EXIF & Embedded Image Metadata

[Andrew Hankinson]

Hi all,

Would there be any interest in having the embedded image metadata (EXIF or JPEG 2000 tags) in the output of an info.json request? I don't think there is a provision for accessing this kind of data now.

We have fairly extensive data about the imaging process that may be useful to display along with our images. I've included a snippet from one of our images below to show some of the image data we have, and certain things (like the capture resolution and capture description with the kit and lighting used) would be useful to retrieve from a remote server.

-Andrew

File Size : 48 MB
File Type : JPX
File Type Extension : jpx
MIME Type : image/jpx
Major Brand : JPEG 2000 with extensions (.JPX)
Minor Version : 0.0.0
Compatible Brands : jpx , jp2 , jpxb
Image Height : 5865
Image Width : 6247
Number Of Components : 3
Bits Per Component : 8 Bits, Unsigned
Compression : JPEG 2000
Color Spec Method : Enumerated
Color Spec Precedence : 0
Color Spec Approximation : Not Specified
Color Space : sRGB
Capture Y Resolution : 208.6614
Capture X Resolution : 208.6614
Capture Y Resolution Unit : cm
Capture X Resolution Unit : cm
XMP Toolkit : XMP toolkit 2.8.2-33, framework 1.5
Description : City.WELLS.Archive.Wells Cathedral Library.Source X4/34/2.Folio recto.Photographer.Julia Craig-McFeely.Date of capture.07/02/2001.Capture device.PhaseOne PowerPhase on medium format Fuji GX680III professional body.light source.reflective/fluorescent.lighting.4 x daylight balanced LARN Softscan high frequency 110W non-dimmable heads.light source distance (cm).70.file format.TIFF.compression ratio.none.compression type.none.scanner mode.24 bit colour.pixel resolution.7000 x 7000.scan resolution.600 dpi.colour space.RGB.colour management.not applied.film curve.Linear response/standard Capture Conditions.software.Phase One 3.1.1.scan settings.custom.orientation..colour correction.Off.focus.manual.cropping.none.rotation..contrast.none.brightness.none.filter.not applied.unsharp mask.none.white point.6500.Gamma 1.8.
Application Record Version : 2
Image Size : 6247x5865
Megapixels : 36.6

[Tom Crane]

Hi Andrew,

Such information is an ideal use case for a service linked to from the info.json

http://iiif.io/api/annex/services/

I wonder if anyone on this list is already publishing more detailed image metadata this way and if so, do they have an example of exif data expressed in JSON-LD?

Tom

[Stern, Randy]

A quick question. I have never seen that web page before.  How would I  know that it exists – should it be a link from http://iiif.io/api/?

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[Jon Stroop]

Randy,
That page is linked from at least the image and presentation specs:

http://iiif.io/api/presentation/2.0/#linking-properties (under service)

http://iiif.io/api/image/2.0/#image-information (in the table next to service)

That said, a link from the API page (similar to the link to Notes) might be a good idea.

-Jon

[Jon Stroop]

I can see a practical use for this, but it's worth noting that the info.json describes a service, not an image--there's no notion of a source image in IIIF because there could be multiple static files driving the service, or the pixels could be vector data drawn on the fly. As such, this information would not fit in the info.json.

[Robert Sanderson]

As Tom says, a good use of service if there's a need to include a lot of external data.

There is an RDF version of the exif schema that could be useful:  https://www.w3.org/2003/12/exif/#vocabulary

That said, I wonder what the value of all the fields would be, beyond what's already available in info.json?

* Height, Width, Image Size, Megapixels are either all there, of trivially derived.

* Capture resolution is available as a service:  http://iiif.io/api/annex/services/#physical-dimensions

* Color space and format are kind of there in quality and format, though not as granular, and are about the capabilities of the service, rather than a specific representation.

* File information is relative to the source image, rather than the images made available via the API.

* We have an open issue for a future version about compression.

Rob

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Rob Sanderson

Information Standards Advocate

Digital Library Systems and Services

Stanford, CA 94305

[Glen Barnes]

On Tuesday, 1 March 2016 05:58:38 UTC+13, Rob Sanderson wrote:

As Tom says, a good use of service if there's a need to include a lot of external data.

There is an RDF version of the exif schema that could be useful:  https://www.w3.org/2003/12/exif/#vocabulary

And Schema.org - https://schema.org/ImageObject has an EXIF field.

[Matt McGrattan]

Andrew,

For what it's worth, when we ingest images into our repository we break out the XMP data from the source tiff into a sidecar XML file, so it'd be pretty easy to create a service that delivered that data (or Exif) as JSON. It might be worth exploring the use case.

Matt