Python經典案例之影象漫水填充分割詳解

floodFill(image, mask, seedPoint, newVal[, loDiff[, upDiff[, flags]]])

src(seed.x, seed.y) - loDiff <= src(x, y) <= src(seed.x, seed.y) +upDiff

# -*- coding: utf-8 -*-
# By: Eastmount
import cv2
import numpy as np

#讀取原始影象
img = cv2.imread('windows.png')

#獲取影象行和列
rows, cols = img.shape[:2]

#目標影象
dst = img.copy()

#mask必須行和列都加2且必須為uint8單通道陣列
#mask多出來的2可以保證掃描的邊界上的畫素都會被處理
mask = np.zeros([rows+2, cols+2], np.uint8)  

#影象漫水填充處理
#種子點位置(30,30) 設定顏色(0,255,255) 連通區範圍設定loDiff upDiff
#src(seed.x, seed.y) - loDiff <= src(x, y) <= src(seed.x, seed.y) +upDiff
cv2.floodFill(dst, mask, (30, 30), (0, 255, 255),
              (100, 100, 100), (50, 50, 50),
              cv2.FLOODFILL_FIXED_RANGE)

#顯示影象
cv2.imshow('src', img)
cv2.imshow('dst', dst)
cv2.waitKey()
cv2.destroyAllWindows()

# coding:utf-8
import cv2
import random
import sys
import numpy as np

#使用說明 點選滑鼠選擇種子點
help_message = '''USAGE: floodfill.py [<image>]
Click on the image to set seed point
Keys:
  f - toggle floating range
  c - toggle 4/8 connectivity
  ESC - exit
'''
 
if __name__ == '__main__':

    #輸出提示文字
    print(help_message)

    #讀取原始影象
    img = cv2.imread('scenery.png')

    #獲取影象高和寬
    h, w = img.shape[:2]

    #設定掩碼 長和寬都比輸入影象多兩個畫素點 
    mask = np.zeros((h+2, w+2), np.uint8)

    #設定種子節點和4鄰接
    seed_pt = None
    fixed_range = True
    connectivity = 4 

    #影象漫水填充分割更新函數
    def update(dummy=None):
        if seed_pt is None:
            cv2.imshow('floodfill', img)
            return
        
        #建立影象副本並漫水填充
        flooded = img.copy()
        mask[:] = 0 #掩碼初始為全0
        lo = cv2.getTrackbarPos('lo', 'floodfill') #畫素鄰域負差最大值
        hi = cv2.getTrackbarPos('hi', 'floodfill') #畫素鄰域正差最大值
        print('lo=', lo, 'hi=', hi)

        #低位位元包含連通值 4 (預設) 或 8
        flags = connectivity
        
        #考慮當前畫素與種子畫素之間的差（高位元也可以為0）
        if fixed_range:
            flags |= cv2.FLOODFILL_FIXED_RANGE
            
        #以白色進行漫水填充
        cv2.floodFill(flooded, mask, seed_pt,
                      (random.randint(0,255), random.randint(0,255),
                       random.randint(0,255)), (lo,)*3, (hi,)*3, flags)

        #選定基準點用紅色圓點標出
        cv2.circle(flooded, seed_pt, 2, (0, 0, 255), -1)
        print("send_pt=", seed_pt)

        #顯示影象
        cv2.imshow('floodfill', flooded)

    #滑鼠響應函數
    def onmouse(event, x, y, flags, param):
        global seed_pt #基準點

        #滑鼠左鍵響應選擇漫水填充基準點
        if flags & cv2.EVENT_FLAG_LBUTTON:
            seed_pt = x, y
            update()

    #執行影象漫水填充分割更新操作
    update()
    
    #滑鼠更新操作
    cv2.setMouseCallback('floodfill', onmouse)

    #設定進度條
    cv2.createTrackbar('lo', 'floodfill', 20, 255, update)
    cv2.createTrackbar('hi', 'floodfill', 20, 255, update)

    #按鍵響應操作
    while True:
        ch = 0xFF & cv2.waitKey()
        #退出
        if ch == 27:
            break
        #選定時flags的高位位元位0
        #鄰域的選定為當前畫素與相鄰畫素的差, 聯通區域會很大
        if ch == ord('f'):
            fixed_range = not fixed_range 
            print('using %s range' % ('floating', 'fixed')[fixed_range])
            update()
        #選擇4方向或則8方向種子擴散
        if ch == ord('c'):
            connectivity = 12-connectivity 
            print('connectivity =', connectivity)
            update()
    cv2.destroyAllWindows()