For your volumetric capture, depth camera calibration is the key. In other words, you need to combine the pointclouds into one view. It’s very hard to do by hand and that’s where EF EVE™ VolCapp auto calibration comes in very handy.
Calibration Window
When you open your Calibration tab 3D view, your pointclouds should look messy, because your cameras are not calibrated with global coordinate system yet. It should look similar to this:
You can see the X, Y, Z axes and the views from your cameras are in random positions. The point of Calibration is to connect those two 2D views into one 3D view, so let’s get started.
You can control your view in this window with your mouse:
- Rotate – left click and drag
- Zoom in / zoom out – scroll wheel
- Drag – click scroll wheel and drag
On your Calibration menu (at the right), you will see your auto calibration toolset (image below):
If you don’t have a business license, you will only see an option for Manual Scene Calibration.
Auto Calibration
Firstly, you need to calibrate your master camera with the global coordinate system in order to have your volumetric videos stand nicely on the ground. To do do that, follow the steps below:
- Open a 2D view and place a single calibration marker on the ground in the center of the capture stage.
Make sure marker’s shoreline is parallel with capture stage shoreline.
- After the marker is placed, open your 3D view in the Calibration tab:
Master camera calibration
- To begin Master camera calibration press Start on Single Marker Calibration tool:
As calibration takes place you will notice a green progress bar next to Sensor 1 (Master).
The Master camera pointcloud will make an automatic transition. The center of the marker will align with the center of the global coordinate system (0;0).
Well done! The next step is to align Slave Camera pointcloud with the Master using Slave Calibration tool.
Slave camera calibration
To begin Slave camera pointcloud calibration press Start on Slave Calibration tool.
As calibration takes place you will notice a green progress bar next to both sensors:
The Slave camera pointcloud will make an automatic transition and align with the master camera pointcloud.
At this time you have two pointclouds calibrated with the global coordinate system at a medium precision. As you want to have a high precision calibration lets use the Bounding Box Presets and Multi Marker Calibration.
Bounding Box Calibration
Bounding Box feature helps to select the capture stage and eliminate the unwanted data. We have created Bounding Box Presets to simplify the selection process as you are able to quickly change between different dimensions of the stage.
- Scroll down to the Bounding Box Calibration section
- Press Enable Bounding Box checkbox.
- Press + to expand functions.
For a 1m x 1m Capture Stage we recommend a MINI size Bounding Box preset.
Each Preset have dimensions next to it. Example: MINI 0.1 is 1.4 meters on 1.4 meters square and 2.3 meters in elevation from the ground (there is an additional 10 centimeters below the ground). This can be adjusted with sliders later on. As of now it will help to have the floor as a reference.
