19 results about "Beam hardening" patented technology

To provide techniques capable of shorting the time required for calibration.SOLUTION: An embodiment comprises: determining an effective voltage value V1 of a high kV on the basis of energy information of X-rays detected in a first sub-region of a detector assembly and energy information of X-rays detected in a second sub-region of the detector assembly, when the high kV is applied to an X-ray tube; determining an effective voltage value V2 of a low kV on the basis of energy information of X-rays detected in the first sub-region of the detector assembly and energy information of X-rays detected in the second sub-region of the detector assembly, when the low kV is applied to the X-ray tube; calculating a correction coefficient required to correct beam hardening on the basis of the effective voltage value V1; and calculating a correction coefficient required to correct beam hardening on the basis of an effective voltage value V2.SELECTED DRAWING: Figure 15

The present invention discloses a method for generating a channel spectrum response difference correction table and a channel spacing correction table, a computer program, a computer readable storage medium and a computer tomography device. The method for generating a channel spectrum response difference correction table and a channel spacing correction table includes using parallel projection P paral (k, r) determines the channel position corresponding to the center of the phantom, and calculates the simulated parallel projection and the ideal projection P accordingly sim (k, r), and finally according to the projection difference diff(k, l, r) and the simulated ideal projection P sim (k, r), calculate the channel spectrum response difference correction table t CCR (k, l) and channel spacing correction table t spacing The method, computer program, computer-readable storage medium, and computer tomography device of the present invention for generating a channel spectrum response difference correction table and a channel spacing correction table are not affected by residual beam hardening and can effectively generate ideal projections.

A deep learning segmentation method for asphalt mixture CT images relates to the technical field of aggregate image segmentation. CT images of asphalt mixtures are collected and voids are removed. Image equalization is performed using a gamma beam hardening correction algorithm. A filter window is selected, and an adaptive bilateral filtering denoising algorithm based on local image information is used to denoise the image. The U-Net model is improved, with the Inception convolution module replacing the standard convolution operation and residual connections replacing skip-layer connections. A spatial attention mechanism is introduced, and a joint loss function is used. Image samples are selected, aggregates are labeled, and data augmentation is used to increase the sample size to form a training set for model training. After training, this set is used to segment other images. By equalizing and denoising CT images and using the improved U-Net model, the method can achieve accurate segmentation of aggregate-mortar boundary information, avoiding aggregate adhesion issues.

The application discloses a kind of simultaneously sparse angle CT reconstruction and metal artifact high-precision correction method, belong to medical imaging field, specifically: simulate the projection data under the influence of beam hardening under sparse angle sampling, obtain sparse sampling and the sinogram of containing metal trace;Interpolation processing is carried out to sparse sinogram, and the sinogram is obtained as the initial sinogram of sinogram domain;According to the additive property of artifact, preliminarily decompose the CT image containing a large number of artifacts, obtain the initial estimated image of image domain and the initial artifact image of artifact domain;A multi-domain optimization model is established, and the constructed multi-domain optimization problem is alternately iterated minimization solution;Iterative update is carried out to sinogram domain, image domain and artifact domain respectively;The high-precision CT image of reconstruction is output.The application can simulate the sinogram containing metal trace and sparse obtained by CT imaging equipment to carry out simultaneously sparse angle CT reconstruction and metal artifact correction, and the reconstruction effect is good and correction precision is high.

The present application relates to a scatter model derivation apparatus, a radiation image processing apparatus, a method thereof, and a storage medium. The apparatus includes: a reference image acquisition unit configured to acquire at least one reference image representing a reference object having different thicknesses, the at least one reference image being obtained by radiographing the reference object with a radiation detector in a state in which the reference object is interposed between the reference object and the radiation detector; a reference object thickness and radiation attenuation coefficient relationship derivation unit configured to derive a relationship between a thickness of the reference object and a radiation attenuation coefficient of the reference object corresponding to an energy characteristic of the radiation and reflecting an influence of beam hardening caused by the reference object and an object; a primary ray component derivation unit configured to derive a primary ray component corresponding to the thickness of the reference object included in the reference image based on the relationship between the thickness of the reference object and the radiation attenuation coefficient of the reference object; a scatter ray component derivation unit configured to derive a scatter ray component corresponding to the thickness of the reference object included in the reference image based on a difference between the reference image and the primary ray component; and a scatter model derivation unit configured to derive a scatter model representing a relationship between the thickness of the reference object and a proportion of the scatter ray component with respect to the primary ray component.

The present invention pertains to a method and system for image reconstruction for computer tomography, in particular for reducing beam hardening effects, wherein image reconstruction is performed based on the generalized Lambert-Beer law for poly-chromatic sources.

The present application relates to an industrial CT beam hardening correction method, comprising: taking the jth row of pixel points in each circumferential DR image to form a projection image; CT reconstruction is carried out on the projection image to obtain a tomographic image; a homogeneous material region in the detected sample is selected in the tomographic image; a function relationship formula corresponding to the minimum standard deviation of all corrected pixel values in the region is obtained, and the obtained function relationship formula is recorded as the optimal function relationship formula; the pixel value of each pixel point in each circumferential DR image is substituted into the optimal function relationship formula to obtain the corrected pixel value of each pixel point, and then the DR image after beam hardening correction is obtained; finally, the DR image after beam hardening correction is reconstructed to obtain the corrected CT image of the detected sample. The method does not need additional processing of contrast test blocks or test samples with known structures, the process is simple, especially for homogeneous material parts, the full-automatic interactive link can be realized, and the image quality and efficiency of industrial CT are improved.

The present application belongs to the technical field of printed circuit board manufacturing quality detection, and particularly relates to a PCB hole defect detection method based on 2D line scanning and 3D-X ray fusion. The method drives the to-be-detected PCB board to perform 2D line scanning through a motion platform, obtains the whole-board 2D image and the physical coordinates of each hole site, extracts the hole ring profile matching degree, the hole inner gray scale statistical features and the hole diameter deviation, and determines the to-be-reviewed hole. According to the physical coordinates, the projection image is collected, 3D data is reconstructed after beam hardening correction and material weighted iteration correction, 2D image and 3D data are registered based on the unified coordinates, the material level is distinguished through gray scale-attenuation coefficient conversion, the adaptive threshold edge detection is performed on the hole wall development, the internal defects such as hole wall cracks and copper plating cavities are extracted, the defect classification and quantization are completed by fusing the 2D surface defect attributes and 3D internal defect attributes, the detection result and quality evaluation report are output, and nondestructive detection of the hole site is realized.

The invention discloses a scattering and hardening artifact eliminating method, system, device and equipment for turbine blade CT imaging and a medium, and relates to the field of aero-engine turbine blade CT detection. The method comprises the following steps: acquiring an original multicolor projection image and a scattering correction projection image of the turbine blade before and after placing a grating correction plate by using a cone beam CT (Computed Tomography) system; the aluminum strips arranged on the grating correction plate at intervals have inclined angles; according to the two images, determining a multi-color projection image for scattering removal of the turbine blade, and further utilizing a beam hardening correction model to obtain a single-color projection image of the turbine blade; weighting the monochromatic projection image and the scattering-removed multicolor projection image by adopting a weighted compensation enhancement correction algorithm which introduces a trade-off factor to obtain a projection image of which the cup artifact is eliminated; and finally, performing three-dimensional reconstruction by adopting a filtered back projection algorithm to obtain a projection correction slice image of the turbine blade. The method can effectively eliminate cup-shaped artifacts caused by scattering and hardening, and improves the image reconstruction quality.

Methods and apparatus are described herein to determine an effective voltage value V1 of a high kV on the basis of energy information of X-rays detected in a first sub-region of a detector assembly and energy information of X-rays detected in a second sub-region of the detector assembly, when the high kV is applied to an X-ray tube, determine an effective voltage value of a low kV on the basis of energy information of X-rays detected in the first sub-region of the detector assembly and energy information of X-rays detected in the second sub-region of the detector assembly, when the low kV is applied to the X-ray tube, calculate a correction coefficient required to correct for beam hardening on the basis of an effective voltage value, and calculate a correction coefficient required to correct for beam hardening on the basis of an effective voltage value.

The application provides a kind of industrial CT scattering and beam hardening coupling artifact suppression method based on deep learning, belongs to the field of industrial CT image processing, for the problem that coupled artifacts cannot be accurately separated and corrected in industrial CT imaging, a beam hardening, scattering coupling artifact model based on real CT image artifact features is constructed, a simulated image and an actual image are mixed to construct a data set by a coupled model representation equation, and artifact suppression and image enhancement are completed by a long-short connection, structure doublet improved neural network, effectively removing multiple types of coupled artifacts and noise, this method is suitable for coupled artifact suppression of any complex structure actual CT image, and the practicability and generality of the method are better.

The present application relates to the technical fields of industrial CT measuring machine, especially to a traceable industrial CT forest ball calibrator device, comprising a base and measuring needles, the measuring needles in the device have high rigidity, when the calibrator device is traced by using a coordinate measuring machine, contact measurement is needed for each standard ball of the measuring needles to obtain the spatial coordinates of each standard ball of the calibrator device, the high rigidity of the measuring needles can reduce the deflection change of the measuring needles in the measurement process, which can be ignored compared with the test accuracy, and the reliability and repeatability of the traceability are ensured, and the projection of the standard ball of the first layer of step measuring needles in the front view direction does not overlap with the projection of the third layer of step measuring needle support seats in the same direction; the first layer and the second layer of steps have 8 and 4 threaded holes respectively, the threaded hole positions are staggered by 30°, so as to reduce the stacking number of the calibrator device in the front view direction projection, the rays attenuate on the path, and the beam hardening is reduced.

Nondestructive evaluation (NDE) of objects can elucidate impacts of various process parameters and qualification of the object. Computed tomography (CT) enables rapid NDE and characterization of objects. However, CT presents challenges because of artifacts produced by standard reconstruction algorithms. Beam-hardening artifacts especially complicate and adversely impact the process of detecting defects. By leveraging computer-aided design (CAD) models, CT simulations, and a deep-neutral network high-quality CT reconstructions that are affected by noise and beam-hardening can be simulated and used to improve reconstructions. The systems and methods of the present disclosure can significantly improve the reconstruction quality, thereby enabling better detection of defects compared with the state of the art.

Provided is a technique capable of shortening the time taken for calibration. [Solution] When a high kV is applied to an X-ray tube 104, an effective voltage value V1 of the high kV is determined on the basis of energy information of X-rays detected in a first sub-region 109B of a detector assembly 109 and energy information of X-rays detected in a second sub-region 109A of the detector assembly 109; determining an effective voltage value V2 of the low kV on the basis of the energy information of the X-rays detected in the first sub-region 109B of the detector assembly 109 and the energy information of the X-rays detected in the second sub-region 109A of the detector assembly 109 when the low kV is applied to the X-ray tube 104; calculating a correction coefficient 75 required for beam hardening correction on the basis of the effective voltage value V1; and calculating a correction coefficient 76 required for beam hardening correction on the basis of the effective voltage value V2.

The application discloses a kind of based on double exponential model pole piece surface density measurement method, comprising: first, the X-ray source is started, the ray intensity when not placing pole piece is measured;Second, replace different surface density standard pole piece to be measured, and measure the ray intensity;Again, different coating surface density corresponding mass attenuation coefficient is obtained according to attenuation formula, and mass attenuation coefficient is corrected according to double exponential model calibration data;Finally, the ray intensity after measuring through the pole piece to be measured, according to the ray intensity attenuation model and the mass attenuation coefficient after calibration, the pole piece surface density measurement can be realized.This application uses the method of double exponential model to correct the mass attenuation coefficient of pole piece to realize the measurement of pole piece surface density, compared with the method of directly calibrating the measured ray intensity and standard surface density value, the problem of the influence of X-ray beam hardening and Compton scattering on pole coating surface density measurement is overcome, and the precision of pole piece surface density measurement is improved.

A computer-implemented method of reducing scatter in an X-ray projection image of an object, the method comprising: generating an initial X-ray projection image of an object with an imaging beam produced by an imaging system; based on a first transmission indicator for the object and on a second transmission indicator for at least one element of the imaging system, selecting a kernel for convolution of the initial projection image; convolving the initial X-ray projection image with the kernel to generate a scatter component of the initial X-ray projection image; and generating a corrected X-ray projection image by removing the scatter component from the initial X-ray projection image.

Disclosed are techniques for performing CT beam hardening correction. The CT beam hardening correction includes scanning a phantom to obtain measured projection data of the phantom and calculating corrected projection data of a measured object according to a calculated beam hardening correction factor, measured projection data of the measured object, a corrected projection data of the measured object, and a relationship among expected projection data of a scanned object.

The invention relates to the technical field of X-ray tomography, and discloses a high-resolution X-ray tomography system and method.According to the system, an X-ray source and a piezoelectric ceramic type mechanical grating form a coding transmitting end, a precise displacement control system is combined to adjust the grating distance, and full-band scanning of X-ray spatial frequency is achieved; the synchronous control unit coordinates three-step phase shift and inclined rotary scanning of the grating to obtain multi-phase projection data, and demodulates and separates a direct-current component and an alternating-current component through a three-step phase shift method; three-dimensional structures under different frequencies are reconstructed based on an FDK algorithm, optimal slices of all layers are screened and fused layer by layer through comprehensive evaluation of indexes such as a modulation transfer function, full width at half maximum and a peak signal-to-noise ratio, and high-resolution three-dimensional reconstruction of the internal structure of the circuit board is achieved; according to the scheme, through hardware coding modulation and multi-frequency data fusion, beam hardening and scattering noise are effectively restrained, the image resolution and the detection precision are improved, and the method is suitable for nondestructive detection of complex structures such as electronic circuit boards.

The invention provides an oral cavity CBCT (cone beam computed tomography) multi-material beam hardening correction method, which is particularly suitable for a multi-material scene and can be used for removing dark bands and stripe artifacts around teeth, bones and metal implants to obtain a reconstructed high-precision image. The method comprises the following steps: firstly, removing scattering artifacts in CBCT imaging data to obtain projection data after scattering correction, then determining all materials included in the data, areas where the materials are located and segmentation volumes, and simulating to obtain multispectral simulation multicolor projection and monochromatic projection simulation data; and calculating a difference value between the fitting multicolor projection simulation data and the optimized reference projection data to obtain a non-linear correction item between a CT measurement value and a true value, and then superposing the non-linear correction item to the projection data after scatter correction to recover the FDK measurement value to the true value so as to complete beam hardening correction of the original CBCT imaging data.