python如何实现图像外边界跟踪？本篇文章小编给大家分享一下python实现图像外边界跟踪代码示例，小编觉得挺不错的，现在分享给大家供大家参考，有需要的小伙伴们可以来看看。

share一些python实现的code

#!/usr/bin/env python

#coding=utf-8

import cv2

img = cv2.imread("trace_border2.bmp")

[img_h, img_w, img_channel] = img.shape

trace = []

start_x = 0

start_y = 0

gray = img[:,:,1]

for h in range(img_h):

for w in range(img_w):

if (gray[h,w] > 128):

gray[h,w] = 255

else:

gray[h,w] = 0

#python 跳出多重循环

#https://www.cnblogs.com/xiaojiayu/p/5195316.html

class getoutofloop(Exception): pass

try:

for h in range(img_h - 2):

for w in range(img_w - 2):

if gray[h,w] == 0:

start_x = w

start_y = h

raise getoutofloop

except getoutofloop:

pass

print("Start Point (%d %d)"%(start_x, start_y))

trace.append([start_x, start_y])

# 8邻域 顺时针方向搜索

neighbor = [[-1,-1],[0,-1],[1,-1],[1,0],[1,1],[0,1],[-1,1],[-1,0]]

neighbor_len = len(neighbor)

#先从当前点的左上方开始，

# 如果左上方也是黑点(边界点)：

# 搜索方向逆时针旋转90 i-=2

# 否则：

# 搜索方向顺时针旋转45 i+=1

i = 0

cur_x = start_x + neighbor[i][0]

cur_y = start_y + neighbor[i][1]

is_contour_point = 0

try:

while not ((cur_x == start_x) and (cur_y == start_y)):

is_contour_point = 0

while is_contour_point == 0:

#neighbor_x = cur_x +

if gray[cur_y, cur_x] == 0:

is_contour_point = 1

trace.append([cur_x, cur_y])

i -= 2

if i < 0:

i += neighbor_len

else:

i += 1

if i >= neighbor_len:

i -= neighbor_len

#print(i)

cur_x = cur_x + neighbor[i][0]

cur_y = cur_y + neighbor[i][1]

except:

print("throw error")

for i in range(len(trace)-1):

cv2.line(img,(trace[i][0],trace[i][1]), (trace[i+1][0], trace[i+1][1]),(0,0,255),3)

cv2.imshow("img", img)

cv2.waitKey(10)

cv2.rectangle(img,(start_x, start_y),(start_x + 20, start_y + 20),(255,0,0),2)

cv2.imshow("img", img)

cv2.waitKey(0)

cv2.destroyWindow("img")

搜索过程，红色标记线如下：