opencv 卡爾曼濾波器鼠標跟蹤器類型錯誤

Question

我正在通過本書學習 opencv 和 python 並使用卡爾曼濾波器進行鼠標跟蹤遇到了這個錯誤：

編碼：

import cv2
import numpy as np

# Create a black image
img = np.zeros((500,500,3), np.uint8)

# Initialize the Kalman filter
kalman = cv2.KalmanFilter(4,2)
kalman.measurementMatrix = np.array(
        [[1, 0, 0, 0],
        [0, 1, 0, 0]], np.float32)
kalman.transitionMatrix = np.array(
        [[1, 0, 1, 0],
        [0, 1, 0, 1],
        [0, 0, 1, 0],
        [0, 0, 0, 1]], np.float32)
kalman.processNoiseCov = np.array(
        [[1, 0, 0, 0],
        [0, 1, 0, 0],
        [0, 0, 1, 0],
        [0, 0, 0, 1]], np.float32) * 0.03

last_measurement = None
last_prediction = None

def on_mouse_moved(event, x, y, flags, param):
    global img, kalman, last_measurement, last_prediction
    
    measurement = np.array([[x], [y]], np.float32)
    if last_measurement is None:
        # This is the first measurement.
        # Update the Kalman filter's state to match the measurement.
        kalman.statePre = np.array(
            [[x],[y], [0],[0]], np.float32)
        kalman.statePost = np.array(
            [[x],[y],[0],[0]], np.float32)
        prediction = measurement
    else:
        kalman.correct(measurement)
        prediction = kalman.predict() # Gets a reference, not a copy
        # Trace the path of the measurement in green.
#         print(f"The lm:{last_measurement[0]}, and dtype: {last_measurement[0].dtype}")
#         print(f"The cm:{measurement[0]}, and dtype: {measurement[0].dtype}")
        

        cv2.line(img, (last_measurement[0], last_measurement[1]),
                    (measurement[0], measurement[1]), (0,255,0))
        
        # Trace the path of the prediction in red.
        cv2.line(img, (last_prediction[0], last_prediction[1]),
                (prediction[0], prediction[1]), (0,0,255))
    
    last_prediction = prediction.copy()
    last_measurement = measurement

cv2.namedWindow('kalman_tracker')
cv2.setMouseCallback('kalman_tracker', on_mouse_moved)

while True:
    cv2.imshow('kalman_tracker', img)
    k = cv2.waitKey(1)
    if k == 27: # Escape
        cv2.imwrite('kalman.png', img)
        break

cv2.destroyAllWindows()

錯誤：

     43         cv2.line(img, (last_measurement[0], last_measurement[1]),
---> 44                     (measurement[0], measurement[1]), (0,255,0))
     45 
     46         # Trace the path of the prediction in red.

error: OpenCV(4.5.1-dev) :-1: error: (-5:Bad argument) in function 'line'
> Overload resolution failed:
>  - Can't parse 'pt1'. Sequence item with index 0 has a wrong type
>  - Can't parse 'pt1'. Sequence item with index 0 has a wrong type

我試圖查看問題是否確實出在 x 和 y 位置的數據類型中（您可以在 comments 中看到 print 語句），但似乎類型是相同的。 那我不知道有什么問題。 甚至作者的代碼文件也給出了同樣的錯誤。 如果您有任何想法，將不勝感激您的回復！

Answer 1

@DanMašek 哇：！ 你說的對！ 我將代碼更改為：

cv2.line(img, (last_measurement[0][0].astype(np.int), last_measurement[1][0].astype(np.int)),
                    (measurement[0][0].astype(np.int), measurement[1][0].astype(np.int)), (0,255,0))
        
# Trace the path of the prediction in red.
cv2.line(img, (last_prediction[0][0].astype(np.int), last_prediction[1][0].astype(np.int)),
                (prediction[0][0].astype(np.int), prediction[1][0].astype(np.int)), (0,0,255))

它奏效了。 很驚訝這本書沒有提到任何關於它的內容，然后書中的代碼是錯誤的。 謝謝！