将背景颜色更改为黑色 [英] Change the background color to black

问题描述

我想将此背景更改为原始黑色.此背景不是纯黑色.它的值包含1、2或3.使用以下代码后，我得到的背景值非常接近黑色，但不是黑色.尽管背景看起来是黑色的

I want to change this background into the original black. This background is not pure black. Its values contain 1, 2 or 3. After using the following code I got the background value very near to black but not black. Although the background looks black

img = cv2.imread("images.bmp")

gray = cv2.cvtColor(img, cv2.COLOR_BGR2GRAY)

ret, thresh = cv2.threshold(gray, 0, 255, cv2. THRESH_BINARY)

img[thresh == 5] = 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()

推荐答案

尝试替换以下内容:

ret, thresh = cv2.threshold(gray, 0, 255, cv2. THRESH_BINARY)

img[thresh == 5] = 0

与此:

# threshold to 10% of the maximum
threshold = 0.10 * np.max(img)
img[gray <= threshold] = 0

问题在于cv2.threshold()不会为您计算阈值，而是应用一个阈值，例如，代码中的thresh已经是阈值图像.

The issue is that cv2.threshold() does not compute a threshold for you, but applies one and, for example, thresh in your code is already the thresholded image.

(已编辑)

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