A filter design method for beam hardening correction in middle-energy x-ray computed tomography

Chen, Siyu; Xi, Xiaoqi; Li, Lei; Luo, Lei; Yu, Han; Wang, Jingyu; Yan, Bin

doi:10.1117/12.2245152

Cited by 8 publications

(6 citation statements)

References 6 publications

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“…Many experiments were required for this previously (Lifton et al 2013;Thomsen et al 2015). Recently, Chen et al (2017) proposed a method to optimize X-ray filters especially for middle energy X-CT, based on Monte Carlo simulation where varying filter materials and thicknesses were simulated and the mean energy ratio (MER) for the post to pre-filter spectrum were calculated (7). The optimum filters were that corresponding to the higher MER for low energy XCT and smaller for higher energy XCT.…”

Section: Filtration Correction Methodsmentioning

confidence: 99%

A Review of Common Beam Hardening Correction Methods for Industrial X-ray Computed Tomography

Ahmed¹,

Song²

2018

JSM

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X-ray computed tomography (XCT) became an important instrument for quality assurance in industry products as a non-destructive testing tool for inspection, evaluation, analysis and dimensional metrology. Thus, a high-quality image is required. Due to the polychromatic nature of X-ray energy in XCT, this leads to errors in attenuation coefficient which is generally known as beam hardening artifact. This leads to a distortion or blurring-like cupping and streak in the reconstruction images, where a significant decrease in imaging quality is observed. In this paper, recent research publications regarding common practical correction methods that were adopted to improve an imaging quality have been discussed. It was observed from the discussion and evaluation, that a problem behind beam hardening reduction for the multi-materials object, especially in the absence of prior information about X-ray spectrum and material characterizations would be a significant research contribution, if the correction could be achieved without the need to perform forward projections and multiple reconstructions.

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Section: Filtration Correction Methodsmentioning

confidence: 99%

A Review of Common Beam Hardening Correction Methods for Industrial X-ray Computed Tomography

Ahmed¹,

Song²

2018

JSM

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“…Physical filtering methods focus on hardware equipment such as flat or bowtie filters placed at the window of the x-ray tube. This can block a fair amount of low-energy photons to make x-ray spectrum pre-hardening [19]. Beam-hardening artifact will be reduced to some extent with filters, and it has also decreased the contrast of the reconstructed images [19][20][21].…”

Section: Introductionmentioning

confidence: 99%

“…This can block a fair amount of low-energy photons to make x-ray spectrum pre-hardening [19]. Beam-hardening artifact will be reduced to some extent with filters, and it has also decreased the contrast of the reconstructed images [19][20][21]. Figure 1 shows an unfiltered spectrum for 140kVp and the corresponding one filtered with cupper and aluminium.…”

Section: Introductionmentioning

confidence: 99%

An iterative method for simultaneous reduction on beam-hardening and scatter artifacts in x-ray CT

Xia¹,

Zhao²,

Zhang³

et al. 2023

Phys. Scr.

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Beam-hardening and scatter are two significant factors leading to contrast reduction and gray value inaccuracy in CT images. The cupping artifacts and obscure boundaries in reconstructed images are also caused mainly by both beam-hardening and scattering. It is difficult to get high-quality CT images with only one of them to make correction. In this paper, we proposed an x-ray CT polychromatic attenuation model with scatter effect, and an iterative method for simultaneous reduction on beam-hardening and scatter artifacts. In this model, the measured data of the detector comprise two parts: an attenuation term and a scatter term. The former is defined by an exponential rational fraction to fit the traditional attenuation process, and the latter is defined by a convolutional scatter intensity. The coefficients of the rational fraction in the attenuation term and the scatter term kernel are all calculated from a calibration phantom which is scanned to get corresponding equations. Based on the polychromatic attenuation model, we proposed an iterative artifacts reduction method combining deconvolution technique with linearized back-projection (iDLB method). This method makes the nonlinear polychromatic attenuation model become easily solvable by linearizing transformation, which simplifies the residuals allocation process. Experiments of both numerical simulation and practical data show the iDLB method has the ability to reduce beam-hardening and scatter artifacts simultaneously, improve the contrast of CT images, and it is highly parallelized for lower computational cost.

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“…The methods used to correct artifacts can be categorized into physical filtering methods and software correction methods. Commonly used during scanning, the physical filtering method [ 5 , 6 , 7 , 8 ] can reduce the artifacts. Meanwhile, however, it also reduces ray intensity, which contributes to SNR (signal noise ratio) reduction.…”

Section: Introductionmentioning

confidence: 99%

Study on the Extraction of CT Images with Non-Uniform Illumination for the Microstructure of Asphalt Mixture

et al. 2022

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An adaptive image-processing method for CT images of asphalt mixture is proposed in this paper. Different methods are compared according to the error analysis calculated between the real gradation and 3D reconstruction gradation. As revealed by the test results, the adaptive image-processing method was effective in carrying out different brightness homogenization processes for each image. The Wiener filter with 7 × 7 size filter was able to produce a better noise reduction effect without compromising image sharpness. Among the three methods, the adaptive image-processing method performed best in the accuracy of coarse aggregate recognition, followed by the ring division method and the global threshold segmentation method. The error of the gradation extracted by the adaptive image-processing method was found to be lowest compared with the real gradation. For a variety of engineering applications, the developed method helps to improve the analysis of CT images of asphalt mixtures.

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A filter design method for beam hardening correction in middle-energy x-ray computed tomography

Cited by 8 publications

References 6 publications

A Review of Common Beam Hardening Correction Methods for Industrial X-ray Computed Tomography

A Review of Common Beam Hardening Correction Methods for Industrial X-ray Computed Tomography

An iterative method for simultaneous reduction on beam-hardening and scatter artifacts in x-ray CT

Study on the Extraction of CT Images with Non-Uniform Illumination for the Microstructure of Asphalt Mixture

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