Cone beam CT temperature drift correction method and system based on centroid projection trajectory fitting

Abstract

The invention belongs to the technical field of CT image reconstruction, and particularly relates to a cone beam CT temperature drift correction method and system based on centroid projection trajectory fitting, which are used for CT projection reconstruction, and the method comprises the following steps: firstly, obtaining a projected object centroid projection trajectory curve according to CT original projection image data; then, through a local interval length proportion and an interval step length, estimating an overall projection trajectory curve of the projected object when temperature drift does not occur by utilizing local interval centroid projection of the projected object under the proportion, and obtaining a temperature drift amount through subtraction; and performing sub-pixel-level translation on the original projection image by using the temperature drift amount to realize CT image offset correction. The projection temperature drift correction can be realized by utilizing the least square fitting mass center motion trail, the image reconstruction cost and resources can be saved while the CT image reconstruction effect is ensured, and the invention has a relatively good application prospect.

Description

technical field [0001] The invention belongs to the technical field of CT image reconstruction, in particular to a method and system for correcting temperature drift of cone beam CT based on centroid projection trajectory fitting. Background technique [0002] X-ray computed tomography (CT) has developed rapidly and has been widely used in industrial fields. For micro-CT and nano-CT, due to their high precision and high resolution, the stability of the radiation source and mechanical structure is highly required. Micro-nano CT scans for a long time during the working process, and the external environment temperature changes during the scanning period, which causes the offset of the ray source and the thermal expansion and contraction of the object, which makes the projection drift in the horizontal and vertical directions, resulting in serious reconstruction of the object. Motion artifacts, manifested as blurring of edge contour positions. In order to observe the fine stru...

AI Technical Summary

Problems solved by technology

Existing temperature drift correction algorithms can be divided into two categories: short-term reference-based iterative compensation methods and phantom-based compensation methods. These methods can eliminate artifacts to a certain extent, but short-term reference compensation methods require Additional scans, wasting time and computing resources

The phantom-based compensation method needs to make additional correction phantoms, which increases the cost of the experiment

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