Sony Corporation (Japan) has today announced that it will be implementing a new four color filter array pattern on a 'consumer CCD' (we can only assume this is the new ICX456 eight megapixel CCD sensor). Instead of the 'traditional' three color RGB bayer pattern the new color filter array has a RGBE layout where 'E' is a light blue color which Sony are referring to as 'Emerald' (although it looks more like Cyan to me). Their claim is that this pattern is "closer to the natural sight perception of the human eye". In addition Sony has developed a new image processor to complement the "4 color filter CCD".

Phil: This is an improvement clearly aimed at color response, having a fourth color will give the image processing system additional gamut with which to reproduce color. Interestingly the Emerald (Cyan) pixel will still response similarly to the old green pixel when it comes to grayscale resolution.

Press Release:

Realization of natural color reproduction in Digital Still Cameras, closer to the natural sight perception of the human eye

Technology development to realize 4-color filter CCD and New Image Processor, achieving halving of color reproduction error

(Tokyo, Japan) - Sony Corporation today announced the world's first practical consumer (home) use of CCD with 4-color (Red <R>, Green <G>, Blue <B> + Emerald <E>) filters, together with a new image processor corresponding to the 4-color filter. By this technology, the color reproduction error is halved compared to Sony's conventional 3-primary-color filter CCD and, expression of images closer to the natural sight perception of the human eye is achieved under various shooting conditions.

3-color filters (RGB) 4-color filters (RGBE)

Conventional digital still cameras mainly use 3-primary-color filter CCD, and the colors are recorded by the intensity of each of the 3 colors, Red(R), Green(G) and Blue(B), corresponding to the color reproduction characteristics of the color TV or monitors. However, the characteristics of these CCD filters are different from those of the human visual system. Color differences therefore emerge compared to natural human sight, resulting in different color reproduction.

In the 4-color filter CCD, a filter with the Emerald (E) color is added to the conventional 3-color RGB filter, in order to reduce the color reproduction errors and to record natural images closer to the natural sight perception of the human eye. As a result, the characteristics of the CCD color filter become much closer to those of the human visual system, achieving dramatic reduction in the color reproduction error.

In addition to the development of the 4 color filter, a new image processor corresponding to the 4-color filter has been developed. With this processor, each of the signals captured by the 4 colors is processed to produce ideal 3 colors close to the natural sight perception the human eye by a matrix calculation. Also, in addition to functioning with 30% less power consumption, by the efficient processor management, functions such as high-speed image shooting and high-speed playback are realized, as well as enhancing the of overall basic functions of digital still cameras.

By the combination of the 4 color filter CCD and the new processor, color reproduction errors have been minimized by half, and the reproduction of blue-green and red colors has been particularly enhanced.

Example photo produced by 3-color filter (RGB) Example photo produced by 4-color filter (RGBE)

Sony plans to integrate the newly developed 4 color filter CCD and the new image processor into the new digital cameras which will be introduced in the near future. This unique Sony original technology will offer the capability to shoot images with enhanced reality.

Sony will continue to further improve the technology in order to enhance image quality in the growing digital still camera market, with the aim of offering customers more fun and joy in taking pictures.

New image processor