The continued increase in image quality expectations of smartphones in recent years has led to smartphone image sensors reducing their pixel size and increasing the density of image pixels to improve image resolution. There is a trade-off between pixel miniaturization and light sensitivity however. The QBC image pixel array was therefore developed by Sony to minimize the reduction in light sensitivity from reduction in pixel size. Large image pixel sensors are generally used in single-lens reflex cameras so there is no need for pixel miniaturization. QBC technology is therefore tailor-made for smartphone image sensors.

QBC is the acronym of Quad Bayer Coding. Each pixel is made up of four sub-pixels that share a moon color filter. Under the Quad Bayer arrangement, neighboring pixels have color filters of the same color to preserve high-sensitivity and high-resolution.

        Conventional Image Sensor                                               QBC Image Sensor 

                "Bayer" Array                                          "Quad Bayer” Array (array of same color every two pixels)


Photo taken with Bayer array image sensor     Photo taken with Quad Bayer array image sensor(IMX689)

QBC image sensors prevent loss of resolution and reduce noise when shooting in low-illuminance environments such as nightscapes. The signal from four neighboring image pixels are combined so that each image pixel is effectively made four times its actual size. Analog addition of neighboring pixels also help to prevent loss of resolution and reduce noise. Light sensitivity is therefore increased even when shooting in low-illuminance environments to produce bright photos and videos with low noise. At the same time, conventional Bayer array is restored through advanced array conversion when shooting in bright, outdoor environments to achieve resolutions equivalent to that of Bayer image sensors.

Array conversion (Re-mosaic) is generally performed in software but Sony’s proprietary technology is integrated into the image sensor circuitry. Power consumption is therefore lower than software processing. Embedded hardware re-mosaic enables real-time processing and allows the feature to be used in video recording mode as well.

Source:https://www.Sony-semicon.co.jp/e/products/IS/mobile/quad_bayer_coding.html