ARGOS2D DEMO IMAGES, GROUND TRUTH
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reference.png and deformed.png are synthetic (speckle pattern, 2048 x 2048 px, 8-bit).
The deformed image was built from a KNOWN displacement field, so you can check what
Argos2D measures against the exact answer.

Displacement at point (x, y) of the REFERENCE image, in pixels
(x to the right, y DOWNWARDS, origin at the top-left pixel):

  u(x, y) = 3.4 + 1.5 * sin(2 pi y / 700) + 0.001 * (x - 1024)  [+ 1.2 beyond the crack]
  v(x, y) = -1.7 + -0.0015 * (y - 1024)                                    [-0.6 beyond the crack]

  Crack: a straight line through the image centre, at 25 degrees.
  "Beyond the crack" means (x - 1024) cos(25 deg) - (y - 1024) sin(25 deg) > 0.
  The crack OPENS by about 1.34 px across its faces.

  Strains away from the crack: exx = 0.001 (0.1 %), eyy = -0.0015 (-0.15 %),
  plus the shear from the wave in u.

ground_truth_ux.tif and ground_truth_uy.tif hold u and v at every pixel of the
reference image (32-bit float TIFF, rounded to 1/1024 px, about 0.001 px). They have the same layout as Argos2D's
displacement export with "Save full image" ticked, so the two can be subtracted pixel
by pixel, for instance in ImageJ / Fiji (Process > Image Calculator > Subtract).

Expect small differences near the crack faces and at the image borders: no
correlation method measures a jump exactly at the discontinuity.
