python - cv2.cvtColor 错误:(-215) scn == 3 ||函数 cv::cvtColor 中的 scn == 4

Question

我正在尝试使用 kmeans 聚类从图像中获取最常见的颜色。它可以很好地处理本地镜像，但会通过从 url 中提取图像的新功能返回此错误。这是抛出错误的行之前的代码:

# import the necessary packages
from sklearn.cluster import KMeans
import numpy as np
import urllib
import argparse
import utils
import cv2

def getCommonColors(url):

    req = urllib.urlopen(url)
    arr = np.asarray(bytearray(req.read()), dtype=np.uint8)
    img = cv2.imdecode(arr,-1)


    image = cv2.imread(np.array_str(img))
    image = cv2.cvtColor(image, cv2.COLOR_BGR2RGB)

如有任何帮助，我们将不胜感激!

Answer 1

也许您可以尝试一下，只需对您的代码进行一些更改..

import numpy as np
import urllib2        #maybe requests is another good choice
import cv2

def getCommonColors(url):

    req = urllib2.urlopen(url)
    arr = np.asarray(bytearray(req.read()), dtype=np.uint8)
    img = cv2.imdecode(arr,-1)

    # image = cv2.imread(np.array_str(img))   <-- I think you shoudn't use this method, it will return NoneType in python
    image = cv2.cvtColor(img, cv2.COLOR_BGR2RGB)