VOC数据集格式转化成COCO数据集格式 |
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VOC数据集格式转化成COCO数据集格式
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VOC数据集格式转化成COCO数据集格式 一、唠叨 之前写过一篇关于coco数据集转化成VOC格式的博客COCO2VOC，最近读到CenterNet的官方代码，实现上则是将voc转化成coco数据格式，这样的操作我个人感觉很不习惯，也觉得有些奇葩，可能是每个人习惯不一样吧，我们知道有时候我们会采用labelImg标注数据，标注出来的格式就是voc，如果直接训练就可以用来训练是不是更加友好。 为了不大规模修改原始训练代码（虽然自己修改了一个版本的voc数据集就能直接训练centernet 😊）,同时也看到网上很多大佬也做了将VOC数据格式转化成COCO用于其训练，这里我自己做一个精细一点的，作为笔记。 二、转化过程 数据格式的转换实际是annotation标注文件的转化，voc的数据标注文件为以.xml结尾的文件，而且每张图片均有一个对应的同名标注文件；COCO则是将所有的标注信息写在一个json文件中。VOC数据集目录如下：
在之前的coco2voc博客中做了详细的介绍，现在直接开始转化，目标就是将Annotations中的所有标注文件中的bbox标注信息转化为json文件，根据训练集和测试集，则主要转化为四个json文件，分别是test.json、train.json、val.json和trainval.json .这里我根据ImageSets中的train.txt val.txt trainval.txt生成后三个json文件，当然也可以直接从Annotations文件夹生成。 VOC2COCO.py import xml.etree.ElementTree as ET import os import json coco = dict() coco['images'] = [] coco['type'] = 'instances' coco['annotations'] = [] coco['categories'] = [] category_set = dict() image_set = set() category_item_id = -1 image_id = 20180000000 annotation_id = 0 def addCatItem(name): global category_item_id category_item = dict() category_item['supercategory'] = 'none' category_item_id += 1 category_item['id'] = category_item_id category_item['name'] = name coco['categories'].append(category_item) category_set[name] = category_item_id return category_item_id def addImgItem(file_name, size): global image_id if file_name is None: raise Exception('Could not find filename tag in xml file.') if size['width'] is None: raise Exception('Could not find width tag in xml file.') if size['height'] is None: raise Exception('Could not find height tag in xml file.') image_id += 1 image_item = dict() image_item['id'] = image_id image_item['file_name'] = file_name image_item['width'] = size['width'] image_item['height'] = size['height'] coco['images'].append(image_item) image_set.add(file_name) return image_id def addAnnoItem(object_name, image_id, category_id, bbox): global annotation_id annotation_item = dict() annotation_item['segmentation'] = [] seg = [] # bbox[] is x,y,w,h # left_top seg.append(bbox[0]) seg.append(bbox[1]) # left_bottom seg.append(bbox[0]) seg.append(bbox[1] + bbox[3]) # right_bottom seg.append(bbox[0] + bbox[2]) seg.append(bbox[1] + bbox[3]) # right_top seg.append(bbox[0] + bbox[2]) seg.append(bbox[1]) annotation_item['segmentation'].append(seg) annotation_item['area'] = bbox[2] * bbox[3] annotation_item['iscrowd'] = 0 annotation_item['ignore'] = 0 annotation_item['image_id'] = image_id annotation_item['bbox'] = bbox annotation_item['category_id'] = category_id annotation_id += 1 annotation_item['id'] = annotation_id coco['annotations'].append(annotation_item) def _read_image_ids(image_sets_file): ids = [] with open(image_sets_file) as f: for line in f: ids.append(line.rstrip()) return ids """通过txt文件生成""" #split ='train' 'va' 'trainval' 'test' def parseXmlFiles_by_txt(data_dir,json_save_path,split='train'): print("hello") labelfile=split+".txt" image_sets_file = data_dir + "/ImageSets/Main/"+labelfile ids=_read_image_ids(image_sets_file) for _id in ids: xml_file=data_dir + f"/Annotations/{_id}.xml" bndbox = dict() size = dict() current_image_id = None current_category_id = None file_name = None size['width'] = None size['height'] = None size['depth'] = None tree = ET.parse(xml_file) root = tree.getroot() if root.tag != 'annotation': raise Exception('pascal voc xml root element should be annotation, rather than {}'.format(root.tag)) # elem is , , , for elem in root: current_parent = elem.tag current_sub = None object_name = None if elem.tag == 'folder': continue if elem.tag == 'filename': file_name = elem.text if file_name in category_set: raise Exception('file_name duplicated') # add img item only after parse tag elif current_image_id is None and file_name is not None and size['width'] is not None: if file_name not in image_set: current_image_id = addImgItem(file_name, size) print('add image with {} and {}'.format(file_name, size)) else: raise Exception('duplicated image: {}'.format(file_name)) # subelem is , , , , for subelem in elem: bndbox['xmin'] = None bndbox['xmax'] = None bndbox['ymin'] = None bndbox['ymax'] = None current_sub = subelem.tag if current_parent == 'object' and subelem.tag == 'name': object_name = subelem.text if object_name not in category_set: current_category_id = addCatItem(object_name) else: current_category_id = category_set[object_name] elif current_parent == 'size': if size[subelem.tag] is not None: raise Exception('xml structure broken at size tag.') size[subelem.tag] = int(subelem.text) # option is , , , , when subelem is for option in subelem: if current_sub == 'bndbox': if bndbox[option.tag] is not None: raise Exception('xml structure corrupted at bndbox tag.') bndbox[option.tag] = int(option.text) # only after parse the tag if bndbox['xmin'] is not None: if object_name is None: raise Exception('xml structure broken at bndbox tag') if current_image_id is None: raise Exception('xml structure broken at bndbox tag') if current_category_id is None: raise Exception('xml structure broken at bndbox tag') bbox = [] # x bbox.append(bndbox['xmin']) # y bbox.append(bndbox['ymin']) # w bbox.append(bndbox['xmax'] - bndbox['xmin']) # h bbox.append(bndbox['ymax'] - bndbox['ymin']) print('add annotation with {},{},{},{}'.format(object_name, current_image_id, current_category_id, bbox)) addAnnoItem(object_name, current_image_id, current_category_id, bbox) json.dump(coco, open(json_save_path, 'w')) """直接从xml文件夹中生成""" def parseXmlFiles(xml_path,json_save_path): for f in os.listdir(xml_path): if not f.endswith('.xml'): continue bndbox = dict() size = dict() current_image_id = None current_category_id = None file_name = None size['width'] = None size['height'] = None size['depth'] = None xml_file = os.path.join(xml_path, f) print(xml_file) tree = ET.parse(xml_file) root = tree.getroot() if root.tag != 'annotation': raise Exception('pascal voc xml root element should be annotation, rather than {}'.format(root.tag)) # elem is , , , for elem in root: current_parent = elem.tag current_sub = None object_name = None if elem.tag == 'folder': continue if elem.tag == 'filename': file_name = elem.text if file_name in category_set: raise Exception('file_name duplicated') # add img item only after parse tag elif current_image_id is None and file_name is not None and size['width'] is not None: if file_name not in image_set: current_image_id = addImgItem(file_name, size) print('add image with {} and {}'.format(file_name, size)) else: raise Exception('duplicated image: {}'.format(file_name)) # subelem is , , , , for subelem in elem: bndbox['xmin'] = None bndbox['xmax'] = None bndbox['ymin'] = None bndbox['ymax'] = None current_sub = subelem.tag if current_parent == 'object' and subelem.tag == 'name': object_name = subelem.text if object_name not in category_set: current_category_id = addCatItem(object_name) else: current_category_id = category_set[object_name] elif current_parent == 'size': if size[subelem.tag] is not None: raise Exception('xml structure broken at size tag.') size[subelem.tag] = int(subelem.text) # option is , , , , when subelem is for option in subelem: if current_sub == 'bndbox': if bndbox[option.tag] is not None: raise Exception('xml structure corrupted at bndbox tag.') bndbox[option.tag] = int(option.text) # only after parse the tag if bndbox['xmin'] is not None: if object_name is None: raise Exception('xml structure broken at bndbox tag') if current_image_id is None: raise Exception('xml structure broken at bndbox tag') if current_category_id is None: raise Exception('xml structure broken at bndbox tag') bbox = [] # x bbox.append(bndbox['xmin']) # y bbox.append(bndbox['ymin']) # w bbox.append(bndbox['xmax'] - bndbox['xmin']) # h bbox.append(bndbox['ymax'] - bndbox['ymin']) print('add annotation with {},{},{},{}'.format(object_name, current_image_id, current_category_id, bbox)) addAnnoItem(object_name, current_image_id, current_category_id, bbox) json.dump(coco, open(json_save_path, 'w')) if __name__ == '__main__': #通过txt文件生成 # voc_data_dir="E:/VOCdevkit/VOC2007" # json_save_path="E:/VOCdevkit/voc2007trainval.json" # parseXmlFiles_by_txt(voc_data_dir,json_save_path,"trainval") #通过文件夹生成 ann_path="E:/VOCdevkit/VOC2007/Annotations" json_save_path="E:/VOCdevkit/test.json" parseXmlFiles(ann_path,json_save_path)生成之后就是这样：
到此就结束了，提供两个关键函数，一个是通过txt，另一个使用过文件夹，然后就可以用于centernet训练了，或者也可以用于其他的算法数据准备。 任何程序错误，以及技术疑问或需要解答的，请添加
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