Getting Started - How to Use the Scanner Sample App
Scanner is a great, simple app to get started with scanning. If you've never scanned before, or you require a quick, easy, and free solution for scanning, Scanner is the app for you! We've written this article as a comprehensive guide to getting started with Scanner and your Mark II or Structure Sensor Pro.
If you require a more robust, full-featured object-scanning solution, please check out some of the apps featured here: Which apps can I use with Structure Sensor Pro and (Mark II)?
We also suggest taking a look at this video for a more visual tutorial.
- Before You Start
- Acceptable Object Sizes
- Dark/Reflective Objects
- Choosing Your Preset
- Post Processing
- Explanation of Settings
- Frequently Asked Questions
Before you start
Scanning with Scanner is fairly straightforward, but there are some things to be aware of before getting started. Please read through the following section to make sure you are aware of all the functionality of Scanner. Even if you're used to using Scanner with the original Structure Sensor, please take a moment to familiarize yourself with some of Scanner's new features.
Update your Firmware
The first thing you should do upon receiving your sensor is to make sure its firmware is up to date. We are constantly working hard to improve our hardware and software. Be sure to get the most out of your new purchase by getting everything up to date.
To update your firmware, please follow these steps:
- Download the Structure app from the App Store.
- Launch Structure and connect your sensor to your iPad.
- After the sensor initializes, tap the "i" icon in the upper right corner. If you have a firmware update available, you will be given the option to update your sensor by tapping the blue button.
Verify your depth feed
Once your sensor's firmware is updated, be sure to verify that your depth coverage is sufficient.
To test this, first, clean your sensor’s glass plate with alcohol and a microfiber cloth. Then, open the Structure app, wait for your sensor to initialize, and face a flat, featureless wall. Standing three to four feet away, please point your sensor toward the wall, ensuring you are in the “Depth” mode. Your depth feed should look something like this:
|Good Depth Coverage||Poor Depth Coverage|
If you have poor depth coverage, you can recalibrate your sensor using the instructions found here: How can I improve my sensor's depth coverage?
Calibrate your sensor.
For the best user experience, we highly recommend using the Calibrator app to calibrate your sensor's depth feed to the iPad's color feed. You will need to do this without the Wide Vision Lens. For full instructions on how to calibrate your sensor, please check out this article: Getting Started - How to Use the Calibrator App
Acceptable object sizes
It is important to know what size objects you can scan. Typically speaking, Structure Sensor (Mark II) and Structure Sensor Pro can scan objects as small as a grapefruit and as large as a medium-sized residential room.
If your objects are too small, you may need to add “tracking objects” to your scene. These are small objects that you can add to help give your scene more geometry that you will later crop out.
The jar by itself is too small and tracking cannot be maintained.
When additional items are added to the scene, the sensor is able to maintain tracking. Extra objects can be removed from the scene later via various post-processing software.
Structure Sensor Pro is an amazing piece of hardware, but it does have a few limits: namely with dark and reflective objects.
With the release of Structure SDK 1.2, we have released the "Dark Object" Streaming Preset, which allows for significantly better detection of objects that previously caused difficulty; however, this is geared less towards object scanning and more towards robotics and machine learning applications.
Structure Sensor (Mark II) and Structure Sensor Pro capture their depth by using an infrared projection pattern. The IR lasers hit the objects and return to the sensor, and the sensor calculates the depth depending on how long it takes for the light to return.
Dark objects absorb the IR pattern, creating the illusion to the sensor that the dark objects aren’t there.
For now, we suggest applying a temporary paint or powder to your objects to allow them to be scanned.
Reflective, shiny objects scatter the IR pattern, confusing the sensor. This can lead to poor tracking or random, unintended artifacts. This can be mitigated by applying different IR gains and exposure settings, switching to “Depth Only” tracking, as well as by applying a temporary matte paint or powder to your object.
Choosing your preset
Unlike the original Structure Sensor, Mark II and Structure Sensor Pro have a lot more customization available for users. Selecting the correct preset is essential for successful scanning.
This is the preset you will use most of the time. It is a good middle ground for indoor scanning. The largest limitation is that it needs to be used indoors, and its minimum focal length is slightly longer than the Body Preset.
If you are intending on scanning an arm, a foot, or any other object that requires a free-floating, groundless bounding box, choose this preset.
One of Mark II’s greatest moves forward is the ability to scan outdoors. If you intend on doing a lot of scanning in sunlight, choose this preset. We also suggest turning on IR Auto Exposure, although this may introduce more noise into the scan.
This preset can be used in both close range and long range, but it may be less accurate than either the Default preset or the Body preset.
Dark Object - Beta
This allows for significantly better detection of dark and reflective objects that previously caused difficulty; however, this is geared less towards object scanning and more towards robotics and machine learning applications. This has not been fully integrated into our SLAM systems and unexpected results may occur.
Now that you are aware of some of the presets Scanner offers, you're ready to start your first scan! Please follow these steps for maximum scanning success.
Setting your scene
To scan well, you need 360-degree access around your object.
Additionally, your object should not be too low, or too high. The perfect object is approximately waist-level, as this will give you easy access to scan both the tops and the bottoms of the object.
When viewed from above, the software has a hard time determining the ground plane and object in question. When viewed at eye level, the software can easily determine the ground plane and positions the bounding box correctly.
Look for uniform, indirect light and stay away from direct sunlight, as sunlight is high in ambient infrared and may drown out the sensor.
Starting your scan
Resize your bounding box by pinching in or pinching out. Your bounding box should be just slightly larger than your object. Too small, and parts of your object will be cut off. Too large, and you will have extremely poor resolution.
Position your object so that it is in the center of the bounding box. If you are accustomed to scanning with the original Structure Sensor, you will find that the focal length is longer with Mark II. When the majority of the object is masked in color, tap “Scan”.
Once you start your scan, move backward slightly to help your sensor maintain tracking. Move slowly around your object, stopping every ten to fifteen degrees for several seconds to allow a full-depth frame to be captured. Make sure to scan the top of your object to avoid having holes. When your object is covered entirely in white, tap “Done”.
Finishing your scan
When your scan is finished, you will see the finished mesh in three forms: depth, X-ray, and color. If you want color and texture data in your scans, you must select “color”; otherwise, your final file will only contain depth information.
If you are satisfied with your scan, tap the "share button" to open standard Apple sharing options. To save your scan to your iPad, select "Save to Files", navigate to the directory of your choosing, and tap "Save".
If you do not have this option, chances are you did not set up an email client on your iPad. To do so, please do so by checking out this article here: https://support.apple.com/en-us/HT201320
For post-processing work, including cropping, point-to-point measurements, mesh smoothing, and CAD file-compatible formats, we recommend either Blender or MeshLab.
Instructions on how to use these post processors are outside the scope of our support; however, both programs are free to download and are professional grade, with plenty of tutorials available.
Explanation of Settings
|Depth Resolution||Changes depth resolution from QVGA (320 x 240), VGA (640 x 480), and Full (1280 X 960). With higher resolution, the user introduces more data, which can become a bandwidth bottleneck. If the iPad's processor is too slow, scans may lose detail.|
|High Resolution Color||Instructs the colorizer to prioritize color keyframe capture. In situations where color is irrelevant, turn this feature off to save processing power.|
|IR Auto Exposure (Pro only)||Dynamically adjusts infrared exposure depending on the environment. Turning it on may improve capture in high-sunlight environments, but will introduce more noise into scans.|
|IR Manual Exposure (Pro only)||Gives users more finite control over infrared exposure. Exposure settings selected here will remain constant throughout the scan (as opposed to the dynamic adjustments of IR Auto Exposure). Longer exposure times are preferred in situations of low ambient infrared; shorter exposure times are preferred in situations of high ambient infrared. In most cases, this does not need to be adjusted.|
|IR Analog Gain (Pro only)||Gives users more finite control over infrared gain (sensitivity to infrared). Gain settings selected here will remain constant throughout the scan. In situations of low ambient infrared, increasing gain can improve capture. Higher gain is preferred in situations of low ambient infrared; lower gain is preferred in situations of high ambient infrared. In most cases, this does not need to be adjusted.|
|Depth Stream Preset||Changes the focal length of the sensor. Discussed in this above section.|
|SLAM Option||Changes the SLAM (simultaneous localization and mapping) system from Default (which was optimized for the original Structure Sensor) to STSLAMManager (a new, experimental SLAM system optimized for Structure Sensor (Mark II)). Switching to STSLAMManager may produce results up to 5X more accurate than the Default SLAM option, but this feature may introduce unexpected issues until we finalize its introduction. Colorizing scans will diminish its efficacy, as colorized meshes are capped at a maximum of 50,000 polygons.|
|Tracker Type||Determines the system the sensor and software used in order to maintain its position in space. Color + Depth is better, so long as the sensor has a good calibration.|
|Improved Tracker (SDK 0.8+)||A tracker type developed for the original Structure Sensor. Users may experience better results when turning off, depending on environment and object.|
|High Resolution Mesh||Instructs the software how best to map the captured depth into a model. In most cases, High Resolution Mesh should remain on.|
|Improved Mapper||A better mapper developed for the original Structure Sensor. In most cases, Improved Mapper should remain on.|
Frequently Asked Questions
Why are my scans the wrong size?
OBJ files are inherently unitless; you can assign units and scale your scans within your preferred post-processing or slicer software. Simply scale your object to the size you prefer.
Why does my bounding box jump around?
This can happen for a large variety of reasons. For the most common reasons and solutions, please check out this article: Why Do I Keep Losing Tracking?
I send my scans via email, but I never receive them. What's going on?
Likely your emails are sitting in your Outbox. You can find information on how to fix this from Apple here.
Why are my color scans losing resolution?
Colorized scans are automatically reduced to 50,000 polygons in order to save space. You can change this in the code itself. For more information and to download our Structure SDK (iOS) with the full Scanner Xcode Project, please visit our Developer Portal.
Why is this app so simple? Why don't you guys add more features?
The purpose of the Scanner SDK app is to give developers a launching point for their own apps, rather than to offer a fully robust scanning application for customers. If you wish for more full-featured apps, please check out the apps listed here.