Backtransformation

ultrasound_processing.transform_back.transform_back(frame, depth, alpha, offset_frame, offset=0, resolution=0.01)[source]

Transforms back the masked image to the original coordinate system. This is the main function that calls the other functions to perform the interpolation.

Parameters:

  • frame (np.ndarray) – The input frame.

  • depth (float) – Depth of the frustum.

  • thetas (Tuple[float, float]) – The range of theta values.

  • alpha (float) – Half angle of the ultrasound device in radians.

  • offset (float) – Offset value between the top of the frame and the US source.

  • offset_frame (float) – Offset value for the frame.

  • resolution (float) – Resolution value for upscaling or downscaling.

Returns:

Interpolated frame.

Return type:

np.ndarray

ultrasound_processing.transform_back.generate_cartesian_volume(depth, thetas, offset, resolution)[source]

Creates a Cartesian grid and corresponding spherical coordinates within a conic frustum.

Returns:

Tuple containing the image shape, filtered R, THETA arrays and valid indices.

ultrasound_processing.transform_back.transform_spherical_to_cartesian(R: ndarray, THETA: ndarray)[source]

Converts spherical coordinates (R, THETA) to Cartesian (X, Z).

Parameters:

  • R (np.ndarray) – Radial distances.

  • THETA (np.ndarray) – Polar angles.

Returns:

X and Z Cartesian coordinates.

Return type:

Tuple[np.ndarray, np.ndarray]

ultrasound_processing.transform_back.transform_cartesian_to_spherical(X: ndarray, Z: ndarray)[source]

Converts Cartesian coordinates (X, Z) to spherical coordinates (R, THETA).

Parameters:

  • X (np.ndarray) – X coordinates.

  • Z (np.ndarray) – Z coordinates.

Returns:

Radial distances R and polar angles THETA.

Return type:

Tuple[np.ndarray, np.ndarray]

ultrasound_processing.transform_back.find_nearest_indices(image_R, image_THETA, frame_R, frame_THETA)[source]

Finds the nearest neighbor indices and interpolation weights.

ultrasound_processing.transform_back.bilinear_interpolation(frame: ndarray, indices, weights, shape, cone_mask_indices)[source]

Performs bilinear interpolation on the image.

Parameters:

  • frame (np.ndarray) – The input frame.

  • indices (tuple) – Index arrays for R and THETA.

  • weights (tuple) – Weight arrays.

  • shape (tuple) – Shape of the output image.

  • cone_mask_indices (tuple) – Indices for valid cone region.

Returns:

Interpolated image.

Return type:

np.ndarray