Doubt about the confidence of the face recognition from the opencv contrib modules

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In the OpenCV contrib modules we find 3 methods to work with face recognition:

recognizer = cv2.face.createEigenFaceRecognizer()
recognizer = cv2.face.createLBPHFaceRecognizer()
recognizer = cv2.face.createFisherFaceRecognizer()

but when I try to predict some face image, each of them returns a different confidence value.

nbr_predicted, conf = recognizer.predict( gray_image )

For example: for the same image, LBPH returns a confidence of 80 and the EigenFace returns a confidence of 1500.

I would like to know if each of them has some range in the confidence value?

For example, the LBPH method returns a confidence between 0 and 250, and the EigenFace returns a confidence between 0 and 3000.

I would like to know this so I can normalize the confidence values to compare the confidence results of each method.