Which process equalizes larger echoes with smaller echoes, changes the grey map of an image, and decreases the dynamic range of the signals?

Which process equalizes larger echoes with smaller echoes, changes the grey map of an image, and decreases the dynamic range of the signals?

• A. Compression
• B. Demodulation
• C. Amplification
• D. Rejection

Answer: (A)

Dynamic range compression in ultrasound imaging reduces the spread between the strongest and weakest echoes and changes how those echoes are mapped to brightness on the display. It uses a nonlinear transfer function that simultaneously boosts weaker echoes and dampens very strong echoes, so large and small signals end up with more similar brightness. This reshapes the grey map because the pixel intensity no longer corresponds directly to raw echo amplitude, but to the compressed scale. By narrowing the range of representable intensities, the overall dynamic range of the image is decreased, helping show details in both bright and dark regions. Amplification raises all echoes by the same amount, so it doesn’t alter the relative differences between echoes or the grey map in the same way. Demodulation and rejection remove or modify other aspects of the signal (frequency content or unwanted components) instead of changing the brightness mapping across the full range of echoes.

Dynamic range compression in ultrasound imaging reduces the spread between the strongest and weakest echoes and changes how those echoes are mapped to brightness on the display. It uses a nonlinear transfer function that simultaneously boosts weaker echoes and dampens very strong echoes, so large and small signals end up with more similar brightness. This reshapes the grey map because the pixel intensity no longer corresponds directly to raw echo amplitude, but to the compressed scale. By narrowing the range of representable intensities, the overall dynamic range of the image is decreased, helping show details in both bright and dark regions.

Amplification raises all echoes by the same amount, so it doesn’t alter the relative differences between echoes or the grey map in the same way. Demodulation and rejection remove or modify other aspects of the signal (frequency content or unwanted components) instead of changing the brightness mapping across the full range of echoes.