如何有效地获得一个Numpy数组中相同值的数量？[重复]

Question

我有一张3D医学图像。我使用scipy.ndimage.measurements.label获取连接的体素组。它非常快。但我还想得到每个标签的体素数量。我使用以下代码获取每个值的编号（假设image\u3d是scipy.ndimage.measurements.label之后的数组）。大约2分钟。

import numpy as np
from skimage.measure import label
import time

image_3d = np.random.randint(100, size=(512, 512, 1024))
t1 = time.time()
pixel_count_list = [np.sum((image_3d== i).astype(int)) for i in range(100)]
t2 = time.time()
print("used time: ", t2-t1)
# 117 seconds

有没有什么高效的方式来高效的获取呢？

Answer 1

import numpy as np
from skimage.measure import label
import time

image_3d = np.random.randint(100, size=(512, 512, 1024))
t1 = time.time()

unique_label, count_list = np.unique(image_3d, return_counts=True)
t2 = time.time()
print("used time: ", t2-t1)
# 2 seconds