Earlier in 2020, widely used browsers like Chrome and Firefox changed their default behavior for rotating images based on image metadata, referred to as EXIF data. Previously, images always displayed in browsers exactly how they’re stored on disk, which is typically unrotated. After the change, images now rotate according to a piece of image metadata called orientation value. This has important implications for the entire machine learning (ML) community. For example, if the EXIF orientation isn’t considered, applications that you use to annotate images may display images in unexpected orientations and result in confusing or incorrect labels.
For example, before the change, by default images would display in the orientation stored on the device, as shown in the following image. After the change, by default, images display according to the orientation value in EXIF data, as shown in the second image.
Here, the image was stored in portrait mode, with EXIF data attached to indicate it should be displayed with a landscape orientation.
To ensure images are predictably oriented, ML annotation services need to be able to view image EXIF data. The recent change to global web standards requires you to grant explicit permission to image annotation services to view your image EXIF data.
To guarantee data consistency between workers and across datasets, the annotation tools used by Amazon SageMaker Ground Truth, Amazon Augmented AI (Amazon A2I), and Amazon Mechanical Turk need to understand and control orientations of input images that are shown to workers. Therefore, from January 12, 2021, onward, AWS requires that you add a cross-origin resource sharing (CORS) header configuration to Amazon Simple Storage Service (Amazon S3) buckets that contain labeling job or human review task input data. This policy allows these AWS services to view EXIF data and verify that images are predictably oriented in labeling and human review tasks.
This post provides details on the image metadata change, how it can impact labeling jobs and human review tasks, and how you can update your S3 buckets with these new, required permissions.
What is EXIF data?
EXIF data is metadata that tells us things about the image. EXIF data typically includes the height and width of an image but can also include things like the date a photo was taken, what kind of camera was used, and even GPS coordinates where the image was captured. For the image annotation web application community, the orientation property of EXIF is about to become very important.
When you take a photo, whether it’s landscape or portrait, the data is written to storage in the landscape orientation. Instead of storing a portrait photo in the portrait orientation, the camera writes a piece of metadata to the image to
Source - Continue Reading: https://aws.amazon.com/blogs/machine-learning/how-an-important-change-in-web-standards-impacts-your-image-annotation-jobs/