The technique of frame averaging during real-time acquisition is designed to:

• A. Decrease pixel size
• B. Redistribute the gray-scale
• C. Enhance spatial resolution
• D. Reduce random noise

Answer: (D)

Frame averaging works by taking several consecutive frames and computing their average, which targets random fluctuations in the image data. The genuine signal stays consistent across frames, while noise tends to vary randomly. Because uncorrelated noise adds more like random wiggles than true structure, averaging reduces its magnitude—its standard deviation drops roughly with the square root of the number of frames averaged. The result is a cleaner image with improved signal-to-noise ratio. This technique doesn’t change the physical pixel size, doesn’t redistribute grayscale, and doesn’t create new spatial detail; it can even blur fast motion and lower temporal resolution, reflecting a trade-off between noise reduction and real-time responsiveness.