OpenCV: Converting from NumPy to IplImage in Python

Question

I have an image that I load using cv2.imread(). This returns an NumPy array. However, I need to pass this into a 3rd party API that requires the data in IplImage format.

I've scoured everything I could and I've found instances of converting from IplImage to CvMat,and I've found some references to converting in C++, but not from NumPy to IplImage in Python. Is there a function that is provided that can do this conversion?

Is it okay with Numpy --> cvMat?

Abid Rahman K
– Abid Rahman K

2012-07-17 18:03:47 +00:00
Commented Jul 17, 2012 at 18:03 — Abid Rahman K
– Abid Rahman K, Commented Jul 17, 2012 at 18:03

Froyo · Accepted Answer · 2012-07-17 18:18:13Z

15

You can do like this.

source = cv2.imread() # source is numpy array 
bitmap = cv.CreateImageHeader((source.shape[1], source.shape[0]), cv.IPL_DEPTH_8U, 3)
cv.SetData(bitmap, source.tostring(), 
           source.dtype.itemsize * 3 * source.shape[1])

bitmap here is cv2.cv.iplimage

answered Jul 17, 2012 at 18:18

Froyo

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2 Comments

steve8918 Over a year ago

Thanks Froyo, this gets me an IplImage, but the image seems to be corrupt. Instead of using cv.CreateImageHeader and cv.SetData, I'm using cv2.cv.CreateImageHearder and cv2.cv.SetData, do you think that makes a difference?

steve8918 Over a year ago

Actually I figured it out, the tile I was trying to convert was binary, not BGR, so that's why it was getting corrupt. So I changed 3 to 1 and it worked perfectly. Thanks again for pointing me in the right direction. In case anyone else needs it, the OpenCV Cookbook has info on how to convert at opencv.willowgarage.com/wiki/PythonInterface

jiangze ren · Accepted Answer · 2018-06-27 02:58:40Z

0

2-way to apply:

img = cv2.imread(img_path) img_buf = cv2.imencode('.jpg', img)[1].tostring()
just read the image file: img_buf = open(img_path, 'rb').read()

answered Jun 27, 2018 at 2:58

jiangze ren

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