External spiral cone beam CT (computed tomography) scanning imaging method of large-size industrial long pipeline pipe wall

Abstract

The invention discloses an external spiral cone beam CT (computed tomography) scanning imaging method of a large-size industrial long pipeline pipe wall, and relates to an external spiral cone beam CT scanning imaging method. Before scanning, a radial source is deflected and a plane array detector is offset to make conical radial beams cover the pipe wall area of one side of the cross section of a pipeline; in scanning, the pipeline is driven by a rotary table to rotate around a rotary shaft, and simultaneously the radial source and the detector are synchronously ascended and descended for scanning along the direction of the rotary shaft so as to obtain external spiral cone beam CT projection data of the pipe wall area; and a three-dimensional image of the pipe wall area to be detected isobtained in an improved external spiral cone beam CT iterative reconstruction algorithm provided by the invention. In the method disclosed by the invention, the detection of the large-size industriallong pipeline pipe wall is realized by a small-size plane array detector and the existing CT machine structure, the scanning process is easy to realize mechanically, one-step spiral cone beam scanning is adopted, and the detection speed is high. The reconstructed image of the pipe wall has good quality and high resolution, and nondestructive evaluation on the pipeline is easy to carry out.

Description

technical field [0001] The invention relates to a CT scanning imaging method, in particular to an external helical cone beam CT scanning imaging method of the pipe wall of a large-scale industrial pipeline. Background technique [0002] Large-scale pipelines (such as oil pipelines, natural gas pipelines, etc.) are widely used in real industries. From manufacture to use, they often go through various processes such as processing, storage, transportation, loading and unloading, etc. In each of these processes Some changes may occur in each part of the pipeline, and some defects may occur. Non-destructive testing is a necessary measure to prevent disasters and reduce economic losses, and has important practical significance. [0003] In the prior art, the non-destructive testing method is commonly used for pipelines, and the non-destructive testing does not require disassembly and assembly of the pipeline, and the method is fast and convenient; but now a large number of perspec...

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Problems solved by technology

However, for the external CT reconstruction problem, the algorithm can only get distorted reconstructed images

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