title: python: OpenCV depth of image unsupported (CV_64F)
body: <p>So, I'm trying to show a binary picture with only black and white using this code:</p>
  
  <pre><code>import cv2
  import numpy as np
  
  x_img = cv2.imread("lenac.tif")
  
  x_img_g = cv2.cvtColor(x_img, cv2.COLOR_BGR2GRAY)
  
  y = x_img_g &gt; 128
  
  cv2.imshow("", y*1.0)
  cv2.waitKey(0)
  cv2.destroyAllWindows()
  </code></pre>
  
  <p>But I'm getting this error:</p>
  
  <pre><code>&gt;Traceback (most recent call last):
  File "ex5.py", line 11, in &lt;module&gt;
  cv2.imshow("", y*1.0)
  cv2.error: OpenCV(4.0.0) c:\projects\opencv- 
  python\opencv\modules\imgproc\src\color.hpp:261: error: (-2:Unspecified 
  error) &gt;in function '__cdecl cv::CvtHelper&lt;struct 
  cv::Set&lt;1,-1,-1&gt;,struct cv::Set&lt;3,4,-1&gt;,struct 
  cv::Set&lt;0,2,5&gt;,2&gt;::CvtHelper(const class cv::_InputArray &amp;,const class 
  cv::_OutputArray &amp;,int)'
  &gt;Unsupported depth of input image:
  &gt;     'VDepth::contains(depth)'
  &gt; where
  &gt;     'depth' is 6 (CV_64F).
  </code></pre>