Sigma DP0 Quattro. The SIGMA dp0 Quattro incorporates a newly developed Foveon X3 direct image sensor. The new sensor structure features a pixel ratio of 1:1:4 from the bottom, middle to top layer. The Foveon X3 Quattro direct image sensor is able to detect a broad range of light wavelengths. While the top layer captures both brightness and color information, the middle and bottom layers with their larger surface area capture color information only. During the image data processing stage, the brightness data captured in the top layer is applied to the top, middle, and bottom layers, resulting in brightness and color data for each individual pixel. Retaining the principle of the three-layer structure where colors are divided vertically, by applying the brightness data captured in the top layer to the layers below, high resolution and high-speed for broad data processing required are achieved.