Problem plotting an image's Fourier transforms. "ValueError: x and y can be no greater than 2-D, but have shapes (2592,) and (2592, 1, 3)"

Question

我正在尝试获取图像的 fft，然后使用 matplotlib 绘制该 fft 的 fraq。然而，这个错误信息：

"ValueError: x and y can be no greater than 2-D, but have shapes (2592,) and (2592, 1, 3)".

我试着像这样重塑我的 np.array：

import numpy as np
from PIL import Image
import matplotlib.pyplot as plt
import tkinter
from scipy.fftpack import fft, fft2, fftshift

resim = Image.open(r'yeni.jpg')

resim_data = np.asarray(resim)

fourier = fft2(resim_data)

#psd2D = np.abs(fourier)**2


plt.figure()
plt.semilogy(abs(fourier).astype(np.uint8))
plt.title('fourier transform fraq')
plt.show()

错误消息爆炸：

Traceback (most recent call last):

File "myfrouier.py", line 21, in

plt.semilogy(abs(fourier).astype(np.uint8)) File

"/home/aybarsyildiz/.local/lib/python3.6/site-packages/matplotlib/pyplot.py",

line 2878, in semilogy return gca().semilogy(*args, **kwargs)
File "/home/aybarsyildiz/.local/lib/python3.6/site-packages/matplotlib/axes/_axes.py", line 1844, in semilogy l = self.plot(*args, **kwargs) File "/home/aybarsyildiz/.local/lib/python3.6/site-packages/matplotlib/init.py", line 1810, in inner return func(ax, *args, **kwargs)
File "/home/aybarsyildiz/.local/lib/python3.6/site-packages/matplotlib/axes/_axes.py", line 1611, in plot for line in self._get_lines(*args, **kwargs):
File "/home/aybarsyildiz/.local/lib/python3.6/site-packages/matplotlib/axes/_base.py", line 393, in _grab_next_args yield from self._plot_args(this, kwargs) File "/home/aybarsyildiz/.local/lib/python3.6/site-packages/matplotlib/axes/_base.py", line 370, in _plot_args x, y = self._xy_from_xy(x, y) File "/home/aybarsyildiz/.local/lib/python3.6/site-packages/matplotlib/axes/_base.py", line 234, in _xy_from_xy "shapes {} and {}".format(x.shape, y.shape)) ValueError: x and y can be no greater than 2-D, but have shapes (2592,) and (2592, 1, 3)

Answer 1

您似乎没有必要的二维数组，而是一个具有额外三维的数组。您必须选择要对该维度执行的操作：

如果只需要一个通道的信息，可以选择只保留第n个维度的值：
```
n = 1
resim_data = resim_data[:, :, n]
```
计算第三维所有值的平均值
```
resim_data = resim_data.mean(axis=-1)
```
选择所有第三维值的最大值
```
resim_data = resim_data.max(axis=-1)
```
...

示例：

我将你的代码与 244x244 像素的示例图像一起使用，但得到了与你的类似的错误：

ValueError: x and y can be no greater than 2-D, but have shapes (244,) and (244, 244, 4)

我只对第一个通道感兴趣，所以我从三维中删除了所有其他不必要的值：

resim_data = np.asarray(resim)
print(resim_data.shape)
n = 0
resim_data = resim_data[:, :, n]
print(resim_data.shape)

打印：

(244, 244, 4)
(244, 244)

如您所见，resim_data 不再有三维空间。之后没有错误。

Problem plotting an image's Fourier transforms. "ValueError: x and y can be no greater than 2-D, but have shapes (2592,) and (2592, 1, 3)"

Problem plotting an image's Fourier transforms. "ValueError: x and y can be no greater than 2-D, but have shapes (2592,) and (2592, 1, 3)"

python

fft

image-processing

matplotlib

python-3.x