117 results about "Digital reconstruction" patented technology

The invention relates to technology for simultaneously measuring multi-phase flow particles online through multi-parameter, and aims to provide a method and a device for simultaneously measuring droplet positions, particle sizes and a complex refractive index. The method comprises the following steps of: (1) dividing a highly coherent continuous laser beam into two beams after spatial filtering and collimating beam expansion, wherein one beam radiates particles in a detected flow field region, and the other beam is used as a reference beam; (2) mixing scattered light of a lateral 30-degree to 90-degree region of particles in the detected flow field region and the attenuated reference beam to perform interference so as to form a hologram, storing the hologram in a computer after being recorded by a digital camera through an imaging device; (3) acquiring a series of reconstructed images of the detected particles along the depth direction by utilizing digital reconstruction technology; and (4) identifying the reflective spot and the refractive spot of the particles from the reconstructed images by utilizing digital image processing technology so as to acquire space coordinates and scattered light intensity ratios. Compared with rainbow measurement technology, the measurement method has the advantages that: a light path system of the measurement device is relatively simple and is easy to implement.

Raw cone beam tomography projection image data are taken from an object and are denoised by a wavelet domain denoising technique and at least one other denoising technique such as a digital reconstruction filter. The denoised projection image data are then reconstructed into the final tomography image using a cone beam reconstruction algorithm, such as Feldkamp's algorithm.

The invention relates to a measuring method of 3D profilometry of free-form surface based on computer-generated hologram, comprising the following steps: generating a computer-generated hologram with an ideal free-form surface wavefront according to a mathematical model of the free-form surface; carrying out holographic record on an actual to-be-measured free-form surface; sampling a hologram recorded by a medium through a charge coupled device so as to obtain a digital hologram; respectively carrying out digital reconstruction on the digital hologram and the computer-generated hologram so as to obtain a to-be-measured free-form surface and CGH wavefront information, and carrying out coherent addition on the two wavefronts so as to obtain an interference pattern; carrying out phase computation on the interference pattern so as to obtain the phase position of an ideal free-form surface and the phase position of the to-be-measured free-form surface; calculating according to the phase positions obtained by calculation so as to obtain the height information of each pixel dot; and then obtaining the 3D profilometry of the free-form surface. Due to the fact that the measuring method is a contactless optical measuring method, the surface of the free-form surface is prevented from damage, and the measuring range and the measuring object are not limited; the precision is high, thus the accurate real-time detection can be realized. The measuring method can provide accurate data for precise processing of the free-form surface.

The embodiment of the invention discloses an augmented reality interaction method and device based on sight line tracking. The method comprises the following steps of: obtaining a scene image corresponding to the current scene, obtaining azimuth information of the head of a user, wherein the head azimuth information comprises head height information and head deflection angle information of the user; and determining a target image in the scene image according to the head azimuth information, obtaining the sight line information of the eyes of the user, determining a target object in the targetimage according to the sight line information, obtaining virtual enhancement information corresponding to the target object, and superposing the virtual enhancement information to a corresponding position in the scene image. Target selection of the photosensitive area is completed by using the head azimuth and the sight line information of the user, and the real scene seen by the user is fused with the virtual enhanced information through three-dimensional digital reconstruction of the computer, so that the interactivity of augmented reality is improved.

The invention discloses a real-time frequency tracking and harmonic measuring method for the AC sampling of a power system, which is characterized by comprising the steps: an AC sampling input is made to enter an analog-to-digital converter at a fixed sampling rate; the analog-to-digital converter at the fixed sampling rate respectively outputs a first segment of digital signals with the length of N points and a second segment of digital signals with the length of N points to enter a first fast Fourier module; the first fast Fourier module outputs phase angles of the highest frequency components of the first segment of digital signals with the length of N points and the second segment of digital signals with the length of N points, and sends the phase angles into a phase discriminator one after another; the phase discriminator outputs a correction frequency, and sends the correction frequency into a digital signal reconstruction filter; the digital signal reconstruction filter performs digital reconstruction sampling on the first segment of digital output signals with the length of N points, of the analog-to-digital converter at the fixed sampling rate, according to the correction frequency, and sends an obtained N-point reconstruction sampling signal into a second fast Fourier module; the phase angle output of the highest frequency component of the second fast Fourier module is sent into the phase discriminator; the third segment of digital signals with the length of N points, of the analog-to-digital converter, enter the first fast Fourier module; and the phase discriminator judges the phase angle based on accuracy requirements, and outputs a correction frequency to a digital signal reconstruction filter. After the iterations of the process reach M, the output of the second fast Fourier module is the values of respective subharmonic components of the AC sampling signal, and the output frequency of the phase discriminator is the frequency of the AC sampling signal.

The invention provides a method for testing the tight oil occurrence state of a reservoir stratum through CT quantitative and three-dimensional visualization. The method comprises the following steps of providing fresh rock core samples in the reservoir stratum; performing CT scan on rock cores so as to obtain two-dimensional slicing images; differentiating out tight oil, water, rock particles and holes by grey scales, and performing digital reconstruction on the two-dimensional slicing images so as to obtain three-dimensional images; and dividing the tight oil into different occurrence states, performing statistics on the volume of the tight oil in each occurrence state, and analyzing the volume or the mass of the tight oil in each occurrence state. Through the adoption of the method, the microcosmic occurrence state of the impact oil in a micro nanometer pore throat can be quantitatively analyzed.

The present invention provides an ADC apparatus and method for improving effective bit resolution and suppressing digital reconstruction artifacts with an anti-aliasing filter and an over-sampled input. ADC resolution can be increased by combining a dither signal with a sampled signal and then after digitization, filtering out the dithered signal. Designing a notch in the filter corresponding to the attenuation frequency attenuates residual effects.

An elemental image array of a three-dimensional object is formed by a micro-lens array, and recorded by a CCD camera. A display device may be connected directly or indirectly to the computer to display the image of the three-dimensional object.

The invention relates to a mineralized collagen-based skull defect restoration based on digital reconstruction and a preparation method of the skull defect restoration. The preparation method comprises the following steps: acquiring skull image data of a patient; conducting threshold setting and a region growing operation, so that a three-dimensional skull model is obtained; establishing a curve model which is matched with a part of skull defect and has an internal repair curve and an external repair curve; leading the curve model into digital model engraving software and conducting detail treatment; suturing the internal repair curve and the external repair curve into an enclosed solid, so that a restoration model is constituted, and conducting a Boolean operation on the restoration model and the three-dimensional skull model, so that the edge of the restoration model is consistent with a skull defect edge; conducting a rollover operation on the restoration model and processing a solid mold; and pouring a mineralized collagen/polycaprolactone mixed suspension into the mold and conducting molding, so that the mineralized collagen-based skull defect restoration is obtained. According to the skull defect restoration and the preparation method thereof provided by the invention, perfect fit between the restoration edge and the skull defect edge is achieved, and moreover, new bone growth is guided, so that a post-operative skull curing effect is guaranteed.

An intelligent recognition method for geological radar echo signal physical property deconstruction and detection target digital reconstruction is disclosed. In the method, the characteristic that a geological radar reflected wave signal has the unique resonance of the frequency response and detection target body frequency response features during the propagation of an underground medium are utilized, an intensity value of the spectral energy contribution rate of the measured target medium response frequency is calculated, inversion and analysis are performed, deep, weak or tiny reflected signals are effectively extracted and identified, interference of clutter signals are removed, and the spatial distribution of the intensity of the spectral energy contribution rate of underground targetbodies or anomaly bodies is interpreted. According to the invention, the detection depth of a geological radar and the accuracy of the interpretation are substantially improved, the uncertainty of theinterpretation of the geological radar results due to the constraints of the differences of data interpreters or the lack of experience and the like is reduced, the problem of the multi-solution of underground anomaly interpretation of the geological radar exploration to some extent is solved, the intelligent recognition of target body reconstruction and anomaly body features can be realized, andthus a new method for digital signal processing and analysis interpretation is provided for the geological radar detection technology.

The embodiment of the invention discloses a CT lumbar spine automatic locating method and device and a storage medium The method comprises the following steps of: the training step: acquiring the initial CT stereoscopic image of the spine; processing the initial CT stereoscopic image of the spine so as to obtain the locating parameters of the lumbar spine position; the prediction step: acquiring the CT stereoscopic image of the spine to be measured; performing projection processing on the CT stereoscopic image of the spine to be measured by using the digital reconstruction radiography and thegeometric relationship so as to obtain the DRR image to be measured; predicting the DRR image to be measured by using the convolutional neural network and locating parameters so as to obtain the position information of the lumbar spine in the DRR image to be measured; and mapping the position information of the lumbar spine in the DRR image to be measured to the CT stereoscopic image of the spineto be measured by using the digital reconstruction radiography technology so as to obtain the position information of the lumbar spine in the CT stereoscopic image of the spine to be measured. With application of the CT lumbar spine automatic locating method and device and storage medium, the robustness, the real-time performance and the accuracy of lumbar spine automatic locating can be enhanced.

The invention provides a digital reconstruction method of a traffic accident scene based on monitoring videos, comprising the following steps of: steps one, continuously extracting frames related to movement positions of a detected vehicle from a monitoring video sequence; step two, calibrating a control point of each frame image in sequence and calculating corresponding values of DLT (direct linear transformation) coefficients; step three, selecting an observation point to acquire image space coordinates of the observation point at different moments and respectively calculating object space coordinates of the observation point at the corresponding moments by combining the values of the DLT coefficients; and step four, carrying out the digital reconstruction of the scene on a movement state of the vehicle to obtain a path line of the vehicle movement, and solving a displacement curve, a speed curve and an accelerating curve of the vehicle movement. The method provided by the inventioncan realize the digital reconstruction on the vehicle movement state in the scene at different road sections, thus the problem of monitoring on the vehicle movement state in a large range is solved, measurement accuracy is improved and cost is reduced.

The method including defining a volume element and packing the volume element with digital elements modelling fiber elements of the composite material, and extending longitudinally along a main axis, the packing including associating each digital element with a position in a plane in three-dimensional space and with an orientation of its main axis; and successively positioning each digital element in the volume element in compliance with the position and the orientation that are associated therewith, this positioning including putting the digital element into contact with a wall of the volume element and/or a previously-positioned digital element, and geometrically adapting the digital element to the wall and/or to the previously-positioned element with which it is in contact; a portion of a digital element being subjected to a deformation other than having its longitudinal axis inclined relative to the main axis of the digital element.

The invention provides a method for measuring the internal stress field of a non-continuous structural body. The final stress measurement result is obtained based on multiple identical transparent three-dimensional physical photoelastic models, the three-dimensional physical photoelastic models are further acquired through digital reconstruction and 3D printing of the microfocus CT scanning resultof the non-continuous structural body, and the method is different from experiments and the test technology only indirectly speculating the internal stress field of a complex structural body in the prior art. The method is advantaged in that in combination with digital reconstruction, the 3D printing technology, the stress freezing technology and the three-dimensional stress characterization method, the internal stress field of the non-continuous structural body can be directly measured through the transparent three-dimensional physical photoelastic models, and a problem of incapability of realizing visual and quantitative display of the internal stress field from the perspective of physics experiments is solved.

The invention relates to a method for designing coefficients of a digital reconstruction filter with random sampling rate conversion. According to the method, the coefficients of the digital reconstruction filter are designed based on a reconstruction theory and an FIR filter window function design method, a window parameter and an intercepting parameter are selected through the minimum attenuation of an attenuation band, the multiphase branch number of the reconstruction filter is determined by the maximum sampling rate conversion factor, and an ideal reconstruction function is subjected to windowing and discrete sampling according to the parameters, so that the coefficients of the digital reconstruction filter are obtained and are quantized. The reconstruction filter with sampling rate conversion designed through the method provided by the invention is small in pass-band fluctuation and can better inhabit a mirror image, FPGA realization is easy, the design complexity is greatly reduced, and in addition, the filter coefficients are stored by reading a multiphase structure of a meter, random sampling rate conversion with high performance is realized with smaller resource consumption, the variable range of the sampling rate is large, and the realizing difficulty is small.

The invention discloses a method for generating a dual-energy X-ray CT image by unisource one-time scanning of an X-ray CT image. The method includes the steps that one-time scanning is conducted on an object under the X-ray with energy being E1, and a CT image of the object under the X-ray with the energy being E1 is obtained; a dual-linear conversion algorithm is used for converting an obtained CT number of the CT image of the object scanned under the X-ray with the energy being E1 into a linear attenuation coefficient of the object under the X-ray with energy being E2; a CT number definition formula is used for converting the obtained linear attenuation coefficient into a CT number under the X-ray with the energy being E2, and thus a CT image under the X-ray with the energy being E2 is obtained; the CT image under the X-ray with the energy being E1 and the CT image under the X-ray with the energy being E2 respectively generate a digital reconstruction image; a logarithm dual-energy subtraction algorithm is used in the generated digital reconstruction images in a combined mode, needed weight factors are selected, and the image for eliminating needless matter is obtained. According to the method, the dual-energy CT image can be obtained only by unisource one-time scanning.

The invention discloses an integral demodulation method of MF-TDMA non-uniform multi-carriers, and relates to related technologies such as filtering, extraction, digital reconstruction, and modulation and demodulation of digital signal processing in a communication field. Different from an integral demodulation method of uniform channel branches based on a multi-phase filter group, the non-uniform channelization technology based on a total reconstruction modulation filter group is adopted, and flexible reconstruction and integral demodulation of non-uniform TDMA signals with multi-path different symbol rates at any frequency point can be realized in a certain bandwidth by means of processing of an analysis filter, a comprehensive filter and the like. According to the invention, the integral demodulation of the non-uniform multi-path TDMA signals in an FPGA is realized, the number of processing paths is larger, the realization complexity is low, and the cost of a central station demodulator is lowered; in addition, when the method is applied to a central station of a large-capacity TDMA satellite communication system, the system is more flexible in networking processing mode, is higher in processing capability and is compatible with a uniform multi-carrier integral demodulation function.

The invention discloses a digital reconstruction system and method for a printed text layout. The system comprises: a layout semantic segmentation module for performing semantic structure analysis on an input text layout image, segmenting the input text layout image into a plurality of semantic blocks according to different semantic types, and realizing segmentation and positioning of different semantic blocks, wherein the semantic blocks include text blocks, table blocks, formula blocks and illustration blocks; an OCR module used for identifying and reconstructing texts in the text blocks or the table blocks; a formula identification module used for identifying formulas in the formula blocks or the table blocks and carrying out formula identification and reconstruction; a table recognition module used for performing table structure and content recognition and reconstruction on the table blocks; and an assembling module used for assembling and synthesizing recognition and reconstruction results of the semantic blocks according to the position structure information of the semantic blocks, and outputting a complete text layout in an HTML (Hypertext Markup Language) format to realize digital reconstruction of a text layout image.

The invention discloses a three dimensional structure detection method of a fiber welding point, based on digital holographic tomography. Based on the digital holographic tomography technology, the fiber welding point three dimensional structure detection method based on digital holographic tomography performs digital reconstruction and correction of axial error on the fiber welding point hologram which is obtained through measurement of the digital holographic technology, by taking different reproduced distances, so as to obtain the phase diagrams of the welding fiber under each angle, and then performs horizontal correction, vertical correction and image inclination correction of rotation deviation on each phase diagram to obtain the phase diagrams that the positions of the fiber welding points are consistent under each angle, and finally utilizes the tomography back projection filtering algorithm to reconstruct the three dimensional structure of the fiber welding points. The three dimensional structure detection method of a fiber welding point, based on digital holographic tomography can realize correction of the rotation deviation as the data processing process is fully digitalized, has the advantages of high precision, no damage and three dimensional quantitative determination, and can be used for detecting the quality of fiber welding, based on the digital holographic tomography technology.

The invention relates to a digital reconstruction method of a multi-level rock core structure. The digital reconstruction method comprises the steps of: firstly, grading rock particles according to different particle sizes of the rock particles in a real oil reservoir rock core and different volume ratios of rock particle volumes to the whole rock volume, so as to form two or more levels of rock particles; secondly, adopting a four-parameter random generation method to generate a pore structure formed by first-stage large particle accumulation in the digital reconstruction process of the rockcore structure, and generating pore structures of corresponding particle sizes formed by stacking the rock particles of the level in the generated pore structure in sequence for the next level rock particles, so that the porosity and the feature size of the digital reconstruction rock core structure conform to the porosity and the feature size of a real rock core. By adopting the reconstruction method provided by the invention, corresponding generation can be carried out only through the size and volume distribution of the particles, and in addition, the reconstruction method has the advantages of low cost, high speed and the like.