How to take pictures of an object to create a good tracking target?

+4 votes
asked Mar 11, 2016 by Alex (6,680 points)

For those having troubles with the (object) target creation process, here are some guidelines that will help you getting the best from the object tracker available in the ARMedia SDK. The guidelines specifically refer to the pictures shooting phase.

 

  1. You MUST use the ARMedia Toolset app (download it from Google Play or AppStore)
     
  2. During the shooting session do NOT move or rotate the target object, instead you MUST move
     
  3. Take pictures of ONE HALF only (front side or back side) covering an angle of almost 180 degrees. When you feel confident with the whole process you can then try to take pictures of the object even from the back (but always keep in mind that unless you really want to recognise and track the object from every point of view, then it is not required to take pictures from the back too!)
     
  4. For each shooting angle take 2 or 3 pictures at DIFFERENT ELEVATIONS
     
  5. When moving from a point of view to another, try to slightly change also the viewing direction, in other words DO NOT just ORBIT around the target object, instead try to PAN as well
     
  6. A good NUMBER of PICTURES to take is something like 32, for some objects even a lower number could work well, for others you could take more pictures but consider that the more pictures you take the longer it will take to generate a target and the longer it will take to initialize the tracker at runtime
     
  7. Once you have all the pictures taken, copy them from the Toolset app onto your computer and check that they are all SHARP and in FOCUS, if some images are blurred then delete them before uploading them on the developer portal
     
  8. If the target object's surface is not RICH in TEXTURES and FEATURES, try to put other features-rich objects all around the target object itself (like magazines for example), this will help the reconstruction process (of course you can remove the added objects later when you will use the generated target if you choose to generate the proper kind of target on the developer portal)
     
  9. When taking pictures of the target object, try to completely FRAME the OBJECT itself in such a way that it fills the capturing device's screen, but also consider that it is also recommended to take pictures from the same POINTS of VIEWS that you expect will be used by the final user of your app (the former approach will make more accurate reconstructions/pointclouds, the latter will make tracker initialization faster at runtime)
     
  10. If you use the "ARMedia Workflow" then, every time you use a NEW DEVICE to take pictures, it is strongly recommended to also take pictures of the CALIBRATION PATTERN and upload them at the beginning of the target creation wizard on the developer portal  (see below for details) - This is NOT required if you use others workflows (for instance the "Photoscan Workflow"

 

IMPORTANT: when a new target has been  generated on the developer portal, download it onto your computer, copy it onto your mobile device in the folder that is shared with the Toolset app and finally run Toolset to TEST and TUNE the new target (this approach is strongly recommended, do not try a new target directly within your Unity3D project or within your native app because other factors, related mainly to rendering, may prevent the content to be displayed even if the tracking target has been generated correctly).

 

When taking pictures of the calibration pattern, keep the following guidelines in mind:

 

  1. You DOWNLOAD the calibration pattern at the beginning of the target creation wizard on the developer portal
     
  2. You MUST PRINT the calibration pattern in such a way that the printer does NOT automatically RESIZE it or STRETCH it in any way to fit the paper sheet's size, it is important that the ORIGINAL SIZE of the calibration pattern is not changed
     
  3. You SHOULD fix the printed calibration pattern on a RIGID, FLAT surface
     
  4. You MUST use the Toolset app to take 50/60 PICTURES of the printed calibration pattern from DIFFERENT ANGLES and ORIENTATIONS
     
  5. Check that each picture is SHARP and in FOCUS and that the whole calibration pattern is always visible in its entirety
     
  6. Finally copy all the pictures from the Toolset app onto your computer and drag & drop them in the space provided at the beginning of the target creation wizard
 
NOTE: once you have provided the calibration pictures for a specific device, the calibration data associated with that device will be SAVED AUTOMATICALLY for later use, so the next time you start a new target creation process you will be able to select the calibration data from a list without the need to provide any other calibration images unless you decide to use a new device to take pictures for the new target. Remember, taking pictures for the calibration pattern is required only for new devices and only if you use the "ARMedia Workflow".

Please log in or register to answer this question.

Welcome to Developer Portal Q&A, where you can ask questions and receive answers from other members of the community.
...