Image sensors and optical devices

Which component is sometimes placed in front of the sensor to suppress moiré, false patterns caused by interference between a fine striped subject and the pixel array?

  1. AOptical low-pass filter
  2. BMicrolens
  3. CPolarizer
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Answer: A. Optical low-pass filter

Patterns finer than the pixel pitch cannot be represented correctly, and aliasing produces moiré and false color. An optical low-pass filter slightly blurs the light to remove overly fine components and suppress this. Because it reduces perceived sharpness, high-resolution cameras sometimes omit it.

  • A. Correct. It slightly blurs light to remove overly fine detail.
  • B. Microlenses focus light onto each pixel's photosensitive area.
  • C. A polarizer passes light of a particular polarization and is not a moiré countermeasure.
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