Scattering Estimation for Cone-Beam CT Using Local Measurement Based on Compressed Sensing

Cone-beam computed tomography (CBCT) plays a critical role in both medical imaging and industrial nondestructive testing with high efficiency and precision. However, scattering poses a significant limitation to image quality. In order to get the complete scattering information when the object is scanned, a simple scattering correction method based on compressed sensing (CS) is proposed, which is based on the assumption that the object scattering (OS) is eliminated by the lead collimator. In the process, the additional scattering from shadow area is first estimated, and then the OS is obtained by using the information in the irradiated area (with the strips pattern) extracted from the primary projection (without the strips pattern). Then, the estimated scatterings are subtracted from each primary projection data to yield an estimate for CBCT reconstruction, and the scattering-corrected CBCT volume is reconstructed by using an alternating direction method of multipliers algorithm. Finally, experimental studies are performed to evaluate the performance of the proposed schemes which has reduced the scattering artifacts. For an aluminum sample, the average gradient (AG) and contrast-to-noise ratio (CNR) were increased by 60% and 80%; for titanium, the AG and signal-to-noise ratio (SNR) were increased by 60% and 20%; and for iron, the AG, CNR, and SNR were increased by 30%–50%. Moreover, this paper studies long-span information sensing by replacing the interpolation algorithm with CS theory; it can provide a certain theoretical guidance for the sparse data recovery and mining.