Title
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IS16 Normalisation of JPEG 2000 images |
| Detailed description |
Problem: within a number digitisation projects, the KB has received JPEG 2000 images that contain features that are a potential preservation risk. Two examples:
- For one project, we have received images created by an Adobe Photoshop plugin that produces images in JPEG 2000 Part 2 (JPX) format, which contain header fields that erroneously identify these files as JPEG 2000 Part 1 (JP2). However, the colour rendering information in these files (ICC profiles) are stored in a way that is incompatible with JP2, so in a future migration to some other format the ICC profiles may be lost.
- For another project, we have received JP2 images in which the resolution information is stored in the ‘default display resolution’ fields (which are ignored by most decoders). From a preservation point of view we would like these values to be stored in the ‘capture resolution’ fields instead. For the first example, we would like to normalise the faulty JPX images to standards-compliant JP2 files, without any loss of colour information or embedded metadata. For the second example, we would simply like to change the affected header fields.
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Scalability Challenge
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Main challenge is the sheer volume of data (numer of files).
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| Issue champion |
Johan van der Knijff (KB) |
Other interested parties
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| Possible Solution approaches |
- JPX images: analyse the contents of each image (especially ICC profiles, metadata), and derive a normalised image from this (based on a user-defined encoding profile). This would probably involve reformatting the whole image, including decoding and re-compressing the image code stream.
- Resolution headers: this is a much simpler problem that could be solved by simply changing a ‘default display resolution’ header tag to ‘capture resolution’. This could be done using a simple, custom-built software tool, without any major reformatting. The use of partial checksums on the source and destination images would ensure the integrity of the newly created image (safeguard against unintentional bit corruption).
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| Context |
Details of the institutional context to the Issue. (May be expanded at a later date)
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| Lessons Learned |
Notes on Lessons Learned from tackling this Issue that might be useful to inform the development of Future Additional Best Practices, Task 8 (SCAPE TU.WP.1 Dissemination and Promotion of Best Practices)
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| Training Needs |
Is there a need for providing training for the Solution(s) associated with this Issue? Notes added here will provide guidance to the SCAPE TU.WP.3 Sustainability WP.
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| Datasets |
To be confirmed. KB could probably prepare sets of JPX images and JP2 images with problematic resolution headers
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| Solutions |
Reference to the appropriate Solution page(s), by hyperlink |