer to obtain a de-noised wavelet coefficient; performing lifting wavelet inverse transformation reconstruction on the denoised wavelet coefficient to obtain a near infrared spectrum signal after preliminary denoising; and finally, carrying out Savitzky-Golay filtering (SG filtering) on the reconstructed near infrared spectrum signal, so as to obtain a final near infrared spectrum signal after denoising. The signal-to-noise ratio of the denoised near infrared spectrum and the original spectrum is high, and the root-mean-square error is low; the denoising effect is thorough, obvious signal distortion is avoided, and the near infrared spectrum analysis precision is improved.

The invention discloses a device for improving the signal to noise ratio of the blood absorption spectrum and a control method thereof. An oversleeve is connected respectively with an air pump and an air release valve through an air tube. The air pump pressurizes the sleeve through the air tube and deflates the sleeve through the air release valve. An import optical signal module and an export optical signal module are arranged at positions opposite to each other at the bottom of the nail of a finger. The import optical signal module is arranged upward and the export optical signal module is arranged downward. A data collecting module is respectively connected with the import optical signal module and the export optical signal module to collect a photoelectrical signal in a normal filling level and a photoelectrical signal in an enhanced filling level. The oversleeve is put on the upper end of the tested arm. The import optical signal module imports detection light and the export optical signal module exports an optical signal to obtain the difference of the photoelectrical signal and obtain the blood absorption spectrum with high signal to noise ratio according to the difference of the photoelectrical signal. The invention solves the problem of insufficient filling, obtains the ideal photoelectrical signal and improves the strength and the noise ratio of blood absorption spectrum.

The invention discloses a device for improving the signal to noise ratio of the blood absorption spectrum and a control method thereof. An oversleeve is connected respectively with an air pump and an air release valve through an air tube. The air pump pressurizes the sleeve through the air tube and deflates the sleeve through the air release valve. An import optical signal module and an export optical signal module are arranged at positions opposite to each other at the bottom of the nail of a finger. The import optical signal module is arranged upward and the export optical signal module is arranged downward. A data collecting module is respectively connected with the import optical signal module and the export optical signal module to collect a photoelectrical signal in a normal filling level and a photoelectrical signal in an enhanced filling level. The oversleeve is put on the upper end of the tested arm. The import optical signal module imports detection light and the export optical signal module exports an optical signal to obtain the difference of the photoelectrical signal and obtain the blood absorption spectrum with high signal to noise ratio according to the difference of the photoelectrical signal. The invention solves the problem of insufficient filling, obtains the ideal photoelectrical signal and improves the strength and the noise ratio of blood absorption spectrum.

The invention discloses a LIBS active-passive dual-mode spectrum detection method, which comprises four steps of self-focus realization, LIBS active spectrum detection, infrared passive spectrum detection and active-passive spectrum analysis. The beneficial effect of the present invention is that the internal structure of the spectrometer is optimized by using ingenious electromechanical switching and grating area splitting, and the compactness and convenience of the system are improved; the same spectrometer and the same optical fiber inlet realize the compounding of LIBS active spectrum and infrared passive spectrum Detection, improve detection efficiency; according to different active and passive spectral characteristics, different designs are adopted at the sensor end to achieve targeted spectral detection, improve LIBS active spectral resolution and infrared passive spectral signal-to-noise ratio.

The invention relates to a tuning window-scanning spectral imaging system for a light filter and a tuning window-scanning spectral imaging method for the light filter, and belongs to the field of spectral imaging. The invention is to add a scanning system into a tuning static spectral imaging system for the light filter to make the tuning window-scanning spectral imaging system capable of performing dynamic window-scanning imaging. Moreover, the invention adopts a data acquisition processing system which is matched with the scanning system to make the tuning window-scanning spectral imaging system be capable of completing data processing in the mode of window scanning and output correct spectral cubical result. The invention has high utilization rate of light energy, high spectral resolution and flexible and adjustable service band of spectrums, has both the image signal-to-noise ratio and the spectrum signal-to-noise ratio easy to reach high level, can only be operated in interested wavebands, reduces the data quantity, increases the regulating range of the integral time, can improve the detection level of weak signals, and is suitable to be widely applied in the fields of agricultural production, resource exploration, environmental monitoring, disaster prevention and reduction, substance identification, public safety and the like.

The invention relates to a method and apparatus of photo-modulation reflection spectroscopy based on step scan. The apparatus comprises a Fourier transform infrared spectrograph measuring system, a laser used as pump light source, a lock-in amplifier and a low-pass filter which connect the Fourier transform infrared spectrograph detector and the circuit controlling plate, wherein the circuit-breaker on the light path between the sample and the laser can transfer the constant pump laser into the modulated laser and feedback it in the reference end of the lock-in amplifier to control the lock-in.

The invention relates to the technical field of laser diagnosis, in particular to a fiber LIBS detection system and method of optional double pulse modes. The system comprises an integrated fiber laser, a fiber LIBS probe, a control detection module and a fiber transmission module. Plasma emission spectrum signals enhanced by different degrees of double pulses are obtained by the system and the method, and the output laser time series of main pulse laser and sub pulse laser can be changed by changing the position of a visor and adjusting the position of a sub probe on a guide rail to switch four double pulse fiber LIBS detection modes for detecting a sample to be detected in multiple directions, thus obtaining obvious characteristic spectral lines for accurately analyzing the element typeand content of the sample to be detected. The system and the method can reduce the influence of matrix effect on detection, are high in repeatability, high in spectral signal-to-noise ratio, high in analysis speed, safe and reliable in measurement and high in element detection limit, and can be used for remote on-line monitoring.

The invention discloses an air pollution composition inversion method based on the ultraviolet-visible hyperspectrum of the Gaofen-5 satellite. Through the inversion calculation of the ultraviolet-visible hyperspectrum of the Gaofen-5 satellite, the column concentration of the air pollution composition can be accurately obtained , so as to achieve continuous and effective observation of air pollution components in a wide range and for a long time. In addition, according to the characteristics and spectral characteristics of the GF-5 instrument, the secondary calibration of the spectrum under the condition of low spectral signal-to-noise ratio and poor stability can be realized, thereby improving the inversion accuracy.

The invention discloses an active and passive dual-mode spectrum detection method, which comprises three steps of active spectrum detection, passive spectrum detection and active and passive spectrum analysis. The beneficial effect of the present invention is that the optimization of the internal structure of the spectrometer is realized by adopting ingenious electromechanical switching and grating area splitting, and the compactness and convenience of the system are improved; the same spectrometer and the same optical fiber inlet realize the composite detection of active and passive spectra, and improve the detection efficiency. Efficiency: According to the different characteristics of active and passive spectra, different designs are adopted at the sensor end to achieve targeted spectral detection, improve active spectral resolution and passive spectral signal-to-noise ratio.

The invention discloses a method for detecting resolution of a three-dimensional density picture of a cryo-electron microscopy based on a mask. The method is characterized in that the three-dimensional density picture reconstructed by the cryo-electron microscopy is segmented through a three-dimensional binary mask, radius power spectrums of an intramembranous particle structure part and an extramembranous background noise part of the three-dimensional density picture based on a three-dimensional shell of a Fourier space are respectively computed to obtain signal power and noise power of the three-dimensional density picture, so that an estimated value of the global resolution is obtained through a spectral signal to noise ratio based on the mask, which is obtained through calculation of the spectral signal to noise ratio, and a selected threshold, and thus evaluation of the reconstruction quality of the cryo-electron microscopy is implemented. According to the method, the resolution can be directly estimated from the three-dimensional density picture reconstructed by the cryo-electron microscopy, an algorithm is simple and practicable, and the method has a larger application space.