Interpolation in the scan converter primarily serves to which of the following?

• A. Amplify the echoes
• B. Increase color depth
• C. Decrease display brightness
• D. Fill in the gaps between scan lines

Answer: (D)

Interpolation in the scan converter is about filling in the gaps between scan lines to produce a continuous image. The display maps the discrete scan lines into a grid, so spaces exist between lines. Interpolation estimates the gray-scale values in those gaps using neighboring line data, creating smoother transitions and a higher apparent line density. This makes structures look more continuous without adding new signal information. It doesn’t amplify echoes, change color depth, or alter brightness—the goal is to produce a seamless image by estimating what lies between the actual scanned lines.