A Bayer color image is a type of color image that uses the Bayer filter array pattern to capture color information. It is a widely used method in digital image sensors.


In a Bayer color image sensor, individual pixels are sensitive to only one color channel: red, green, or blue. The sensor arranges these pixels in a specific pattern known as the Bayer pattern, which typically consists of alternating rows of green and red pixels, with the remaining rows containing blue and green pixels.


The Bayer filter array allows the image sensor to capture color information by interpolating the missing color channels for each pixel. This interpolation process, known as demosaicing, estimates the missing color values based on the known color values of neighboring pixels.


Phoranso automatically recognizes Bayer color FITS files by the presence of the FITS keyword BAYERPAT. It offers two methods to process Bayered FITS images:
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  • Automatic conversion to grayscale: Phoranso can automatically convert Bayered FITS images to grayscale images during the photometry process. This is particularly useful when high photometric precision is desired, as it simplifies the data by focusing on luminance information.​ Phoranso  displays a corresponding message during photometry when working with grayscale images

  • Splitting into RGB Channels: Phoranso provides a feature to first split Bayered FITS images into three separate monochrome images corresponding to the Red (TR), Green (TG), and Blue (TB) channels, before doing photometry. This allows for color-specific photometric analysis.


Example of a Bayer color image showing the typical Bayer pattern:



Same image after demosaicing and conversion to greyscale: