283 results about "Echo intensity" patented technology

Methods and apparatus are provided for operating a radar system to provide a thunderstorm image to a pilot. The method comprises using one or more radar scans depending upon the aircraft altitude, a single upward tilted scan at or below a datum level of about 15,000±3000 feet wherein a clutter free storm image may be obtained and two scans above the datum level; a first upward tilting scan to determine, clutter free, a storm head perimeter and a second lower tilting scan for the storm body with ground clutter. The perimeter is used to discard return echoes from the second scan that lie outside the perimeter or an expansion thereof and retain those lying on or within the perimeter. The result is presented to the pilot. Optionally, the thunderstorm image is graded from center to edge so as to indicate weaker echo intensity near the edge.

The invention discloses an on-line transmission line lightning shielding failure trip early-warning method. The method comprises the following steps of: performing statistics on historical lightning shielding failure trip information to obtain transmission line lightning shielding failure trip probability distribution by a two-dimensional information diffusion theory and a conditional probability method; selecting radar forecast data, such as echo intensity, echo tops and vertical accumulated liquid water content; establishing a lightning current magnitude prediction model based on a back propagation neural network; and sending real-time early warning and an early warning grade of transmission line lightning shielding failure trip probability according to the predicted lightning current magnitude and the side distance to lightning stroke and by virtue of the transmission line lightning shielding failure trip probability distribution model. According to the real-time forecast data of a meteorological radar, the method provided by the invention can predict the trip probability of a transmission line and send an early warning signal, thereby providing reference for decision-making analysis of grid dispatching operators, making a transmission line dispatching strategy in time, improving power supply reliability, lowering economic loss of a grid, and improving the reliable running ability of the grid.

The invention discloses a regional automatic weather station hourly rainfall data quality control method. The method comprises the steps that a discriminant model is established according to historical data; raindrop spectrometer data, weather radar data and automatic weather station rainfall data are collated in real time; the data of a number of raindrop spectrometers are used to evaluate and revise a radar echo intensity result; the relationship between the radar echo intensity and the rain intensity is fitted according to different precipitation types; the fitted relationship is substituted into a radar quantitative estimation precipitation module to realize radar quantitative rainfall estimation to acquire hourly rainfall; the set of weather radar estimated hourly rainfall and regional automatic weather station hourly rainfall is established; and comparing with the pre-established discriminant model is carried out to judge whether the regional automatic weather station hourly rainfall data are abnormal. The automatic weather station rainfall data are accurate and reliable. The observation data quality is improved. The method lays a good foundation for weather monitoring, early warning, forecasting and other businesses.

The invention discloses a dual-polarization Doppler weather radar ground clutter inhibition method based on fuzzy logic, and the method comprises the steps: processing volume scanning data of a dual-polarization Doppler weather radar into 360 radial lines, wherein the interval between each two adjacent radial lines is one degree, and the data of each radial line comprises seven echo characteristic physical quantities: intensity, a mean Doppler speed, a spectrum width, a difference reflectivity factor, a difference propagation phase shift, and a correlation coefficient; setting the seven physical quantities which respectively comprise the intensity, the mean Doppler speed, the spectrum width, the difference reflectivity factor, the difference propagation phase shift, and the correlation coefficient; enabling seven fuzzy results to be assigned with corresponding weight values, carrying out accumulating and obtaining a ground clutter criterion of one echo point; Determining that the intensity echo of the point is the ground clutter when the ground clutter criterion of one echo point is greater than a threshold value; inhibiting the ground clutter of the dual-polarization Doppler weather radar through the ground clutter criterion of each echo point, and compensating a hole of a current layer after clutter inhibiting through employing the echo intensity value of a corresponding point in an upper layer in the volume scanning data.

The invention provides a city region power line detection method based on airborne LiDAR (light detection and ranging) data, relates to the field of city region power line detection and aims to solve problems that power line point cloud is very similar to building edge point cloud and a large quantity of power line information can be lost due to the fact that rasterization treatment is performed on the power line point cloud directly during power line information extraction in a city region environment. The method comprises steps as follows: 1, acquiring LiDAR data after gross error rejection; 2, finding out point cloud in a first echo position; 3, finding out echo point cloud with the echo intensity quantized to be zero; 4, acquiring point cloud after the filter result; 5, acquiring a grid image after point cloud rasterization; 6, determining the linear structure of the grid image after point cloud rasterization; 7, obtaining the final power line detection result and the like. The method is applied to the field of city region power line detection.

An ultrasound system includes an ultrasound transducer adapted to obtain a dynamic series of echo signals of a subject tissue at different deformation states, and an image processor for generating and displaying ultrasound images of the tissue. The processor is configured to generate dynamic images that correspond to the dynamic series of echo signals, identify a plurality of pixels within a region of interest (ROI) of a first of the generated images, evaluate local tissue mechanical behavior by tracking the displacement, deformation, and echo intensity of the identified plurality of pixels from the first image to subsequent images based on groups of pixels that correspond to each of the identified plurality of pixels, determine tissue functionality in the subject at the tracked pixel locations, and display the tissue functionality in dynamic images that corresponds to the tracked pixel locations.

The invention discloses a local maximum value based vehicle radar target detection method. The local maximum value based vehicle radar target detection method includes the following steps that step one, a microwave detection device on the road surface uploads collected echoes to an upper computer through a serial port, radar echo distribution conditions of the road surface are observed through the upper computer, and radar echo areas are partitioned; step two, the range of a search window is calculated according to a distance resolution ratio of frequency modulation continuous wave (FMCW) radar and width information of a lane; step three, all lane echo points extracted in the step one are traversed, the search window in the step two is set in the neighborhood of each echo point for each echo point, and subsequently, the echo point is compared with other echo points in the search window; step four, whether an echo intensity value of a searched local maximum value point is larger than a set echo threshold is judged, the searched local maximum value point is a target point if the searched local maximum value point is larger than the set echo threshold, and otherwise, the searched local maximum value point is considered to be a non-target point; step five, the target point is marked, and an echo signal is turned into a two-value signal so as to achieve target detection.

The invention provides a seabed sediment reflectivity extraction method and system for laser radar sounding data. The method comprises: seabed echo waveform data included by airborne full-waveform laser radar sounding data are obtained and solution processing is carried out on the seabed echo waveform data based on a Richardson-Lucy deconvolution iterative algorithm to obtain an echo intensity and a seawater depth; according to a linear regression method, seabed echo waveform data solution is carried out to obtain sea water attenuation coefficient; echo intensity correction is carried out on a hot-spot effect caused by a seabed topographic slope and pulse broadening, thereby obtaining a slop of the seabed sediment and a seabed sediment reflectivity. According to the invention, the influence on the seabed echo intensity by various factors like a seawater attenuation coefficient, pulse broadening, and a hot spot effect are taken into consideration; and the seabed sediment reflectivity is inverted precisely.

The invention provides a method of identifying a warm cloud precipitation rate based on Doppler radar information. The method is characterized in that a radar echo intensity ref vertical profile VPR identification module is used to identify a warm cloud; a warm cloud identification module is used to establish a polar coordinate in a cache region according to the radar echo intensity, and is used to identify the precipitation rate of the warm cloud of the stratus cloud and the precipitation rate of the warm cloud of the convection cloud according to the ref interpolation and the wet bulb temperature; a processing module is used to calculate the precipitation rate. The method is advantageous in that the precipitation estimation error can be reduced effectively, the scientific concrete calculation method is provided, the high-quality data is provided, and the property loss of the people can be effectively reduced.

The invention aims to provide a method for inversing the sea wind direction through navigation radar images based on relative radiation correction. The method comprises navigation radar image sequence collection, navigation radar image preprocessing, navigation radar image relative radiation correction and sea wind direction reversing. According to the method, the navigation radar image relative radiation correction link is added to the wind direction inversing process through wind stripes, and influence of radial damping of the navigation radar echo intensity on wind direction inversing is eliminated effectively. A self-adaptive Lagrange least square segmentation fitting correction method is adopted for the navigation radar image relative radiation correction, so that it is guaranteed that sea clutter image features are not destroyed after correction is conducted, and applicability of engineering is improved as well.

The invention discloses an ocean wave parameter extraction method based on an SFS technology. According to the Lambertian scattering law, relations between the relative echo intensity and the incident angle, the direction slope and the distance slope are derived, the SFS technology and transformation formulas of polarization direction angles caused by the direction slope and the distance slope of the ocean surface are combined to solve slope values of pixels of the ocean surface, and a direction slope spectrum and a distance slope spectrum are obtained respectively by using fast Fourier transform. Spectral peak positions are searched, wave number vector information is acquired, 180-degree ocean wave direction blur is eliminated, ocean wave propagation directions are determined, the wavelength is calculated according to relations between the wave number and the wavelength, the ocean wave period is solved through ocean wave dispersion relations, and the significant wave height is calculated by the average slope and the wavelength. According to the ocean wave parameter extraction method, ocean wave spectrum inversion can be performed without a modulation transfer function, parameters such as the ocean wavelength, the period, the significant wave height and the ocean wave direction can be extracted, and the method is applicable to images acquired by high-frequency radars.

The invention discloses a waveguide beyond-visual-range wave monitoring radar which is provided with a sensor unit for measuring hydro meteorology data and further provided with a waveguide computation module, a beyond-visual-range estimation module and a wave monitoring module. The waveguide computation module is used for computing whether sea surface evaporation waveguide is provided or not under the current meteorological condition, and the beyond-visual-range estimation module is used for judging whether the radar has beyond-visual-range performance or not under the current meteorological condition. The wave monitoring module is used for delimiting isometric grids in the any direction of the detection range of the current radar under the sea surface evaporation waveguide, recording radar echo intensity of each grid, removing strong signals of the sea surface targets, keeping weak signals of the sea clutter in the echo, judging that a plurality of grids are crest, wherein the intensity of the weak signals of the sea clutter in the echo is larger than that of the periphery grids, obtaining echo signals of all wave crests in the scanning area, obtaining the lengths of the adjacent crests, namely the wavelengths, recording the scanning period of two adjacent radars, obtaining the movement direction, the movement distance and the movement speed of the wave, computing the wave frequency and completing the wave monitoring.

The invention provides a vibration Raman laser radar scattering optical processing system based on a narrow bandpass filter and a reflex prism, and a processing method thereof. Aiming at two problems of a wide dynamic range of laser radar signal intensity and strong noise signal relative to a Raman scattering signal, the method and the system divide back scattering light into a high channel and a low channel for detecting and sufficiently utilize the narrow bandpass filter to improve the accuracy of temperature measurement and enlarge the range of the temperature measurement. An upper noise signal is relative weak, and can be fed into a photoelectric detection system for detecting through the narrow bandpass filter for once; and a lower noise signal is strong, the back scattering light of atmosphere passes through the same optical filter for twice by special optical technology, and spectrum of total transmittance is equivalent to squared spectrum of single transmittance so as to furthest suppress photonoise. After elastic scattering and background light of emission wavelength are compressed, under the condition of a multiplier tube is unsaturated, the echo intensity of the Raman scattering signal can be improved by increasing single pulse energy of emission laser, thereby achieving the aims of improving the accuracy of the temperature measurement and enlarging the range of the temperature measurement.

The invention discloses a sounding laser full-waveform data-based diffuse attenuation coefficient extraction method and system. The method comprises the following steps: filtering to obtain effective laser sounding points from full-waveform data in sounding laser data; extracting emission intensity and echo intensity of each effective laser sounding point obtained by filtering from the full-waveform data, and after extracting the echo intensity, generating a water body back scattering function corresponding to a water body back scattering waveform according to an algorithm; selecting a plurality of time point pairs with a preset time interval from the water body back scattering function corresponding a single laser sounding point, and calculating an initial diffuse attenuation coefficient of each time point pair; taking an average value of the initial diffuse attenuation coefficients of all the time point pairs as a final diffuse attenuation coefficient of the laser sounding points. According to the invention, the diffuse attenuation coefficient value can be calculated by using the full-waveform data of the single sounding points, and echo intensity information and a depth value of each sounding point do not need to be acquired, the calculation accuracy of the diffuse attenuation coefficient is high.

Provided is a tissue mimicking phantom technology capable of controlling an ultrasonic echo intensity and hardness and offering excellent stability. A tissue mimicking phantom includes a first portion and a second portion which is incorporated in the first portion and whose hardness and/or ultrasonic echo intensity is different from that of the first portion. The first portion and second portion are gel structures that are formed with a covalent bond of macromolecular strands or a chemical bond that is as strong as the covalent bond. The gel structure has a solid scatterer (for example, metal-oxide microparticles) dispersed therein. The first portion and second portion exhibit mutually different hardness levels and ultrasonic echo intensities.

The invention discloses an atmospheric aerosol particulate matter detection laser radar and a retrieval method; the laser radar comprises an emitter laser unit (1), a receive telescope (2), a receive fiber (3), a signal detection unit (4) and a signal processing unit (5); the retrieval method comprises the following steps: using a high resolution spectrum detection method to measure a Raman scattering spectral signal formed by laser exciting atmospheric molecules, and to measure a Mie-Rayleigh scattering spectral signal formed by laser exciting atmospheric aerosol particulate matter and atmospheric molecules; using the features that the Raman scattering spectrum in proportional to the Rayleigh scattering spectrum in echo intensity, the Rayleigh scattering spectrum formed by atmospheric molecules is quantitatively deducted from the Mie-Rayleigh scattering spectrum signal, thus obtaining the signal only containing the atmospheric aerosol particulate matter, and retrieving to obtain the atmospheric aerosol particulate matter information. The Raman scattering channel is added to correct the low altitude echo signal, thus removing Rayleigh scattering caused influences from the low altitude Mie scattering, and improving atmospheric aerosol particulate matter detection precision.

The invention provides a precipitation strong center tracking and prediction method of a rainfall radar. The method includes the following steps that: tracking is performed, and a TREC vector field is obtained; smoothing processing is performed on a moving vector field; and the echo location and echo intensity of a precipitation strong center are predicted. According to the method of the invention, a TREC method is used to perform precipitation center tracking on an X-band intermediate-frequency coherent rainfall radar, and therefore, erroneous moving directions or zero vectors generated by the clutter of ground objects can be eliminated, the continuity of the TREC vector field can be improved; and additional processing is performed according to grids to which a plurality of data are shifted into, and grids to which no data are shifted to, and therefore, the accuracy of prediction is greatly improved.

The invention discloses a method for calculating the farthest detection distance of a Gm-APD laser radar. The method comprises the following steps: 1, acquiring echo intensity by using a laser radar equation; 2, obtaining the triggering probability of each time interval of the Gm-APD laser radar; 3, acquiring simulation data under different statistical frame number conditions by using a Monte Carlo method; 4, echo parameters are obtained through a signal detection method according to the Gm-APD trigger probability curve obtained in the step 2 and the simulation data obtained in the step 3; and5, calculating echo detection probability and confirming optimal parameters of the system. The Gm-APD performs optimal argumentation on parameters such as laser parameters and optical aperture underthe condition that the index parameters are determined, so that the laser radar system realizes optimal power consumption and volume on the premise of meeting the indexes, and has a very important promotion effect on further engineering of the Gm-APD laser radar.

The invention relates to a high-resolution aerial image partition method based on LEGION and under assisting of a LiDAR. The high-resolution aerial image partition method comprises the following steps of utilizing LiDAR laser point cloud data to generate a laser echo intensity image, conducting registration of the laser echo intensity image and a remote sensing image panchromatic wave band, using a principal component analysis (PCA) to conduct fusing of the laser echo intensity image and the remote sensing image panchromatic wave band after registration of the laser echo intensity image and the remote sensing image panchromatic wave band, obtaining a fusing image, and conducting LEGION image partition for the fusing image. Compared with the prior art, the PCA is utilized to fuse the laser echo intensity image and the high-resolution remote sensing image panchromatic wave band, two different data sources are comprehensively utilized to be used as LEGION partition method input data, LiDAR data and characteristics of a panchromatic wave band image are well reserved, and partition precision of a high-resolution remote sensing image is effectively improved. The LiDAR data and information of the remote sensing image are comprehensively utilized to conduct LEGION partition, and practice shows that the technology can effectively conduct remote sensing image partition and obtain satisfying partition effect.

Provided are an ultrasonic testing method and an ultrasonic testing apparatus capable of accurately detecting flaws present in a weld zone of a test object, such as a welded pipe, regardless of the position of the flaws. An ultrasonic testing apparatus 100 includes an ultrasonic probe 1 which is provided with n (n≧2) transducers 11 arranged along a direction orthogonal to the weld line of a weld zone P1 of a test object P and is arranged so as to face the weld zone, and transmission/reception control means 2 which selects m (n>m≧1) transducers from the n transducers, causes the selected transducers to transmit and receive ultrasonic waves to and from the weld zone, and switches the selected transducers one after another. The transmission/reception control means switches the selected transducers one after another so that the range of an effective beam width of each of the selected transducers that have been switched for a flaw to be detected has an overlapping portion, and in the transmission/reception control means, the flaw detection sensitivity is adjusted beforehand for each of the selected transducers so that maximum echo intensities from a flaw to be detected, which are each received by each of the selected transducers that have been switched, become substantially equal to each other.

The invention belongs to technical field of signal characteristic control and specifically relates to a method for accurately acquiring near field echo. The method comprises following steps of: a step 1, establishing a target coordinate system O-XtYtZt, an antenna coordinate system O-XaYaZa, and a scattering unit coordinate system O-XmYmZm; a step 2, acquiring a field incident on a mth scattering unit from the surface of a scattering body; a step 3, acquiring scattered fields of the scattering units; a step 4, acquiring a scattered field of the mth scattering unit received by a receiving antenna; a step 5, superposing the scattered fields of each scattering unit received by the receiving antenna in order to acquire a total scattered field; and a step 6, calculating the total scattered field so as to acquire near field echo intensity and power characteristics. The method establishes a complex target near field scattering model with a PO+PTD+GP method and introduces a concept of near field polarization scattering matrix so as to express scattering properties with different mechanisms by using a unified expression, thereby simplifying a calculating process.

The invention discloses a method for measuring a canopy gap three-dimensional structure based on laser radar. The method includes a first step of obtaining and pre-treating laser radar data which is remote sensing data obtained by laser radar loaded on a fixed wing aircraft or an unmanned aerial vehicle, the data of each laser point including X, Y, Z coordinate data and echo intensity data, a second step of processing canopy layer data, a third step of identifying canopy gaps, and a fourth step of measuring a three-dimensional canopy gap structure. The method is easy to realize, and is not affected by surveyed land and forest types and ground situations. Rapid, accurate, large-scale and multi-dimensional canopy structure measurement can be realized.

The invention provides a method for embedding and extracting a digital watermark in an audio signal, belonging to the field of information hiding. A digital watermark embedding part and a digital watermark extracting part are provided in the method. The digital watermark embedding part comprises the following steps of: firstly, separating the frames of the audio signal; then, carrying out wavelet packet decomposition on each frame, calculating the masking threshold of a wavelet packet sub-band and the watermark intensity of the corresponding wavelet packet sub-band, and selecting an appropriate echo delay to complete watermark embedding; and finally, carrying out inverse wavelet packet decomposition. The digital watermark extracting part comprises the following steps of: firstly, separating the frames of the audio signal; then, carrying out wavelet packet decomposition on each frame, calculating the power cepstrum of a wavelet packet sub-band coefficient, and extracting the watermark according to the position of a peak value. By embedding the watermark in the wavelet packet sub-band, the robustness to attacks is higher, and meanwhile, the echo intensity is adaptively adjusted along with the wavelet packet sub-band. After the watermark is embedded, the perception distortion of the signal is smaller, so that the method is applicable to the copyright protection of digital audio signals.

The invention discloses a multi-threshold squall line identification method based on a radar echo three-dimensional puzzle. The multi-threshold squall line identification method comprises the following steps of A, converting a current volume scan data of a new generation weather radar net into radar echo intensity three-dimensional puzzle data; B, conducting storm cell automatic identification for the radar echo intensity three-dimensional puzzle data by using a storm cell identification tracking algorithm; C, according to statistical analysis results of convective cloud characteristics in a squall line identification region, setting multiple sets of thresholds of parameters required for squall line identification to form multiple sets of parameter schemes; and D, designing a dynamic template and a score function method by using a fitted ellipse long axis, conducting squall line identification respectively using the multiple sets of parameter schemes, if one or more of linear scores corresponding to multiple sets of identification results are higher than a set score, taking the identification result of the highest linear score as the squall line identification result. The invention greatly improves the accuracy of the squall line identification and provides a reliable early warning mechanism for thunderstorm weather forecast.