问什么标签格式在标签中有负的Bbox值？

EN

import cv2
import pandas as pd 
df = pd.read_csv('train.csv')

directory = 'dataset/images'

color = (255, 0, 0)
thickness = 2
org = (50, 50)
fontScale = 1
font = cv2.FONT_HERSHEY_SIMPLEX

for i in df.index:
  image_path = df.iloc[i]['image_path']
  xmax = int(df.iloc[i]['xmax'])
  xmin = int(df.iloc[i]['xmin'])
  ymax = int(df.iloc[i]['ymax'])
  ymin = int(df.iloc[i]['ymin'])
  txt = df.iloc[i]['name']

  x= xmax - xmin
  y = ymax - ymin 
  start_point = (xmin,ymin)
  end_point = (xmax,ymax)

  img = cv2.imread(directory+ '/'+image_path)


  image = cv2.putText(img, txt, org, font, 
               fontScale, color, thickness, cv2.LINE_AA)

  bbox_img = cv2.rectangle(image, start_point, end_point, color, thickness)

  cv2.imshow('image window', bbox_img)
  # add wait key. window waits until user presses a key
  cv2.waitKey(0)
  # and finally destroy/close all open windows
  cv2.destroyAllWindows()