Which term describes the artifact that can produce a Moire pattern in digital radiography?

• A. Moiré pattern
• B. Noise
• C. Aliasing
• D. Blur

Answer: (C)

Aliasing is the phenomenon where sampling a signal at discrete intervals misrepresents high-frequency details, and in digital radiography this misrepresentation can create Moire patterns. When a periodic structure (like grid lines or fine texture) has a frequency near the detector’s sampling rate, the sampling process interferes with the pattern, producing those characteristic interference stripes—the Moire pattern. So aliasing describes the underlying artifact that can lead to a Moire appearance.

The Moire pattern you might see is the visual result of that aliasing. Noise is random variation and doesn’t specifically cause a Moire pattern, and blur refers to a loss of sharpness rather than a structured interference pattern.