您好，我面临着一个问题，在原始图像上绘制轮廓使用面具下面的代码，我正在使用它请您知道这是什么问题吗？

import cv2
import numpy as np
def contour_image_mask(image_path, mask_path):
    # Read the original image
    image = cv2.imread(image_path)
    #print(image.shape) # (512, 512, 3)
    # Read the segmentation mask, here is a white mask with a black background in this data set
    mask_2d = cv2.imread(mask_path, cv2.IMREAD_GRAYSCALE)
    # Cropped to the same size as the original image
    mask_2d = mask_2d[0:399, 0:428]
    h, w = mask_2d.shape

    # Applying threshold on binary mask. and then find the counter with the binary mask.
    ret, thresh = cv2.threshold(mask_2d, 127, 255, 0)
    contours, hierarchy = cv2.findContours(thresh, cv2.RETR_TREE, cv2.CHAIN_APPROX_SIMPLE)
    cnt = contours[0]
    cv2.drawContours(image, [cnt], 0, (0, 255, 0), 1)
    cv2.imwrite(os.path.join(outdir,os.path.basename(imgfile)),image)

outdir="/data/Hammad/Hammad/countor/"
for imgfile in glob.glob(r'/data/Hammad/Hammad/*.jpg'):
    for maskfile in glob.glob(r'/data/Hammad/Hammad/resize/*.jpg'):
        contour_image_mask(imgfile, maskfile)

IndexError                                Traceback (most recent call last)
<ipython-input-37-2b2baa0d3065> in <module>
      2 for imgfile in glob.glob(r'/data/Hammad/Hammad/*.jpg'):
      3     for maskfile in glob.glob(r'/data/Hammad/Hammad/resize/*.jpg'):
----> 4         contour_image_mask(imgfile, maskfile)

<ipython-input-36-ab9e8a92d580> in contour_image_mask(image_path, mask_path)
     14     ret, thresh = cv2.threshold(mask_2d, 127, 255, 0)
     15     contours, hierarchy = cv2.findContours(thresh, cv2.RETR_TREE, cv2.CHAIN_APPROX_SIMPLE)
---> 16     cnt = contours[0]
     17     cv2.drawContours(image, [cnt], 0, (0, 255, 0), 1)
     18     cv2.imwrite(os.path.join(outdir,os.path.basename(imgfile)),image)

IndexError: list index out of range