Transforming a COCO dataset - Rekognition

Transforming a COCO dataset

Use the following Python example to transform bounding box information from a COCO format dataset into an Amazon Rekognition Custom Labels manifest file. The code uploads the created manifest file to your Amazon S3 bucket. The code also provides an AWS CLI command that you can use to upload your images.

To transform a COCO dataset (SDK)

  1. If you haven't already:

    1. Make sure you have AmazonS3FullAccess permissions. For more information, see Set up SDK permissions.

    2. Install and configure the AWS CLI and the AWS SDKs. For more information, see Step 4: Set up the AWS CLI and AWS SDKs.

  2. Use the following Python code to transform a COCO dataset. Set the following values.

    • s3_bucket – The name of the S3 bucket in which you want to store the images and Amazon Rekognition Custom Labels manifest file.

    • s3_key_path_images – The path to where you want to place the images within the S3 bucket (s3_bucket).

    • s3_key_path_manifest_file – The path to where you want to place the Custom Labels manifest file within the S3 bucket (s3_bucket).

    • local_path – The local path to where the example opens the input COCO dataset and also saves the new Custom Labels manifest file.

    • local_images_path – The local path to the images that you want to use for training.

    • coco_manifest – The input COCO dataset filename.

    • cl_manifest_file – A name for the manifest file created by the example. The file is saved at the location specified by local_path. By convention, the file has the extension .manifest, but this is not required.

    • job_name – A name for the Custom Labels job.

    import json
import os
import random
import shutil
import datetime
import botocore
import boto3
import PIL.Image as Image
import io

#S3 location for images
s3_bucket = 'bucket'
s3_key_path_manifest_file = 'path to custom labels manifest file/'
s3_key_path_images = 'path to images/'
s3_path='s3://' + s3_bucket  + '/' + s3_key_path_images
s3 = boto3.resource('s3')

#Local file information
local_path='path to input COCO dataset and output Custom Labels manifest/'
local_images_path='path to COCO images/'
coco_manifest = 'COCO dataset JSON file name'
coco_json_file = local_path + coco_manifest
job_name='Custom Labels job name'
cl_manifest_file = 'custom_labels.manifest'

label_attribute ='bounding-box'

open(local_path + cl_manifest_file, 'w').close()

# class representing a Custom Label JSON line for an image
class cl_json_line:  
    def __init__(self,job, img):  

        #Get image info. Annotations are dealt with seperately
        sizes=[]
        image_size={}
        image_size["width"] = img["width"]
        image_size["depth"] = 3
        image_size["height"] = img["height"]
        sizes.append(image_size)

        bounding_box={}
        bounding_box["annotations"] = []
        bounding_box["image_size"] = sizes

        self.__dict__["source-ref"] = s3_path + img['file_name']
        self.__dict__[job] = bounding_box

        #get metadata
        metadata = {}
        metadata['job-name'] = job_name
        metadata['class-map'] = {}
        metadata['human-annotated']='yes'
        metadata['objects'] = [] 
        date_time_obj = datetime.datetime.strptime(img['date_captured'], '%Y-%m-%d %H:%M:%S')
        metadata['creation-date']= date_time_obj.strftime('%Y-%m-%dT%H:%M:%S') 
        metadata['type']='groundtruth/object-detection'
        
        self.__dict__[job + '-metadata'] = metadata


print("Getting image, annotations, and categories from COCO file...")

with open(coco_json_file) as f:

    #Get custom label compatible info    
    js = json.load(f)
    images = js['images']
    categories = js['categories']
    annotations = js['annotations']

    print('Images: ' + str(len(images)))
    print('annotations: ' + str(len(annotations)))
    print('categories: ' + str(len (categories)))


print("Creating CL JSON lines...")
    
images_dict = {image['id']: cl_json_line(label_attribute, image) for image in images}

print('Parsing annotations...')
for annotation in annotations:

    image=images_dict[annotation['image_id']]

    cl_annotation = {}
    cl_class_map={}

    # get bounding box information
    cl_bounding_box={}
    cl_bounding_box['left'] = annotation['bbox'][0]
    cl_bounding_box['top'] = annotation['bbox'][1]
 
    cl_bounding_box['width'] = annotation['bbox'][2]
    cl_bounding_box['height'] = annotation['bbox'][3]
    cl_bounding_box['class_id'] = annotation['category_id']

    getattr(image, label_attribute)['annotations'].append(cl_bounding_box)


    for category in categories:
         if annotation['category_id'] == category['id']:
            getattr(image, label_attribute + '-metadata')['class-map'][category['id']]=category['name']
        
    
    cl_object={}
    cl_object['confidence'] = int(1)  #not currently used by Custom Labels
    getattr(image, label_attribute + '-metadata')['objects'].append(cl_object)

print('Done parsing annotations')

# Create manifest file.
print('Writing Custom Labels manifest...')

for im in images_dict.values():

    with open(local_path+cl_manifest_file, 'a+') as outfile:
            json.dump(im.__dict__,outfile)
            outfile.write('\n')
            outfile.close()

# Upload manifest file to S3 bucket.
print ('Uploading Custom Labels manifest file to S3 bucket')
print('Uploading'  + local_path + cl_manifest_file + ' to ' + s3_key_path_manifest_file)
print(s3_bucket)
s3 = boto3.resource('s3')
s3.Bucket(s3_bucket).upload_file(local_path + cl_manifest_file, s3_key_path_manifest_file + cl_manifest_file)

# Print S3 URL to manifest file,
print ('S3 URL Path to manifest file. ')
print('\033[1m s3://' + s3_bucket + '/' + s3_key_path_manifest_file + cl_manifest_file + '\033[0m') 

# Display aws s3 sync command.
print ('\nAWS CLI s3 sync command to upload your images to S3 bucket. ')
print ('\033[1m aws s3 sync ' + local_images_path + ' ' + s3_path + '\033[0m')

  3. Run the code.

  4. In the program output, note the s3 sync command. You need it in the next step.

  5. At the command prompt, run the s3 sync command. Your images are uploaded to the S3 bucket. If the command fails during upload, run it again until your local images are synchronized with the S3 bucket.

  6. In the program output, note the S3 URL path to the manifest file. You need it in the next step.

  7. Follow the instruction at Creating a dataset with a SageMaker Ground Truth manifest file (Console) to create a dataset with the uploaded manifest file. For step 8, in .manifest file location, enter the Amazon S3 URL you noted in the previous step. If you are using the AWS SDK, do Creating a dataset with a SageMaker Ground Truth manifest file (SDK).