openslide · bgilbert · Jun 6, 2026 · May 31, 2026 · May 31, 2026
diff --git a/_includes/links.md b/_includes/links.md
@@ -29,6 +29,7 @@
 
 [formats]: /formats/
 [format-aperio]: /formats/aperio/
+[format-argos]: /formats/argos/
 [format-dicom]: /formats/dicom/
 [format-generic-tiff]: /formats/generic-tiff/
 [format-hamamatsu]: /formats/hamamatsu/

diff --git a/demo/_synctiles.py b/demo/_synctiles.py
@@ -72,6 +72,7 @@
 OVERLAP = 1
 LIMIT_BOUNDS = True
 GROUP_NAME_MAP = {
+    'Argos': 'ARGOS',
     'Generic-TIFF': 'Generic TIFF',
     'Hamamatsu': 'Hamamatsu NDPI',
     'Hamamatsu-vms': 'Hamamatsu VMS',

diff --git a/docs/newformat/index.md b/docs/newformat/index.md
@@ -124,6 +124,7 @@ Your driver is also responsible for setting some
 [standard properties][doc-properties], when they apply to your format:
 
 - `openslide.background-color`
+- `openslide.barcode`
 - `openslide.bounds-height` (must be an integer)
 - `openslide.bounds-width` (must be an integer)
 - `openslide.bounds-x` (must be an integer)
@@ -140,6 +141,9 @@ Your driver is also responsible for setting some
 `openslide.background-color` should be set with
 `_openslide_set_background_color_prop()`.
 
+`openslide.barcode` should be set to the decoded value of the label's
+barcode if included in the slide metadata.
+
 The `openslide.bounds-*` properties should be set for slides that omit image
 data along an entire edge of level 0.  Drivers that use a single grid per
 level can set these properties with

diff --git a/docs/properties/index.md b/docs/properties/index.md
@@ -15,6 +15,9 @@ redirect_from:
 : The background color of the slide, given as an RGB hex triplet. This property
  is not always present.
 
+`openslide.barcode`
+: The contents of the slide's barcode. This property is not always present.
+
 `openslide.bounds-height`
 : The height of the rectangle bounding the non-empty region of the slide.
 This property is not always present.

diff --git a/formats/argos/index.md b/formats/argos/index.md
@@ -0,0 +1,93 @@
+---
+title: ARGOS format
+permalink: /formats/argos/
+---
+
+Format
+: single-file pyramidal tiled BigTIFF with non-standard metadata
+
+File extensions
+: `.avs`
+
+OpenSlide vendor backend
+: `argos`
+
+
+## Vendor Documentation
+
+[Documentation PDF](https://github.com/user-attachments/files/15580286/ARGOS.AVS.File.Format.pdf)
+
+
+## Detection
+
+ARGOS slides are stored in single-file BigTIFF format.  OpenSlide will detect
+a file as ARGOS if:
+
+ 1. The file is TIFF.
+ 2. The initial image is tiled.
+ 3. Tag 65000 contains valid XML whose root element is  `Argos.Scan.Metadata`.
+
+
+## Relevant TIFF tags
+
+Tag                 | Description                    |
+--------------------|--------------------------------|
+65000               | Metadata XML                   |
+
+
+## Metadata XML
+
+The first TIFF directory includes metadata XML in TIFF tag 65000.  The
+field type is ASCII, but in our samples the value is not NUL-terminated
+as required by TIFF, causing libtiff to warn about it.
+
+Value               | Description                    |
+--------------------|--------------------------------|
+`MaxZ`              | Integer identifier for highest focal plane |
+`MinZ`              | Integer identifier for lowest focal plane |
+`ScanArea`          | Coordinates of scanned portion of the slide (cm) |
+`ZRange`            | Distance between outermost focal planes (μm) |
+
+
+## TIFF Image Directory Organization
+
+The TIFF file contains the image pyramid of the lowest focal plane,
+followed by each higher plane in succession.  Images are sparse, with
+missing tiles represented by a zero `TileOffset` and a zero `TileByteCount`.
+
+The last two TIFF directories are the thumbnail and macro images, which are
+both stripped.
+
+
+## Associated Images
+
+`thumbnail`
+: second-to-last image in the file, non-tiled
+
+`macro`
+: last image in the file, non-tiled
+
+
+## Known Properties
+
+All simple key-value data encoded in the metadata XML is represented as
+properties prefixed with "`argos.`".
+
+`openslide.barcode`
+: `argos.Barcode`
+
+`openslide.mpp-x`
+: calculated as `10000/tiff.XResolution`, if `tiff.ResolutionUnit` is
+`centimeter`
+
+`openslide.mpp-y`
+: calculated as `10000/tiff.YResolution`, if `tiff.ResolutionUnit` is
+`centimeter`
+
+`openslide.objective-power`
+: normalized `argos.ObjectiveMagnification`
+
+
+## Test Data
+
+<https://openslide.cs.cmu.edu/download/openslide-testdata/Argos/>
diff --git a/formats/dicom/index.md b/formats/dicom/index.md
@@ -84,6 +84,9 @@ _ICC Profile_ of the associated image.
 Many DICOM attributes are represented hierarchically as properties prefixed
 with "`dicom.`".
 
+`openslide.barcode`
+: _Barcode Value_ from highest-resolution level
+
 `openslide.mpp-x`
 : normalized X component of _Pixel Spacing_ from highest-resolution level
 

diff --git a/formats/index.md b/formats/index.md
@@ -26,6 +26,20 @@ More info
 : [Aperio format][format-aperio]
 
 
+## ARGOS
+
+Single-file pyramidal tiled BigTIFF with non-standard metadata.
+
+File extensions
+: `.avs`
+
+OpenSlide vendor backend
+: `argos`
+
+More info
+: [ARGOS format][format-argos]
+
+
 ## DICOM
 
 International standard multi-file medical imaging format.

diff --git a/formats/leica/index.md b/formats/leica/index.md
@@ -104,6 +104,9 @@ OpenSlide mailing list.)*
 `leica.objective`
 : the `objective` of the main image
 
+`openslide.barcode`
+: `leica.barcode`
+
 `openslide.mpp-x`
 : calculated as `10000/tiff.XResolution`, if `tiff.ResolutionUnit` is
 `centimeter`

diff --git a/formats/philips/index.md b/formats/philips/index.md
@@ -84,6 +84,9 @@ All key-value data encoded in the `DPUfsImport` object, in the first
 object's `PixelDataRepresentation` objects is represented as properties
 prefixed with "`philips.`".
 
+`openslide.barcode`
+: Base64-decoded `philips.PIM_DP_UFS_BARCODE`
+
 `openslide.mpp-x`
 : calculated as `1000 * philips.DICOM_PIXEL_SPACING[1]`
 

diff --git a/formats/zeiss/index.md b/formats/zeiss/index.md
@@ -100,6 +100,11 @@ properties prefixed with "`zeiss.`".  The available properties are those
 from the `AttachmentInfos`, `DisplaySetting`, `Information`, and `Scaling`
 elements of `ImageDocument.Metadata`.
 
+`openslide.barcode`
+: the value of the property matching
+  `zeiss.AttachmentInfos.*.Label.Barcodes.*.Content` that occurs earliest
+  in the XML metadata
+
 `openslide.mpp-x`
 : calculated as 1000000 times `zeiss.Scaling.Items.X.Value`
 

diff --git a/index.md b/index.md
@@ -44,6 +44,7 @@ terms of the [GNU Lesser General Public License, version 2.1][license].
 The library can read virtual slides in the following formats:
 
  * [Aperio (.svs, .tif)][format-aperio]
+ * [ARGOS (.avs)][format-argos]
  * [DICOM (.dcm)][format-dicom]
  * [Hamamatsu (.vms, .vmu, .ndpi)][format-hamamatsu]
  * [Huron (.tif)][format-huron]