Wednesday, February 6, 2008

Better feedback!

Since having a pointer representing the gaze position on the screen becomes distracting some other form of feedback is needed. As mentioned before having a pointer will cause your eyes to more or less automatically fixate on the moving object. Remember, the eyes are never still and even more the eye tracker does create additional jitter.

What we need is a subtle way of showing the user that the eye tracker has captured the gaze coordinates to the same location as he/she is looking at. It's time for trying to make it look a bit nicer than the previous example where the whole background color of the button would change on a gaze fixation.

The reason for choosing to work with Windows Presentation Foundation is that it provides rich functionality for building modern interfaces. For example you can define a trigger to an event, such as GazeEnter (ie. MouseEnter) on a button and then apply a build in graphical effect on the object. These effects are rendering in real time such as a glowing shadow around the object or a gaussian filter that gives the object an out of focus effect. Very useful for this project. Let's give it a try.

This is the "normal" button. Notice the out-of-focus effect on the globe in the center.

Upon receving a glance the event "Image.IsMouseOver" event is trigged. This starts the built-in rendering function BitmapEffect OuterGlowBitmapEffect which generates a nice red glowing border around the button.

The XAML design code (screenshot) for the button. Click to enlarge.
Notice the GlowColor and GlowSize attributes to manipulate the rendering of the effects.
To apply this to the button we define the element Style="{StaticResource GlowButton}" inside the button tag. Further the globe in the center can be brought back in focus and highlighed with a green glow surrounding it inside the button canvas.

The globe is defined as an image object. Upon focus the triggers will set the gaussian blur effect to zero, which means in focus. The glow effect produces the green circle surrounding the globe.

Putting it all together in a nice looking interface, using the Glass Window style, it looks promising and a real improvement since yesterdays boring interface. Providing a small surrounding glow of giving the image focus upon fixation is much better than changing the whole button color. The examples here are perhaps somewhat less subtle than they should, just to demonstrated the effect.

Screenshots of the second prototype with new U.I effects and events.

The "normal" screen with no gaze input.

OnGazeEnter. Generate a glowing border around the button

The other example with a green glow and the globe in full focus.

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