Practice question · Multiple choice
Half the photosites under a Bayer array carry a green filter and each photosite measures only one colour, yet the finished file gives red, green and blue for every pixel. How is that possible?
Hints
- Count how many measurements exist and how many values the file contains.
- The gap is filled by an algorithm, not by a measurement.
Show the answer
C. The missing two thirds of colour data is interpolated from neighbours during demosaicing
Why
By interpolation. One measurement per photosite and three values per pixel means two thirds of the colour in every digital photograph is calculated from neighbours rather than measured. Demosaicing does this very well, and where it shows is fine coloured detail close to the sampling limit.
Practise Digital Capture and the Input-Output Chain
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