Python OpenCV 4 TypeError：参数“标签”的预期 cv::UMat
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OpenCV 4 TypeError: Expected cv::UMat for argument 'labels'
提问by Tyler Strouth
I am writing a facial recognition program and I keep getting this error when I try to train my recognizer
我正在编写面部识别程序，但在尝试训练识别器时不断收到此错误
TypeError: Expected cv::UMat for argument 'labels'
my code is
我的代码是
def detect_face(img):
gray = cv2.cvtColor(img, cv2.COLOR_BGR2GRAY)
face_cascade = cv2.CascadeClassifier(cv2.data.haarcascades + "haarcascade_frontalface_default.xml")
faces = face_cascade.detectMultiScale(gray, scaleFactor=1.2, minNeighbors=5);
if (len(faces)==0):
return None, None
(x, y, w, h) = faces[0]
return gray[y:y+w, x:x+h], faces[0]
def prepare_training_data():
faces = []
labels = []
for img in photo_name_list: #a collection of file locations as strings
image = cv2.imread(img)
face, rect = detect_face(image)
if face is not None:
faces.append(face)
labels.append("me")
return faces, labels
def test_photos():
face_recognizer = cv2.face.LBPHFaceRecognizer_create()
faces, labels = prepare_training_data()
face_recognizer.train(faces, np.ndarray(labels))
labels is list of labels for each photo in the image list returned from prepare_training_data, and I convert it to a numpy array because I read that is what train() needs it to be.
标签是从 prepare_training_data 返回的图像列表中每张照片的标签列表，我将其转换为一个 numpy 数组，因为我读到了 train() 需要它。
回答by PolyGlot
Solution - labels should be list of integers, and you should use numpy.array(labels)(or np.array(labels)).
解决方案 - 标签应该是整数列表，您应该使用numpy.array(labels)（或np.array(labels)）。
Dummy example to check an error absence:
检查错误缺失的虚拟示例：
labels=[0]*len(faces)
face_recognizer.train(faces, np.array(labels))
I haven't found any documentation for openCV face recodnisers on python, so i've started to look over c++ documentation and examples. And due to documentationthis library uses labelsinput for trainas a std::vector<int>. A cpp example, provided by openCV docs, also uses vector<int> labels. And so on, library even have an error for not an integer input.
我还没有在 python 上找到任何关于 openCV 人脸识别器的文档，所以我开始查看 C++ 文档和示例。并且由于文档，这个库使用labels输入train作为std::vector<int>. 甲CPP例如，通过OpenCV的文档提供，也使用vector<int> labels。等等，库甚至有一个错误不是整数 input。
