Huron format

Format

single-file pyramidal tiled TIFF with non-standard metadata

File extensions

.tif

OpenSlide vendor backend

huron

Detection

Huron slides are stored in single-file TIFF format. OpenSlide will detect a file as Huron if:

1. The file is TIFF.
2. The initial image is tiled.
3. The ImageMake tag starts with Huron.

Relevant TIFF tags

Tag	Description
ImageDescription	Stores some important key-value pairs, see below
ImageMake	Starts with Huron
NewSubfileType	1 for the label associated image, 9 for the macro associated image
XResolution, YResolution, ResolutionUnit	The pixel size in pyramid level 0

Extra data stored in ImageDescription

The ImageDescription tag of the first TIFF directory contains newline-delimited key-value pairs. A key-value pair is equals-delimited with extra padding spaces. These key-values are stored as properties starting with “huron.”. Currently, OpenSlide does not use any of the information present in these key-value fields.

TIFF Image Directory Organization

The directory organization follows the same pattern as the Aperio format.

Associated Images

There are up to three stripped images: a thumbnail image, which is always the second image in the file; and label and macro images at the end of the file, with subfile types 1 and 9 respectively.

label

optional, non-tiled image with subfile type 1

macro

optional, non-tiled image with subfile type 9

thumbnail

the second image in the file

Known Properties

All key-value data encoded in the ImageDescription TIFF field is represented as properties prefixed with “huron.”.

openslide.mpp-x

normalized TIFF resolution

openslide.mpp-y

normalized TIFF resolution

Test Data

https://openslide.cs.cmu.edu/download/openslide-testdata/Huron/