python OpenCV GrabCut使用实例解析

# -*- coding:utf-8 -*-'''  Python: 3.5.7  opencv 3.x  在图上用鼠标左键和右键标记前景和后景即可.  如果需要重新标记图像,关闭程序重新运行.  By Ynxf http://www.zhouws.com'''import cv2import numpy as npimport timeimg_src = '../test_images/3.jpg'drawing = Falsemode = Falseclass GrabCut:  def __init__(self, t_img):    self.img = t_img    self.img_raw = img.copy()    self.img_width = img.shape[0]    self.img_height = img.shape[1]    self.scale_size = 640 * self.img_width // self.img_height    if self.img_width > 640:      self.img = cv2.resize(self.img, (640, self.scale_size), interpolation=cv2.INTER_AREA)    self.img_show = self.img.copy()    self.img_gc = self.img.copy()    self.img_gc = cv2.GaussianBlur(self.img_gc, (3, 3), 0)    self.lb_up = False    self.rb_up = False    self.lb_down = False    self.rb_down = False    self.mask = np.full(self.img.shape[:2], 2, dtype=np.uint8)    self.firt_choose = True# 鼠标的回调函数def mouse_event2(event, x, y, flags, param):  global drawing, last_point, start_point  # 左键按下：开始画图  if event == cv2.EVENT_LBUTTONDOWN:    drawing = True    last_point = (x, y)    start_point = last_point    param.lb_down = True    print('mouse lb down')  elif event == cv2.EVENT_RBUTTONDOWN:    drawing = True    last_point = (x, y)    start_point = last_point    param.rb_down = True    print('mouse rb down')  # 鼠标移动，画图  elif event == cv2.EVENT_MOUSEMOVE:    if drawing:      if param.lb_down:        cv2.line(param.img_show, last_point, (x,y), (0, 0, 255), 2, -1)        cv2.rectangle(param.mask, last_point, (x, y), 1, -1, 4)      else:        cv2.line(param.img_show, last_point, (x, y), (255, 0, 0), 2, -1)        cv2.rectangle(param.mask, last_point, (x, y), 0, -1, 4)      last_point = (x, y)  # 左键释放：结束画图  elif event == cv2.EVENT_LBUTTONUP:    drawing = False    param.lb_up = True    param.lb_down = False    cv2.line(param.img_show, last_point, (x,y), (0, 0, 255), 2, -1)    if param.firt_choose:      param.firt_choose = False    cv2.rectangle(param.mask, last_point, (x,y), 1, -1, 4)    print('mouse lb up')  elif event == cv2.EVENT_RBUTTONUP:    drawing = False    param.rb_up = True    param.rb_down = False    cv2.line(param.img_show, last_point, (x,y), (255, 0, 0), 2, -1)    if param.firt_choose:      param.firt_choose = False      param.mask = np.full(param.img.shape[:2], 3, dtype=np.uint8)    cv2.rectangle(param.mask, last_point, (x,y), 0, -1, 4)    print('mouse rb up')if __name__ == '__main__':  img = cv2.imread(img_src)  if img is None:    print('error: 图像为空')  g_img = GrabCut(img)  cv2.namedWindow('image')  # 定义鼠标的回调函数  cv2.setMouseCallback('image', mouse_event2, g_img)  while (True):    cv2.imshow('image', g_img.img_show)    if g_img.lb_up or g_img.rb_up:      g_img.lb_up = False      g_img.rb_up = False      start = time.process_time()      bgdModel = np.zeros((1, 65), np.float64)      fgdModel = np.zeros((1, 65), np.float64)      rect = (1, 1, g_img.img.shape[1], g_img.img.shape[0])      print(g_img.mask)      mask = g_img.mask      g_img.img_gc = g_img.img.copy()      cv2.grabCut(g_img.img_gc, mask, rect, bgdModel, fgdModel, 5, cv2.GC_INIT_WITH_MASK)      elapsed = (time.process_time() - start)      mask2 = np.where((mask == 2) | (mask == 0), 0, 1).astype('uint8') # 0和2做背景      g_img.img_gc = g_img.img_gc * mask2[:, :, np.newaxis] # 使用蒙板来获取前景区域      cv2.imshow('result', g_img.img_gc)      print("Time used:", elapsed)    # 按下ESC键退出    if cv2.waitKey(20) == 27:      break