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I am trying to convert an image from cartesian to polar so that I can unravel the image, but I am getting a runtime error. If you are curious how this looks visually, see this example.

Code:

import scipy
import scipy.ndimage
import numpy as np
from math import *
import cv2

def logpolar(input):
    # This takes a numpy array and returns it in Log-Polar coordinates.

    coordinates = np.mgrid[0:max(input.shape[:])*2,0:360] # We create a cartesian array which will be used to compute log-polar coordinates.
    log_r = 10**(coordinates[0,:]/(input.shape[0]*2.)*log10(input.shape[1])) # This contains a normalized logarithmic gradient
    angle = 2.*pi*(coordinates[1,:]/360.) # This is a linear gradient going from 0 to 2*Pi

    # Using scipy's map_coordinates(), we map the input array on the log-polar coordinate. Do not forget to center the coordinates!
    lpinput = scipy.ndimage.interpolation.map_coordinates(input,(log_r*np.cos(angle)+input.shape[0]/2.,log_r*np.sin(angle)+input.shape[1]/2.),order=3,mode='constant')

    # Returning log-normal...
    return lpinput


# Load image
image = cv2.imread("test.jpg")
result = logpolar(image)


Error message in console:

Traceback (most recent call last):
  File "test.py", line 23, in <module>
    result = logpolar(image)
  File "test.py", line 15, in logpolar
    lpinput = scipy.ndimage.interpolation.map_coordinates(input,(log_r*np.cos(angle)+input.shape[0]/2.,log_r*np.sin(angle)+input.shape[1]/2.),order=3,mode='constant')
  File "/Library/Python/2.7/site-packages/scipy-0.13.0.dev_c31f167_20130415-py2.7-macosx-10.8-intel.egg/scipy/ndimage/interpolation.py", line 295, in map_coordinates
    raise RuntimeError('invalid shape for coordinate array')
RuntimeError: invalid shape for coordinate array
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1 回答 1

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我的第一个猜测是您正在传递一个 3 维的彩色图像。乍一看，我认为您的代码无法处理。

我的猜测是基于您粘贴的错误，特别是“坐标数组的形状无效”当使用像这样的高维数组时，通常您必须围绕指定要重复操作的轴传递额外的参数，即使这样有时它也不起作用. 我没有在您的参数列表末尾看到重复的额外整数，所以我认为您没有尝试明确处理这种情况，并且可能在读取图像后忘记检查您的数组尺寸。

很高兴它有帮助:)

于 2013-05-20T21:34:53.547 回答