cropImages.py

"""
Crops the images in subfolders of current directory according to annotations in 'Annotation' Folder and places then in 'Cropped'
Instructions: 
	1.In an empty directory, store this script and all the folders containing the images that will be processed
	2.In the same directory, add the \Annotation\ folder, containing a respective folder for each one in the directory, which in turn contain the annotation files
	3.run python cropImages.py
	4.Output will be in \Cropped\
"""
import os
from PIL import Image
import xml.etree.ElementTree as ET
import sys

def get_immediate_subdirectories(a_dir):
    return [name for name in os.listdir(a_dir)
            if os.path.isdir(os.path.join(a_dir, name))]


rootdir = os.getcwd()
CroppedFolder = "Cropped"
Annotation = "Annotation"
if not os.path.exists(CroppedFolder):
    os.makedirs(CroppedFolder)
    print 'Created "/Cropped/" directory'

for directory in get_immediate_subdirectories(rootdir):	#loop over all dirs
		if directory != CroppedFolder and directory != Annotation:
			print "Processing Directory: " + directory
			if not os.path.exists(os.path.join(CroppedFolder, directory)):
    				print 'Created "/Cropped/' + directory + '" directory'
    				os.makedirs(os.path.join(CroppedFolder, directory))
			for filename in os.listdir(directory):
				basename =  os.path.splitext(filename)[0]
				try:
					file = open ( os.path.join( Annotation, directory, basename))
					root = ET.fromstring(file.read())
					file.close()
					xmin = int (root.find('object').find('bndbox').find('xmin').text)
					ymin = int (root.find('object').find('bndbox').find('ymin').text)
					xmax = int (root.find('object').find('bndbox').find('xmax').text)
					ymax = int (root.find('object').find('bndbox').find('ymax').text)
					img =  Image.open( os.path.join(directory, filename) )
					cropped = img.crop((xmin, ymin, xmax, ymax))
					save_file = open (os.path.join(CroppedFolder, directory, filename), 'w')
					cropped.save(os.path.join(CroppedFolder, directory, filename), "JPEG")
					save_file.close()


				except Exception, e:
					print "Exception encountered at basename " + basename + " with path as " +  os.path.join( Annotation, directory, basename) 
					print "Unexpected error:", str(e)