Capture guide: ground-based image capture from cellular phones

by Asseti Insights

This week we're talking about the expanding use of ground-based imagery in Asseti, captured with a cellphone or mobile phone. Ground-based image data capture can be used for 3D modelling and tagging of issues.

Asseti builds a picture using geolocated image data, other site sources (such as discrete sensors or SCADA), and 3rd party data sources such as weather feeds.

Asseti is a visual platform, built around maps and models at a site level, and around visual dashboards of charts and graphs at a higher asset network level.

A-LT-dual imagery, site focus and dash focus

Above: Asseti is a graphical platform - site-level at left, and dashboard analytics shown right

Asseti and 3D models

At an asset network or site level, Asseti builds a picture using drawn map, satellite, and captured imagery. Aerial data is popular in the platform as it is captured in a resolution that lends itself to 3D modeling – most subscribers have a site foundation of 3D modelled assets.

While aerially-captured imagery has inherent advantages, ground-based data (including that from a cellphone) is just as viable in building 3D models of the built environment – so long as images have the required geolocation and time stamps, level of overlap for photogrammetric model-making, and resolution. Where a sufficiency of ground-based imagery is captured, Asseti will assess and construct a 3D model automatically.

 

Asseti and ground-based image capture for issue tagging

It is common for subscribers to create 3D structure models using aerial imagery or LiDAR, and add ground-captured images to highlight areas with issues to resolve.

In these cases, individual images or small datasets are taken by cellphone, uploaded, and tagged with an issue. The images are not always incorporated into any 3D models – this is dependent on the volume of photographs taken in the dataset. Tagged issues and associated images are used in operational issue identification, communication, maintenance and repair operations (MRO), and prioritization.

Where large datasets are captured from the ground with sufficient overlap, the images will stitch into a 3D model. Issues can be tagged in the image and model.

Detail from both circumstances feeds higher-level reporting and dashboards.

A-LT-screen with defect, ground based (in frame)Above: Ground based image and issue, uploaded and managed on a 3D modelled facility

 

Client example: facility management

Aged care network and Asseti

A network of aged care facilities is under management by a facility management (FM) services organization. There are 24 aged care facilities in this regional network.

The FM has engaged Asseti with this client. In additional to standard features which include 3D modeling and manual issue management, the FM has contracted Asseti to provide automated issue tagging.

The FM uploaded numerous existing (ie, old) aerial datasets. These datasets were sorted by their EXIF data and processed into orthographic maps for each time period. The datasets further processed 3D models – different models for each periodic dataset. The FM and aged care facilities teams can access and easily slide across those datasets to see change over time.

A new aerial dataset is captured monthly and uploaded to Asseti. Progressively, as more data is loaded or streamed in, a more sophisticated view of site change over time is being revealed.

 

Ground-based capture

The aged care facility has numerous staff members that manage direct operations – gardeners, waste collection, maintenance, reception.

Each of these team-members is empowered and requested to take photos of issues they spot, which aren’t already logged in Asseti, with their mobile phone. These images are easily uploaded to Asseti by the reception team, with the images selected and tagged with the issue. Priority, risk, and repair cost are automatically added by the Asseti algorithm.

Workflows involving staff maintenance team members and authorized contractors update repair cost and priority if necessary.

Cyclical aerial captures are supplemented by incidental issue capture, which improves site safety and improvements on the ground. With Asseti, the intelligence feeds up to the network level, so that group management can understand, report and set policy around changing circumstances in virtual real-time.

 

Ground-based cellphone image capture best-practice

This best practice guide is written for capture with cellular or mobile phone devices.

Device settings

  • Ensure location services are turned on, including for photography
  • Confirm your images capture in JPG format
    • Note that iPhones encourage use of HEIF or HEVC image file types, which are not currently supported in Asseti
  • High-resolution file sizes are recommended

 

Capture recommendations

For simple capture of an issue:

  • Take a contextual image that captures the entire location
  • Take one or more close up images of the issue, so that remote analysts can understand, diagnose and estimate repair costs

For ground-based capture to stitch into a 3D model

  • Take a lot of images with at least 70% overlap at every edge
  • Overlap of 80% will add confidence to your 3D model build
  • Capture 70%+ overlap with elements already stitched into existing model/s
  • Each point in the area captured for 3D modeling must appear in at least 5 separate images

 

The majority of Asseti Help Center guides are restricted to Asseti users (free and paid accounts). 

Asseti users can see the Help Center guide for best-practice cellphone/mobile phone image capture for issue tagging and 3D model build in the Help Center

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