CODEWITHSUNDEEP
pythonopencvtypeerrorflann
user2268507
user2268507

Reputation:

Python - Using "FLANN" - "Type Error"

I am trying to use the code from this link: OpenCV python's API: FlannBasedMatcher

However, I am receiving the error: 

File "C:\Users\User\Desktop\lktracker\lktrack.py", line 22, in match_flann
flann = cv2.flann_Index(desc2, flann_params)
TypeError: features is not a numpy array, neither a scalar

Here is the part of my code that makes a call to the FLANN function: 

for i in range(rowsInOrigDes):
        for j in range(rowsInNextDes):

            origDesArr = np.array(origDes[i,:])             
            nextDesArr = np.array(nextDes[j,:])             
            origDesArr = [float(x) for x in origDesArr]
            nextDesArr = [float(x) for x in nextDesArr]
            b = match_flann(origDesArr, nextDesArr, r_threshold = 0.6)
            if b:
                print b

Am I using this function correctly? I'm not sure what to declare b either..

If anyone can help out with this, I'd greatly appreciate it.

Upvotes: 1

Views: 2094

Answers (1)

user1737647
user1737647

Reputation:

The problem is that features is a list, not a numpy array. That's what the TypeError tells you. Flann only accepts numpy arrays of type float32.

It's a little hard to give you a solution without seeing your entire code, but it is quite simple. Here is a complete tutorial for OpenCV FLANN based matching in Python: https://opencv-python-tutroals.readthedocs.org/en/latest/py_tutorials/py_feature2d/py_matcher/py_matcher.html

Note that it based on OpenCV 3.0.0 dev version, but it should be pretty easy to adapt to the version of your choice.

Upvotes: 3

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