Convert yolo coordinates to VOC format

yolo_to_voc.py

# Script to convert yolo annotations to voc format

# Sample format
# <annotation>
#     <folder>_image_fashion</folder>
#     <filename>brooke-cagle-39574.jpg</filename>
#     <size>
#         <width>1200</width>
#         <height>800</height>
#         <depth>3</depth>
#     </size>
#     <segmented>0</segmented>
#     <object>
#         <name>head</name>
#         <pose>Unspecified</pose>
#         <truncated>0</truncated>
#         <difficult>0</difficult>
#         <bndbox>
#             <xmin>549</xmin>
#             <ymin>251</ymin>
#             <xmax>625</xmax>
#             <ymax>335</ymax>
#         </bndbox>
#     </object>
# <annotation>
import os
import xml.etree.cElementTree as ET
from PIL import Image

ANNOTATIONS_DIR_PREFIX = "annotations"

DESTINATION_DIR = "converted_labels"

CLASS_MAPPING = {
    '0': 'name'
    # Add your remaining classes here.
}


def create_root(file_prefix, width, height):
    root = ET.Element("annotations")
    ET.SubElement(root, "filename").text = "{}.jpg".format(file_prefix)
    ET.SubElement(root, "folder").text = "images"
    size = ET.SubElement(root, "size")
    ET.SubElement(size, "width").text = str(width)
    ET.SubElement(size, "height").text = str(height)
    ET.SubElement(size, "depth").text = "3"
    return root


def create_object_annotation(root, voc_labels):
    for voc_label in voc_labels:
        obj = ET.SubElement(root, "object")
        ET.SubElement(obj, "name").text = voc_label[0]
        ET.SubElement(obj, "pose").text = "Unspecified"
        ET.SubElement(obj, "truncated").text = str(0)
        ET.SubElement(obj, "difficult").text = str(0)
        bbox = ET.SubElement(obj, "bndbox")
        ET.SubElement(bbox, "xmin").text = str(voc_label[1])
        ET.SubElement(bbox, "ymin").text = str(voc_label[2])
        ET.SubElement(bbox, "xmax").text = str(voc_label[3])
        ET.SubElement(bbox, "ymax").text = str(voc_label[4])
    return root


def create_file(file_prefix, width, height, voc_labels):
    root = create_root(file_prefix, width, height)
    root = create_object_annotation(root, voc_labels)
    tree = ET.ElementTree(root)
    tree.write("{}/{}.xml".format(DESTINATION_DIR, file_prefix))


def read_file(file_path):
    file_prefix = file_path.split(".txt")[0]
    image_file_name = "{}.jpg".format(file_prefix)
    img = Image.open("{}/{}".format("images", image_file_name))
    w, h = img.size
    with open(file_path, 'r') as file:
        lines = file.readlines()
        voc_labels = []
        for line in lines:
            voc = []
            line = line.strip()
            data = line.split()
            voc.append(CLASS_MAPPING.get(data[0]))
            bbox_width = float(data[3]) * w
            bbox_height = float(data[4]) * h
            center_x = float(data[1]) * w
            center_y = float(data[2]) * h
            voc.append(center_x - (bbox_width / 2))
            voc.append(center_y - (bbox_height / 2))
            voc.append(center_x + (bbox_width / 2))
            voc.append(center_y + (bbox_height / 2))
            voc_labels.append(voc)
        create_file(file_prefix, w, h, voc_labels)
    print("Processing complete for file: {}".format(file_path))


def start(dir_name):
    if not os.path.exists(DESTINATION_DIR):
        os.makedirs(DESTINATION_DIR)
    for filename in os.listdir(ANNOTATIONS_DIR_PREFIX):
        if filename.endswith('txt'):
            read_file(filename)
        else:
            print("Skipping file: {}".format(filename))


if __name__ == "__main__":
    start()

You need to create annotation for that. Don't create bounding box. Just annotate it as no object. And it will save that as an XML

…

On Mon, Apr 13, 2020, 13:46 QuandoSJ ***@***.***> wrote: ***@***.**** commented on this gist. ------------------------------ Yes Even if the class/object you want is not present in the image. You need XML which has the annotation for no object. Regards, Usman Khalid Mian, 20100061. … <#m_5070020001616353865_> Thank you！ But the code in this repo does not generate xml for non-object image. where it ignored YOLO empty txt file, which represents the non-object images. Is there any way to fix this issue? — You are receiving this because you commented. Reply to this email directly, view it on GitHub <https://gist.github.com/7ca514458d24af980669b8b1c8bcdafd#gistcomment-3252178>, or unsubscribe <https://github.com/notifications/unsubscribe-auth/AL2CTUY4RI4EPWIRECWGY6LRMLGOXANCNFSM4IRCUUAQ> .

You need to create annotation for that. Don't create bounding box. Just annotate it as no object. And it will save that as an XML
…

Thank you! I guess I did not phrase my question well, I have already created a yolo label for images without object, and the label file is an empty file, but the code here will omit cases when the txt file is empty, so what should I save in label.txt for yolo label when there is no object so that this code will work and transfer to an empty xml file?

You need to create annotation for that. Don't create bounding box. Just annotate it as no object. And it will save that as an XML
…

Thank you! I guess I did not phrase my question well, I have already created a yolo label for images without object, and the label file is an empty file, but the code here will omit cases when the txt file is empty, so what should I save in label.txt for yolo label when there is no object so that this code will work and transfer to an empty xml file?

A useful tip:

• Make sure that you have all your images in a folder name images in the same directory where you execute this script

I would like to suggest one edit on line #78
Change
with open(file_path, 'r') as file:
To
with open(os.path.join(ANNOTATIONS_DIR_PREFIX,file_path), 'r') as file:

Otherwise script generates an error, as it tries to read the filename (label .txt file) without complete path.

Absolutely right. Congratulations. Code is working with this plugin. Also, it is mandatory to use a round in voc.append calculation. XML does not accept comma numbers. labeling map is not available with this reason. If;
voc.append (round (center_x - (bbox_width / 2)))
             voc.append (round (center_y - (bbox_height / 2)))
             voc.append (round (center_x + (bbox_width / 2)))
             voc.append (round (center_y + (bbox_height / 2)))

If you use the form, your data will be easily tagged.

full working of code. thanks @goodhamgupta

import os
import xml.etree.cElementTree as ET
from PIL import Image

ANNOTATIONS_DIR_PREFIX = "data"

DESTINATION_DIR = "converted_labels"

CLASS_MAPPING = {
    '0': 'name'
    # Add your remaining classes here.
}


def create_root(file_prefix, width, height):
    root = ET.Element("annotation")
    ET.SubElement(root, "folder").text = "converted_labels"
    ET.SubElement(root, "filename").text = "{}.jpg".format(file_prefix)
    ET.SubElement(root, "path").text = "D:\PycharmProjects\convert\converted_labels\{}.jpg".format(file_prefix)
    source = ET.SubElement(root, "source")
    ET.SubElement(source, "database").text = "Unknown"
    size = ET.SubElement(root, "size")
    ET.SubElement(size, "width").text = str(width)
    ET.SubElement(size, "height").text = str(height)
    ET.SubElement(size, "depth").text = "3"
    ET.SubElement(root, "segmented").text = "0"
    return root


def create_object_annotation(root, voc_labels):
    for voc_label in voc_labels:
        obj = ET.SubElement(root, "object")
        ET.SubElement(obj, "name").text=str(voc_label[0])
        ET.SubElement(obj, "pose").text = "Unspecified"
        ET.SubElement(obj, "truncated").text = str(0)
        ET.SubElement(obj, "difficult").text = str(0)
        bbox = ET.SubElement(obj, "bndbox")
        ET.SubElement(bbox, "xmin").text = str(voc_label[1])
        ET.SubElement(bbox, "ymin").text = str(voc_label[2])
        ET.SubElement(bbox, "xmax").text = str(voc_label[3])
        ET.SubElement(bbox, "ymax").text = str(voc_label[4])
    return root


def create_file(file_prefix, width, height, voc_labels):
    root = create_root(file_prefix, width, height)
    root = create_object_annotation(root, voc_labels)
    tree = ET.ElementTree(root)
    tree.write("{}/{}.xml".format(DESTINATION_DIR, file_prefix))


def read_file(file_path):
    file_prefix = file_path.split(".txt")[0]
    image_file_name = "{}.jpg".format(file_prefix)
    img = Image.open("{}/{}".format("data", image_file_name))
    w, h = img.size
    with open(os.path.join(ANNOTATIONS_DIR_PREFIX,file_path), 'r') as file:
        lines = file.readlines()
        voc_labels = []
        for line in lines:
            voc = []
            line = line.strip()
            data = line.split()
            CLASS_MAPPING.get(data[0])
            a = int(data[0])
            if  a == 0:
                voc.append("al")
            else:
                voc.append("sat")
            bbox_width = float(data[3]) * w
            bbox_height = float(data[4]) * h
            center_x = float(data[1]) * w
            center_y = float(data[2]) * h
            voc.append(round(center_x - (bbox_width / 2)))
            voc.append(round(center_y - (bbox_height / 2)))
            voc.append(round(center_x + (bbox_width / 2)))
            voc.append(round(center_y + (bbox_height / 2)))
            voc_labels.append(voc)
        create_file(file_prefix, w, h, voc_labels)
    print("Processing complete for file: {}".format(file_path))


def start():
    if not os.path.exists(DESTINATION_DIR):
        os.makedirs(DESTINATION_DIR)
    for filename in os.listdir(ANNOTATIONS_DIR_PREFIX):
        if filename.endswith('txt'):
            read_file(filename)
        else:
            print("Skipping file: {}".format(filename))


if __name__ == "__main__":
    start()

Thanks @goodhamgupta @mjahanifar

hello. Just change the Annotations_dir_prefix and DESTINATION_DIR files and your code will run perfectly given that YOU HAVE THE ANNOTATIONS AND IMAGES IN THE SAME FOLDER.

`import os
import xml.etree.cElementTree as ET
from PIL import Image

ANNOTATIONS_DIR_PREFIX = "C:/Users/Murtaza Kazmi/Folder/"

DESTINATION_DIR = "C:/Users/Murtaza Kazmi/Corrected_Annotations_to_XML/"

CLASS_MAPPING = {
'0': '0',
'1':'1',
'2': '2',
'3': '3',
'4': '4',
'5': '5',
'6':'6',
'7':'7',
'8':'8',
'9':'9',
# Add your remaining classes here.
}

def create_root(file_prefix, width, height):
root = ET.Element("annotations")
ET.SubElement(root, "filename").text = "{}.jpg".format(file_prefix)
ET.SubElement(root, "folder").text = "images"
size = ET.SubElement(root, "size")
ET.SubElement(size, "width").text = str(width)
ET.SubElement(size, "height").text = str(height)
ET.SubElement(size, "depth").text = "3"
return root

def create_object_annotation(root, voc_labels):
for voc_label in voc_labels:
obj = ET.SubElement(root, "object")
ET.SubElement(obj, "name").text = voc_label[0]
ET.SubElement(obj, "pose").text = "Unspecified"
ET.SubElement(obj, "truncated").text = str(0)
ET.SubElement(obj, "difficult").text = str(0)
bbox = ET.SubElement(obj, "bndbox")
ET.SubElement(bbox, "xmin").text = str(voc_label[1])
ET.SubElement(bbox, "ymin").text = str(voc_label[2])
ET.SubElement(bbox, "xmax").text = str(voc_label[3])
ET.SubElement(bbox, "ymax").text = str(voc_label[4])
return root

def create_file(file_prefix, width, height, voc_labels):
root = create_root(file_prefix, width, height)
root = create_object_annotation(root, voc_labels)
tree = ET.ElementTree(root)
tree.write("{}/{}.xml".format(DESTINATION_DIR, file_prefix))

def read_file(file_path):
file_prefix = file_path.split(".txt")[0]
image_file_name = "{}.jpg".format(file_prefix)
img = Image.open(image_file_name)
w, h = img.size
print(file_path, '101')
with open(ANNOTATIONS_DIR_PREFIX + file_path, 'r') as file:
lines = file.readlines()
voc_labels = []
for line in lines:
voc = []
line = line.strip()
data = line.split()
voc.append(CLASS_MAPPING.get(data[0]))
bbox_width = float(data[3]) * w
bbox_height = float(data[4]) * h
center_x = float(data[1]) * w
center_y = float(data[2]) * h
voc.append(center_x - (bbox_width / 2))
voc.append(center_y - (bbox_height / 2))
voc.append(center_x + (bbox_width / 2))
voc.append(center_y + (bbox_height / 2))
voc_labels.append(voc)
create_file(file_prefix, w, h, voc_labels)
print("Processing complete for file: {}".format(file_path))

def start():
if not os.path.exists(DESTINATION_DIR):
os.makedirs(DESTINATION_DIR)
for filename in os.listdir(ANNOTATIONS_DIR_PREFIX):
if filename.endswith('txt'):
read_file(filename)
else:
print("Skipping file: {}".format(filename))

if name == "main":
start()
`

this code works

import os
from xml.dom import minidom
import xml.etree.cElementTree as ET
from PIL import Image

ANNOTATIONS_DIR_PREFIX = "path to your yolo annotations"

DESTINATION_DIR = "output path"

CLASS_MAPPING = {
    '1': 'Char'
}

def formatter(elem):
    """Return a pretty-printed XML string for the Element.
    """
    rough_string = ET.tostring(elem, 'utf-8')
    reparsed = minidom.parseString(rough_string)
    return reparsed.toprettyxml(indent="    ")

def create_root(file_prefix, width, height):
    root = ET.Element("annotation")
    ET.SubElement(root, "filename").text = "{}.jpg".format(file_prefix)
    size = ET.SubElement(root, "size")
    ET.SubElement(size, "width").text = str(width)
    ET.SubElement(size, "height").text = str(height)
    ET.SubElement(size, "depth").text = "3"
    return root


def create_object_annotation(root, voc_labels):
    for voc_label in voc_labels:
        obj = ET.SubElement(root, "object")
        ET.SubElement(obj, "name").text = voc_label[0]
        bbox = ET.SubElement(obj, "bndbox")
        ET.SubElement(bbox, "xmin").text = str(voc_label[1])
        ET.SubElement(bbox, "ymin").text = str(voc_label[2])
        ET.SubElement(bbox, "xmax").text = str(voc_label[3])
        ET.SubElement(bbox, "ymax").text = str(voc_label[4])
    return root


def create_file(file_prefix, width, height, voc_labels):
    root = create_root(file_prefix, width, height)
    root = create_object_annotation(root, voc_labels)
    with open("{}/{}.xml".format(DESTINATION_DIR, file_prefix), "w") as f:

            f.write(formatter(root))
            f.close()

def read_file(file_path):
    file_prefix = file_path.split(".txt")[0]
    image_file_name = "{}.jpg".format(file_prefix)
    img = Image.open("{}/{}".format("sites", image_file_name))
    w, h = img.size
    with open("labels/"+file_path, 'r') as file:
        lines = file.readlines()
        voc_labels = []
        for line in lines:
            voc = []
            line = line.strip()
            data = line.split()
            voc.append(CLASS_MAPPING.get(data[0]))
            bbox_width = float(data[3]) * w
            bbox_height = float(data[4]) * h
            center_x = float(data[1]) * w
            center_y = float(data[2]) * h
            voc.append(round(center_x - (bbox_width / 2)))
            voc.append(round(center_y - (bbox_height / 2)))
            voc.append(round(center_x + (bbox_width / 2)))
            voc.append(round(center_y + (bbox_height / 2)))
            voc_labels.append(voc)
        create_file(file_prefix, w, h, voc_labels)


def start():
    if not os.path.exists(DESTINATION_DIR):
        os.makedirs(DESTINATION_DIR)
    for filename in os.listdir(ANNOTATIONS_DIR_PREFIX):
        if filename.endswith('txt'):
            read_file(filename)
        else:
            print("Skipping file: {}".format(filename))


if __name__ == "__main__":
    start()