filter array (CFA), usually a Bayer filter, consisting of a mosaic of a 2x2 matrix of red, green, blue and (second) green filters. One variation on the Bayer filter is the RGBE filter of the Sony Cyber-shot DSC-F828, which exchanged the green in the RG rows with "emerald" (a blue-green or cyan color). Other sensors, such as the Foveon X3 sensor, capture information directly in RGB form (using three pixel sensors in each location). This RGB raw data still needs to be processed to make an image file, because the raw RGB values correspond to the responses of the sensors, not to a standard color space like sRGB. As there is no color filter array, there is no need for demosaicing. Flatbed and film scanner sensors are typically straight narrow RGB or RGBI (where "I" stands for the additional infrared channel for automatic dust removal) strips that are swept across an image. The HDRi raw data format is able to store the infrared raw data, which can be used for infrared cleaning, as an additional 16-bit channel. The remainder of the discussion about raw files applies to them as well. Some scanners do not allow the host system access to the raw data at all, as a speed compromise. The raw data are processed very rapidly inside the scanner to select out the best part of the available dynamic range so only the result is passed to the computer for permanent storage, reducing the amount of data transferred and therefore the bandwidth requirement for any given speed of image throughput. To obtain an image from a raw file, this mosaic of data must be converted into standard RGB form. This is often referred to as "raw development". When converting from the four-sensor 2x2 Bayer-matrix raw form into RGB pixels, the green pair is used to control the luminance detail of the processed output pixel, while the red and blue, which each have half as many samples, are used mostly for the more slowly-varying chroma component of the image. If raw format data is available, it can be used in high-dynamic-range imaging conversion, as a simpler alternative to the multi-exposure HDI approach of capturing three separate images, one underexposed, one correct and one overexposed, and "overlaying" one on top of the other. Standardization Providing a detailed and concise description of the content of raw files is highly problematic. There is no