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I have seen on Dpreview that fujifilm has been granted a patent for a new type of sensor with a strange non-Bayer pattern.

dropped from internet

Thinking about it... Is there a camera using a simpler Bayer RGBW pattern? It would be interesting, because:

  1. you certainly loose some color resolution, but

  2. the photodiode under the clear filter will receive more light (up to three time for a gray target),

So you could have a kind of mix between a normal camera and a Leica MM one, with less luminance noise in exchange for less color resolution...

Did any firm explore this path in the past? Or I am missing some big shortcoming?

PS: RGBW displays do exist and have advantages versus normal ones, so for reciprocity sensors could have some advantage too, our not?

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    \$\begingroup\$ The idea of getting away from the bayer pattern or using it in a different way certainly has previous form. Fuji's particularly have form for it since way back to the S2 which used supersampling and differing sensitivity levels in the sensor. Also differing colour and image capture methods are quite common in video cameras where it's not uncommon to find a prism / mirror array directing the image to multiple sensors. \$\endgroup\$ Jan 25, 2014 at 9:31
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    \$\begingroup\$ I couldn't find any cameras, but there are two 2007 patents on RGBW sensors. Maybe Fujifilm just wanted to avoid an existing patent? Interesting sensor, but writing the de-"Bayering" algorithm looks rather challenging... \$\endgroup\$ Jan 25, 2014 at 9:43
  • \$\begingroup\$ Less challenging than you'd think - if you're used to thinking in other colourspaces. Something like a hybrid RGB/Lab conversion would be straightforward enough. The question would be if, for the extra work of having different sensitivity levels on the die and the slight processing overhead, it would yield a significant enough improvement in colour fidelity. \$\endgroup\$ Jan 25, 2014 at 14:43
  • \$\begingroup\$ The most unusual sensor arrangement I can recall was the Foveon X3 Sensor which had the RGB sensors stacked on top of each other so that each point on the sensor face detected all three colours. Very appealing idea, and it was used in several camera bodies, but I don't believe it gained much ground. \$\endgroup\$
    – Bobulous
    Jan 25, 2014 at 20:51

2 Answers 2

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"Are there digital cameras with a RGBW sensor?"

Answering this: No.

"Did any form exploited this path in the past?"

Answering this: Yes.

There were some tryouts from Sony but they reverted back to the classical RGB design due of 'image quality issues'.

Also Nikon filled a patent for this.

But the oldest research on the area is from Kodak. They even produced a sensor with this technology but it was intended for "non-camera devices such as mobile phones and automotive vehicles"

As a bottom line: There were enough tryouts in this area but it seems that the idea, although promising, still has some caveats for a photographic camera.

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It doesn't include any unmasked white pixels in the pattern but the Fuji X-Trans sensor, found in cameras such as the X-Pro 1, uses a non-Beyer 6x6 repeating pattern. This pattern allows R, G, & B photo sites in every line both horizontally and vertically. It also distributes 20 Green, 8 Red, and 8 Blue per 36 photosites instead of the normal 9/18/9 R/G/B distribution. The more 'irregular' pattern compared to a standard 4x4 RGGB Bayer pattern also allows for the reduction or moire without the use af an anti-aliasing filter.

X-Trans mask pattern

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    \$\begingroup\$ Slightly offtopic - Do you know if this sensor was derived from what Fuji did for the S2 where some photosites had different sensitivities and used supersampling? \$\endgroup\$ Jan 25, 2014 at 9:26

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