Split CFA Channels...

NoteCFA only⚓

This extraction function is only available when the current image has CFA[1] information and is opened as monochrome.

Warning

Opening a CFA image in Siril is required for pre-processing, like removing the dark signal before interpolating the image into 3-channel color.

TipWe can also use the color filter information to extract images like this:⚓

  • Split CFA Channels: four images are created from the CFA image, each representing one filter of the Bayer matrix, so in general R.fit, G1.fit, G2.fit and B.fit. It is useful if the goal is to process separately the different colors of the image.

  • Extract Ha: using an H-alpha filter with a color camera image (OSC: on-sensor color, or one-shot color camera) means that only the pixels with red filters will be useful, so in general only a quarter of them.

    This function creates a new image that contains only the pixels associated with the red filter documented in the Bayer matrix of the image.

  • Extract Ha/OIII: for OSC cameras, filters that let through photons from H-alpha and O-III wavelength have appeared.

    This extraction creates two images: an image from the red pixels like the Extract Ha, and an image combining the green and blue pixels into one for O-III. Both images are half the definition of the input image.

  • Extract Green: for photometry, it's often useful to only process the green part of the CFA image, because it is more sensitive and has two pixels to average, reducing noise even more.

    Of course, the created image also sees its definition halved by two.

NoteNote:⚓

These functions only work if the Bayer matrix has been properly documented by the acquisition software and if the image format supports it, so in general FITS or SER.

NoteNote:⚓

This does not work with other filter matrices than the Bayer matrices, like the Fujifilm X-TRANS.