dpivsoft.SyIm

dpivsoft.SyIm.Analytic_Syntetic(dirSave, Name, saveData=True, randTransform=False)[source]

Generates a pair of imnages where the trazers particles moves accordly to an analytical flow velocity field. The parameters of the generated images are defined on the class Synt_Img (see class Synt_Img for more info).

dpivsoft.SyIm.Custom_Syntetic(xx, yy, uu, vv, scale, dirSave, Name, dt, limits=None, randTransform=False)[source]

Generates a pair of syntetic images where the trazers particles move accordly a custom velocity field loaded from a numpy array.

The numpy array must be saved in colums as: | x | y | u | v |

dpivsoft.SyIm.random_transformation(x, y, u, v)[source]

Apply a random symmetry operation to a velocity field for data augmentation.

One of 8 equally likely outcomes (transpose and/or sign flips, including the identity). For isotropic turbulence each outcome is an equally valid realization, so this multiplies the effective dataset size 8x. Requires square images (transpose mixes the axes).

Parameters:

  • x (2d np.ndarray) – Grid coordinates (returned unchanged).

  • y (2d np.ndarray) – Grid coordinates (returned unchanged).

  • u (2d np.ndarray) – Velocity components to transform.

  • v (2d np.ndarray) – Velocity components to transform.

Returns:

x, y, u, v – The (possibly transposed / sign-flipped) field.

Return type:

2d np.ndarray

dpivsoft.SyIm.Velocity_Profile()[source]

Build the analytical velocity field used to advect the tracers.

The profile is selected by Synt_Img.vel_profile and evaluated on the pixel grid: ‘Constant’, ‘Couette’, ‘Poiseuille’, ‘Vortex’ (Lamb-Oseen-like) or ‘Frequency’ (sinusoidal shear). Exits if the profile name is unknown.

Returns:

  • xv, yv (2d np.ndarray) – Pixel-coordinate meshgrid.

  • u, v (2d np.ndarray) – Velocity components on that grid.

dpivsoft.SyIm.Gen_trazers()[source]

Randomly sample the brightness and diameter of the tracer particles.

Both are drawn from triangular distributions centred on the class means (Shine_m, D_m) with half-widths d_Shine / d_D, one value per particle.

Returns:

  • trazers_shine (1d np.ndarray) – Peak brightness of each particle.

  • trazers_D (1d np.ndarray) – Diameter of each particle (pixels).

dpivsoft.SyIm.Img_Generation(u, v, xv, yv, trazers_shine, trazers_D)[source]

Render the synthetic image pair from a velocity field and tracers.

Particles are seeded at random subpixel positions for the first image, then advected to their second-image positions by integrating the velocity field with RK4 over Synt_Img.n_steps substeps. Particles are drawn as Gaussian spots; those leaving the frame re-enter periodically from the opposite side. Triangular-distributed background noise is added and intensities are clipped to [0, 255].

Parameters:

  • u (2d np.ndarray) – Per-pixel displacement field (pixels between the two exposures).

  • v (2d np.ndarray) – Per-pixel displacement field (pixels between the two exposures).

  • xv (2d np.ndarray) – Pixel-coordinate meshgrid matching u, v.

  • yv (2d np.ndarray) – Pixel-coordinate meshgrid matching u, v.

  • trazers_shine (1d np.ndarray) – Per-particle brightness and diameter (from Gen_trazers).

  • trazers_D (1d np.ndarray) – Per-particle brightness and diameter (from Gen_trazers).

Returns:

img1, img2 – The synthetic image pair.

Return type:

2d np.ndarray

dpivsoft.SyIm.Pix2PIV(Xv, Yv, Uv, Vv, no_boxes_x, no_boxes_y, box_size_1_x, box_size_1_y, box_size_2_x, box_size_2_y)[source]

Downsample a per-pixel velocity field onto the coarse PIV grid.

Averages the pixel-level field over each interrogation window, reproducing the window-averaging inherent to classical PIV so a ground-truth field can be compared with a PIV result (or used as the coarse prior in the Stage 2 PIV-conditioned DL model). The grid is laid out with the same margin/spacing as grid.generate_mesh.

Parameters:

  • Xv (2d np.ndarray) – Pixel-coordinate meshgrid.

  • Yv (2d np.ndarray) – Pixel-coordinate meshgrid.

  • Uv (2d np.ndarray) – Per-pixel velocity components.

  • Vv (2d np.ndarray) – Per-pixel velocity components.

  • no_boxes_x (int) – Number of interrogation windows in x and y.

  • no_boxes_y (int) – Number of interrogation windows in x and y.

  • box_size_1_x (int) – First- and second-pass window sizes (first pass sets the margin, second pass sets the averaging window).

  • box_size_1_y (int) – First- and second-pass window sizes (first pass sets the margin, second pass sets the averaging window).

  • box_size_2_x (int) – First- and second-pass window sizes (first pass sets the margin, second pass sets the averaging window).

  • box_size_2_y (int) – First- and second-pass window sizes (first pass sets the margin, second pass sets the averaging window).

Returns:

  • Xi, Yi (1d np.ndarray) – PIV grid coordinates.

  • Ui, Vi (2d np.ndarray) – Window-averaged velocity components on the PIV grid.

dpivsoft.SyIm.SaveImg(Img1, Img2, dirSave, Name)[source]

Save the syntetic Images