The Metadata Working Group's schema for image region metadata.

• Exiv2 keys are nested in the form Xmp.mwg-rs.Regions/mwg-rs:RegionList/mwg-rs:<Property>
• The schema namespace URI is http://www.metadataworkinggroup.com/schemas/regions/
• The preferred schema namespace prefix is mwg-rs

Reference: Guidelines for Handling Image Metadata

Property	Label	Value type	Exiv2 type	Category	Description
Regions	Regions	RegionInfo	XmpText	Internal	Main structure containing region based information
AppliedToDimensions	Applied To Dimensions	Dimensions	XmpText	External	Width and height of image when storing region data
RegionList	Region List	bag RegionStruct	XmpBag	External	List of Region structures
Area	Area	Area	XmpText	External	Descriptive markers of catalog items by content
Type	Type	closed Choice of Text	XmpText	External	Type purpose of region (Face|Pet|Focus|BarCode)
Name	Name	Text	XmpText	External	Name/ short description of content in image region
Description	Description	Text	XmpText	External	Usage scenario for a given focus area (EvaluatedUsed|EvaluatedNotUsed|NotEvaluatedNotUsed)
FocusUsage	Focus Usage	closed Choice of Text	XmpText	External	Descriptive markers of catalog items by content
BarCodeValue	Bar Code Value	Text	XmpText	External	Decoded BarCode value string
Extensions	Extensions	Text	XmpText	Internal	Any top level XMP property to describe the region content