python - multiprocessing.pool.RemoteTraceback，TypeError : Incorrect type of self (must be 'Feature2D' or its derivative)

Question

我想使用 python 多处理通过 openCV brisk 计算关键点和描述符。当我运行以下代码时，发生了一些错误。但是当我使用 python 线程运行代码时，就可以了。

import cv2
import os
from multiprocessing import Pool


class Test:
    def __init__(self):
        self.brisk = cv2.BRISK_create(thresh=70, octaves=4)

    def apply_brisk(self, test_img_path):
        # brisk = cv2.BRISK_create(thresh=70, octaves=4)

        frame = cv2.imread(test_img_path)
        img_gray = cv2.cvtColor(frame, cv2.COLOR_BGR2GRAY)
        img_kp = self.brisk.detect(img_gray, None)
        img_kp, img_des = self.brisk.compute(img_gray, img_kp)
        print(img_kp)
        print(img_des)


if __name__ == '__main__':
    # test images directory
    test_images_dir = '/home/limin/pcb/images'
    test_images_name = [f for f in os.listdir(test_images_dir)]

    p = Pool(4)
    for test in test_images_name:
        # test image path
        test_image_path = test_images_dir + '/' + test

        t = Test()
        p.apply(t.apply_brisk, (test_image_path,))
        # p.apply_async(t.apply_brisk, (test_image_path,))

    p.close()
    p.join()

错误:

multiprocessing.pool.RemoteTraceback: 
"""
Traceback (most recent call last):
  File "/usr/lib/python3.5/multiprocessing/pool.py", line 119, in worker
    result = (True, func(*args, **kwds))
  File "/home/limin/Desktop/classifier_cv_tf/test.py", line 15, in apply_brisk
    img_kp = self.brisk.detect(img_gray, None)
TypeError: Incorrect type of self (must be 'Feature2D' or its derivative)
"""

The above exception was the direct cause of the following exception:

Traceback (most recent call last):
  File "/home/limin/Desktop/classifier_cv_tf/test.py", line 32, in <module>
    p.apply(t.apply_brisk, (test_image_path,))
  File "/usr/lib/python3.5/multiprocessing/pool.py", line 253, in apply
    return self.apply_async(func, args, kwds).get()
  File "/usr/lib/python3.5/multiprocessing/pool.py", line 608, in get
    raise self._value
TypeError: Incorrect type of self (must be 'Feature2D' or its derivative)

当我更改“BRISK”对象的位置时，错误将丢失:

import cv2
import os
from multiprocessing import Pool


class Test:
    def __init__(self):
        # self.brisk = cv2.BRISK_create(thresh=70, octaves=4)
        pass

    def apply_brisk(self, test_img_path):
        brisk = cv2.BRISK_create(thresh=70, octaves=4)

        frame = cv2.imread(test_img_path)
        img_gray = cv2.cvtColor(frame, cv2.COLOR_BGR2GRAY)
        img_kp = brisk.detect(img_gray, None)
        img_kp, img_des = brisk.compute(img_gray, img_kp)
        print(img_kp)
        print(img_des)


if __name__ == '__main__':
    # test images directory
    test_images_dir = '/home/limin/pcb/images'
    test_images_name = [f for f in os.listdir(test_images_dir)]

    p = Pool(4)
    for test in test_images_name:
        # test image path
        test_image_path = test_images_dir + '/' + test

        t = Test()
        p.apply(t.apply_brisk, (test_image_path,))
        # p.apply_async(t.apply_brisk, (test_image_path,))

    p.close()
    p.join()

环境:

• Ubuntu16.04
• python3.5
• opencv3.4.8

我想知道这个，如果我想在代码中使用 python 多处理，谁能帮助我。谢谢你!

Answer 1

import cv2
import os
from multiprocessing import Process


class Test:
    def __init__(self):
        self.brisk = cv2.BRISK_create(thresh=70, octaves=4)

    def apply_brisk(self, test_img_path):
        frame = cv2.imread(test_img_path)
        img_gray = cv2.cvtColor(frame, cv2.COLOR_BGR2GRAY)
        img_kp = self.brisk.detect(img_gray, None)
        img_kp, img_des = self.brisk.compute(img_gray, img_kp)
        print(img_kp)
        print(img_des)


if __name__ == '__main__':
    # test images directory
    test_images_dir = '/home/limin/pcb/images'
    test_images_name = [f for f in os.listdir(test_images_dir)]

    # subprocess
    ps = []
    t = Test()

    for test in test_images_name:
        # test image path
        test_image_path = test_images_dir + '/' + test

        p = Process(target=t.apply_brisk, args=(test_image_path,))
        ps.append(p)
        p.start()

    for p in ps:
        p.join()