21 Nov Defining Photo Documentation Best Practice: A New USIBD Imagery Specification
What is USIBD?
Using imaging systems to document current conditions on a construction project is now standard practice. With members comprising professionals from across the US and internationally, the US Institute of Building Documentation (USIBD) is a “non-profit mutual benefit corporation dedicated to furthering excellence of building documentation by promoting, educating, guiding and supporting stakeholders with an interest in the built environment in a way that cultivates networking and information sharing.”
Building documentation takes a central role in the planning and management of any construction or building project, recognized by the co-location of the USIBD’s Annual Symposium with Building Smart’s BIMForum convention. As in the case of most user communities, the results of building documentation practices are typically specified and used by professionals who are not scanning, imagery, or survey specialists. A popular deliverable from subcommittees on the USIBD are specifications for laser scanning and imaging technology that relate to building documentation project requirements. In addition to specifying these frameworks, USIBD have also provided template documents that might be used by construction managers or asset owners to tender for building documentation services.
Following the publication last year of specifications related to describing, scanning, and modelling accuracies, USIBD are introducing this year specifications related to images captured on a construction site.
An Imagery Specification
Comprised of professionals from across the building documentation industry, the USIBD Imagery Subcommittee (which includes Photodocufy’s own Will Tompkinson) has been working over the past year on defining a framework that can be used to characterize the qualities of any type of image taken on a construction site. At the 2018 USIBD Annual Symposium, Ken VanBree of eBuilt Inc., Chair of USIBD’s Imagery Subcommittee, introduced the Imagery Specification that is due for release by the end of the year.
The Imagery Subcommittee has compiled guidelines that allow images to be categorized in terms of the minimum size of a component (or element) on the construction site that can be identified in an image, and where those images were taken. Best-practice recommendations are also being made for how those images should be indexed, managed, and delivered to the project stakeholders. This includes providing suggestions and samples of what should be included in the RFP and RFQ tender documents for photo documentation projects.
Level of Resolution and Accuracy of Pose
To characterise photographs from a technical perspective, the USIBD has defined the qualities of Level of Resolution (LoR) and Accuracy of Pose (AoP).
Click to Zoom images above. Examples of (left) establishing minimum size of components on a construction site, and (right) how a rebar component can be interpreted in an image of suitable resolution
In the case of LoR, the important factor is not the resolution of the imaging sensor, but whether specific types of objects can be resolved in the image. Of course, in addition to image resolution, this is dependent upon the distance and angle at which the image has been captured. In the Imagery Subcommittee guidance document to be published by USIBD, examples will be provided on the minimum LoR required to interpret specific component types found on a construction site.
To characterise how images across a site have been positioned, indexed, and recorded (and hence which images will show specific objects), the Subcommittee has defined the AoP specification. The way images are captured, stored, and managed varies dramatically. Sometimes images are not stored in an organized way or “dumped” in a folder, sometimes they are referenced to a floor plan, other times the position of the imaging device may have been surveyed to an onsite coordinate system.
The level of AoP will influence the quality of service in terms of extent of coverage of photographs, in addition to the type of indexing (whether to floorplan) and delivery (e.g., web-based or static files). Through specifying the level of AoP, stakeholders can award photo documentation tenders that deliver information that better matches with existing processes, IT infrastructure, and available budget.
Assisting to reduce the “blind spot” experienced by facility managers immediately following handover from the general contractor, by using LoR and AoP together, an index of images can be compiled that can be searched more efficiently in the future. Finally, the AoP helps future-proof a photo documentation image-set; this includes being able to potentially reference images to new types of reality capture or laser scanning devices that may be used on that site in the future.
The USIBD Imaging Specification and Photodocufy
The USIBD Imaging Specification is due for release by the end of 2018. When Underhill Geomatics entered the photo documentation marketplace with the Photodocufy service over 5 years ago, we were already leading the market in the types of cameras that we use, the way that we position our images, and the web delivery methods that we use to deliver to our stakeholders. Our practices already ensure that we comply with high levels of both LoR and AoP, once these specifications are formally released. Both Photodocufy and its service partners will be pleased to help you interpret how the USIBD guidelines relate to the photo documentation requirements of your next project.