Image Cross-Correlation and Interlacing¶

A module that provides algorithm for creating sub-pixel cross-correlation images and computing displacements.

Author:	Mihai Cara (for help, contact HST Help Desk)
License:	LICENSE

subpixal.cc.find_displacement(ref_image, image00, image10, image01, image11)[source]¶

Find subpixel displacements between one reference cutout and a set of four “dithered” cutouts. This is achieved by finding peak position in a “supersampled” cross-correlation image obtained by interlacing cross-correlation maps of reference cutout with each dithered cutout.

Parameters:

ref_image : numpy.ndarray: Image of a reference cutout.
image00 : numpy.ndarray: Image whose displacement relative to reference image needs to be computed. It must have same shape as ref_image.
image10 : numpy.ndarray: “Same” image as image00 but sampled at a 1/2 pixel displacement along the X-axis. It must have same shape as ref_image.
image01 : numpy.ndarray: “Same” image as image00 but sampled at a 1/2 pixel displacement along the Y-axis. It must have same shape as ref_image.
image11 : numpy.ndarray: “Same” image as image00 but sampled at a 1/2 pixel displacement along both X-axis and Y-axis. It must have same shape as ref_image.

Returns:

dx : float: Displacement of image00 with regard to ref_image along the X-axis (columns).
dy : float: Displacement of image00 with regard to ref_image along the Y-axis (rows).