Segmentation‐free empirical beam hardening correction for CT

Abstract

sfEBHC generates beam hardening-reduced images and is furthermore capable of dealing with images which are affected by high noise and strong artifacts. The algorithm can be used to recover structures which are hardly visible inside the beam hardening-affected regions.

Correction of severe beam‐hardening artifacts via a high‐order linearization function using a prior‐image‐based parameter selection method

“…For a polynomial beam‐hardening correction function , we needed to find the coefficients of the correction function that satisfied , where is monochromatic projection data. In the conventional beam‐hardening correction method, the path lengths or the repeated evaluation of the artifacts in the reconstructed images are used to obtain these coefficients . In our study, we proposed a method to effectively determine the coefficients using a prior image without the time‐consuming repeated evaluation of the multiple reconstructions.…”

“…In the conventional beam-hardening correction method, the path lengths or the repeated evaluation of the artifacts in the reconstructed images are used to obtain these coefficients. 6,7,13,14 In our study, we proposed a method to effectively determine the coefficients using a prior image without the time-consuming repeated evaluation of the multiple reconstructions. If we know the ideal p mono , we can determine the optimal coefficients that minimize the difference between Gðp raw Þ and p mono .…”

“…Therefore, a nonlinearity between the line integrals of the object and the projection measurement data in the energy-integrating detectors occurs, resulting in the formation of beam-hardening artifacts such as cupping, dark and white bands, and streaks, in the reconstructed images. Several correction methods have been proposed to solve this problem, [1][2][3][4][5][6][7][8][9][10][11][12][13][14][15][16][17][18][19][20] and these can be categorized into four types of beam-hardening correction methods.…”

Local filtration based scatter correction for cone‐beam CT using primary modulation

“…As shown in the results of the Rando® phantom, this technique needs further improvement when the scanned object contains dense materials and the SPR on projections is high. A more sophisticated model, as used in the beam-hardening correction of CT imaging, 33 will increase the scatter estimation accuracy. Since the signal modulation is not required to be uniform in LFPM, one may use an irregular modulation pattern to optimize scatter correction.…”

Iterative metal artifact reduction for x‐ray computed tomography using unmatched projector/backprojector pairs

“…Various methods have been proposed to decrease metal artifacts and improve image quality. To our knowledge, two strategies have been widely investigated: (1) improvement in the system model by introducing the imaging physics, such as beam hardening and scattering [4][5][6][7][8][9] and (2) involvement of reconstruction methods that only adopt the unaffected projection data. The strategy that involves the modeling of the physics of the data acquisition is shown to remove metal artifacts while preserving the edges and structures when the projection data through the metal could still provide information.…”