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python - ValueError：形状不匹配

问题描述

我正在尝试 K-means 图像压缩，但出现此错误 

File "C:/Users/[user]/PycharmProjects/project/CompressMe.py", Line23, in <module>
    final[pixel_centroids == cluster_no] = cluster_centers[cluster_no]
ValueError: shape mismatch: value array of shape (4,) could not be broadcast to indexing result of shape (267049,3)

我的代码：

import numpy as np
from PIL import Image
from sklearn.cluster import KMeans
import matplotlib.pyplot as mpimg
import matplotlib.pyplot as plt

import os

img = Image.open('Capture.png')
img_np = np.asarray(img)


pixels = img_np.reshape(img_np.shape[0] * img_np.shape[1], img_np.shape[2])

model = KMeans(n_clusters = 32)
model.fit(pixels)

pixel_centroids = model.labels_
cluster_centers = model.cluster_centers_
final = np.zeros((pixel_centroids.shape[0], 3))
for cluster_no in range(32):

    final[pixel_centroids == cluster_no] = cluster_centers[cluster_no]

comp_image = final.reshape(img_np.shape[0], img_np.shape[1], 3)
comp_image = Image.fromarray(np.uint8(comp_image))

comp_image.save('Capture_compressed.png')
img1 = mpimg.imread('Capture.png')
img2 = mpimg.imread('Capture_compressed.png')
fig, (ax1, ax2) = plt.subplots(1, 2, figsize=(20,20))
ax1.imshow(img1)
ax1.set_title('Original image')
ax2.imshow(img2)
ax2.set_title('Compressed image')
plt.show()
print('size of original image: ', int(os.stat('Capture.png').st_size / 1024), 'kB')
print('size of compressed image:', int(os.stat('Capture_compressed.png').st_size / 1024), 'kB')

标签： pythonnumpyk-means

解决方案

当您初始化“最终”数组时，您将 png 输出通道的数量硬编码为 3，这可能与输入不同。更正以下行：

final = np.zeros((pixel_centroids.shape[0], img_np.shape[2]))

和

comp_image = final.reshape(img_np.shape[0], img_np.shape[1], img_np.shape[2])

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