33 results about "Detector geometry" patented technology

A method of 3D-2D registration for medical imaging includes the following steps: providing a first input interface for acquiring a three-dimensional image; providing a second input interface for acquiring a fixed two-dimensional image using an imaging system that includes a source and a detector and that has an unknown source-detector geometry; initializing image transformation parameters and source-detector geometry parameters; generating a reconstructed two-dimensional image from the three-dimensional image using the image transformation parameters and the source-detector geometry parameters; determining an image similarity metric between the fixed two-dimensional image and the reconstructed two-dimensional image; and updating the image transformation parameters and the source-detector geometry parameters using the image similarity metric, and a corresponding non-transitory computer-readable medium and apparatus.

Excitation light of a selected wavelength from an excitation monochromator is directed along the long axis of a flow cell containing the sample to be analyzed, generating fluorescence. An emission monochromator is positioned at right angles to the plane of the excitation monochromator and receives the fluorescence from the flow cell utilizing optical components positioned such that the entrance slit of the emission monochromator is aligned with the long axis of the emission window. The intensity of the output from the flow cell is further maximized by positioning a retro-reflecting mirror at the end of the flow channel to effectively double the path-length of the excitation beam, and a reflecting surface on the side of the cell opposite the emission window to increase the collection efficiency and thereby increase the sensitivity of the detector.

A coded localization system includes a plurality of optical channels arranged to cooperatively image at least one object onto a plurality of detectors. Each of the channels includes a localization code that is different from any other localization code in other channels, to modify electromagnetic energy passing therethrough. Output digital images from the detectors are processable to determine sub-pixel localization of the object onto the detectors, such that a location of the object is determined more accurately than by detector geometry alone. Another coded localization system includes a plurality of optical channels arranged to cooperatively image partially polarized data onto a plurality of pixels. Each of the channels includes a polarization code that is different from any other polarization code in other channels to uniquely polarize electromagnetic energy passing therethrough. Output digital images from the detectors are processable, to determine a polarization pattern for a user of the system.

Methods and systems are provided for correcting positional errors in an image arising from gaps in a detector assembly. In one embodiment, a method comprises generating a sinogram based on a plurality of photon coincidence events, selectively inserting one or more pseudo-slices into the sinogram, and generating an image based on the sinogram including the one or more pseudo-slices. In this way, positional errors may be reduced without modifying an image reconstruction algorithm to include a full detector geometry or modifying the detector geometry itself.

The invention provides a method for calibrating the geometric position relationship between an X-ray machine and a detector, which includes: placing at least two small balls in the imaging area, and recording the distance d between the two small balls and the distance between the two small balls and the detector respectively. The distance between the planes of the X-ray machine; choose one of the digital X-ray projection pictures arbitrarily, and record the projection positions C and D corresponding to the position information of the two small balls A and B; estimate the initial X coordinate P of the X-ray machine x and the Y coordinate P y , and calculate the Z coordinate P of the X-ray machine according to the geometric imaging relationship z ;According to the geometric imaging relationship and the Z coordinate P of the X-ray machine z , calculate the X and Y coordinates A of the two balls x 、A y and B x , B y ; Utilize the three-dimensional coordinates of the two small balls A, B and the projections C, D of the two small balls A, B, and obtain the position of the X-ray machine in all digital X-ray projection diagrams according to the imaging geometric relationship.

The invention relates to a low-resolution gamma energy spectrum inversion analysis process and method based on Monte Carlo response matrix. The analysis process includes instrument spectrum detection, establishment of detector geometric model, simulation of detector response function, response function characteristic parameter extraction, Card response matrix generation, inversion analysis, according to the physical process of instrument spectrum formation, the geometric model of the detector is established, and the response function of the NaI(Tl) scintillation detector to the gamma photon is simulated by the Monte Carlo method, the characteristic parameters of the response function are determined, and The Monte Carlo response matrix is ​​constructed between the radioactive source and the γ spectrum through the interpolation algorithm, and combined with the Gold or Boosted-Gold algorithm, the inversion and analysis of the γ instrument spectrum of other measured samples is realized under the response matrix. Applying the analytical method of the present invention eliminates complex processing procedures such as spectrum smoothing, peak finding, and multiple peak decomposition, and the analytical result is that the spectral line to be measured is close to the solution of the theoretical physical spectral line under the response matrix. The ability has improved.

The invention discloses a splicing detector geometry correction body model and a correction method thereof. The method comprises the following steps of S1, installing a geometry correction body model on a splicing detector top surface so that metal round dots on a geometry correction body model substrate are uniformly distributed a photon counting chip; S2, taking the photon counting chip as an unit, dividing a photon counting detector top surface into a plurality of module groups, and according to positions of the metal round dots, calculating center coordinates of all the metal round dots in each module group; S3, calculating a pixel of each module group image, according to the pixel of each module group image, determining whether a seam exists between the adjacent module groups, if the seam exists, entering into a stepS4; otherwise, the seam does not exist, the image does not need to be corrected; and S4, calculating a pixel number of the seam existing between the adjacent module groups and restoring the pixel at the seam to the image. By using the method, actual image detected by the splicing detector can be effectively corrected and image accuracy is ensured.

The invention relates to a respiratory gating technology based on the characteristic of sensitivity of a three-dimensional positron emission (PET) detector, belonging to the field of nuclear medicine imaging. A gating method provided by the invention can effectively compensate image artifacts caused by respiration, thus improving accurate diagnostic rate of a doctor. In the three-dimensional PET imaging, the invention utilizes the change characteristic of geometric sensitivity of a scanning detector, and carries out frame segmentation to acquired dynamic data; the intra-frame photon number thereof can reflect the motion phase position where the organ motion is located; and the same positions in each circle are overlapped and the image is reconstructed, thus being capable of improving the image artifacts caused by respiration in PET imaging. Compared with the existing gating technology, the method does not relate to hardware device, does not need to make extra preparation before scanning for patients and clinics, and is simpler, more effective and more reliable in practical operation.

The invention discloses an autonomous attitude maneuver control method of a deep space probe, which relates to the autonomous attitude maneuver control method and belongs to the technical field of spacecraft attitude control. The autonomous attitude maneuver control method comprises the following steps of carrying out random sampling on uniformly-distributed nodes of an attitude space with an ORRT (Optimized Rapidly Exploring Random Tree) algorithm as a path planning method, making a balance and choosing the optimum path to expand, carrying out incremental expansion in a safety space in a greedy expansion manner, respectively establishing a probe attitude maneuver dynamic constraint model, an actual engineering constraint model and a probe geometric constraint model under a probe body coordinate system to obtain path nodes which meet the constraint and generate a control moment for the nodes, thereby generating a probe attitude maneuver path and a required control moment, and implementing the purpose that probe maneuvers to a target attitude according to the generated probe attitude maneuver path and the required control moment. According to the autonomous attitude maneuver control method, the path planning time is shortened and the efficiency that the probe maneuvers to the target attitude from the initial attitude is improved under the condition that all kinds of complicated constraint conditions faced by the probe are met.

The invention discloses a device and a method for geometric correction of a detector of a cone-beam CT (computed tomography) system. The correction device comprises a correction board, an adjusting board, the detector, an X-ray source device and an X-ray source table, wherein the X-ray source table and the adjusting board are arranged at two ends of the correction device respectively, the X-ray source device is located on the X-ray source table, the bottom surface of the detector is placed on a horizontal table surface of the adjusting table, the correction board is arranged on the table surface of the adjusting table and positioned between the X-ray source device and the detector, a plurality of round through holes are formed in the correction board and form a through hole array, sizes of the through holes are the same, and the through holes are axially parallel. According to the device and the method for geometric correction of the detector of the cone-beam CT system, by means of the correction board with the through hole array, the detector of the cone-beam CT system can be subjected to convenient, fast, and effective geometric correction without calculation; by means of the correction board, the geometric position of the detector is firstly corrected, the position of a rotation table is subsequently corrected, and the operation is simple and fast.