OME-TIFF extension

[kylebarron]

OME-TIFF is a microscopy extension for TIFF. I don't know microscopy data at all, but I'd love to support others to build support around async-tiff. Broader use of async-tiff could ensure the stability of the library.

I'm assuming that, similar to GeoTIFF, OME-TIFF defines a set of extension tags, and implementing support for OME-TIFF means implementing a parser for the tag data.

The groundwork for this would probably be in #100, so that Geo and OME TIFF could be defined as extension points rather than being tied to the core implementation of the library.

If anyone is interested in working on this, please comment and I'll try to finish #100

[kylebarron]

cc @weiji14 too for awareness since I think you've tested async-tiff on some files already

[weiji14]

I'm assuming that, similar to GeoTIFF, OME-TIFF defines a set of extension tags, and implementing support for OME-TIFF means implementing a parser for the tag data.

Not quite. OME-TIFF stores its metadata as an XML in the ImageDescription tag (see example at #101 (comment)). Full spec is at https://ome-model.readthedocs.io/en/stable/ome-tiff/specification.html#ome-xml-metadata

So I don't think the extension tags issue #100 is relevant, unless you want a way to parse the OME-XML into more standard TIFF or EXIF tags somehow?

[kylebarron]

So I don't think the extension tags issue #100 is relevant, unless you want a way to parse the OME-XML into more standard TIFF or EXIF tags somehow?

I was thinking that an OME-TIFF extension could inject code for parsing the metadata into strongly-typed structs that clarify how to access the underlying metadata. Kinda like how GeoKeyDirectory works:

async-tiff/src/geo/geo_key_directory.rs

Lines 69 to 80 in 780fc48

	/// Metadata defined by the GeoTIFF standard.
	///
	/// <http://docs.opengeospatial.org/is/19-008r4/19-008r4.html#_requirements_class_geokeydirectorytag>
	#[derive(Debug, Clone, PartialEq)]
	pub struct GeoKeyDirectory {
	pub model_type: Option<u16>,
	pub raster_type: Option<u16>,
	pub citation: Option<String>,
	pub geographic_type: Option<u16>,
	pub geog_citation: Option<String>,
	pub geog_geodetic_datum: Option<u16>,