nOVEL INTERACTION TECHNOLOGIES CMT 3321 COURSEWORK …€¦ · Web viewnovel interaction...

MODULE LECTURERDR. P.RAMSAMY

nOVEL INTERACTION TECHNOLOGIES CMT 3321 COURSEWORK 2 HAPTIC INTERACTION PROJECT

HAPTIMAZE RESEARCH REPORT BY BUGEMBE DENNIS M00424054

GROUP MEMEBERS

ANTHONY SEVERINE BONIFACE M00429782

SAHIL M KHATRI M00429909

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Table of ContentsABSTRACT....................................................................................................................................................2

RESEARCH QUESTION..................................................................................................................................3

INTRODUCTION...........................................................................................................................................3

CONCEPT.....................................................................................................................................................3

Purpose of the experiment......................................................................................................................4

Test bed Idea...........................................................................................................................................4

Test Scenarios..........................................................................................................................................5

PROTOTYPE.................................................................................................................................................6

EVALUATION................................................................................................................................................8

Results Obtained.....................................................................................................................................9

Findings.................................................................................................................................................10

CONCLUSION.............................................................................................................................................10

Reflective Report...................................................................................................................................10

Reference list and Bibliography.................................................................................................................10

APPENDIX..................................................................................................................................................12


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ABSTRACTIntroduction

The meteoric rise of haptic technology has led to it being applied in several fields to enhance interaction between human and machine (HCI). An experiment will be carried out to evaluate how effective haptic feedback is as a standalone method in object discovery and shape identification.

Design Concept

A test-bed application was designed and using a vibro-box, processing and reacTIVision an experiment was carried out to test the effectiveness of haptic feedback compared to visual and a combination of both haptic and visual feedback. The overall effectiveness of tangible user interface objects (TUI) as regards perceptual coupling was reason enough to base the prototype construction on it. The aim of the experiment was to obtain data that would aid the analysis and conclusion of the research.

Evaluation

The results that were obtained were tabulated and used to draw graphs that represented the users’ results after interacting with the prototype. The four user’s obtained varying results but critical analysis of these results showed that users’ erred more when they were guided by pure haptic feedback than they did under the guidance of haptic and visual feedback combine.

Conclusion

The results obtained in the experiment indicated that haptic feedback is not effective as a standalone feedback method in object discovery and shape identification. They also showed that a combination of both feedback methods (haptic and visual) was more effective the any of the other methods applied alone.


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RESEARCH QUESTION

Is haptic feedback effective as a standalone feedback method in path finding and object discovery??

INTRODUCTIONAn increase in the processing power of computers and technology as a whole has enhanced the development of haptics in an endeavour to improve human – computer interaction. It is, Haptics, defined as the modality of touch and associated sensory feedback. Similarly, taken from the English Oxford dictionary, haptics is a technical term that pertains to a sense of touch or tactile sensation. Force feedback and Tactile feedback are widely considered to constitute Haptic feedback the latter considered to be sensed by human receptors closer to the skin surface while the former links users and computers by applying force on the users. Devices used, referred to as haptic devices, have components called actuators that exert force on the user as a form of feedback. The most common form of actuator is the electric motor. It is important to note that the degrees of freedom ( DOF) of haptic interfaces allow users a variety of interaction dimensions that range from 2 (DOF) x-y plane to more realistic three dimensional space. According to Orozco et al (2012) the interaction that allows the user to receive tactile and force feedback can either embrace the whole body or just a tip of the finger, giving the user information about the nature of the objects in the virtual environment. These objects are digitally simulated using display technology as a medium for physically tangible interaction, permitting controlled forces through the haptic interface to be delivered to the user depending on the physical properties of the object that can be perceived. Haptic interaction is of a bi-directional nature due to the energy and information flow both from the user to the haptic interface and vice versa. The extent of progress in the haptic realm is such that it has been adopted in numerous fields including medical realm for surgical simulation and medical training, assistive technology for the blind and visually impaired, military applications, museum displays, painting, sculpting and computer assisted designs (CAS).

Gepshtein et al (2005) argues that the nervous system often combines information from different senses in a way that approaches statistical optimality. Consequently, the resultant precision is much better than what could be derived from the discrete senses. This invariable ability of the nervous system to interchangeably select between single modality and inter-modality of the visual and haptic senses will be assessed in this report by coupling digital information using tangible User interface (TUI) in object discovery and shape perception.

CONCEPTTo find the effectiveness of haptic feedback in object finding and shape discovery, it is imperative that a comparison is drawn between haptics and any other relevant form of feedback which in this case would


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be visual and audio. By keeping one of the variables constant, audio, and varying the other two haptics and visual would give us a clear idea of which one is more effective. The inter-sensory ability of the nervous system would allow for the assessment of the combination of the two feedback method visual and haptics.

Purpose of the experimentPrimarily, the experiment will be carried out in order to collect data (measurement variables*) from the users’ interaction with the prototype, which will be manipulated and interpreted to provide information that will verify or negate the aforementioned research question.

An experiment will be set up with a secondary aim of evaluating the relative ease with which a user can be guided by either visual, haptic or visual and haptic feedback to hit a static target that will be invisible. After the object is discovered, the experiment will seek to establish the accuracy of these different forms of feedback to identify the shape of the object.

*measurement variables – will be obtained automatically from the system and will include Slip Off time, Elapsed time and Off Target hits.

Test bed IdeaThe idea for the test bed was to use a tangible user interface object (TUIO) which in this case is a vibro-box assembled and enabled by Arduino 1.0.3, with a fudicial marker attached to it so as to enable reacTIVision capture and couple it with the digital information within processing that will be manipulated.

The initial idea for the test bed application to be designed representing a sea bed with a pictorial menu of the objects to be discovered but it was later refined to ensure the users interacting with the test bed did not have an idea of what kind of object they were to discover and were indeed guided by the feedback in their discovery. Furthermore, the objects that were initially suggested were of relatively complicated shapes like nails, wood and stones in which case a user would almost certainly not identify them correctly since they are composition of shapes (basic shapes like squares and circles).

Secondly, with the hardware provided, there was a limitation in terms of how detailed the path drawn during the discovery could be. The size of the vibro-box in relation to the screen on which the information was to be coupled was not big enough to allow this kind of detailed movement. This implied that it was mandatory for the improved design to address that matter by reducing the number of objects to be discovered hence reducing the cognitive load which according to Schvaneveldt et al (1999) reduces the users accuracy of the results considerably especially as far as shape identification is concerned.

After refining the initial idea, the objects that were to be discovered were narrowed down to a square, triangle and circle but the circle was eventually eliminated because of the nature of feedback required especially because it is easier to follow a straight path as compared to the circular one.

For the visual feedback, in the second iteration of the prototype, the feedback signal was transferred from the area contained the object being sought in the environment to the graphical representation of the tangible user object (TUI). This would help to further emphasize the discovery element of the experiment.


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To help the Users interacting with the environment, a menu was included in the interface design of the prototype which would enable users’ navigate the environment and select the desired section or action. A timer and counter were included as well in the lay out design which would give the user an idea of how well they interpreted the feedback from the system as they interacted with the environment and indeed how long it took them to discover the object despite the fact that the values were for evaluation rather than competitive purposes.

Final test bed version

The final version of the prototype was designed to adhere to the design principles of Don Norman especially as far as consistency was concerned, that users interacting with the prototype were able to locate elements of the prototype interface easily for example recovery from system or unintentional errors effortlessly with a permanently positioned exit area (key).As regards the primary aim of the prototype, it was designed with a relatively narrow but invisible path that was programed to give the appropriate feedback for the user who were executing tasks in the environment, but allowed users room for error and would invariably inform the users if the object was discovered or in the second instance the object shape was successfully established.

There was a permanent location for the results of the tests which included the number of Slip Off time, Elapsed time and Off Target hit which would constitute the relevant measurement variables. These will be discussed in details later sections of this report.

The test bed also included a section that would help the users acclimatise to the prototype and the different ranges of feedback as well as guide them on how to respond to the feedback is all the possible scenarios. For this, the users were guided through by the team with a detailed explanation of what would be expected of them and in no uncertain terms, the aim of the experiment.

Test ScenariosThe test scenarios will help in obtaining data from the users that will interact with the prototype, which will be used for analysing the effectiveness of the feedback

The test scenarios were divided into three distinct sections -:

Haptic Feedback Test

In this part of the test, the vibro-box will be used to navigate in the environment with only tactile feedback enabled. The users will be guided to the object using a series of vibrations on an invisible path and if correctly interpreted will lead them to the object they seek to discover or the shape they are identifying. Data from this unit of the experiment will be gathered carefully because of their sheer relevance to the research and will be recorded both by the system and manually to establish how effective haptic feedback is compared to the other selected feedback methods.

Visual Feedback Test

This part of the test will have only the visual feedback enabled in the prototype. The test will therefore be carried out to establish whether the users interacting with the environment are able to interpret the feedback effectively on the invisible path to the location of the hidden object or shape identification. Relevant data will be taken from the users’ interaction with this unit of the prototype and used in the


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analysis of the research question. An assumption will be made in this section of the experiment, that the users are not colour blind and their vision is 20-20.

Haptic and Visual Feedback Test

This unit of the test, will have both haptic and visual feedback enabled in the prototype to evaluate the effectiveness of the two feedback methods because according to Gepshtein et al (2005) the nervous system has the ability to combine information from different senses for perceptual precision. This implies that results obtained from this test will be reliable only on the assumption that users interacting with the prototype have their visual and haptic sense working normally. The results obtained from this test will be analysed and compared to the previously mentioned test for a conclusive result.

PROTOTYPEOn successful completion of the test bed application, the team proceeded to set up the prototype and readied the environment for the experiment and user trials to take place. The setup of the prototype can be seen clearly in the diagram below (See diagram 1) and the key features will be described below:-

Physical Components of the set up included the camera, a monitor, computer and a vibro-box which were assembled as shown in figure 2 below.

Vibro box

The vibro-box, which is a crucial component of the setup was assembled and installed using an open source software Arduino-1.0.3 and an Arduino microcontroller board which according to Durfee (2011) is a low cost hardware used in interaction design. Some of the key libraries installed along included Firmata which enabled the vibration in the prototype, LiquidCrystal and Ethernet which were of less relevance to the application compared to Firmata.

A fudicial marker was attached to the vibro-box, a combination which formed the tangible user object. Ulmer and Ishii (2001) defined these as user interfaces that couple physical representations or spatially manipulable physical objects with digital representations yielding interactive systems. This coupling of digital information would aid the users interacting with the prototype carry out the tasks using natural gestures as the attempt to discover the object in the environment. This would ultimately lead to more accurate results, an argument put forward by Xie (2000).

The camera, which with the aid of reacTIVision captures this information and relays it to processing for manipulation and is eventually represented digitally. The setup is inform of an interactive table-top because of the advantages stated by Xie (2000) in her research on interactive table tops, which pointed out two important factors that give these environments an edge. These include room for synchronous collaborative task which would allow collaboration especially the section of the experiment where the users would require the researchers’ guidance on navigating and interpreting feedback in the environment. The manipulation of objects in a 3D space with tactile objects also encouraged interaction.


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Figure 1:- User interacting with the prototype

To effectively utilize the space available on the play area, the vibro-box position was altered such that it occupied a smaller surface area on the screen. This allowed the users more room to manoeuvre in finding the invisible object and tracing it actual shape.

The major limitation with the design, especially of the vibro-box, was the degrees of freedom. Since it was attached to the computer, the already limited 2 DOF were more restricted by the code attaching the box to the central processing unit (CPU) of the computer.

Prior to the actual user trials, the prototype was designed with a test section which would allow the research team establish the psychophysical variables of the individual users before they interacted with the environment. This was purposely because different individuals have different sensory threshold values and the prototype had to cater for all the users that were going to perform the test. The research team used the test scenario to establish the sensory threshold, which was the weakest detectable sensation of the vibration stimulus for all the users.

This was obtained by testing and tabulating the absolute threshold values for all the users and then by altering the basic dimensions of the relevant vibration, the differential value was obtained.

USER THRESHOLDUser 1 70User 2 50User 3 30User 4 100


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Figure 2:- laboratory set up of prototype.

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*These values were obtained by changing both the duration and period of the pulse vibration for each user to arrive at their individual absolute thresholds.

This implied that the differential threshold was 100. Using this the vibration values were set for the individual users before they interacted with the environment.

USER ABSOLUTE THRESHOLD RELATIVE THRESHOLDUser 1 70 30.0User 2 50 50.0User 3 30 70.0User 4 100 00.0

*Absolute threshold is the lowest level of intensity at which stimulus can be detected.

*Relative threshold is the amount that a stimulus of standard intensity must be changed in order for a difference to be noticed.

A variety of vibration sensations was used in the test bed which included and limited to only pulse and Edge. These were set with the standard vibration sensation and used in different area as feedback for the users.

-Edge vibration pattern was used to indicate that the user was crossing to an area that was prohibited with the assumption that the constant nuisance would compel the individual to return to the area with no vibration. When combined with the visual feedback, this was the red section which is associated with incorrectness according to Norman’s (1990) design principles Norman (1990).

-The pulse vibration pattern was used to indicate that the user was supposed to turn in the environment a concept which was used because the natural human relation to the car indicator and when combined with the visual feedback this area was indicated by the blinking of the TUI representation in the environment.

EVALUATIONEvaluation of the system was carried out because according to Preece et al (2011) evaluation is an integral part of any design process. Regardless of the fact that the interface design in the prototype was secondary in terms of importance, a formative evaluation was carried out. Focus was mainly on two forms of evaluation:-

Heuristic Evaluation – where knowledge of typical users interacting with the environment was applied to identify usability problems and improve the design of the prototype for more accurate results.

Predictive Evaluation – where the research team used theory based knowledge to predict user performance while interacting with the environment. This helped to improve the prototype in areas that would theoretically be problematic to the users especially as far as interpreting feedback was concerned. The feedback in these areas was made distinct and clear. The team could also have a futuristic idea of what kind of results they expected from the users.

For the purpose of this research, users in a natural setting (lab) to evaluate how they interacted with the prototype.


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The method used in this phase of the evaluation were:-

Observation: - Users were observed as they interacted with the prototype and data was collected from the interaction. They were also requested to think aloud as the performed the tests and logs of data were captured from each users’ interaction an evaluation method referred to as logging.

Results ObtainedThe results that were captured by the system were displayed in their respective areas illustrated in the figure below. (See Appendix C)

The Off Target hits were obtained from two areas which were the data logs from the system from which a graph was plotted.

For Pure Haptic (See Appendix A)

USER OFF TARGET HITSUser 1 1User 2 4User 3 1User 4 3

For Pure Haptic + Visual (See Appendix B)

USER OFF TARGET HITSUser 1 1User 2 0User 3 0User 4 1

Using correlation, some of the point (x, y) that were captured were ignored because they did not fall within the range for the graph that was being plotted. Therefore it was necessary to analyse these results side by side with the graph to obtain a clear picture of exactly what the results were communicating.

Using the following code snippet on the next page,

if(targethitGREEN){o.fillCol=color(0,255,0);

slipOff = watch.mills() - slipOffCounter;}

if(targethitORANGE)

{o.fillCol=color(255,183,0);slipOffCounter = mill();}


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The slipOff time was obtained automatically using the mills function of processing whenever the user slipped out of the zone shown in the graph below (See Appendix A) as the green. Whenever the user slipped out of this zone, a time stamp was taken that helped calculate how much time they spent out of this zone, and the action is repeated for every time the user slips out. The resultant slipOff time is obtained by subtracting the total time from the total slipOff time.

The coordinated were also constantly captured and stored in a notepad file, these were eventually transferred to an excel sheet which automatically plotted the graph. (See Appendix A & B)

FindingsFrom the results obtained during the experiment, it was observed that the number of Off Target hits obtained in pure haptic feedback were 5 more than those observed in haptic and visual feedback combined. These results where related to the graphs drawn from the x and y coordinates taken at regular time intervals (See Appendix D & E) to clear any doubt before a conclusive decision was made. These indicate that haptic feedback is not effective as a standalone feedback method and that a combination of haptic and visual feedback would be more reliable under the circumstances.

CONCLUSIONThe test bed and the entire prototype helped the research team carry out the experiment successfully and obtain conclusive results about how effective haptic technology is especially in object discovery and shape identification but this is not to say that haptic feedback is not effective at all. It is very clear from the results that haptic feedback is more effective when it is combine with another form of feedback which in this case is visual feedback.

In future, for an important experimental research like this one, a more advanced technology would be used simply because the vibro-box which had an attachment code did not allow users freedom to explore in addition to the fact that as a gadget, it is restricted to only 2 DOF (Degrees Of Freedom).

The processing and reacTIVision also appeared to show unexpected bugs a clear indication that the two elements are not quite ready for main stream use. Some of the unexpected results during the tests were mainly attributed to this. The unexpected results were omitted at the analysis stage of the experiment. A better software combination in future would most probably lead to more accurate results.

Reflective ReportThis research was very educative for someone that is as interested in novel technologies as me, because as part of the team, I was in charge of all research that included theory based evaluation and all other information required regarding evaluation and the subject as a whole. With the help of my colleagues Sahil Khatri and Severine Boniface we brainstormed on the research question. The test bed and the coding to ensure the prototype was working perfectly was one of my secondary roles. Since I was rich with the theory of the experiment, I was in charge of the observation process during the user trials, gathered and recorded all relevant data to enable the team come up with conclusive results.

Reference list and Bibliography


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1. Xie, Z. (2008) Comparing Children’s Enjoyment and Engagement Using Physical, Graphical and

Tangible User Interfaces. Partial fulfilment of master of science degree , Spring (2008)

2. Ishii, H. and Ullmer, B (2001) Emerging Frameworks for Tangible User Interfaces. Human-

Computer Interaction in the New Millennium, (January), pp. 579 – 601.

3. Preece et al. (2011) Interaction Design – Beyond Human Computing. 3rd ed. Chapter 12.

4. Lederman, S.J. and Klatzky, R.L, (2009). Haptic Perception: A tutorial. Attention, Perception &

Psychophysics. 71 (7), pp.1439-1459

5. Lederman, S.J. and Klatzky, R.L, (2009). Haptic Perception: A tutorial. Attention, Perception &

Psychophysics. 71 (7), pp.1439-1459

6. Norman, D. (1998). The Design of Everyday Things. Reprinted Ed. USA: MIT Press.

7. Ishii, H. (2006). Tangible User Interfaces. CHI Workshop. pp.1-127

8. Johansson, R.S. and Vallbo, A.B, (1983). Tactile sensory coding in the glabrous skin of the human

hand. Trends in NeuroSciences. 6 (1), pp.27-32

9. Gescheider, G.A, (1985). Psychophysics method, theory and application. 2nd ed. New Jersey:

Lawrence Erbaum Associates.

10. Gepshtein, S., Burge, J., Ernst, M.O., and Banks, M.S., (2005). The combination of vision and

touch depends on spatial proximity. Journal of Vision. 5, pp.1013-1023

11. Huang, Y., Moll, J., Sallanas, E., and Sundblad, Y, (2007). Integrating audio and haptic feedback

in a collaborative virtual environment. Proceedigs of HCI International. HCI-74.

12. Johansson, R.S. and Vallbo, A.B, (2011). Estimation of Vibration and Force Stimulus Thresholds

for Haptic Guidance in MIS Training. Journal of Biomedical Engineering. 5 (10), pp.17-22

13. Norman, D. (2002). Psychology of Everyday Things. New York: Basic Books.

14. Waard, D., (1996). The Measurement of Driver's Mental Workload. Netherlands: The Traffic

Research Centre.

15. Sharma, N., Uppal, S. and Gupta, S., (2011). Technology Based On Touch: Haptics Technology.

IJCEM. 12, pp.34-38


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APPENDIX

Appendix A

Appendix B


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Appendix C

Appendix D


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Appendix E

END


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