This part of ISO/IEC 12087 facilitates the interchange of digital images. For this purpose, conceptual, architectural, and functional definitions of the Image Interchange Facility (IPI-IIF) are established. ISO/IEC 12087-3 consists of two major parts, the:

• IIF data format (IIF-DF) definition (by means of a formal syntax, described according to the Abstract Syntax Notation One (ASN. 1) -- refer to clause 5), and the
• IIF Gateway definition (by means of a manual page description of the functionality of an Application Program Interface (API) -- refer to clause 7).

An IPI-IIF-conformant implementation has to fulfill the functionality specification of the IIF Gateway, as outlined in clause 7. Besides the IIF Gateway, there may be information processing systems (software such as parsers, generators, etc.) which read and/or write the IIF-DF.

The IPI-IIF is based on the definitions described in ISO/IEC 12087-1, the “Common Architecture for Imaging”. The IPI-IIF, as a whole, may be characterized briefly as follows:

• By means of the IIF data format and Gateway, image data objects and image-related data objects are transported to and from application environments.
• By means of the full PIKS profile of the IPI-IIF data format (i.e., a format for data interchange between IPI-IIF and IPI-PIKS), image data objects and image-related data objects are imported to and exported from the Programmer's Imaging Kernel System (IPI-PIKS), defined in ISO/IEC 12087-2.
• The IPI-IIF facilitates the storage of image data objects and image-related data objects in a variety of pre-defined storage modalities, including different periodicity organizations, such as pixel-interleaving or band-interleaving.
• This part of ISOiIEC 12087 defines syntax of image data (and image-related data) streams. The encoding of IIF data types is defined in ISO/IEC 12089. See also 5.3.3.
• The IPI-IIF supports a concept of standardized conformance profiles. Initially, three conformance profiles are defined within ISO/IEC 12087.
• An IIF data stream may be stored in devices such as file systems. An IIF data stream may beinterchanged and communicated in data networks (e.g., LANs and WANs) or in other data communication facilities. All low-level data storage and transfer is delegated, for instance, to the operating system of the target hardware.
• The IIF Gateway performs compression and decompression of image data objects using standardized compression and decompression techniques. These techniques are referenced in this part of ISO/IEC 12087. See 1.45 and 5.3.3 and 7.5 for further definition.
• The IIF Gateway is accessible via an API to perform image interchange functions. See clause 7 for a definition of IIF Gateway functionality.

Reference shall be made to this part of ISO/IEC 12087, and its definitions shall be employed, whenever images are interchanged, according to the IPI-IIF, among different imaging applications environments or among imaging devices. The IPI-IIF is applicable to scenarios requiring the interchange of digital images, as outlined in Annex C.

The use of the IIF data format as a superset of the functionality of most of the existing image interchange formats solves the problem of application-independent syntactical and semantical interpretation and understanding of image data.

The IPI-IIF is applicable to image interchange in and among different application domains. The following application areas have been considered:

• Medical imaging
• Remote sensing
• Publishing
• Industrial vision
• Computer graphics arts
• Computer animation
• Scientific visualization
• Mission planning
• Document processing
• Outdoor scene surveillance

The limiting of the IPI-IIF scope to certain application domains is a matter of profiling. This is treated in clause 6.