CT reconstruction method based on fractal and compression sensing

A compressive sensing and fractal technology, applied in the generation of 2D images, instruments, calculations, etc., can solve the problem of reduced signal-to-noise ratio of CT images, achieve the effect of improving imaging quality and avoiding data rearrangement

Active Publication Date: 2015-02-18
CHONGQING UNIV
View PDF2 Cites 4 Cited by
  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Problems solved by technology

Using the first method will lead to a decrease in the signal-to-noise ratio of the CT image, and the image reconstructed by the second method will have more artifacts. However, as the compressed sensing theory is widely used in CT image reconstruction, people often use the second method. A method to reduce the dose of X-ray radiation

Method used

the structure of the environmentally friendly knitted fabric provided by the present invention; figure 2 Flow chart of the yarn wrapping machine for environmentally friendly knitted fabrics and storage devices; image 3 Is the parameter map of the yarn covering machine
View more

Image

Smart Image Click on the blue labels to locate them in the text.
Viewing Examples
Smart Image
  • CT reconstruction method based on fractal and compression sensing
  • CT reconstruction method based on fractal and compression sensing
  • CT reconstruction method based on fractal and compression sensing

Examples

Experimental program
Comparison scheme
Effect test

Embodiment Construction

[0027] The following further explains the principle of the present invention is the realization method:

[0028] 1. CT principle and compressed sensing

[0029] The principle of CT is as figure 1 As shown, the X-ray intensity emitted by the X-ray source is I 0 , Because the X-ray energy is very high and can penetrate the object being scanned, the emitted X-ray intensity is I 1 , According to the lambert-beer law we have

[0030] I 1 = I 0 e -∫μds (1)

[0031] Among them, μ is the attenuation coefficient corresponding to the attenuation of the X-ray passing by the scanned object on the X-ray path. Different materials have different attenuation coefficients, and CT is the attenuation coefficient of the object mapped to the gray value to obtain CT Image u.

[0032] To deal with (1), we can get

[0033] ln I 0 I 1 = ∫ μds - - - ( 2 )

[0034] among them Is the projection data, that is, the projection data is the line integral of the X-ray attenu...

the structure of the environmentally friendly knitted fabric provided by the present invention; figure 2 Flow chart of the yarn wrapping machine for environmentally friendly knitted fabrics and storage devices; image 3 Is the parameter map of the yarn covering machine
Login to view more

PUM

No PUM Login to view more

Abstract

The invention provides a CT reconstruction method based on fractal and compression sensing. The method includes the steps that (1) CT projection data b, a corresponding projection angle theta and initialization parameters beta, lambda and lambda n are known, and a CT image u is equal to zero; (2) a corresponding projection matrix A is calculated according to the projection angle theta; (3) a CT image uART is calculated by means of a formula (5); (4) fractal encoding processing is carried out on uART, so that fai (u) is obtained, and alpha is obtained by means of a formula (12); (5) decoding processing is carried out on the fai (u), so that fai T(u) is obtained; (6) fai T(u), fai (u), fai T(u) alpha, ATA and ATb are solved; (7) a formula (15) is solved in a conjugate gradient method, and accordingly a CT image is obtained; (8) whether a condition of finishing iteration is met is detected, if the answer is positive, a step (9) is carried out and otherwise the step (3) is carried out; (9) operations are finished, and the CT image is output. According to the method, fractal serves as sparse transform so that a more sparse coefficient representation can be obtained, an alternating and continuity algorithm is used for obtaining solutions and the high-quality CT image is constructed on the condition that a little of projection exists.

Description

Technical field [0001] The invention relates to the technical field of tomographic image reconstruction, in particular to a low-dose CT reconstruction algorithm. Background technique [0002] Since its inception in 1973, CT (computed tomography) has been widely used in medical diagnosis, industrial non-destructive testing and other fields, especially in the medical diagnosis to play a pivotal role. However, the light source used in CT is X-rays that are harmful to the human body, which may cause genetic mutations, cancer and other diseases, so it is imperative to reduce the X-ray radiation dose as much as possible. There are two basic ideas for reducing X-ray radiation dose. First, reduce the intensity of X-rays. Second, fewer X-ray projections reduce the number of projections. Using the first method will cause the signal-to-noise ratio of CT images to decrease, and the images reconstructed by the second method will have more artifacts. However, as the compressed sensing theory...

Claims

the structure of the environmentally friendly knitted fabric provided by the present invention; figure 2 Flow chart of the yarn wrapping machine for environmentally friendly knitted fabrics and storage devices; image 3 Is the parameter map of the yarn covering machine
Login to view more

Application Information

Patent Timeline
no application Login to view more
Patent Type & Authority Applications(China)
IPC IPC(8): G06T11/00A61B6/03
Inventor 陈绵毅冯鹏魏彪何鹏张伟邓露珍米德伶
Owner CHONGQING UNIV
Who we serve
  • R&D Engineer
  • R&D Manager
  • IP Professional
Why Eureka
  • Industry Leading Data Capabilities
  • Powerful AI technology
  • Patent DNA Extraction
Social media
Try Eureka
PatSnap group products

Browse by: Latest US Patents, China's latest patents, Technical Efficacy Thesaurus, Application Domain, Technology Topic.

© 2024 PatSnap. All rights reserved.Legal|Privacy policy|Modern Slavery Act Transparency Statement|Sitemap