Two days before my PhD defense, I found out that a manuscript that I submitted to ToCHI on unintended touch (aka palm rejection) was accepted for publication! The manuscript is entitled “Exploring and Understanding Unintended Touch during Direct Pen Interaction” (previously titled, “Is it Intended or Unintended? Palm Rejection during Direct Pen Interaction”)  details a data collection experiment and an algorithmic analysis of various possible solutions to unintended touch on tablets. The work was part of the larger collection of pen-based work that I performed while I was an intern at Microsoft Research (yippee! for publication #4 from my MSR time).

An example of unintended touch information from the perspective of a digitizer. The current stylus location is denoted in blue and the unintentional touch events from the palm and little finger are denoted in varying shades of orange.

The manuscript will not be published until December 2014, so here is the abstract:

The user experience on tablets that support both touch and styli is less than ideal, due in large part to the problem of unintended touch or palm rejection. Devices are often unable to distinguish between intended touch, i.e., interaction on the screen intended for action, and unintended touch, i.e., incidental interaction from the palm, forearm, or fingers. This often results in stray ink strokes and accidental navigation, frustrating users. We present a data collection experiment where participants performed inking tasks, and where natural tablet and stylus behaviors were observed and analyzed from both digitizer and behavioral perspectives. An analysis and comparison of novel and existing unintended touch algorithms revealed that the use of stylus information can greatly reduce unintended touch. Our analysis also revealed many natural stylus behaviors that influence unintended touch, underscoring the importance of application and ecosystem demands, and providing many avenues for future research and technological advancement.

Today is a big day in the world of Michelle because I have lots of news to share! In addition to the CHI 2014 publication on the High Performance Stylus System, I am happy to report that I also have a follow-up paper that will be presented a Graphics Interface 2014 in Montreal entitled, “How Low Should We Go? Understanding the Perception of Latency While Inking”! (Yaaah again for no cell phone roaming fees to attend the conference!) As the paper is forthcoming, I can’t release all of the details but I can share the abstract and a short video that we shot. Once the full paper is available, I will provide a link to it.

Abstract:
Recent advances in hardware have enabled researchers to study the perception of latency. Thus far, latency research has utilized simple touch and stylus-based tasks that do not represent inking activities found in the real world. In this work, we report on two studies that utilized writing and sketching tasks to understand the limits of human perception. Our studies revealed that latency perception while inking is worse (~50 milliseconds) than perception while performing non-inking tasks reported previously (~2-7 milliseconds). We also determined that latency perception is not based on the distance from the stylus’ nib to the ink, but rather on the presence of a visual referent such as the hand or stylus. The prior and current work has informed the Latency Perception Model, a framework upon which latency knowledge and the underlying mechanisms of perception can be understood and further explored.

Although every accepted paper is cause for celebration, I am especially happy that this paper was accepted because the proposed Latency Perception Model is a nice summary of all the latency work that has been done by myself and others thus far. Here is the YouTube video summarizing our work:

Woo hoo! It’s finally time that I can talk about some of the awesome work that I did at Microsoft Research while I was on my extended internship! One of my forthcoming papers, entitled “In the Blink of an Eye: Investigating Latency Perception during Stylus Interaction” is going to appear in the proceedings of CHI 2014. The conference will take place at the end of April in Toronto (yippeee no cell phone roaming fees!) but here is sneak preview of the abstract and the video we shot for the project. The follow-up to this work will be published at Graphics Interface 2014, and can be seen here.

The HPSS was built by Albert Ng and Paul Dietz, who collaborated previously on the High Performance Touch System that you can see here on YouTube. The psychophysical just-noticeable difference studies were incepted, conducted, and analyzed by me! Anoop Gupta and my supervisor Walter acted as mentors on the project.

Abstract:
While pen computing has become increasingly more popular, device responsiveness, or latency, still plagues such interaction. Although there have been advances in digitizer technology over the last few years, commercial end-to-end latencies are unfortunately similar to those found with touchscreens, i.e., 65 – 120 milliseconds. We report on a prototype stylus-enabled device, the High Performance Stylus System (HPSS), designed to display latencies as low as one millisecond while users ink or perform dragging tasks. To understand the role of latency while inking with a stylus, psychophysical just-noticeable difference experiments were conducted using the HPSS. While participants performed dragging and scribbling tasks, very low levels of latency could be discriminated, i.e., ~1 versus 2 milliseconds while dragging and ~7 versus 40 milliseconds while scribbling. The HPSS and our experimentation have provided further motivation for the implementation of latency saving measures in pen-based hardware and software systems.