step2_train_mass_segmenter.py 文件源码

def elastic_transform(image, alpha, sigma, random_state=None):
    global ELASTIC_INDICES
    shape = image.shape

    if ELASTIC_INDICES == None:
        if random_state is None:
            random_state = numpy.random.RandomState(1301)

        dx = gaussian_filter((random_state.rand(*shape) * 2 - 1), sigma, mode="constant", cval=0) * alpha
        dy = gaussian_filter((random_state.rand(*shape) * 2 - 1), sigma, mode="constant", cval=0) * alpha
        x, y = numpy.meshgrid(numpy.arange(shape[0]), numpy.arange(shape[1]))
        ELASTIC_INDICES = numpy.reshape(y + dy, (-1, 1)), numpy.reshape(x + dx, (-1, 1))
    return map_coordinates(image, ELASTIC_INDICES, order=1).reshape(shape)