Opencv 4.5.4 LBPHFaceRecognizer train error

this is entirely wrong, you cannot call train() for a single image,
also labels are ints, not strings
instead, you need to collect all training images into an array,
and make a numpy array of integer ids for the labels. then you can call

model.train(images, ids)

https://docs.opencv.org/4.x/dd/d65/classcv_1_1face_1_1FaceRecognizer.html#ac8680c2aa9649ad3f55e27761165c0d6

@sky may i ask, what you try to achieve with the face recognition ?
which problem should be solved ?