6 results about "Ct measurements" patented technology

The invention discloses a method for evaluating the defect size of an industrial CT measurement additive manufacturing product. The method comprises the following steps: setting printing parameters for prefabricating defects, and determining the parameters, shape, material and quantity of a sample; and performing CT detection on the sample with the prefabricated defect, setting optimal parameters of sample detection, and finally obtaining a two-dimensional slice image of the sample. Determining the position of a sample defect according to a CT scanning result, cutting according to the position of the sample defect, carrying out metallographic detection on the sample, observing the defect by using a metallographic microscope, and keeping the amplification ratio consistent with a CT slice image. And finally, carrying out image processing on the two-dimensional slice image obtained by the industrial CT and the metallographic detection defect image. The defect size precision of the metal additive manufacturing product is calculated by calculating the coincidence degree of the industrial CT two-dimensional slice defect graph and the metallographic detection defect graph; and the defect size of the metal additive manufacturing product measured by the industrial CT can be effectively evaluated.

The invention provides a direct current system pure light CT measurement method and system under fast transient large current and a simulation method, and the method comprises the steps: setting a threshold current Ith, the interval time N of a sample during differential operation, and the time Tdown for keeping in a large current algorithm as preset values; and a condition that a measurement error is generated when a fast transient large current is encountered is avoided by utilizing reasonable setting of a parameter N in a pure light CT (Computed Tomography) demodulation algorithm. Different demodulation algorithms (an Arctan demodulation method of small current and a di / dt integral demodulation method of large current) are selected according to the magnitude of the current, so that the rapid transient large current can be measured more accurately. According to the method, the measurement defects of a traditional pure light CT are overcome, accurate data measurement under rapid transient large current can be achieved, current state quantities of various devices under similar lightning stroke working conditions can be reproduced and analyzed, and the method has remarkable practical value.

Computed tomography (CT) measurement data of the patient is acquired using a CT device having a quantum counting X-ray detector, and the CT measurement data is processed to generate result data, considering a specific information content of the CT measurement data resulting from the use of the quantum counting X-ray detector in acquiring the CT measurement data. The result data is suitable for use in the planning of irradiation of the patient. The result data is provisioned to an interface such that the result data is usable for planning the irradiation of the patient.

A computer system, a non-transitory computer readable medium, and a method for computed tomography (CT) reconstruction. The computer system is configured to perform the method and the computer readable medium is configured to store instructions for performing the method. The method includes obtaining two or more spectral CT measurement data of different materials of a target from one or more 2D or 3D spectral CT images acquired by a CT imaging system using more than one CT imaging energy regimes; and producing a pair reconstructed spectral CT images that are representative of densities of the different materials of the target by performing one or more iterations on the two or more spectral CT measurement data using a trained machine learning network that is trained to performing a diffusion sampling operation and a forward-model-based likelihood on one or more intermediate data sets representing the two or more spectral CT measurement data.

A method for adapting depth structure model data to coherence tomography measurement data of a sample having a plurality of layers composed of layer materials in a layer construction in a depth direction. A plurality of layers having layer thicknesses and a plurality of layer transitions upstream of the respective layers in the depth direction are derived from the depth structure. Furthermore, model reflectivity coefficients are adapted to the respective layer-transition-specific, spectrally resolved reflectivity coefficients by way of a value that optimizes the adaptation being calculated in each case for the at least one parameter of one of the model layer transitions. On the basis of the value calculated for the at least one parameter, depth structure model data can be obtained, the resolution of which in the depth direction goes beyond the resolution predefined by a CT measurement on which the spectral complex field reflectivity is based.

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.