open photogrammetry format (OPF) - a standard for photogrammetry?
Pix4D has announced they are launching a new open-source file format for photogrammetry workflows. Called Open Photogrammetry Format (OPF), this file format aims to ensure compatibility across a variety of software and allow easier collaboration and sharing of photogrammetry data. This may be exciting news for the developing integration of 3D modelling in the cultural heritage space.
Currently, within the photogrammetry world, there is a large range of file formats, most of which are proprietary systems created to work with specific software. Proprietary systems cause a multitude of issues, especially within the heritage sector where the preservation of data is of the utmost importance, these issues include:
Compatibility: as the files are created to work with specific software, they are limited to that software. Opening the files becomes impossible when trying to work within another software environment, and can even become difficult within the same software when trying to open a newer file in an older version of the same software. People are forced to rely on potentially sub-standard conversion software, which removes information or upgrade their software just to open old files they may have created.
Accessibility: companies often move on from older ways of doing things or just stop existing, and thus stop supporting formats and software. This can leave people in the lurch, especially in heritage, effectively destroying the data collected as it can no longer be accessed in modern software. Archiving the data does not matter as it is essentially destroyed, without a big rescue effort.
Dependency: proprietary formats can also force users into dependency on a single vendor, making competition in pricing and development decrease. Think of the Office suite, Adobe products or ESRI, they are getting more much expensive while changing very little of their core functionality, because people are dependent and have very few actual competitors.
Cost: proprietary formats force consumers' hands into purchasing subscriptions or specific software to open, edit or share files. This often limits the ability of a technique such as photogrammetry, as the purchasing cost of multiple packages is usually a deterrent.
Licensing and legal concerns: Proprietary file formats are typically protected by intellectual property laws and licenses. This can restrict users from reverse-engineering or creating alternative implementations of the format, limiting innovation and competition. It can also lead to legal complications if users try to circumvent these restrictions or use the formats in ways not explicitly permitted by the license terms.
So, will OPF assist the cultural heritage sector remove many of the fears when considering photogrammetry based on the above factors?
OPF aims to create “a flexible and extensible format that stores all of the data related to a reconstructed 3D model made with photogrammetry. This data includes information on both inputs and outputs of the photogrammetry process”
This means all data relating to the photogrammetry process will be stored within the files, that will be open and accessible to all. Ensuring that software updates won’t render your model useless, old data can easily be preserved and replicated and we won’t have to rely on a single supplier to ensure our data is compatible with each other. It will also allow for the generation of a standard format, which will ensure that models are compatible with a wide array of software and can easily be integrated into users’ preferred workflows. The hope is that this format can then be easily integrated into other workflows. For example, automatically feeding the model into a machine learning algorithm to automatically detect the type of stone tool, reconstruct an entire plate from a shard, detect the best places to excavate from a landscape model or automatically translate an inscription.
It is an important step forward for the photogrammetry space, creating a open-source standard format will encourage a lot of collaboration and development. However, it remains to be seen if the format will be taken up by these large companies that designed the proprietary software in the first place. It is also a cause for concern when one of these large companies has a controlling stake in the development of the format, as it is not completely controlled by the community. The format may then be at-risk from the higher-ups within the company deciding to limit this format to their own software in the future, to ensure they hold a controlling stake in the industry. It is definitely something to think about, as the intentions of Pix4D may not be as wholesome as they are presenting. At least we can see what’s under the hood, and data can be preserved without a huge reverse-engineering attempt. It is a good first step and we may see a community-driven open-source standard format appear in the near future. Will photogrammetry take up a standard format? For cultural heritage in general, I hope it does! A standard open-source format should do a lot to allay the fears many cultural heritage professionals have related to the shelf life of 3D modelling.
Information on the format can be found here: https://www.pix4d.com/labs/opf-open-photogrammetry-format/
The GitHub can be found here: https://github.com/Pix4D/opf-spec
One of the roadblocks for photogrammetry in cultural heritage
A closed box
