opencv python图像转换

执行代码后，我得到一张黑白图像，它由两个维度（宽度高度）和值本身组成，从0到255- 从黑色到白色。为了将来使用，我需要将其转换为rgb8. 例如，该功能cv2.floodFill不接受我收到的图像。这是代码本身：

import sys
import cv2
import numpy as np
import time
from matplotlib import pyplot as plt

img = cv2.imread('2.jpg')
gray = cv2.cvtColor(img, cv2.COLOR_BGR2GRAY)
ret, thresh = cv2.threshold(gray, 0, 255, cv2.THRESH_BINARY_INV+cv2.THRESH_OTSU)
# noise removal
kernel = np.ones((3, 3), np.uint8)
opening = cv2.morphologyEx(thresh, cv2.MORPH_OPEN, kernel, iterations = 2)
# sure background area
sure_bg = cv2.dilate(opening, kernel, iterations=3)
# Finding sure foreground area
dist_transform = cv2.distanceTransform(opening, cv2.DIST_L2, 5)
ret, sure_fg = cv2.threshold(dist_transform, 0.55 * dist_transform.max(), 255, 0)
# Finding unknown region
sure_fg = np.uint8(sure_fg)
unknown = cv2.subtract(sure_bg, sure_fg)
# Marker labelling
ret, markers = cv2.connectedComponents(sure_fg)
# Add one to all labels so that sure background is not 0, but 1

markers = markers+10
# Now, mark the region of unknown with zero
markers[unknown == 255] = 0
markers = cv2.watershed(img, markers)
img[markers == -1] = [255, 0, 0]
cv2.imwrite('6.jpg', markers)

是否可以转换markers为普通图像？