What is CT image reconstruction?
Image reconstruction in CT is a mathematical process that generates tomographic images from X-ray projection data acquired at many different angles around the patient. Image reconstruction has fundamental impacts on image quality and therefore on radiation dose.
What is back projection in CT scan?
Backprojection. The standard method of reconstructing CT slices is backprojection. This involves “smearing back” the projection across the image at the angle it was acquired. By smearing back all of the projections, you reconstruct an image.
How many projections are required to reconstruct an image?
Field of View. CT images are reconstructed from approximately 1000 projections that are acquired as the x-ray tube rotates through 360º around the object (patient).
What are reconstruction algorithms?
Iterative reconstruction refers to iterative algorithms used to reconstruct 2D and 3D images in certain imaging techniques. For example, in computed tomography an image must be reconstructed from projections of an object.
What is back projection in image reconstruction?
The backprojection procedure reconstructs an image in which each point in the “actual” image is blurred by this pattern, and this 2-D profile is referred to as the point-spread-function (PSF) for the reconstruction process.
What does back projection mean?
: the projection of a motion or still picture upon a large translucent screen from the rear to serve as a background for performances of motion-picture actors being photographed in front of the screen.
Why do commercial CT scanners still employ traditional filtered back projection for image reconstruction?
In general, on a commercial diagnostic scanner, it is possible to extract raw data in the chain, while the steps of data correction and image reconstruction often form a tightly coupled pipeline that generally allows no intermediate data storage.
What is CT kernel?
The kernel, also known as a convolution algorithm, refers to the process used to modify the frequency contents of projection data prior to back projection during image reconstruction in a CT scanner 1. This process corrects the image by reducing blurring 1.
What is CT technology?
The term “computed tomography”, or CT, refers to a computerized x-ray imaging procedure in which a narrow beam of x-rays is aimed at a patient and quickly rotated around the body, producing signals that are processed by the machine’s computer to generate cross-sectional images—or “slices”—of the body.
What is back projection in image processing?
Back Projection is a way of recording how well the pixels of a given image fit the distribution of pixels in a histogram model. To make it simpler: For Back Projection, you calculate the histogram model of a feature and then use it to find this feature in an image.