Capture System & Environment
- Elliott Round
- Nathan Dunne
- Duncan Baird
Overview
Capture Systems come in many different shapes and sizes, M-XR’s goal is to work with what you already have. However, all of these different Set-Ups do have their own unique ways of working which can require slightly different considerations when approaching a scan. For these reasons, we have broken systems down into three key categories.
Single Camera; Tripod or Handheld
Systems capturing with a single camera, on top of a tripod or freehand. Either with the object stationary, or the object on a turntable.
Multi-Axis Robot controlled
Systems that are able to move a camera node around an object freely. This may also include the object moving along with the camera gantry.
Multi-Camera Node; Static, Moving or Turntable
Systems that are able to move a camera node around an object freely. This may also include the object moving along with the camera gantry.
There may be situations whereby your system does not fit into such categories. We are working hard to ensure Marso is compatible with as many systems as possible.
Please contact us at info@m-xr.com to tell us more about your specific system.
Environment
Ambient Lighting
Irrespective of which of the above systems you are working with, it is important that the environment you are shooting within is dark. This ensures that Marso is able to measure how the object is interacting with known lighting instead of any ambient light. That being said, if your flash is powerful enough that it is able to overpower ambient lighting that will suffice.
Perfect | Okay | Bad |
|---|---|---|
 Flash Off, No Ambient
|  Flash off, Minimal Ambient |  Flash Off, Strong Ambient
|
 Flash On |  Flash On |  Flash On |
Background
In addition to reducing the ambient lighting, it is also important to reduce any bounced or reflected light. This is quite easy to do by ensuring that you are shooting against black, or by avoiding too much white in your surrounding area.
Markers
Scale is highly important to Marso’s ability to deliver accurate material properties. Placing a minimum of two markers with a known distance within your environment will make the process of measuring scale later on easier. As a tip, having even more markers within the scene will generally improve the quality of photogrammetry and ensure all camera positions can be solved with minimal intervention.
If your subject is moving or on a turn table, it’s crucial for the markers to move relative to the object.
If you are using markers and a turntable, it can be helpful to add a skirt to the turntable with additional markers.
This ensures that the camera is always able to see markers even in low angles (red).
Coverage
For Marso to work properly, it is important to have good coverage. This means capturing enough perspectives of the object from directly above as well as below.
Red - Areas at the areas that cameras cannot see.
Perfect | Okay | Bad |
|---|---|---|
 Able to capture top and bottom, plenty of angles |  Able to capture top and bottom, enough angles, but more would improve results |  Able to capture top and bottom, but not enough increments |
|  Could be improved with higher-up cameras. |  Not high/low enough, even though there are a lot of cameras |
Overshooting on the rotation will not compensate for missing positions at the top and bottom.
Perfect | Bad |
|---|---|
 10 angles X 25 Rotations |  5 Angles X 50 Rotations |
It is recommended to have a spacing of no less than 12° on both axes (30 positions to do a full 360° capture), but the spacing between each axis does not have to be equal to one another - e.g.: a latitude spacing of 10° with a longitude spacing of 5° will work well. However, a latitude spacing of 50° and a longitude of 5° will not - as this is above our maximum recommended spacing.
You may be able to capture the shape of an object with fewer images using photogrammetry, but please follow the above guidance to ensure Marso can solve materials correctly.
M-XR has yet to conclude full testing on what is the lower limit of camera spacing - these numbers are based on past scans from vendors. As Marso become more robust, such requirements will become less stringent.
Framing
It is important to keep as much of the object within the frame where possible. If regions of the object are occasionally clipped out of frame due to the size or shape, that is fine. However, if all images are zoomed in on small regions of the object this will cause issues.
Perfect | Okay | Bad |
|---|---|---|
 Object is kept in the frame throughout, not too small in the frame. |  Object is kept in frame, but small
 Mostly in frame, occasional crop
|  Object not kept in the frame |
Orientation
A scan can be captured in either Landscape or Portrait, but be sure to keep the orientation as consistent as possible. If you photograph in portrait, keep the camera portrait for the duration of a scan.
For images where the camera is pointing directly down or up, the internal gyroscope may flip these images. This is not an issue as the orientation will be stored in metadata.
The orientation of the scan must be the same as the calibration image that you capture. If the calibration image is photographed in portrait, but the scan is captured in Landscape it will not work
Single Camera: Tripod of Handheld
This section is still being written, please bear with us.
Multi-Axis Robot Controlled
This section is still being written, please bear with us.
Notes :
Avoid the camera rotating on the Roll Axis
Be mindful of speed, avoid wobble
Multi-Camera Node: Static, Moving or Turntable
This section is still being written, please bear with us.
Notes :
All cameras must have the same orientation
Be mindful of speed, avoid wobble