[英]How to set background color on image to white with OpenCV in Python
在此圖像中,您需要在幾個區域中填充填充,因為所有背景綠色都沒有連接。
import cv2
import numpy as np
# load image and get dimensions
img = cv2.imread("soccer.jpg")
h, w, c = img.shape
# create zeros mask 2 pixels larger in each dimension
mask = np.zeros([h + 2, w + 2], np.uint8)
# do floodfill
result = img.copy()
cv2.floodFill(result, mask, (0,0), (255,255,255), (3,151,65), (3,151,65), flags=8)
cv2.floodFill(result, mask, (38,313), (255,255,255), (3,151,65), (3,151,65), flags=8)
cv2.floodFill(result, mask, (363,345), (255,255,255), (3,151,65), (3,151,65), flags=8)
cv2.floodFill(result, mask, (619,342), (255,255,255), (3,151,65), (3,151,65), flags=8)
# write result to disk
cv2.imwrite("soccer_floodfill.jpg", result)
# display it
cv2.imshow("result", result)
cv2.waitKey(0)
cv2.destroyAllWindows()
輸入:
結果:
根據需要調整低顏色和高顏色范圍以去除更多的綠色。
見洪水填充
添加:
這是我的評論中建議的在 HSV 中進行 inRange 閾值處理的代碼。 但請注意,全局閾值影響了襯衫中的一些接近白色的部分,使其成為純白色。 其中一些可以通過關閉一些大尺寸的形態或用白色填充較小的輪廓來去除。
import cv2
import numpy as np
import skimage.exposure
# load image and get dimensions
img = cv2.imread("soccer.jpg")
# convert to hsv
hsv = cv2.cvtColor(img,cv2.COLOR_BGR2HSV)
# threshold using inRange
range1 = (20,80,80)
range2 = (90,255,255)
mask = cv2.inRange(hsv,range1,range2)
mask = 255 - mask
# apply morphology opening to mask
kernel = np.ones((3,3), np.uint8)
mask = cv2.morphologyEx(mask, cv2.MORPH_ERODE, kernel)
mask = cv2.morphologyEx(mask, cv2.MORPH_CLOSE, kernel)
# antialias mask
mask = cv2.GaussianBlur(mask, (0,0), sigmaX=3, sigmaY=3, borderType = cv2.BORDER_DEFAULT)
mask = skimage.exposure.rescale_intensity(mask, in_range=(127.5,255), out_range=(0,255))
result = img.copy()
result[mask==0] = (255,255,255)
# write result to disk
cv2.imwrite("soccer_mask.png", mask)
cv2.imwrite("soccer_green2white.jpg", result)
# display it
cv2.imshow("mask", mask)
cv2.imshow("result", result)
cv2.waitKey(0)
cv2.destroyAllWindows()
面具:
結果:
加法2:
這是我發現可以有效去除綠屏的另一種方法。 轉換為 LAB。 然后否定 A 並將其乘以 B。然后對其進行 inRange() 閾值處理以創建掩碼。 然后用面具把綠色變成白色。 它比以前的方法更好地防止襯衫中的近白色被強制為純白色。 但不幸的是留下了一點綠色。
import cv2
import numpy as np
import skimage.exposure
# load image and get dimensions
img = cv2.imread("soccer.jpg")
# convert to hsv
lab = cv2.cvtColor(img,cv2.COLOR_BGR2LAB)
L = lab[:,:,0]
A = lab[:,:,1]
B = lab[:,:,2]
# negate A
A = (255 - A)
# multiply negated A by B
nAB = 255 * (A/255) * (B/255)
nAB = np.clip((nAB), 0, 255)
nAB = np.uint8(nAB)
# threshold using inRange
range1 = 100
range2 = 160
mask = cv2.inRange(nAB,range1,range2)
mask = 255 - mask
# apply morphology opening to mask
kernel = np.ones((3,3), np.uint8)
mask = cv2.morphologyEx(mask, cv2.MORPH_ERODE, kernel)
mask = cv2.morphologyEx(mask, cv2.MORPH_CLOSE, kernel)
# antialias mask
mask = cv2.GaussianBlur(mask, (0,0), sigmaX=3, sigmaY=3, borderType = cv2.BORDER_DEFAULT)
mask = skimage.exposure.rescale_intensity(mask, in_range=(127.5,255), out_range=(0,255))
# put white where ever the mask is zero
result = img.copy()
result[mask==0] = (255,255,255)
# write result to disk
cv2.imwrite("soccer_green2white_inrange_lab.jpg", result)
# display it
cv2.imshow("nAB", nAB)
cv2.imshow("mask", mask)
cv2.imshow("result", result)
cv2.waitKey(0)
cv2.destroyAllWindows()
結果:
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