279 results about "Image reconstruction algorithm" patented technology

An imaging system includes a source and a detector that can be quickly and easily moved out of the way after scanning. During scanning, the actual paths that the source and detector travel are tracked, such as by an associated surgical navigation system tracking system. The actual locations of the source and detector during each x-ray image are used in the image reconstruction algorithm. Since the actual locations are used in the algorithm, the locations do not have to be as precisely controlled. In one embodiment, the source and detector are mounted proximate outer ends of first and second c-arm sections. The first and second c-arm sections are extendable to form a complete c-arm and retractable to a collapsed position when not in use. In the disclosed embodiment, the c-arm sections are mounted to a base or carriage under the patient support surface (such as the surgical table).

A method for imaging objects in a highly scattering turbid medium comprises: using a group of sources and detectors to generate a plurality of emergent energy waves from the medium, determining the intensity data of the emergent energy waves and processing the intensity data by using an image reconstruction algorithm. Arrangement of sources-detectors may be in parallel (transmission and/or backscattering) geometry or in cylinder geometry. The reconstruction algorithm is a novel hybrid dual Fourier tomographic algorithm for a fast 3D image reconstruction. The forward models are the radiative transfer model based on the cumulant solution of the radiative transfer equation or the diffusion model based on the approximate diffusion equation.

An image reconstruction algorithm begins with an initial acquisition of a preoperative imaging volume followed by a second imaging sequence subsequent to an applied deformation. A computational domain (model) is generated from the preoperative image series and boundary conditions are derived from a pre-post deformation comparison, as well as from information gathered from deformation source application (i.e., displacement and/or force). Using boundary conditions, a series of model-based image deformations is accomplished while varying model material properties. A calculation of a Jacobian matrix relating the change in regional mutual information is performed with respect to the change in material properties. Upon completion of this process, matrix regularization techniques are used to condition the system of equations and allow for inversion and subsequent delivery of model-property adjustments.

Image reconstruction approaches that use standard Cartesian-sampled, frequency-domain SAR data, which can be collected by a platform with a single radar antenna, together with its associated metadata as the input and generate an output comprised of a set of images that show the directions of moving targets, estimates of their motions, and focused images of these moving targets.

The invention discloses a method of dose reversal of the target of a patient in radiotherapy, the method makes use of a light source and a flat panel detector to carry out the rotary scanning around the target of the patient, so as to obtain the data of the target image of the patient and the dose data which penetrates the target of the patient; the invention applies a virtual PI line reconstruction algorithm to carry out the reconstruction and processing, and the treatment is carried out by adjusting the position of the patient and the input dose distribution data according to the processing results. As the invention adopts a true three-dimensional image reconstruction algorithm which is based on the flat panel detector, the spatial resolution of the true three-dimensional image is isotropic, the invention does not need interpolation, and can directly realize the processing of the image on the three-dimensional space, thus greatly improving the imaging precision and solving the problem that the imaging is not precise due to the interpolation error during the integration process into a quasi three-dimensional image of the existing radiotherapy, which can further affect the accurate implementation of the treatment plan of focus.

The invention relates to a CT image reconstruction method based on GPU hardware acceleration, which belongs to the field of X-ray CT technology. The software portion of the invention generally comprises a GPU-based CT data preprocessing module, a GPU-based CT data filter module, a GPU-based CT orthogonal protection module, and a GPU-based CT image reconstruction and back projection module. The method can achieve acceleration of CT image reconstruction algorithm by using GPU hardware, and the reconstructed portion and the data processing portion are achieved on GPU. The invention provides a segmentation processing method used for processing larger data, which aims to solve the prior problems of insufficient display memory of GPU and low data transmission speed from memory to the display memory. Different from prior methods, the segmentation processing method only needs a portion of projection data desired for each segment to be reconstructed, thus reducing data transmission and improving the entire reconstruction speed.

An optical IR touch sensing apparatus can determine, based on output signals of light detectors, a light energy value for each light path across a touch surface, and generate a transmission value for each light path based on the light energy value. A processor can operate an image reconstruction algorithm on at least part of the thus-generated transmission values and determine a position of a touching object on the touch surface, an attenuation value corresponding to the attenuation of the light resulting from the object touching the touch surface, and an occlusion compensation value for compensating the occlusion affect from other objects on the touch surface. Using these values, the processor can identify the type of object.

In the present invention, the fast high-resolution image reconstruction of PET projection data is realized by introducing the organic combination of super-laxation speeding factor and variable background constraint, the reconstruction speed and spatial resolution are superior to available ordered subset expectation maximum (OSEM) process, and the antijamming capacity is superior to traditional filtering back projection (FBP) process. The present invention is the improvement of OSEM, and said algorithm combines several kinds of data processing technology in the reconstruction of the heat source image to obtain reconstructed image with high spatial resolution and low noise.

An optical imaging method using a single-pixel detector. An image of a target object is expressed by using discrete pixels, and the size of the image is M×N pixels. A cosine structured light field generator is used for generating a series of light fields that have different frequencies and are distributed according to cosine, wherein each set of frequencies corresponds to at least three different initial phase φ values; the light fields with cosine distribution that have different frequencies and different initial phases are used to sequentially irradiate the target object; an optical detector (2) is used for sequentially receiving light intensity signals from the target object and then response values of the optical detector (2) are sequentially collected and recorded; An image reconstruction algorithm is established on the basis of the light fields, the number of measurements can be greatly reduced, and a high-quality reconstructed image can be obtained.

The invention belongs to the thermoacoustic imaging technology field, in particular to an image reconstruction algorithm of the sound velocity uneven medium thermoacoustic imaging. The method modifies the time domain reconstruction method of the sound velocity uneven medium thermoacuostic imaging, which leads to that the propagation time of acoustic waves between two points in medium is no longer proportional to the distance and is worked out through the estimated sound velocity distribution. Currently, the prior knowledge of the sound velocity distribution is mostly required by the reconstruction algorithm on the sound velocity uneven medium thermoacuostic imaging. And an iterative method is adopted for the calculation and the speed is slow. The invention does not require the prior knowledge of the sound velocity distribution in the medium and is a direct inverse approach. The invention can rapidly reconstruct a whole thermoacoustic image.

The invention relates to a PXI-bus-based respiration process three-dimensional electrical impedance imaging system and an imaging method thereof. According to the PXI-bus-based respiration process three-dimensional electrical impedance imaging system and the imaging method thereof, the three-dimensional electrical impedance imaging system which is in three layers and comprises 48 electrodes is constructed by means of highly integrated hardware and software tool kits of the PXI bus; a pair of adjacent exciting electrodes is selected sequentially through a gating switch; safe alternating currents are injected into a thoracic cavity, voltage signals on the other electrodes are collected synchronously; a distribution image of sensitive areas of electrical impedances inside the thoracic cavity during a respiration process is obtained on a computer through filtration, amplification, analog-digital conversion, demodulation and transmission and finally through an image reconstruction algorithm. Compared with the existing electric resistance imaging system, the PXI-bus-based respiration process three-dimensional electrical impedance imaging system has the advantages of being high in measuring accuracy, rapid in speed and high in reliability, having no damage to human bodies, achieving continuous real-time bedside monitoring and continuously monitoring respiration variations of human lungs clinically in real time.

The invention discloses a compressed sensing magnetic resonance imaging method controlled by a radio-frequency pulse, and relates to the magnetic resonance imaging method. The invention provides the compressed sensing magnetic resonance imaging method controlled by the radio-frequency pulse, wherein the compressed sensing magnetic resonance imaging method controlled by the radio-frequency pulse is capable of controlling a space K to spread spectrum easily. The method includes the spectrum spreading to the space K from the radio-frequency pulse, undersampling at random and image reconstruction. In the magnetic resonance imaging, the radio-frequency pulse of linear frequency modulation is exerted along the phase encoding direction to control the energy diffusion of magnetic resonance imaging data space. The undersampling at random is carried out to the imaging data with spread spectrum, and sampling time is reduced. In terms of the undersampling data, suggested fast reconstruction algorithm is adopted to carry out sparse reconstruction to the imaging. Due to the fact that radio-frequency pulse sequence is utilized to carry out the spread spectrum of the space K, compared with space K with a shim coil, the controllable property of the spread spectrum of the space K is good. The purposes of reducing imaging time and accelerating the magnetic resonance imaging are achieved by adopting the methods of undersamping the magnetic resonance signal at random and the image reconstruction algorithm.

The invention brings forward a method and device for measuring two-dimensional angle distribution of the radiation dose rate of a radioactive substance. The method comprises: a gamma camera detecting gamma photons incident from each direction of a defining object angle plane in an object area, and respectively recombining to form projection data and power spectrum data; reconstructing the projection data by use of an image reconstruction algorithm to obtain a radiation gamma image; based on this, obtaining the two-dimensional angle distribution of the fluence rate of the gamma photons incident from each direction in the object area; and according to incident photon energy, searching for corresponding conversion coefficients, and by use of the conversion coefficients, converting the two-dimensional angle distribution of the fluence rate of the gamma photons into the two-dimensional angle distribution of the dose rate of radiation of the radioactive substance to the position of the gamma camera. The measuring method provided by the invention realizes measurement of the two-dimensional angle distribution of the radiation dose rate of the gamma photons incident from the different directions in the object area by use of such devices as the gamma camera and the like.

Methods, systems and processes for providing efficient, accurate and exact image reconstruction using portable and easy to use C-arm scanning devices and rotating gantries, and the like, that combines both a circle and a curve scan. The invention can provide exact convolution-based filtered back projection (FBP) image reconstruction by combining two curved scans of the object. The curved scan can be less than or greater than a full circle about an object being scanned. The invention can be done by a first curve within a first plane followed by a second curve within a second plane that is transversal to the first plane.

The invention discloses a limited angle CT image reconstruction algorithm based on boundary-preserving diffusion and smoothing. The algorithm comprises the steps of inputting a variable; performing initialization; assuming that an estimated image u(k) has been obtained, using the u(k) as an initial value, scanning a data set p by using a limited angle CT, updating the estimated image u(k+1/3)=RG(p, u(k)); performing the boundary-preserving diffusion correction in the x-axis direction on the image u(k+1/3) to obtain u(k+2/3) =P(u(k+1/3)); performing the boundary-preserving smoothing correctionin y-axis direction on the image u(k+2/3) to obtain u(k+1)=S(u(k+2/3)); determining whether a difference between two adjacent iterative images is less than a given threshold, or whether the upper limit of iteration times reaches N, terminating the iteration if so, otherwise starting the new iteration with the u(k+1) as the initial value until the condition is satisfied, and ending the limited angle CT image reconstruction algorithm based on boundary-preserving diffusion and smoothing. The algorithm of the invention eliminates the image blurring and the limited angle artifact caused by the lackof the boundary-preserving diffusion elimination angle, and simultaneously eliminates the possible linear artifacts introduced by the boundary-preserving smoothing diffusion, thereby improving the quality and usability of the limited angle CT image.