Higher fill factor directly improves detection efficiency and signal-to-noise ratio.

Higher fill factor directly improves detection efficiency and signal-to-noise ratio.

• A. False
• B. It worsens SNR
• C. True
• D. Only affects contrast

Answer: (C)

Fill factor is the fraction of a pixel that is sensitive to light. When this area is larger, a greater portion of incoming photons are collected and converted into signal, increasing the detected signal for a given scene brightness. With more detected photons, the shot noise (which grows with the square root of the signal) also grows, but the overall signal-to-noise ratio improves because you gain more signal per photon than the relative noise added. In short, higher fill factor boosts the amount of light you capture, raising detection efficiency and improving SNR in photon-limited imaging. It’s not just about contrast—the primary impact is on how much light you collect and how reliably that signal stands out from noise.

Fill factor is the fraction of a pixel that is sensitive to light. When this area is larger, a greater portion of incoming photons are collected and converted into signal, increasing the detected signal for a given scene brightness. With more detected photons, the shot noise (which grows with the square root of the signal) also grows, but the overall signal-to-noise ratio improves because you gain more signal per photon than the relative noise added. In short, higher fill factor boosts the amount of light you capture, raising detection efficiency and improving SNR in photon-limited imaging. It’s not just about contrast—the primary impact is on how much light you collect and how reliably that signal stands out from noise.