Adopting the JPEG systems layer to create interoperable imaging ecosystems

Abstract

JPEG Systems aims to lay the groundwork to build uniform applications and extensions on top of the various JPEG coding standards. In 1992 JPEG released the first JPEG standard which is still the most commonly used image file format to date. However, over the years, JPEG developed several other standards that became popular in specific domains. JPEG 2000 for example is widely adopted in medical imaging, digital cinema and geographical information systems. The original JPEG file format supported extensions by using app marker segments. These app marker segments allow to embed chunks of data in an image file. The content will be ignored if it is not recognized by the decoder. Hence, it allows to build extensions while retaining backwards compatibility with legacy decoders. JPEG 2000 and several other newer formats on the other hand use box-based formats. Boxes are containers of data with a specific type that allow more flexibility with respect to length and structure compared to marker segments. Again, if the decoder doesn't recognize the particular box type the content will be ignored. JPEG XT defines extensions to the legacy JPEG file format such as transparency, HDR support and a lossless mode. To this end, JPEG XT introduced a file format which allows embedding boxes in app marker segments. Using this principle, new extensions can be uniformly defined across the various JPEG file formats, i.e. by defining boxes. Therefore, JPEG Systems defines tools and extensions by the definition of boxes. The JPEG Universal Metadata Box Format (JUMBF) allows embedding any type of metadata in any type of JPEG image file and supports the possibility to reference this data from within or outside this image. Using this structure, JPEG Privacy and Security, 360 and JLINK define mechanisms to support privacy and security tools, 360 images and linked images respectively. This paper gives an overview of the JPEG Systems architecture and illustrates its working by introducing JPEG 360 and the recently initiated activity JLINK.