Pointing on TV: A Comparative Study of Touch vs. Motion

Transcription

1 Pointing on TV: A Comparative Study of Touch vs. Motion

2 Overview As demand for Internet content on television increases, service providers and consumer electronics manufacturers need alternative technologies to the traditional up/down/left/right remote control in order to delight consumers with new interactive experiences on TV. This paper describes why pointing is the right solution for controlling the TV experience, and compares two technologies that enable pointing remote controls: touchpad and motion control. A series of studies compare these two methods of pointing for two common use-cases: navigation and casual gaming. Results show that pointing by motion is superior to pointing with touchpad for both use-cases. The Emergence of the Connected TV Internet connectivity has slowly made its way into our home theaters. This trend started with Home Theater PC s and continued with a variety of Internetconnected-video appliances. Connected televisions have recently become available, and their numbers are increasing. Internet connectivity transforms the TV from primarily a display device for Pay TV services, DVD players and game consoles, to a fully interactive platform with myriad content and services sourced directly from the Internet. Video content, such as that offered by YouTube, Netflix and Amazon, social networking services, such as Facebook and Twitter, information widgets, such as news, weather and stocks, and games, such as Sudoku and QuizzMaster, are typical examples of content available on Internet-connected TV s. However, to control these interactive experiences, consumers need an easier and more efficient input device than the traditional up/down/left/right remote control. The connected TV needs a new user control paradigm that is as flexible, simple and efficient as those available on other connected consumer devices, such as PC s and smartphones, but designed specifically for the TV viewing experience. Controlling the Connected TV Personal computers used directional keys in the early days, but the introduction of the mouse brought pointing-based user interfaces. One cannot imagine the Internet revolution with arrow keys as the means of navigating the World Wide Web. Smartphones also use pointing as their control interface for applications and the Internet. Directional keys alone could not possibly support the breadth of applications running on typical smartphones today. Pointing is natural to humans. Babies point to convey their desires long before they learn to speak. Pointing allows us to select things at random. In the context of computers, pointing allows direct access to any object onscreen, irrespective of order. Directional control interfaces are dependent on order; once an object is identified, it cannot be accessed until all objects prior to it have been traversed Hillcrest Laboratories, Inc. All rights reserved. 2 / 14

3 one by one. This type of interaction is unnatural, frustrating and inefficient; it takes more time and demands more effort from the user than pointing does. This lack of efficiency leads to a lack of scalability. In a directional control interface, the number of user actions grows with the number of items onscreen. In a pointing interface, the number of actions is independent of the number of items. Acquiring an item is a single point-and-click interaction, regardless of how many items are onscreen. Figure 1 shows the contrast in the number of user actions when using pointing vs. arrow keys. In this example, it takes seven user actions to arrive at the item of interest when using arrow keys versus one action with pointing. Figure 1 Pointing vs. Arrow Keys to Navigate a 5x4 Grid The limitations of directional control interfaces make them nearly unusable for certain applications. For example, navigating a Web browser is very difficult with arrow keys but simple with a pointer. A pointing interface also allows for flexibility in the layouts of screens. Application designers can take advantage of random access and place selectable items around the screen in ways that are not confined to a grid. Pointing is not only intuitive, efficient and scalable, but its flexibility allows for advanced interactions such as drag and drop, freehand drawing, and arbitrary gestures. These capabilities can enable innovation and new classes of interactive applications on TV. The connected TV needs a new remote control that uses pointing as the primary means of user control. Recognizing this need, many service providers and consumer electronics manufacturers are rolling out pointing-based products. Pointing Remote Control A pointing interface for the television must be designed for the TV experience. Pointing remote controls must be comfortable to use in typical settings where users watch TV, at different angles to the TV, and with a variety of seated and reclining positions (also known as lean-back positions). In addition, low latency and high accuracy are critical requirements. Several forms of pointing technologies, such as joystick, trackball, touchpad, and motion control, are used in input devices for computers, mobile handsets and Hillcrest Laboratories, Inc. All rights reserved. 3 / 14

4 game consoles,. Of these input methods, touchpad and motion control are the most suitable for controlling the TV experience, due to their performance and practicality of usage. LG Electronics INFINIA line of Smart TVs, and the Logitech Revue with Google TV are two pioneering Internet TV products that have adopted pointing. The LGE Smart TV uses Hillcrest s Freespace inertial motion control to enable its wand-like pointing remote control, and the Logitech Revue with Google TV uses a touchpad pointer that is integrated with a full QWERTY keyboard. Figure 2 shows Internet TV products with pointing remote controls from LGE and Logitech. Courtesy: Logitech Figure 2 Internet TV products with Pointing Remote Controls from LGE and Logitech Touchpad A touchpad measures the relative position of the user s finger as it moves on the pad, and translates that movement into a cursor position onscreen. The most commonly deployed touchpad technology uses capacitive sensing. The touch of the finger - a conductive medium - causes a capacitance change between layers of conductors below the surface of the pad. This change is detected to determine the presence and position of the finger. The Logitech dinovo Mini, the SMK-Interlink Touchpad Remote and the GlideTV Navigator are examples of offthe-shelf touchpad devices designed for use in a lean-back position. Optical finger navigation (OFN) is another finger tracking technology. It uses optical sensors to detect the presence and movement of the finger. The Sony Internet TV with Google TV comes with a remote control that uses this type of technology to enable pointing. Motion Control A motion pointing device responds to movements of the user s hand in space; this interaction is also referred to as in-air pointing. Motion control technology can be implemented in two primary ways: inertial and optical. Inertial motion control uses MEMS accelerometers and gyroscopes to sense motion in three dimensions and translate those movements into a cursor position onscreen. Optical motion control uses a camera and LEDs to triangulate the movement of the controller and translate those movements into a cursor position onscreen. A Hillcrest Laboratories, Inc. All rights reserved. 4 / 14

5 comparison of these solutions can be found in the research report, Comparison of Relative Versus Absolute Pointing Devices. 1 Inertial motion control is a relative pointing mechanism, like a computer mouse and a touchpad, and is suitable for controlling user interfaces. An inertial motion pointing device allows the user to hold the device in any position without the need to point at the screen, making it ideal for use in the living room. This is not the case with optical motion pointing, as described in the referenced research report. A motion pointer also enables complex gestures and motion gaming. The Logitech MX Air and Hillcrest Loop pointer are examples of off-the-shelf inertial motion pointing devices and are designed for use in a lean-back position. In the remainder of this paper, the term motion control refers to inertial motion control. Which Is the Right Pointing Technology for the TV? Touchpad and motion control are two viable technologies for controlling the TV experience. But which is better? This paper compares the two input methods along two axes: performance and user satisfaction. A series of user studies were designed to compare these two methods side by side. These studies evaluated two use-cases: 1) navigation, which encompasses all general user interactions and 2) point-and-click gaming, which is a potentially explosive growth area for applications on TV. In these studies, the Loop pointer - an in-air pointing device enabled by Freespace motion technology from Hillcrest Labs - was compared with touchpad devices from Logitech, SMK and GlideTV. These devices are shown in Figure 3. SMK-Interlink Logitech dinovo Mini Touchpad Remote GlideTV Navigator Hillcrest Loop Pointer Figure 3 - Pointing Devices Used in the Comparative Study 1 Comparison of Relative Versus Absolute Pointing Devices, Kent L. Norman, University of Maryland, College Park, Kirk D. Norman, University of Maryland, Baltimore Campus, Steve Francz and Brian Cook, Hillcrest Laboratories, Inc Hillcrest Laboratories, Inc. All rights reserved. 5 / 14

6 Comparative Study Methodology For these studies, men and women of different ages participated in half-hour to one-hour test sessions. The studies were conducted in a living room setting, where participants were asked to sit in a comfortable chair 9 feet away from a 42- inch plasma TV. The dimensions of the TV and the distance to the sofa were configured to meet the guidelines recommended by the Society of Motion Picture and Television Engineers (SMPTE). The participants were presented with interactive applications on the TV screen, which were sourced from a PC attached to the TV. The devices under test were paired with the PC and used in turn with each application. Each study started with an initial survey to collect demographic data and to assess the participants prior usage and familiarity with the two input technologies. The participants were asked about their usage of touchpad devices, which are widely available on laptops, and their familiarity and frequency of using motion pointing, which is best known in association with the Nintendo Wii. The survey was followed by hands-on interactive exercises, where participants were given the different pointing devices and asked to interact with applications on the TV. The first task in each study was a warm-up exercise intended to familiarize the participant with the setup and the devices under test. An instruction sheet was provided for each device. In each exercise, multiple devices were used with a given application, and the order of the devices was varied with each participant. Study 1: Basic Navigation The goal of this study was to compare touchpad and motion control pointing methods for navigating a TV application. Navigation is the foundation for interactivity and includes all user operations to move about an application and control one s experience. This study had two components: one to measure the performance of each pointing method and the other to measure the participants satisfaction rating with each method. For this study, the Hillcrest Loop with Freespace motion technology was compared with the Logitech dinovo Mini and the SMK-Interlink touchpad devices. The 18 participants recruited for this study consisted of 11 males and 7 females and were between the ages of 18 and 60. The initial survey found that 17 of the 18 participants use touchpad on laptops daily and 11 have familiarity with motion pointing Hillcrest Laboratories, Inc. All rights reserved. 6 / 14

7 User Satisfaction As a warm-up exercise, the participants were presented with Microsoft Paint (an off-the-shelf drawing application) on the TV and were asked to draw shapes of their liking using the different devices under test. After warm-up, the participants were presented with Hillcrest s made-for-tv browser application, Kylo, and were asked to select and navigate their preferred Internet sites for a few minutes. The test applications are shown in Figure 4. At the completion of this exercise, the participants were given a survey and asked to rate their satisfaction level with each device. MS Paint Kylo TV Internet Browser Findings Figure 4 Navigation Study Test Applications The results of participants satisfaction ratings, shown in Figure 5, demonstrate that in each category, participants rated motion pointing with the Freespaceenabled loop pointer higher than pointing with touchpad devices. The users found motion pointing with the Freespace-enabled Loop pointer less fatiguing than with touchpad devices and selected the Loop as their device of choice for navigating Internet content on TV. Users also rated the Loop higher for overall satisfaction Hillcrest Laboratories, Inc. All rights reserved. 7 / 14

8 Q1: Can Complete Tasks Accurately Q2: Can Complete Tasks Quickly Q3: Did Not Feel Tired After Use Q4: Would Use Device to Browse the Internet Q5: Overall Satisfaction Hillcrest Loop Pointer SMK Interlink Touchpad Remote Logitech dinovo Mini Figure 5 User Satisfaction Rating for Navigating the Internet on TV Hillcrest Laboratories, Inc. All rights reserved. 8 / 14

9 Pointing Performance For this segment of the study, a Fitts Law application was used to measure the speed and accuracy of the pointing devices. Fitts Law Test Fitts Law is widely used in academia and industry as a standard for measuring the performance of pointing devices. It describes the time it takes to point and click on an object onscreen (referred to as target acquisition time) as a function of its size and the moving distance from it. The mathematical relationship is as Dis tan e follows: Time = a log ( + 1) + b 2 Size. Fitts Law tests present targets of varying sizes appearing at random locations onscreen and measure both the time to move from one target to the next, and the rate of accuracy of acquiring targets. Fitts Law shows that targets that are smaller and/or farther away take more time to acquire, and that the accuracy of target acquisition goes down as the acquisition rate goes up. The Fitts test application used in this study is shown in Figure 6. The placement and sizes of objects were designed to simulate the layout and icon sizes of a typical made-for-tv application. Findings Figure 6 Fitts Law Test Application The results as shown in Figure 6 demonstrate that the Freespace-enabled Loop pointer outperformed touchpad devices by 69% on speed. Figure 7 takes into account both speed and accuracy (referred to as throughput) and shows that the Loop Freespace pointer performed 79% better Hillcrest Laboratories, Inc. All rights reserved. 9 / 14

10 / 3.7% 0.8 Speed (Targets per Second) / 2.8% / 1.9% Hillcrest Loop Pointer SMK Interlink Touchpad Remote Logitech dinovo Mini Freespace Touchpad Devices Figure 7 Fitts Law Test, Average Speed per Device (Targets per Second) / 0.17 Throughput (Bits per Second) / / Hillcrest Loop Pointer SMK Interlink Touchpad Remote Logitech dinovo Mini Freespace Touchpad Devices Figure 8 Fitts Law Test, Average Throughput per Device (Bits per Second) Hillcrest Laboratories, Inc. All rights reserved. 10 / 14

11 Study 3: Casual Gaming The goal of this study was to compare touchpad and motion control as pointing methods for playing casual games on TV. Casual games have simple rules and typically require little time commitment from the user. Sudoku, Bejeweled, Mahjong and Whack-a-Mole are examples of casual games. Many casual games are played on computers with mice and require a pointing interface. The nine participants in this study consisted of seven males and two females between the ages of 18 and 49. The initial survey found that eight of the nine participants use touchpad devices on laptops daily, and six have familiarity with motion pointing. The participants were asked to play a game called Gophers. In this game, animated gophers appear in random locations onscreen and stay visible for a short period of time. The object of the game is to hit the gophers as fast as possible and to complete the game in the shortest time possible. The participants were asked to complete two rounds of tests in hard mode after completing a warm-up round in easy mode. This study measured the time to complete the game with each device. Each participant also completed the test using an optical desktop mouse as a benchmark for optimal pointing performance. The application used in this study is shown in Figure 9. Gopher Game Opening Screen Gopher Game Figure 9 Casual Gaming Study Test Application Hillcrest Laboratories, Inc. All rights reserved. 11 / 14

12 Findings 120 The results, as shown in 86 +/ / / 13.4 Time (Seconds) / / Glide TV Navigator Logitech dinovo Mini SMK Interlink Touchpad Remote Hillcrest Loop Pointer Mouse Touchpad Devices Freespace Figure 10, demonstrate that it took less time to complete the game with the Freespace-enabled Loop pointer than with touchpad devices. On average, the Freespace-enabled Loop pointer performed 2.9 times better than the touchpad devices, and almost as well as the mouse. The general feedback from participants indicated that touchpad was not a viable pointing method for playing point-and-click games Hillcrest Laboratories, Inc. All rights reserved. 12 / 14

13 / / / 13.4 Time (Seconds) / / Glide TV Navigator Logitech dinovo Mini SMK Interlink Touchpad Remote Hillcrest Loop Pointer Mouse Touchpad Devices Freespace Summary Figure 10 Time to Complete Game, Average per Device (Seconds) Internet connectivity has transformed the TV viewing experience. Consumers now have access to a plethora of content from the Internet and need an easy, effective way to interact with this content on their TVs. Companies like LG Electronics, Google, Sony and Logitech have led the way by adopting pointing technologies to control Internet-connected TVs, and more consumer electronics companies are following suit. Pointing dramatically improves the TV input method, but the design of the pointing remote control and TV user interface determines the consumer experience for the product. Google TV s adoption of pointing is a step in the right direction, but the complexity of the remote control and user interface hamper the consumer experience of the Google TV products. Pointing remote controls should be simple devices with very few buttons. The user interface should use point-and-click as the dominant interaction and minimize the need for the user to search for buttons on the remote. Furthermore, the pointing method should operate at high performance and be highly satisfying to users. The two technologies that are best suited for pointing on TV are touchpad and motion control. Through a series of quantitative and qualitative studies, this paper demonstrates that motion pointing powered by Freespace motion Hillcrest Laboratories, Inc. All rights reserved. 13 / 14

14 technology outperforms touchpad pointing. Pointing with Freespace exhibited 79% higher throughput (combined speed and accuracy) than touchpads. For casual gaming, pointing with Freespace performed three times faster than touchpads, and nearly as fast as a desktop mouse. Users selected Freespace as their pointing method of choice for navigating the Internet on TV, and rated pointing with Freespace 43% higher for overall satisfaction. Touchpads have historically had relatively low cost due to their broad distribution in portable computers. However, in recent years MEMS-based motion sensors have come down in cost significantly as they have become commonplace in the high volume consumer electronics market. Video game controllers such as the Sony Move and Nintendo Wii use MEMS-based sensors, and so do smartphones such as the Apple iphone. Motion pointing is now an economically viable solution for TV remote controls. With only a small margin above the cost of touchpads but significantly better performance, a state-of-the-art motion control technology such as Freespace is positioned as the best solution for pointing remote controls. Motion control not only has better pointing performance and viability for supporting point-and-click games, but it also offers unique benefits through advanced capabilities such as 3D gestures and motion gaming. These types of capabilities further differentiate a product and have greater potential for consumer interest and added revenue Hillcrest Laboratories, Inc. All rights reserved. 14 / 14