rebin_image¶
- sofia_redux.instruments.forcast.undistort.rebin_image(image, factor, header=None, variance=None, platescale=None)[source]¶
Rebin the image to square pixels
Here factor represents dy/dx (pixel height/width). If the pixels were square, then 11*dx == 11*dy, or nx*dy == ny*dy. The smaller the pixels, the larger the number of them across the array for the same angular distance. We can make the pixels square by re-binning such that the above equation holds, but must assume one dimension is the reference with 256 pixels.
We can adopt the principle that the re-binned array should be as close to 256 x 256 as possible. In that case nx’*ny’ == 256*256 and nx’ == ny’ * (dy/dx).
- Parameters:
- imagenumpy.ndarray
input image with rectangular pixels (nrow, ncol)
- factorfloat
the ration dy/dx (pixel height/width)
- headerastropy.io.fits.header.Header
FITS header containing WCS. Values will be updated and HISTORY messages will be written.
- variancenumpy.ndarray
variance array to update in parallel
- platescalefloat
if set, CDELT will be set to this value in header WCS. Should be provided as arc seconds.
- Returns:
- 2-tuple
numpy.ndarray : the rebinned image (nrow, ncol) numpy.ndarray : the rebinned variance (nrow, ncol)