Source code for optika.targets._airforce._airforce

import pathlib
import matplotlib.pyplot as plt
import pymupdf
import named_arrays as na

__all__ = [
    "airforce",
]




def airforce(
    axis_x: str,
    axis_y: str,
    num_x: int = 1000,
    num_y: int = 1000,
) -> na.ScalarArray:
    """
    A `1951 USAF resolution test target <https://en.wikipedia.org/wiki/1951_USAF_resolution_test_chart>`_
    used for testing the performance of optical systems.

    Parameters
    ----------
    axis_x:
        The name of the horizontal axis.
    axis_y:
        The name of the vertical axis.
    num_x:
        The number of pixels along the horizontal axis.
    num_y:
        The number of pixels along the vertical axis.

    Examples
    --------

    Load and display the test target

    .. jupyter-execute::

        import matplotlib.pyplot as plt
        import named_arrays as na
        import optika

        # Load the test target
        target = optika.targets.airforce("x", "y")

        # Display the test target
        fig, ax = plt.subplots(constrained_layout=True)
        na.plt.pcolormesh(C=target);
    """
    path = pathlib.Path(__file__).parent / "USAF-1951.svg"

    doc = pymupdf.open(path)

    page = doc[0]

    zoom_x = num_x / page.rect.width
    zoom_y = num_y / page.rect.height

    mat = pymupdf.Matrix(zoom_x, zoom_y)

    pix = page.get_pixmap(matrix=mat)

    fn = "tmp.png"
    pix.save(fn)

    img = plt.imread(fn)

    img = img.astype(float)[::-1].sum(~0)

    img = img / img.max()

    img = -img + 1

    return na.ScalarArray(
        ndarray=img,
        axes=(axis_y, axis_x),
    )