如何修复Python中OpenCV+MediaPipe手部识别的参数类型错误

问题背景 #

参照网上视频复刻手部识别项目，初始代码运行正常，在VS Code项目文件夹中添加另一个脚本后，程序每次运行均抛出错误。已尝试重新安装并升级所有依赖包，但问题仍未解决。

项目代码 #

import cv2
import mediapipe as mp
import time
 
class handDetector():
    def __init__(self, mode=False, maxHands=2, detectionCon=0.5, trackCon=0.5):
        self.mode = mode
        self.maxHands = maxHands
        self.detectionCon = detectionCon
        self.trackCon = trackCon
 
        self.mpHands = mp.solutions.hands
        self.hands = self.mpHands.Hands(self.mode, self.maxHands,
                                        self.detectionCon, self.trackCon)
        self.mpDraw = mp.solutions.drawing_utils
 
    def findHands(self, img, draw=True):
        imgRGB = cv2.cvtColor(img, cv2.COLOR_BGR2RGB)
        self.results = self.hands.process(imgRGB)
 
        if self.results.multi_hand_landmarks:
            for handLms in self.results.multi_hand_landmarks:
                if draw:
                    self.mpDraw.draw_landmarks(img, handLms,
                                               self.mpHands.HAND_CONNECTIONS)
        return img
 
    def findPosition(self, img, handNo=0, draw=True):
 
        lmList = []
        if self.results.multi_hand_landmarks:
            myHand = self.results.multi_hand_landmarks[handNo]
            for id, lm in enumerate(myHand.landmark):
                h, w, c = img.shape
                cx, cy = int(lm.x * w), int(lm.y * h)
                lmList.append([id, cx, cy])
                if draw:
                    cv2.circle(img, (cx, cy), 15, (255, 0, 255), cv2.FILLED)
 
        return lmList
 

def main():
    pTime = 0
    cTime = 0
    cap = cv2.VideoCapture(1)
    detector = handDetector()
    while True:
        success, img = cap.read()
        img = detector.findHands(img)
        lmList = detector.findPosition(img)
        if len(lmList) != 0:
            print(lmList[4])
        cTime = time.time()
        fps = 1 / (cTime - pTime)
        pTime = cTime
        cv2.putText(img, str(int(fps)), (10, 70), cv2.FONT_HERSHEY_PLAIN, 3,
                    (255, 0, 255), 3)
 
        cv2.imshow("Image", img)
        cv2.waitKey(1)
if __name__ == "__main__":
    main()

错误信息 #

Traceback (most recent call last):
  File "d:\Hand Gensture Tracking AI\HandTrackingModule.py", line 71, in <module>
    main()
  File "d:\Hand Gensture Tracking AI\HandTrackingModule.py", line 51, in main
    detector = handDetector()
  File "d:\Hand Gensture Tracking AI\HandTrackingModule.py", line 14, in __init__
    self.hands = self.mpHands.Hands(self.mode, self.maxHands,
  File "C:\Users\user\AppData\Local\Packages\PythonSoftwareFoundation.Python.3.10_qbz5n2kfra8p0\LocalCache\local-packages\Python310\site-packages\mediapipe\python\solutions\hands.py", line 114, in __init__
    super().__init__(
  File "C:\Users\user\AppData\Local\Packages\PythonSoftwareFoundation.Python.3.10_qbz5n2kfra8p0\LocalCache\local-packages\Python310\site-packages\mediapipe\python\solution_base.py", line 288, in __init__
    self._input_side_packets = {
  File "C:\Users\user\AppData\Local\Packages\PythonSoftwareFoundation.Python.3.10_qbz5n2kfra8p0\LocalCache\local-packages\Python310\site-packages\mediapipe\python\solution_base.py", line 289, in <dictcomp>
    name: self._make_packet(self._side_input_type_info[name], data)
  File "C:\Users\user\AppData\Local\Packages\PythonSoftwareFoundation.Python.3.10_qbz5n2kfra8p0\LocalCache\local-packages\Python310\site-packages\mediapipe\python\solution_base.py", line 591, in _make_packet
    return getattr(packet_creator, 'create_' + packet_data_type.value)(data)
TypeError: create_int(): incompatible function arguments. The following argument types are supported:
    1. (arg0: int) -> mediapipe.python._framework_bindings.packet.Packet

Invoked with: 0.5

问题分析与解决 #

核心原因 #

错误信息明确显示：create_int()需要传入整数，但代码中传入了0.5这个浮点数。问题出在mediapipe版本差异上：新版本的Hands类要求detectionCon和trackCon参数为整数（代表百分比，如50即50%），而代码中传入的是0-1范围的浮点数。

添加新脚本后触发问题，大概率是新脚本安装/升级了mediapipe版本，导致参数规则变化。

两种修复方案 #

方案1：修改代码适配新版本

将handDetector类的初始化参数改为整数，并保持传入一致：

class handDetector():
    # 修改默认值为整数（50代表50%）
    def __init__(self, mode=False, maxHands=2, detectionCon=50, trackCon=50):
        self.mode = mode
        self.maxHands = maxHands
        self.detectionCon = detectionCon
        self.trackCon = trackCon
 
        self.mpHands = mp.solutions.hands
        self.hands = self.mpHands.Hands(self.mode, self.maxHands,
                                        self.detectionCon, self.trackCon)
        self.mpDraw = mp.solutions.drawing_utils

方案2：回退到兼容浮点数的旧版本

如果想继续使用0-1范围的浮点数参数，可以安装旧版本的mediapipe（比如0.8.11版本）：

pip install mediapipe==0.8.11

内容的提问来源于stack exchange，提问作者Karen Movsesyan