import xml.etree.ElementTree as ET

def parse_annotation(ann_dir, labels=None):

    all_imgs = []

    seen_labels = {}

    img = {'object': []}

    tree = ET.parse(ann_dir)

    for elem in tree.iter():

        if 'width' in elem.tag:

            img['width'] = int(elem.text)

        if 'height' in elem.tag:

            img['height'] = int(elem.text)

        if 'object' in elem.tag or 'part' in elem.tag:

            obj = {}

            for attr in list(elem):

                if 'name' in attr.tag:

                    obj['name'] = attr.text

                    if obj['name'] in seen_labels:

                        seen_labels[obj['name']] += 1

                    else:

                        seen_labels[obj['name']] = 1

                    if len(labels) > 0 and obj['name'] not in labels:

                        break

                    else:

                        img['object'] += [obj]

                if 'bndbox' in attr.tag:

                    for dim in list(attr):

                        if 'xmin' in dim.tag:

                            obj['xmin'] = int(round(float(dim.text)))

                        if 'ymin' in dim.tag:

                            obj['ymin'] = int(round(float(dim.text)))

                        if 'xmax' in dim.tag:

                            obj['xmax'] = int(round(float(dim.text)))

                        if 'ymax' in dim.tag:

                            obj['ymax'] = int(round(float(dim.text)))

    if len(img['object']) > 0:

        all_imgs += [img]

    return all_imgs, seen_labels