需求：
数据集的数据增强中，有时需要用到图像水平翻转的操作，图像水平翻转后，对应的xml标注文件也需要做坐标的调整。
解决方法：
使用python+opencv+import xml.etree.ElementTree对图像水平翻转和xml标注文件坐标调整。代码如下：
import cv2
import os
import glob
import xml.etree.ElementTree as etdef flip_images(source_dir):images_list = glob.glob(os.path.join(source_dir, "*.jpg"))index = 0for image_path in images_list:image = cv2.imread(image_path)flip_image = cv2.flip(image,1)cv2.imwrite(image_path.replace(".jpg", "_flip.jpg"), flip_image)tree_ = et.ElementTree()tree_.parse(image_path.replace(".jpg", ".xml"))root = et.Element("annotation")folder = et.SubElement(root, "folder")folder.text = "images"filename = et.SubElement(root, "filename")filename.text = tree_.find(".//filename").text.replace(".jpg", "_flip.jpg")path = et.SubElement(root, "path")path.text = "/home/mapgoo/test"source = et.SubElement(root, "source")database = et.SubElement(source, "database")database.text = "Unknown"size = et.SubElement(root, "size")width = et.SubElement(size, "width")width.text = tree_.find(".//width").textheight = et.SubElement(size, "height")height.text = tree_.find(".//height").textdepth = et.SubElement(size, "depth")depth.text = "3"segmented = et.SubElement(root, "segmented")segmented.text = "0"for bndbox in tree_.findall(".//object"):xmin = bndbox.find(".//xmin")ymin = bndbox.find(".//ymin")xmax = bndbox.find(".//xmax")ymax = bndbox.find(".//ymax")xmin_text = xmin.textymin_text = ymin.textxmax_text = xmax.textymax_text = ymax.textobject_ = et.SubElement(root, "object")name = et.SubElement(object_, "name")name.text = bndbox.find("name").textpose = et.SubElement(object_, "pose")pose.text = "Unspecified"truncated = et.SubElement(object_, "truncated")truncated.text = "0"difficult = et.SubElement(object_, "difficult")difficult.text = "0"bndbox = et.SubElement(object_, "bndbox")xmin = et.SubElement(bndbox, "xmin")xmin.text = str(image.shape[1] - int(xmax_text))ymin = et.SubElement(bndbox, "ymin")ymin.text = ymin_textxmax = et.SubElement(bndbox, "xmax")xmax.text = str(image.shape[1] - int(xmin_text))ymax = et.SubElement(bndbox, "ymax")ymax.text = ymax_texttree = et.ElementTree(root)tree.write(image_path.replace(".jpg", "_flip.xml"), encoding="utf-8")print(image_path, index)index += 1if __name__ == '__main__':source_dir = "/home/Desktop/test"flip_images(source_dir)
使用以上代码需要修改原图像和标注文件所在文件夹路径（source_dir）。亲测可用。
