Category Archives: multi-touch

Paper: Experimental Study of Stroke Shortcuts for a Touchscreen Keyboard with Gesture-Redundant Keys Removed

Text Entry on Touchscreen Keyboards: Less is More?

When we go from mechanical keyboards to touchscreens we inevitably lose something in the translation. Yet the proliferation of tablets has led to widespread use of graphical keyboards.

You can’t blame people for demanding more efficient text entry techniques. This is the 21st century, after all, and intuitively it seems like we should be able to do better.

While we can’t reproduce that distinctive smell of hot metal from mechanical keys clacking away at a typewriter ribbon, the presence of the touchscreen lets keyboard designers play lots of tricks in pursuit of faster typing performance. Since everything is just pixels on a display it’s easy to introduce non-standard key layouts. You can even slide your finger over the keys to shape-write entire words in a single swipe, as pioneered by Per Ola Kristensson and Shumin Zhai (their SHARK keyboard was the predecessor for Swype and related techniques).

While these type of tricks can yield substantial performance advantages, they also often demand a substantial investment in skill acquisition from the user before significant gains can be realized. In practice, this limits how many people will stick with a new technique long enough to realize such gains. The Dvorak keyboard offers a classic example of this: the balance of evidence suggests it’s slightly faster than QWERTY, but the high cost of switching to and learning the new layout just isn’t worth it.

In this work, we explored the performance impact of an alternative approach that builds on people’s existing touch-typing skills with the standard QWERTY layout.

And we do this in a manner that is so transparent, most people don’t even realize that anything is different at first glance.

Can you spot the difference?

Snap quiz time

Stroke-Kbd-redundant-keys-removed-fullres

What’s wrong with this keyboard?  Give it a quick once-over. It looks familiar, with the standard QWERTY layout, but do you notice anything unusual? Anything out of place?

Sure, the keys are arranged in a grid rather than the usual staggered key pattern, but that’s not the “key” difference (so to speak). That’s just an artifact of our quick ‘n’ dirty design of this research-prototype keyboard for touchscreen tablets.

Got it figured out?

All right. Pencils down.

Time to check your score. Give yourself:

  • One point if you noticed that there’s no space bar.
  • Two points if you noticed that there’s no Enter key, either.
  • Three points if the lack of a Backspace key gave you palpitations.
  • Four points and a feather in your cap if you caught the Shift key going AWOL as well.

Now, what if I also told you removing four essential keys from this keyboard–rather than harming performance–actually helps you type faster?

One Trick TO WOO THEM ALL

All we ask of people coming to our touchscreen keyboard is to learn one new trick. After all, we have to make up for the summary removal of Space, Backspace, Shift, and Enter somehow. We accomplish this by augmenting the graphical touchscreen keyboard with stroke shortcuts, i.e. short straight-line finger swipes, as follows:marking-menu-overlay-5

  • Swipe right, starting anywhere on the keyboard, to enter a Space.
  • Swipe left to Backspace.
  • Swipe upwards from any key to enter the corresponding shift-symbol. Swiping up on the a key, for example, enters an uppercase A; stroking up on the 1 key enters the ! symbol; and so on.
  • Swipe diagonally down and to the left for Enter.

marking-menu-overlay-with-finger

DESIGN PROPERTIES OF A STROKE-AUGMENTED GRAPHICAL KEYBOARD

In addition to possible time-motion efficiencies of the stroke shortcuts themselves, the introduction of these four gestures–and the elimination of the corresponding keys made redundant by the gestures–yields a graphical keyboard with number of interesting properties:

  • Allowing the user to input stroke gestures for Space, Backspace, and Enter anywhere on the keyboard eliminates fine targeting motions as well as any round-trips necessary for a finger to acquire the corresponding keys.
  • Instead of requiring two separate keystrokes—one to tap Shift and another to tap the key to be shifted—the Shift gesture combines these into a single action: the starting point selects a key, while the stroke direction selects the Shift function itself.
  • Removing these four keys frees an entire row on the keyboard.
  • Almost all of the numeric, punctuation, and special symbols typically relegated to the secondary and tertiary graphical keyboards can then be fit in a logical manner into the freed-up space.
  • Hence, the full set of characters can fit on one keyboard while holding the key size, number of keys, and footprint constant.
  • By having only a primary keyboard, this approach affords an economy of design that simplifies the interface, while offering further potential performance gains via the elimination of keyboard switching costs—and the extra key layouts to learn.
  • Although the strokes might reduce round-trip costs, we expect articulating the stroke gesture itself to take longer than a tap. Thus, we need to test these tradeoffs empirically.

RESULTS AND PRELIMINARY CONCLUSIONS

Our studies demonstrated that overall the removal of four keys—rather than coming at a cost—offers a net benefit.

Specifically, our experiments showed that a stroke keyboard with the gesture-redundant keys removed yielded a 16% performance advantage for input phrases containing mixed-case alphanumeric text and special symbols, without sacrificing error rate. We observed these performance advantages from the first block of trials onward.

Even in the case of entirely lowercase text—that is, in a context where we would not expect to observe a performance benefit because only the Space gesture offers any potential advantage—we found that our new design still performed as well as a standard graphical keyboard. Moreover, people learned the design with remarkable ease: 90% wanted to keep using the method, and 80% believed they typed faster than on their current touchscreen tablet keyboard.

Notably, our studies also revealed that it is necessary to remove the keys to achieve these benefits from the gestural stroke shortcuts. If both the stroke shortcuts and the keys remain in place, user hesitancy about which method to use undermines any potential benefit. Users, of course, also learn to use the gestural shortcuts much more quickly when they offer the only means of achieving a function.

Thus, in this context, less is definitely more in achieving faster performance for touchscreen QWERTY keyboard typing.

The full results are available in the technical paper linked below. The paper contributes a careful study of stroke-augmented keyboards, filling an important gap in the literature as well as demonstrating the efficacy of a specific design; shows that removing the gesture-redundant keys is a critical design choice; and that stroke shortcuts can be effective in the context of multi-touch typing with both hands, even though previous studies with single-point stylus input had cast doubt on this approach.

Although our studies focus on the immediate end of the usability spectrum (as opposed to longitudinal studies over many input sessions), we believe the rapid returns demonstrated by our results illustrate the potential of this approach to improve touchscreen keyboard performance immediately, while also serving to complement other text-entry techniques such as shape-writing in the future.

Stroke-Keyboard-GI-2014-thumbArif, A. S., Pahud, M., Hinckley, K., and Buxton, B.,  Experimental Study of Stroke Shortcuts for a Touchscreen Keyboard with Gesture-Redundant Keys Removed In Proc. Graphics Interface 2014 (GI’14).  Canadian Information Processing Society, Toronto, Ont., CanadaMontreal, Quebec, Canada, May 7-9, 2014. Received the Michael A. J. Sweeney Award for Best Student Paper.  [PDF] [Talk Slides (.pptx)] [Video .MP4] [Video .WMV]

Watch A Touchscreen Keyboard with Gesture-Redundant Keys Removed video on YouTube

Paper: Motion and Context Sensing Techniques for Pen Computing

I continue to believe that stylus input — annotations, sketches, mark-up, and gestures — will be an important aspect of interaction with slate computers in the future, particularly when used effectively and convincingly with multi-modal pen+touch input. It also seems that every couple of years I stumble across an interesting new use or set of techniques for motion sensors, and this year proved to be no exception.

Thus, it should come as no surprise that my latest project has continued to push in this direction, exploring the possibilities for pen interaction when the physical stylus itself is augmented with inertial sensors including three-axis accelerometers, gyros, and magnetometers.

Figure-1-Sensor-Pen-hardware

In recent years such sensors have become integrated with all manner of gadgets, including smart phones and tablets, and it is increasingly common for microprocessors to include such sensors directly on the die. Hence in my view of the world, we are just at the cusp of sensor-rich stylus devices becoming  commercially feasible, so it is only natural to consider how such sensors afford new interactions, gestures, or context-sensing techniques when integrated directly with an active (powered) stylus on pen-operated devices.

In collaboration with Xiang ‘Anthony’ Chen and Hrvoje Benko I recently published a paper exploring motion-sensing capabilities for electronic styluses, which takes a first look at some techniques for such a device. With some timely help from Tom Blank’s brilliant devices team at Microsoft Research, we built a custom stylus — fully wireless and powered by an AAAA battery — that integrates these sensors.

These range from very simple but clever things such as reminding the user if they have left behind the pen — a common problem that users encounter with pen-based devices — to fun new techniques that emulate physical media, such as the gesture of striking a loaded brush on one’s finger in water media.

fig-ink-spatter

Check out the video below for an overview of these and some of the other techniques we have come up with so far, or read more about it in the technical paper linked below.

We are continuing to work in this area, and have lots more ideas that go beyond what we were able to accomplish in this first stage of the project, so stay tuned for future developments along these lines.

Motion-Context-Pen-thumbHinckley, K., Chen, X., and Benko, H., Motion and Context Sensing Techniques for Pen
Computing. 
In Proc. Graphics Interface 2013 (GI’13).  Canadian Information Processing Society, Toronto, Ont., CanadaRegina, Saskatchewan, Canada, May 29-31, 2013. [PDF] [video - MP4].

Watch Motion and Context Sensing Techniques for Pen Computing video on YouTube

GroupTogether — Exploring the Future of a Society of Devices

My latest paper discussing the GroupTogether system just appeared at the 2012 ACM Symposium on User Interface Software & Technology in Cambridge, MA.

GroupTogether video available on YouTube

I’m excited about this work — it really looks hard at what some of the next steps in sensing systems might be, particularly when one starts considering how users can most effectively interact with one another in the context of the rapidly proliferating Society of Devices we are currently witnessing.

I think our paper on the GroupTogether system, in particular, does a really nice job of exploring this with strong theoretical foundations drawn from the sociological literature.

F-formations are small groups of people engaged in a joint activity.

F-formations are the various type of small groups that people form when engaged in a joint activity.

GroupTogether starts by considering the natural small-group behaviors adopted by people who come together to accomplish some joint activity.  These small groups can take a variety of distinctive forms, and are known collectively in the sociological literature as f-formations. Think of those distinctive circles of people that form spontaneously at parties: typically they are limited to a maximum of about 5 people, the orientation of the partipants clearly defines an area inside the group that is distinct from the rest of the environment outside the group, and there are fairly well established social protocols for people entering and leaving the group.

A small group of two users as sensed by GroupTogether's overhead Kinect depth-cameras

A small group of two users as sensed via GroupTogether’s overhead Kinect depth-cameras.

GroupTogether also senses the subtle orientation cues of how users handle and posture their tablet computers. These cues are known as micro-mobility, a communicative strategy that people often employ with physical paper documents, such as when a sales representative orients a document towards to to direct your attention and indicate that it is your turn to sign, for example.

Our system, then, is the first to put small-group f-formations, sensed via overhead Kinect depth-camera tracking, in play simultaneously with the micro-mobility of slate computers, sensed via embedded accelerometers and gyros.

The GroupTogether prototype sensing environment and set-up

GroupTogether uses f-formations to give meaning to the micro-mobility of slate computers. It understands which users have come together in a small group, and which users have not. So you can just tilt your tablet towards a couple of friends standing near you to share content, whereas another person who may be nearby but facing the other way — and thus clearly outside of the social circle of the small group — would not be privy to the transaction. Thus, the techniques lower the barriers to sharing information in small-group settings.

Check out the video to see what these techniques look like in action, as well as to see how the system also considers groupings of people close to situated displays such as electronic whiteboards.

The full text of our scientific paper on GroupTogether and the citation is also available.

My co-author Nic Marquardt was the first author and delivered the talk. Saul Greenberg of the University of Calgary also contributed many great insights to the paper.

Image credits: Nic Marquardt

Paper: Cross-Device Interaction via Micro-mobility and F-formations (“GroupTogether”)

GroupTogetherMarquardt, N., Hinckley, K., and Greenberg, S., Cross-Device Interaction via Micro-mobility and F-formations.  In ACM UIST 2012 Symposium on User Interface Software and Technology (UIST ’12). ACM, New York, NY, USA,  Cambridge, MA, Oct. 7-10, 2012, pp. (TBA). [PDF] [video - WMV]. Known as the GroupTogether system.

See also my post with some further perspective on the GroupTogether project.

Watch the GroupTogether video on YouTube

Paper: Informal Information Gathering Techniques for Active Reading

This is my latest project, which I will present tomorrow (May 9th) at the CHI 2012 Conference on Human Factors in Computing Systems.

I’ll have a longer post up about this project after I return from the conference, but for now enjoy the video. I also link to the PDF of our short paper below which has a nice discussion of the motivation and design rationale for this work.

Above all else, I hope this work makes clear that there is still tons of room for innovation in how we interact with the e-readers and tablet computers of the future– as well as in terms of how we consume and manipulate content to produce new creative works.

Informal Information Gathering Techniques for Active ReadingHinckley, K., Bi, X., Pahud, M., Buxton, B., Informal Information Gathering Techniques for Active Reading. 4pp Note. In Proc. CHI 2012  Conf. on Human Factors in Computing Systems, Austin, TX, May 5-10, 2012. [PDF]

[Watch Informal Information Gathering Techniques for Active Reading on YouTube]

Paper: CodeSpace: Touch + Air Gesture Hybrid Interactions for Supporting Developer Meetings

CodeSpace systemBragdon, A., DeLine, R., Hinckley, K., and Morris, M. R., Code space: Touch + Air Gesture Hybrid Interactions for Supporting Developer Meetings.  In Proc. ACM International Conference on Interactive Tabletops and Surfaces (ITS ’11). ACM, New York, NY, USA,  Kobe, Japan, November 13-16, 2011, pp. 212-221. [PDF] [video - WMV]. As featured on Engadget and many other online forums.

Watch CodeSpace video on YouTube

Paper: Enhancing Naturalness of Pen-and-Tablet Drawing through Context Sensing

Context-Sensing Pen with multi-touch and orientation sensorsSun, M. Cao, X., Song, H., Izadi, S., Benko, H., Guimbretiere, F., Ren, X., and Hinckley, K. Enhancing Naturalness of Pen-and-Tablet Drawing through Context Sensing.  In Proc. ACM International Conference on Interactive Tabletops and Surfaces (ITS ’11). ACM, New York, NY, USA,  Kobe, Japan, November 13-16, 2011, pp. 212-221. [PDF] [video - WMV].

Watch Enhancing Naturalness of Pen through Context Sensing video on YouTube