最快的3D到2D投影

您可以如下计算：

>>> data = np.random.random_sample((200, 300, 100)) > 0.5>>> data.any(axis=-1).shape # show the result has the shape we want(200, 300)>>> data.any(axis=-1)array([[ True,  True,  True, ...,  True,  True,  True],       [ True,  True,  True, ...,  True,  True,  True],       [ True,  True,  True, ...,  True,  True,  True],       ...,       [ True,  True,  True, ...,  True,  True,  True],       [ True,  True,  True, ...,  True,  True,  True],       [ True,  True,  True, ...,  True,  True,  True]], dtype=bool)>>>

您可以根据需要缩放值

>>> data.any(axis=-1) * 255array([[255, 255, 255, ..., 255, 255, 255],       [255, 255, 255, ..., 255, 255, 255],       [255, 255, 255, ..., 255, 255, 255],       ...,       [255, 255, 255, ..., 255, 255, 255],       [255, 255, 255, ..., 255, 255, 255],       [255, 255, 255, ..., 255, 255, 255]])>>>