matrix.cpp:310: error: (-215) s >= 0 in function cv::setSize

Question

I very new to python. Im using face_recognizer = cv2.face.LBPHFaceRecognizer_create() and defined my predict function as

#this function recognizes the person in image passed
#and draws a rectangle around detected face with name of the 
#subject
def predict(test_img):
#make a copy of the image as we don't want to chang original image
img = test_img.copy()
#detect face from the image
face, rect = detect_face(img)

#predict the image using our face recognizer 
label= face_recognizer.predict(face)
#get name of respective label returned by face recognizer
label_text = subjects[label]

#draw a rectangle around face detected
draw_rectangle(img, rect)
#draw name of predicted person
draw_text(img, label_text, rect[0], rect[1]-5)

return img`

and i get the following error while predicting the face using predict function

---------------------------------------------------------------------------
error                                     Traceback (most recent call last)
<ipython-input-13-d6517b4e38bd> in <module>()
  6 
  7 #perform a prediction
----> 8 predicted_img1 = predict(test_img1)
  9 #predicted_img2 = predict(test_img2)
 10 print("Prediction complete")

<ipython-input-12-b46266ecb9d5> in predict(test_img)
  9 
 10     #predict the image using our face recognizer
---> 11     label= face_recognizer.predict(face)
 12     #get name of respective label returned by face recognizer
 13     label_text = subjects[label]

error: C:\projects\opencv-python\opencv\modules\core\src\matrix.cpp:310: 
error: (-215) s >= 0 in function cv::setSize

Many thanks in advance

Answer 1

I was testing the same github project and encountered the same error when adding new training images and testing image. The problem goes away when using one of the images from the training data as test image. So the problem would be there's nothing in place to deal with when no match is found as @DaveW.Smith suggests.