Sometimes the iPad camera just doesn’t cut it. Especially if you have over £1000 worth of Cannon EOS camera sitting on your desk. In this blog post we will walk you through the process of uploading and calibrating DSLR photography to provide a better quality visualisation. Here is an example of the photomontage output created from a DSLR photograph for a single building project.
There are three steps to using DSLR photography in VentusAR gallery. These are described below.
1. Setup Project
The project should be set up in the VentusAR portal as normal. A layout should created and objects defined or imported. Once complete, the layout should be validated using My View (Wireline) and Fly Through. We setup a test project at Dumglass north Glasgow which will be used to demonstrate the process.
2. Capture Photography
Before DSLR photography can be used, it must meet certain requirements. A photographer should deliver the base images for upload into the portal. They should provide:
- Photography taken on a full frame sensor camera with 50mm lens
- High resolution JPG files (not RAW) with embedded EXIF data
- The coordinates of the tripod and tripod height (in addition to the EXIF values for validation)
- If panorama’ are going to be created, a panoramic head should be used with an interval of 20°.
DSLR photographs must contain the following EXIF fields:
- Image Height and Width
- FocalLength (We actually calculate it from FocalPlaneResolutionUnit, FocalPlaneXResolution, FocalPlaneYResolution and FocalLength)
- Location (optional, see below for association with a VentusAR defined viewpoint location)
Once the project has been set up and the photography delivered, the following process can be used to create visualisations based on the DSLR photography.
1. Create Viewpoint & Upload Media
In the portal, create the viewpoints for the project using the exact coordinates that the photography was taken from – these should have been provided by the photographer or read from the EXIF data within the images.
Then from the media tab, click on the new Viewpoint Name to expand it to show all the media. Choose Manage Base Images for the new viewpoint:
- Choose Browse to select the photographs to upload
- Choose Begin Upload to start the upload process – this can take a long time if you have a lot of photos and/or a slow internet connection
All photography will be uploaded to the co-ordinates of the viewpoint. Viewpoint location will be used even if the EXIF contains a GPS location. Photography will be set as parallel to the ground and initialised to face North (due to limitations on EXIF data orientation). This can be calibrated in Step 3 in this process.
2. Download to Device
The project setup above will now be visible on your tablet device. Go to the project and enter the Gallery. The gallery will be empty as we need to Sync to download the base image. This is done by choosing Options (in the top right) then Sync All to copy all the new media from device to portal and from portal to device.
The sync process can take a long time on a slow internet connection or if there are a lot of images.
3. Calibrate each Base Image
The images we uploaded in Step 1 will be parallel to the ground and facing North, if the photographer provided the heading, this can be entered by long-tapping on the image thumbnail in the gallery and editing the heading value.
Each base image will then need to be finely calibrated to ensure that the terrain wireline exactly matches the photography. If there aren’t enough visible features to get a good match, reference structures can be used to ensure a good fit. Calibration is covered in more detail during VentusAR training.
View in the Gallery
From here they can be used as part of the single frame photomontage for a Viewpoint Pack. This is what we use when creating video montage. Or it could simply be that the users want to be confident there is minimal distortion in the lens used (the iPad camera produces some distortion around the edges of the frame due to its short focal length) or want to follow external (e.g SNH) guidance.
This process can be used to in any of our domains (wind, solar, grid or buildings). Our clients are re-using their existing photography to present digital visualisations of their development during planning and public engagement events.
Contact us at firstname.lastname@example.org to find out more about producing visualisations of developments using existing photography.