rescale slope and rescale intercept

Question

I have few questions about the rescale slope and rescale intercept in CT DICOM:

1. Are they us

Answer 1

This is my implementation:

def window_ct(dcm, w, c, ymin, ymax):
    """Windows a CT slice.
    http://dicom.nema.org/medical/dicom/current/output/chtml/part03/sect_C.11.2.html

    Args:
        dcm (pydicom.dataset.FileDataset):
        w: Window Width parameter.
        c: Window Center parameter.
        ymin: Minimum output value.
        ymax: Maximum output value.

    Returns:
        Windowed slice.
    """
    # convert to HU
    b = dcm.RescaleIntercept
    m = dcm.RescaleSlope
    x = m * dcm.pixel_array + b

    # windowing C.11.2.1.2.1 Default LINEAR Function
    #
    y = np.zeros_like(x)
    y[x <= (c - 0.5 - (w - 1) / 2)] = ymin
    y[x > (c - 0.5 + (w - 1) / 2)] = ymax
    y[(x > (c - 0.5 - (w - 1) / 2)) & (x <= (c - 0.5 + (w - 1) / 2))] = \
        ((x[(x > (c - 0.5 - (w - 1) / 2)) & (x <= (c - 0.5 + (w - 1) / 2))] - (c - 0.5)) / (w - 1) + 0.5) * (
                ymax - ymin) + ymin

    return y