python - opencv创建圈出界

Question

我正在尝试创建一个在图像上添加随机圆的函数。该圆不应穿过图像的边界。我这样尝试过:

def create_circle(image):
  found = False
  color = (np.random.randint(low=0, high=255),
           np.random.randint(low=0, high=255),
           np.random.randint(low=0, high=255))
  while not found:
    pos = (np.random.randint(low=0, high=image.shape[1]),
           np.random.randint(low=0, high=image.shape[0]))
    rad = np.random.randint(low=0, high=image.shape[0]//2)
    if( rad +pos[0]< image.shape[0] and rad +pos[1]< image.shape[1]
       and rad -pos[0] >= 0 and rad -pos[1]>= 0):
      found = True
  cv2.circle(image,pos,rad,color,-1)    

圆圈不断脱离图像边界

Answer 1

确定所生成的位置和半径是否有效的逻辑上有一个小错误。条件

rad - pos[0] >= 0 and rad - pos[1] >= 0

相当于

rad >= pos[0] and rad >= pos[1]

仅当半径同时超过圆心的True和x坐标时，才为y。您想要相反的情况，即

pos[0] >= rad and pos[1] >= pos[1]
# or
pos[0] - rad >= 0 and pos[1] - rad >= 0

仅当圆心的True和x坐标都超过半径时，它才会评估y。