我目前正在研究从二进制图像中提取线条。我最初执行了一些图像处理步骤,包括阈值分割,并获得了以下二值图像。
从二值图像中可以看出,线条被分割或断开。我想加入虚线,如下图所示,用红色标记。我手动标记了红线以进行演示。
仅供参考,我使用以下代码来执行预处理。
img = cv2.imread('original_image.jpg') # loading image
gray_image = cv2.cvtColor(img, cv2.COLOR_BGR2GRAY) # coverting to gray scale
median_filter = cv2.medianBlur (gray_image, ksize = 5) # median filtering
th, thresh = cv2.threshold (median_filter, median_filter.mean(), 255, cv2.THRESH_BINARY) # theshold segmentation
# small dots and noise removing
nlabels, labels, stats, centroids = cv2.connectedComponentsWithStats(thresh, None, None, None, 8, cv2.CV_32S)
areas = stats[1:,cv2.CC_STAT_AREA]
result = np.zeros((labels.shape), np.uint8)
min_size = 150
for i in range(0, nlabels - 1):
if areas[i] >= min_size: #keep
result[labels == i + 1] = 255
fig, ax = plt.subplots(2,1, figsize=(30,20))
ax[0].imshow(img)
ax[0].set_title('Original image')
ax[1].imshow(cv2.cvtColor(result, cv2.COLOR_BGR2RGB))
ax[1].set_title('preprocessed image')
如果您对如何连接线路有任何建议或步骤,我将不胜感激?谢谢你
使用以下一系列方法,我能够得到一个粗略的近似值。这是一个非常简单的解决方案,可能不适用于所有情况。
1。形态学运算
要合并相邻线,请对二值图像执行形态(膨胀)操作。
img = cv2.imread('image_path', 0) # grayscale image
img1 = cv2.imread('image_path', 1) # color image
th = cv2.threshold(img, 150, 255, cv2.THRESH_BINARY)[1]
kernel = cv2.getStructuringElement(cv2.MORPH_ELLIPSE, (19, 19))
morph = cv2.morphologyEx(th, cv2.MORPH_DILATE, kernel)
2。寻找轮廓和极值点
cnts1 = cv2.findContours(morph, cv2.RETR_EXTERNAL, cv2.CHAIN_APPROX_SIMPLE)`
cnts = cnts1[0] # storing contours in a variable
让我们快速绕道看看这些极值点出现在哪里:
# visualize extreme points for each contour
for c in cnts:
left = tuple(c[c[:, :, 0].argmin()][0])
right = tuple(c[c[:, :, 0].argmax()][0])
top = tuple(c[c[:, :, 1].argmin()][0])
bottom = tuple(c[c[:, :, 1].argmax()][0])
# Draw dots onto image
cv2.circle(img1, left, 8, (0, 50, 255), -1)
cv2.circle(img1, right, 8, (0, 255, 255), -1)
cv2.circle(img1, top, 8, (255, 50, 0), -1)
cv2.circle(img1, bottom, 8, (255, 255, 0), -1)
(注意:极值点是基于形态学运算的轮廓,而是在原始图像上绘制的)
3.查找相邻轮廓之间的最近距离
抱歉,循环很多。
for i in range(len(cnts)):
min_dist = max(img.shape[0], img.shape[1])
cl = []
ci = cnts[i]
ci_left = tuple(ci[ci[:, :, 0].argmin()][0])
ci_right = tuple(ci[ci[:, :, 0].argmax()][0])
ci_top = tuple(ci[ci[:, :, 1].argmin()][0])
ci_bottom = tuple(ci[ci[:, :, 1].argmax()][0])
ci_list = [ci_bottom, ci_left, ci_right, ci_top]
for j in range(i + 1, len(cnts)):
cj = cnts[j]
cj_left = tuple(cj[cj[:, :, 0].argmin()][0])
cj_right = tuple(cj[cj[:, :, 0].argmax()][0])
cj_top = tuple(cj[cj[:, :, 1].argmin()][0])
cj_bottom = tuple(cj[cj[:, :, 1].argmax()][0])
cj_list = [cj_bottom, cj_left, cj_right, cj_top]
for pt1 in ci_list:
for pt2 in cj_list:
dist = int(np.linalg.norm(np.array(pt1) - np.array(pt2))) #dist = sqrt( (x2 - x1)**2 + (y2 - y1)**2 )
if dist < min_dist:
min_dist = dist
cl = []
cl.append([pt1, pt2, min_dist])
if len(cl) > 0:
cv2.line(img1, cl[0][0], cl[0][1], (255, 255, 255), thickness = 5)
4。后期处理
由于最终输出并不完美,可以进行额外的形态学操作,然后将其骨架化。