Which term describes filling in a missing brightness value for a pixel in an image?

• A. Pixel Interpolation
• B. Pixel
• C. Pixel Density
• D. Pulse Inversion

Answer: (A)

Filling in a missing brightness value for a pixel in an image is about estimating that unknown value from surrounding information. This practice is pixel interpolation. It’s the method used whenever an image needs a value at a location where data isn’t directly available, such as when resizing or reconstructing an image. Interpolation smoothly blends nearby pixel values—common approaches like bilinear or bicubic interpolation use neighboring pixels to infer a plausible brightness for the gap, creating a natural-looking result. The other terms don’t describe this process: a pixel is the tiny element that holds brightness data, not the act of estimating missing values; pixel density refers to how many pixels fit in a given area (resolution), and pulse inversion is an ultrasound technique used to enhance contrast, not to fill in missing image data.