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Trigger Images Explained

What is a Trigger Image?

Trigger Images are the real world images or (flat sided) objects you want HP Reveal to be able to recognise in order to deliver an AR experience on your mobile device. You can upload Trigger Images to your Studio account where they will automatically be trained by our Studio to be recognised by our technology.

What specifications do Trigger Images need to meet to be uploaded and recognised successfully?

A Trigger Image needs to be:

• A JPEG or PNG file
• Less than 500,000 pixels in size (width x height) when uploaded to your account (we usually stick to 512 pix on the shortest side)

What makes for a strong, easily recognisable Trigger Image?

Using a good Trigger is the most crucial step in creating a great HP Reveal experience. You can have the most amazing video content or 3D animations, but without a dependable Trigger Image, the performance of the Aura will be negatively affected. Therefore, if you want to be a Trigger expert, it is important to distinguish between Triggering and Tracking.

A good Trigger Image will result in an Aura which activates quickly – if it is good enough, it is even possible for the camera to find the Trigger without being fully in focus.

Once the image has been recognised, it is important that the Overlays track smoothly. This means that they don’t wobble whilst the content is playing.

Qualities for good Trigger Images are:

  • Tonal variation and contrast
  • Unique shapes and forms
  • Lots of detail across the entire image 

Triggering

Considerations that need to be made so that the image is quickly recognised by the HP Reveal technology

Things to Consider

  • Tonal variation and contrast

  • Distinguishable shapes across the image

  • Matte finished print in order to avoid glare or reflections

  • In cases where users will be far away from the image when trying to trigger, images should be printed as large as possible – this is because images should take up at least 20% of the view of the camera

  • Position images against a background so that the camera can easily focus

  • Flat 3D objects with the image uploaded to Studio taken in a neutral light

Things to Avoid

  • Very dark images with no tonal variation
  • Glossy print can cause images to look different with lighting conditions
  • Positioning printed trigger images against a background in the real world where the elements of the image are no longer distinguishable
  • Uploading high-res images as triggers to the Studio (will take longer to recognise)
  • Trying to trigger from very small images, or being too far away from the image – it should take up at least 20% of the view of the camera
  • Non-uniform 3D objects e.g., fruit, sports balls

 

Tracking

Considerations that need to be made so that the HP Reveal technology can continue to maintain the experience

Things to Consider

  • Tonal variation and contrast

  • Distinguishable but inconsistent shapes across the entire image

  • Matte finished print in order to avoid glare or reflections

  • Position images against a background so that the camera can easily continue to focus on the image without being ‘distracted’

  • Flat 3D objects with the image uploaded to Studio taken in a neutral light, and in cases where the user is not expecting to move their device around the image very much

Things to Avoid

  • Sparse images can mean the technology triggers, but can affect tracking because there is not enough information to maintain the experience
  • Symmetrical images can cause confusion, resulting in Overlays appearing upside down
  • Busy images, with recurring and identical features (including pattern, text or basic shapes)
  • Blurs and gradients
  • Glossy print can cause images to look different with lighting conditions
  • Try to avoid circumstances where users trigger & once recognised try to move to far away from the image
  • Non-uniform 3D objects e.g., fruit, sports balls

 

To help assist you with Triggers we have included an attachment below that can help guide you through the process of having a good Trigger image.

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Comments

  • Avatar
    John Sham

    Hi, I am reading this thread on a LED / LCD monitor. And the good example traigger image cannot be detected by my Aurasma app!! In fact, my aurasma app can only detect about 1 out of 10 trigger images via a monitor. Are signal interferences the reason behind?
    This is essential for my audience as well as creator as usability will be key for my aura project to be successful. Would you please provide a solution?
    Thank you very much.

  • Avatar
    Simon

    Would love to know the answer to this.

  • Avatar
    Aurasma Services Team
    When viewing images on a monitor the devices camera adjusts its exposure balance - commonly images are viewed with a white background/surround (like here on the website). so the camera is compensating for all the while by making the view darker (because it thinks its really bright light). If you viewed the same image on a darker background it would look brighter, you'll see it too if you move closer to the image on the screen, filling the view with more image and less white space. Just one of those hardware things!
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