193 results about "Scatter correction" patented technology

A method of acquiring scatter data and image projection data in computed tomography is provided that includes attenuating a radiation source using a pattern of blockers arranged to provide blocked and unblocked regions of the radiation source, and acquiring image data and scatter data of a target using an imaging device. A scatter map in the projection image can be estimated by interpolation and/or extrapolation of the projection image using an appropriately programmed computer, subtracting the estimated scatter map from the projection image to obtain scatter-corrected projections, reconstructing a CBCT volume using a total variation regularization algorithm, and applying an iterative regularization process to suppress the noise level on the reconstructed CBCT volume. Reconstructing a CBCT volume can include using a total variation regularization algorithm and applying an iterative regularization process to suppress the noise level on the reconstructed CBCT volume, where scatter-induced artifacts are corrected in the projection image.

A device (1) for computer tomography, which is set up for x-ray scatter correction, features an evaluation unit (17) which evaluates values stored as a table in a data memory for x-ray scatter correction, which have been determined in advance with the aid of a Monte Carlo simulation which take account of interactions of the photons with the object (2) to be investigated.

A method and system for controlling a positron emission tomography (PET) system is disclosed. The method includes acquiring image data and time-of-flight information from a PET system during an imaging scan. Further, the method includes performing scatter correction on the image data using the time-of-flight information.

Apparatus and methods for three dimensional image reconstruction from data acquired in a positron emission tomograph (PET). This invention uses a parallel/pipelined architecture for processing the acquired data as it is acquired from the scanner. The asynchronously acquired data is synchronously stepped through the stages performing histogramming, normalization, transmission/attenuation, Mu image reconstruction, attenuation correction, rebinning, image reconstruction, scatter correction, and image display.

An apparatus for projection radiography is set up for correcting stray radiation. The apparatus comprises an evaluation unit which evaluates the distribution of stray radiation, which is arranged in a tabular manner in a data memory, for correcting stray radiation, said distribution being initially determined with the aid of Monte-Carlo-Simulation which takes into account multiple interactions of the photons with the object which is to be analyzed.

This invention relates to a method for identifying near infrared spectrum of rosewood including the following steps: applying rosewood and non-rosewood samples to collect several times of near infrared spectrums at different positions on the surface of the sample by a near infrared spectrum device and collect spectrums of 3-19 positions at a same sample to set up distinguishing models of true and false rosewood and its kind through spectrum pre-process such as smoothing, base line correction, a first stage derivative, a second stage derivative, multiple dispersion correction or pre-process of dimensionality reduction of data by a multivariable data analysis method of soft independent modeling sorting or deflection of the least square differential analysis so as to realize quick and harmless identification to true and false of rosewood and their kinds in several minutes.

Method of and system for adaptive scatter correction in the absence of scatter detectors in multi-energy computed tomography are provided, wherein input projection data acquired using at least two x-ray spectra for scanned objects may include a set of low energy projections and a set of high energy projections; wherein a low-pass filter of variable size is provided; the method comprises estimating the size of the low-pass filter; computing amounts of scatter; and correcting both sets of projections for scatter. The estimation of low-pass filter size comprises thresholding high energy projections into binary projections; filtering the binary projections; finding the maximum of the filtered binary projections; calculating the low-pass filter size from the found maximum. The computation of amounts of scatter comprises exponentiating input projections; low-pass filtering the exponentiated projections with the estimated filter size; computing the amounts of scatter from the filtered projections.

A technique for establishing texture metrics and bone mineral density (BMD) within an anatomical region of interest. A digital imaging system is used to acquire a standard digital X-ray image with a wide field of view. The standard digital X-ray image is used to guide the imaging system to obtain an image of a region of interest. The standard digital X-ray image is used to calculate various texture metrics, such as a length of a fracture. A dual-energy digital X-ray image of the region of interest is acquired. The dual-energy digital X-ray image is corrected for scatter. The BMD of the region of interest may be established from the scatter-corrected dual-energy digital X-ray image. The BMD, the texture metrics, and/or the scatter-corrected dual-energy X-ray image may be displayed on the standard digital X-ray image.

The invention provides a method for correcting and calibrating three-dimensional fluorescence data of colored soluble organic matters. The method comprises the steps of setting measurement conditions such as three-dimensional fluorescence excitation, a wavelength generation range and a scanning speed; measuring a three-dimensional fluorescence spectrum of a sample; measuring a three-dimensional fluorescence spectrum of ultrapure water; performing Raman scattering correction by subtracting excitation-emission three-dimensional fluorescence spectrum of the ultrapure water from the excitation-emission three-dimensional fluorescence spectrum of the sample; assigning 0 to a triangular region of each three-dimensional fluorescence spectrum to perform Rayleigh scattering correction; performing calibration on the fluorescence intensity through the excitation wavelength of 350nm and the emission wavelength of 371-428nm of the ultrapure water; measuring an absorption spectrum of the sample to obtain the absorbency of the sample; performing inner filering effect correction on the three-dimensional fluorescence data according to the absorbency of the sample. According to the method disclosed by the invention, the influence of the inner filtering effect of the high-concentration sample on the fluorescence intensity can be eliminated without dilution of the sample.

An embodiment of the invention provides a model generation method, an image processing method and medical imaging equipment. The model generation method includes: under specified imaging parameters, acquiring first image data with scattering component and second image data without scattering component, selecting input data from the first image data or related data thereof, and selecting label data from the second image data or related data thereof; according to the input data and the label data, performing machine learning by adopting a neutral network to generate a scattering-correction model. Machine learning is performed by the aid of the neutral network to generate the scattering-correction model, the scattering-correction model is used for performing scattering correction on DR (digital radiography) images, increasing of radiation dose of X-rays is not needed, better safety is achieved, adding of a grid in DR equipment is not needed, cost of the DR equipment can be reduced, and problems that the DR equipment with the grid is poor in safety and high in cost in the prior art are solved to some extent.

The invention discloses a convolution-based X-ray CT system beam hardening correction method, belonging to the applying field of industrial CT systems. The method comprises the following steps of: I. conducting scattering correction by clinging an aluminum foil filter plate to a rear collimator; II. setting the scanning parameter of a CT system; III. collecting the background value of the system with a ray source not opening; IV. opening the ray source, and scanning the air in the current laboratory to obtain the ray strength of the current air; V. scanning a group of standard parts, and collecting the projection data under different thicknesses; VI. fitting a curve to obtain a hardening model and a convolution correction model; VII. conducting hardening correction by utilizing the function of the convolution correction model to obtain the corrected ray strength data; and VIII. conducting image reconstruction by using the corrected ray strength data. With the correction method, the beam hardening correction effect is obvious, the edge of a detected object can be well maintained, the detail part of the detected object can be saved, and the high-precision detection need can be met.

The present invention relates to a method for scattered radiation correction of a CT system, including at least two focus/detector systems operated angularly offset from one another, is disclosed. In the method, at at least one phantom, similar to the examined object at least in a subregion, for at least one of the focus/detector systems, the scattered radiation intensity occurring is determined in the detector of a focus/detector system during the operation of the at least one focus of at least one other focus/detector system. Further, the spatial distribution thereof is stored for a number of angles of rotation of the focus/detector systems. During scanning of the object, the scattered radiation intensities, determined with the aid of a similar phantom that originate from the at least one other focus/detector system, are subtracted from the measured intensities of the first focus/detector system while taking account of the spatial orientation of the focus/detector systems and the beam respectively considered. Finally, absorption values are calculated with the aid of the intensity values thus corrected, and CT pictures or CT volume data are thereby reconstructed.

The method calculates a scatter estimate for annihilation photons in a subject having a distribution of attenuation. The method can be used for scatter correction of detection data from a positron emission tomographic scanner. The method uses the following steps: —select a first scatter point S₁ and a second scatter point S₂, —determine a first scatter probability for scattering of a photon at scatter point S₁ and a second scatter probability for scattering of a photon at scatter point S₂, —determine an integral of the attenuation over a line connecting S₁ and S₂, —multiply the integral and the scatter probabilities and use the product in the calculation of the scatter estimate.

The invention relates to a cone beam CT scatter correction method and system. The method comprises the following steps that an attenuation coefficient matrix of an X-ray passing through an attenuation screen on a detector is calculated; under the condition that the attenuation screen is included, projected images of a radiated object are acquired; scatter correction is conducted on each projected image; the projected image of a template body without the attenuation screen is estimated through the attenuation coefficient matrix; the image is reconstructed through a FDK algorithm. The cone beam CT scatter correction method can effectively lower the scatter influence on cone beam CT image reconstruction, and the image quality is improved. Circular scanning is only conducted on cone beam CT for one time, and irradiation dose is not additionally increased. The cone beam CT scatter correction method is simple to implement, and the main structure and the stability of the cone beam CT are not changed. The cone beam CT scatter correction system can effectively lower the scatter influence on cone beam CT image reconstruction, improve the image quality, and overcome the technical difficulty of poor cone beam CT imaging quality.

A method of correcting scatter includes obtaining a voxellized representation of a 3D image of an object from a plurality of projection data. A single scatter profile for the object is calculated using the voxellized representation of the 3D image of the object. A total scatter profile for the object is determined using the single scatter profile and an adjustment factor and the projection data is corrected using the total scatter profile to obtain a scatter corrected projection data. A beam hardening correction method includes simulating a number of attenuation data for an x-ray spectrum, at least one object material, and a detector spectral response. A function is fitted to the attenuation data to obtain an attenuation curve. A number of projection data for an object are corrected using the attenuation curve to obtain a number of beam hardening corrected projection data. A corrected image of the object is reconstructed from the beam hardening corrected image data.

Approaches for deriving scatter information using inverse tracking of scattered X-rays is disclosed. In certain embodiments scattered rays are tracked from respective locations on a detector to a source of the X-ray radiation, as opposed to tracking schemes that proceed from the source to the detector. In one such approach, the inverse tracking is implemented using a density integrated volume that reduces the integration steps performed.

The invention discloses a cone beam CT scatter correction method and device based on complementary gratings. The scatter correction of projected images is achieved through simple and reliable complementary grating scanning and a small amount of calculation, and scatter correction slice images can be rebuilt out through the projected images obtained after scatter correction is finished. The cone beam CT scatter correction method and device based on the complementary gratings are suitable for tested objects of any complexities, the method is good in accuracy, reliability, stability and convenience, adverse effects on cone beam CT images from scattering are reduced to the maximum extent, and therefore the quality of the cone beam CT slice images is improved obviously.

A system and method for forming an adjusted estimate of scattered radiation in a radiographic projection of a target object, which incorporates scattered radiation from objects adjacent to the target object, such as a patient table. A piercing point equalization method is disclosed, and a refinement of analytical kernel methods which utilizes hybrid kernels is also disclosed.