How to Improve the Structure Sensor's Depth Coverage

“All of our sensors leave our manufacturing facility well-calibrated but a rough delivery, a drop, or other similar physical impact may create a discrepancy between the sensor’s twin IR cameras. The result is similar to if you were to cross your eyes--the sensor will not be able to converge the two IR feeds to generate full depth coverage. This phenomenon is called an IR offset.

Fortunately, this is not a physical defect of the sensor and in most cases, this can easily be fixed with a process called Stereo Image Refinement. Users in the past may have done this through CorePlayground; now this functionality can be done much more easily through Calibrator.”

-STRUCTURE by Occipital

Outline

*Do I have an IR offset?

Getting set up

Running Stereo Image Refinement

Verifying your improved depth coverage

Do I have an IR offset?

The following symptoms are associated with an IR offset:

No depth coverage

Bouncing bounding box

Instant tracking loss

Inability to capture a scan

To verify this, please follow these steps.

1) Download the Structure app.

2) Clean your sensor’s glass plate (as fingerprints and smudges can also lead to decreased depth coverage).

3) Move to a room away from sunlight and face a flat, matte, non-black wall, around 1-1.5 meters (~3-5 feet) away.

4) Launch Structure, wait for the sensor to initialize, and aim the sensor towards the wall.

5) Good depth coverage will be shown with a solid colorization across the whole screen, like this:



6) Poor depth coverage will be shown with anything less, such as this image:




If you are seeing anything less than the top image, your depth coverage can be improved. To do so, please follow the steps below.

Getting set up

1) Launch the Structure app on your iPad and verify you are running at least firmware 1.2. Wait for the sensor to initialize. Once initialized, you can check your firmware status by tapping the “i” icon in the upper right. If you have a firmware update available, you can tap the blue button to update your firmware (iPhone users will need to scroll down). This process will take several minutes.




2) Download Calibrator. Make certain the version number is at least 4.0. You can check this by either uninstalling the app and then reinstalling it from the App Store, or by going to Settings -> General -> iPad Storage -> Calibrator.

3) Clean your sensor's glass plate. Make sure the plastic film that ships with your sensor is removed. If there are any smudges, dust, or fingerprints on the glass, clean them with rubbing alcohol and a microfiber cloth. Clean the glass plate in small circles, rather than from side to side, until all oils and particles have been removed.

4) Set the scene. Stereo image refinement can only be performed indoors. Move away from any windows and find a blank wall. This wall should be neither black nor reflective. You will need to be at least 1-1.5 meters (~3-5 feet) away from the wall and ensure your sensor/iPad configuration is parallel to the wall.

Running Stereo Image Refinement

Launch Calibrator.

When prompted, connect your sensor to your iPad.

In the panel in the upper left, tap the "?" icon. This will pull up the Calibration Status pane with the option to run Stereo Image Refinement. Tap "Perform Refinement."




You will be guided through a small explanation of Stereo Image Refinement. Swipe through the tutorial.

Face a flat, featureless wall away from sunlight. Stand with the sensor perpendicular to the wall. When ready, tap "Start Refinement".




Stay still. The refinement process will finish automatically. If you are satisfied with your refinement, tap "Save Refinement". Correct alignment should be 90% coverage within the inner 70% of the map.

Verifying your improved depth coverage

At this point, it is good to double check and make sure everything has saved correctly to the sensor.


1) Connect your sensor to your iPad again using the lightning or USB-C cable.

2) Launch the Structure app, as mentioned in the “Do I have an IR offset?” section.

3) Face a flat wall, away from sunlight, and make sure your depth feed looks the same as you saw in Calibrator.

4) Start scanning!

Updated on: 11/11/2024