python - 如何清理这张图片(opencv-python)？

Question

我对opencv真的很陌生。如何在不丢失信息的情况下消除背景噪音？
我是从这个开始的:Otsu 对它进行了阈值化。我试过腐 eclipse 、膨胀、双边过滤。我的目标是在边界上得到一个矩形，这样我就可以透视变换阈值图片，但它很难找到轮廓。或者也许有不同的更好的方法？

Answer 1

这是在 Python/OpenCV 中执行此操作的一种方法。

阅读输入

模糊它

转换为HSV并提取饱和 channel

阈值饱和图像

用形态关闭和打开清理它并保存为掩码

重新创建您的 OTSU 阈值图像

将黑色写入掩码为黑色(零)的 OTSU 图像

为了比较，将黑色写入掩码为黑色(零)的输入图像

保存结果

输入:

import cv2
import numpy as np

# read image
img = cv2.imread('circuit_board.jpg')

# blur
blur = cv2.GaussianBlur(img, (3,3), 0)

# convert to hsv and get saturation channel
sat = cv2.cvtColor(blur, cv2.COLOR_BGR2HSV)[:,:,1]

# threshold saturation channel
thresh = cv2.threshold(sat, 50, 255, cv2.THRESH_BINARY)[1]

# apply morphology close and open to make mask
kernel = cv2.getStructuringElement(cv2.MORPH_ELLIPSE, (9,9))
morph = cv2.morphologyEx(thresh, cv2.MORPH_CLOSE, kernel, iterations=1)
mask = cv2.morphologyEx(morph, cv2.MORPH_OPEN, kernel, iterations=1)

# do OTSU threshold to get circuit image
gray = cv2.cvtColor(img, cv2.COLOR_BGR2GRAY)
otsu = cv2.threshold(gray, 0, 255, cv2.THRESH_BINARY+cv2.THRESH_OTSU)[1]

# write black to otsu image where mask is black
otsu_result = otsu.copy()
otsu_result[mask==0] = 0

# write black to input image where mask is black
img_result = img.copy()
img_result[mask==0] = 0

# write result to disk
cv2.imwrite("circuit_board_mask.png", mask)
cv2.imwrite("circuit_board_otsu.png", otsu)
cv2.imwrite("circuit_board_otsu_result.png", otsu_result)
cv2.imwrite("circuit_board_img_result.png", img_result)


# display it
cv2.imshow("IMAGE", img)
cv2.imshow("SAT", sat)
cv2.imshow("MASK", mask)
cv2.imshow("OTSU", otsu)
cv2.imshow("OTSU_RESULT", otsu_result)
cv2.imshow("IMAGE_RESULT", img_result)
cv2.waitKey(0)

蒙版图片:



OTSU 阈值图像:



大通结果:



图像结果: