I am trying to convert the white background of the input image into black using python OpenCV.But all the white pixels are not completely getting converted to black. I have attached the input and output images.
Input Image :
Output Image:
I have used the following code for conversion:
img[np.where((img==[255,255,255]).all(axis=2))] = [0,0,0];
What should I do?
I know this has already been answered. I have a coded python solution for you.
Firstly I found this thread explaining how to remove white pixels.
The Result:
Another Test img:
Edit This is a way better and shorter method. I looked into it after @ZdaR commented on looping over an images matrix.
[Updated Code]
img = cv2.imread("Images/test.pnt")
gray = cv2.cvtColor(img, cv2.COLOR_BGR2GRAY)
ret, thresh = cv2.threshold(gray, 240, 255, cv2.THRESH_BINARY)
img[thresh == 255] = 0
kernel = cv2.getStructuringElement(cv2.MORPH_ELLIPSE, (5, 5))
erosion = cv2.erode(img, kernel, iterations = 1)
cv2.namedWindow('image', cv2.WINDOW_NORMAL)
cv2.imshow("image", erosion)
cv2.waitKey(0)
cv2.destroyAllWindows()
[Old Code]
img = cv2.imread("Images/test.png")
gray = cv2.cvtColor(img, cv2.COLOR_BGR2GRAY)
ret, thresh = cv2.threshold(gray, 240, 255, cv2.THRESH_BINARY)
white_px = np.asarray([255, 255, 255])
black_px = np.asarray([0, 0, 0])
(row, col) = thresh.shape
img_array = np.array(img)
for r in range(row):
for c in range(col):
px = thresh[r][c]
if all(px == white_px):
img_array[r][c] = black_px
kernel = cv2.getStructuringElement(cv2.MORPH_ELLIPSE, (5, 5))
erosion = cv2.erode(img_array, kernel, iterations = 1)
cv2.namedWindow('image', cv2.WINDOW_NORMAL)
cv2.imshow("image", erosion)
cv2.waitKey(0)
cv2.destroyAllWindows()
Other Sources used: OpenCV Morphological Transformations
I think not all the "white" pixels in the image are [255,255,255]. Instead, make a threshold. Try [220,220,220] and above and convert them to [0, 0, 0].
