错误消息“预期的 Ptr<cv::umat> 对于参数“垫子””</cv::umat>

Question

Just a standard Screen Grab code here:-

import numpy as np
import cv2
from PIL import ImageGrab

while True:
    Speed = np.array(ImageGrab.grab(bbox = (1060,510, 100, 60)))
    cv2.imshow('Speed' , Speed)
    

    if cv2.waitKey(25) & 0xFF == ord('q'):
        cv2.destroyAllWindows()
        break

Returns the aforementioned error for the imshow line, What am I doing wrong?

Answer 1

Your ImageGrab is not getting any images. Take a look at Speed.shape , it'll be an empty tuple () . There's an issue with your bbox.

import numpy as np
import cv2
from PIL import ImageGrab

while True:
    # your bbox order or params was wrong: left_x, left_y, right_x and right_y
    Speed = np.array(ImageGrab.grab(bbox = (100, 60, 1060, 510)))
    cv2.imshow('Speed' , Speed)
    

    if cv2.waitKey(25) & 0xFF == ord('q'):
        cv2.destroyAllWindows()
        break