Provided is a method for processing images. In the method, upon acquiring projection data of an object to be detected, a parsed image is acquired by performing parsing reconstruction on the projection data by calling a first image processing unit. Then a first registered image is acquired by registering the parsed image and a reference image by calling a second image processing unit, and an iterated image is acquired by performing iterative reconstruction on the projection data by calling the first image processing unit.

For controlling reconstruction in emission tomography, the quality of data for detected emissions and/or the application controls the settings used in reconstruction. For example, a count density of the detected emissions is used to control the number of iterations in reconstruction to more likely avoid over and under fitting. The count density may be adaptively determined by re-binning through pixel size adjustment to find a smallest pixel size providing a sufficient count density. As another example, the detected data may have poor quality due to motion or high body mass index (BMI) of the patient, so the reconstruction is set to perform differently (e.g., less smoothing for high motion or a different number of iterations for high BMI). The quality of the data may be used in conjunction with the application or task for imaging the patient to control the reconstruction.

Medical imaging methods for processing a three-dimensional (3D) image data set with two-dimensional X-ray images from an X-ray machine using a target function. Methods can include providing a 3D image data set of at least one examination zone in which anatomical structures are present, segmenting the image data set to provide a 3D vascular structure model and a 3D bone structure model, recording a first two-dimensional (2D) X-ray image containing at least a portion of the vascular structure and at least a portion of the bone structure, recording a second 2D X-ray image of the examination zone at a different contrast agent concentration, and subtracting the first and second 2D X-ray images to generate a subtraction image. An optimum projective geometry may then be determined using a three-part target function based on the 3D image data and the 2D X-ray images.

For controlling reconstruction in emission tomography, the quality of data for detected emissions and/or the application controls the settings used in reconstruction. For example, a count density of the detected emissions is used to control the number of iterations in reconstruction to more likely avoid over and under fitting. The count density may be adaptively determined by re-binning through pixel size adjustment to find a smallest pixel size providing a sufficient count density. As another example, the detected data may have poor quality due to motion or high body mass index (BMI) of the patient, so the reconstruction is set to perform differently (e.g., less smoothing for high motion or a different number of iterations for high BMI). The quality of the data may be used in conjunction with the application or task for imaging the patient to control the reconstruction.

According to the method and the apparatus for acquiring a CBCT image based on adaptive sampling according to the exemplary embodiment of the present disclosure, a final CBCT image is acquired by reconstructing a plurality of cone beam computed tomography (CBCT) images acquired based on adaptive sampling so that a dose applied to the target patient may be reduced.

Aspects of the disclosure provide a method for denoising an image. The method can include receiving an acquired image from an image acquisition system, and processing the acquired image with a nonlinear diffusion coefficient based filter having a diffusion coefficient that is calculated using gradient vector orientation information in the acquired image.

The present invention seeks to reduce the burden of producing high-resolution tomograms by using an initial scan on a predetermined grid 10 to obtain a minimal set of images, and then regions of interest 20 are identified for further scanning. The further scanning locations 40 are determined by image entropy or gradient found in the previous iteration; such regions are indicative of edges, cracks or complex structure within the region. After each iteration, the level of information (e.g. image entropy or gradient) will decrease relative to the pixel/voxel size. In this way, a more efficient way to scan is achieved.

A method may include obtaining first image data relating to a region of interest (ROI) of a first subject. The first image data corresponding to a first equivalent dose level may be acquired by a first device. The method may also include obtaining a model for denoising relating to the first image data and determining second image data corresponding to an equivalent dose level higher than the first equivalent dose level based on the first image data and the model for denoising. In some embodiments, the method may further include determining information relating to the ROI of the first subject based on the second image data and ecording the information relating to the ROI of the first subject.

A system and method for reconstructing an image of a target object using an iterative reconstruction technique can include a machine learning model as a regularization filter (100). An image data set for a target object generated using an imaging modality can be received, and an image of the target object can be reconstructed using an iterative reconstruction technique that includes a machine learning model as a regularization filter (100) used in part to reconstruct the image of the target object. The machine learning model can be trained prior to receiving the image data using learning datasets that have image data associated with the target object, where the learning datasets providing objective data for training the machine learning model, and the machine learning model can be included in the iterative reconstruction technique to introduce the object features into the image of the target object being reconstructed.

Methods and systems for improved regularization associated with tomographically resolved image based measurements of semiconductor structures are presented herein. The regularizations described herein are based on measurement data and parameterization of a constrained voxel model that captures known process variations. The constrained voxel model is determined based on simplified geometric models, process models, or both, characterizing the structure under measurement. A constrained voxel model has dramatically fewer degrees of freedom compared to an unconstrained voxel model. The value associated with each voxel of the constrained voxel model depends on a relatively small number of independent variables. Selection of the independent variables is informed by knowledge of the structure and the underlying fabrication process. Regularization based on a constrained voxel model enables faster convergence and a more accurate reconstruction of the measured structure with less computational effort. This enables semiconductor measurements with reduced data acquisition requirements, and reduced measurement time.