Acquisition of a single grid-based phase-contrast X-ray image using instantaneous frequency and noise filtering

• Published in: Biomedical engineering online Vol. 21; no. 1; p. 92
• Main Authors: Yang, Jae-Suk, Jeon, Sun-Young, Choi, Jang-Hwan
• Format: Journal Article
• Language: English
• Published: England BioMed Central Ltd 27.12.2022; BioMed Central; BMC
• Subjects: Algorithms; Analysis; CT imaging; Fourier analysis; Image Processing, Computer-Assisted - methods; Imaging systems; Instantaneous frequency; Methods; Moire artifact; Noise control; Noise filtering; Phantoms, Imaging; Phase-contrast X-ray image; Tomography, X-Ray Computed; X-Rays; South Korea; Fourier analysis; Instantaneous frequency; Moire artifact; Noise filtering; Phase-contrast X-ray image
• ISSN: 1475-925X; 1475-925X
• DOI: 10.1186/s12938-022-01061-z

To obtain phase-contrast X-ray images, single-grid imaging systems are effective, but Moire artifacts remain a significant issue. The solution for removing Moire artifacts from an image is grid rotation, which can distinguish between these artifacts and sample information within the Fourier space. However, the mechanical movement of grid rotation is slower than the real-time change in Moire artifacts. Thus, Moire artifacts generated during real-time imaging cannot be removed using grid rotation. To overcome this problem, we propose an effective method to obtain phase-contrast X-ray images using instantaneous frequency and noise filtering. The proposed phase-contrast X-ray image using instantaneous frequency and noise filtering effectively suppressed noise with Moire patterns. The proposed method also preserved the clear edge of the inner and outer boundaries and internal anatomical information from the biological sample, outperforming conventional Fourier analysis-based methods, including absorption, scattering, and phase-contrast X-ray images. In particular, when comparing the phase information for the proposed method with the x-axis gradient image from the absorption image, the proposed method correctly distinguished two different types of soft tissue and the detailed information, while the latter method did not. This study successfully achieved a significant improvement in image quality for phase-contrast X-ray images using instantaneous frequency and noise filtering. This study can provide a foundation for real-time bio-imaging research using three-dimensional computed tomography.