stafflines.py 文件源码

def staffline_surroundings_mask(staffline_cropobject):
    """Find the parts of the staffline's bounding box which lie
    above or below the actual staffline.

    These areas will be very small for straight stafflines,
    but might be considerable when staffline curvature grows.
    """
    # We segment both masks into "above staffline" and "below staffline"
    # areas.
    elevation = staffline_cropobject.mask * 255
    # Blur, to plug small holes somewhat:
    elevation = gaussian(elevation, sigma=1.0)
    # Prepare the segmentation markers: 1 is ABOVE, 2 is BELOW
    markers = numpy.zeros(staffline_cropobject.mask.shape)
    markers[0, :] = 1
    markers[-1, :] = 2
    markers[staffline_cropobject.mask != 0] = 0
    seg = watershed(elevation, markers)

    bmask = numpy.ones(seg.shape)
    bmask[seg != 2] = 0
    tmask = numpy.ones(seg.shape)
    tmask[seg != 1] = 0

    return bmask, tmask


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