python代碼——批量改變圖像尺寸

轉自

http://www.cnblogs.com/neo-T/p/6477378.html

import os, sys
import cv2

#按照指定圖像大小調整尺寸
def resize_image(image, height, width):
     top, bottom, left, right = (0, 0, 0, 0)

     #擷取圖像尺寸
     h, w, _ = image.shape

     #對于長寬不相等的圖檔，找到最長的一邊
     longest_edge = max(h, w)

     #計算短邊需要增加多上像素寬度使其與長邊等長
     if h < longest_edge:
         dh = longest_edge - h
         top = dh // 2
         bottom = dh - top
     elif w < longest_edge:
         dw = longest_edge - w
         left = dw // 2
         right = dw - left
     else:
         pass

     #RGB顔色
     BLACK = [0, 0, 0]

     #給圖像增加邊界，是圖檔長、寬等長，cv2.BORDER_CONSTANT指定邊界顔色由value指定
     constant = cv2.copyMakeBorder(image, top , bottom, left, right, cv2.BORDER_CONSTANT, value = BLACK)

     #調整圖像大小并傳回
     return cv2.resize(constant, (height, width))

def resizeImg(path_name, newpath):
     for dir_item in os.listdir(path_name):
         #從初始路徑開始疊加，合并成可識别的操作路徑
         full_path = os.path.abspath(os.path.join(path_name, dir_item))

         if os.path.isdir(full_path):    #如果是檔案夾，繼續遞歸調用
             read_path(full_path)
         else:   #檔案
             if dir_item.endswith('.jpg'):
                 image = cv2.imread(full_path)
                 image = resize_image(image, 640, 640)
                 cv2.imwrite(newpath + '/' + dir_item, image)

def main():
    # 調整圖檔大小
    f = 'J:/images/old'
    fnew = 'J:/images/new' # resize後的圖檔存儲路徑
    resizeImg(f, fnew)

if __name__ == "__main__":
    main()