1. 将QImage转化成 opencv 下的 MAT(numpy ndarray) 对象：

from PyQt5.QtGui import QImage

def QImageToCvMat(incomingImage):
    '''  Converts a QImage into an opencv MAT format  '''

    incomingImage = incomingImage.convertToFormat(QImage.Format.Format_RGBA8888)

    width = incomingImage.width()
    height = incomingImage.height()

    ptr = incomingImage.bits()
    ptr.setsize(height * width * 4)
    arr = np.frombuffer(ptr, np.uint8).reshape((height, width, 4))
    return arr

2. 将QImage对象转化为 PIL image 对象

import io
from PIL import Image
from PyQt5.QtGui import QImage
import numpy as np
from PyQt5.QtCore import QBuffer

def QImage2PILImage(img):
    buffer = QBuffer()
    buffer.open(QBuffer.ReadWrite)
    img.save(buffer, "PNG")
    pil_im = Image.open(io.BytesIO(buffer.data()))
    return pil_im