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Mobile Interaction with Visual and RFID Tags – A Field
Study on User Perceptions
Kaj Mäkelä¹, Sara Belt², Dan Greenblatt³, Jonna Häkkilä¹
¹ Nokia Research Center
Itämerenkatu 11-13
00180 Helsinki
Finland
firstname.lastname@nokia.com
² Nokia Multimedia
Yrttipellontie 6
90230 Oulu
Finland
sara.belt@nokia.com
³ College of Computing
Georgia Inst. of Technology
Atlanta, GA 30332
USA
dmgreen@cc.gatech.edu
ABSTRACT
In this paper, we present a study of user perceptions on
mobile interaction with visual and RFID tags. Although
mobile interaction with tags has been proposed in several
earlier studies, user perceptions and usability comparisons
of different tag technologies have not been intensively
investigated. In contrast to earlier studies, which report on
user studies with evaluating new concepts or interaction
techniques, we take another approach and examine the
current understanding of the techniques and user
perceptions on them. Our field study of 50 users charts
currently existing user perceptions and reveals potential
usability risks that are due to the limited or erroneous
understanding of the interaction technique.
Author Keywords
User studies, RFID, visual tags, mobile interaction
ACM Classification Keywords
H5.m. Information interfaces and presentation (e.g., HCI):
Miscellaneous.
INTRODUCTION
Interacting with the physical world via a mobile handheld
device is a relatively new paradigm, which has quickly
emerged during recent years. Integrating cameras, motion
sensors, and radio frequency identification (RFID) or
barcode readers into mobile devices has made new
interaction concepts possible. Tags utilizing different
technologies have been introduced for interacting with
physical objects in a variety of applications and uses. For
instance, augmented reality applications have been
demonstrated [4], gesture recognition based on visual tags
has been performed [1], and tags have been used for
annotating the physical environment [5]. The use scenarios
also include accessing information through interacting with
a tag or using the tag for initiating some other information
channel, e.g. Bluetooth or internet connection [3, 7].
Typically, interaction with a tag employs a physical gesture
where the user (or more precisely, user’s device) points at
or touches a tag, which can be for instance an RFID tag
recognized with a device integrated reader or a visual tag
read with a camera [7, 8]. In [6], gesture semantics, i.e.
touching, pointing and scanning gestures, and their
suitability in different contexts has been examined.
Most of the research has so far focused on creating new
concepts, or utilizing tags as part of a larger system, as
opposed to specifically studying the interaction paradigm
itself. Typical for the existing studies is that they are often
used as a proof of concept with only a small sample of
users, often in a laboratory environment, with guided
instruction prior to performing interaction tasks. There
exists very little data on how users would interact with tags
without any specific instruction, their expectations of the
technology, and their perceptions regarding interacting with
these objects in public places.
In this paper we report on a field study with RFID and
visual 2D barcodes, where 50 people were interviewed and
asked to interact with the tags. The goals of our study,
conducted in ‘everyday life environment’ was to assess the
current knowledge or expectations people had with the tag
technology, the intuitiveness of usage, social acceptability,
and to predict any potential barriers to use.
DESIGN OF THE STUDY
Hypotheses
The study had a strongly exploratory nature, as it sought out
to chart the general perceptions people had with interacting
with RFID and visual tags. In addition, we had the
following hypotheses:
1. RFID and visual tags are perceived similarly in terms of
data storage and transfer.
2. Based on the ubiquity of cameraphones, camera-based
interaction in comparison to touch is perceived as more
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CHI 2007, April 28–May 3, 2007, San Jose, California, USA.
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CHI 2007 Proceedings • Tags, Tagging & Notetaking April 28-May 3, 2007 • San Jose, CA, USA
991
familiar, and thus the interaction with visual tags is more
intuitive.
Study Set-Up
The study consisted of semi-structured interviews
accompanied by interaction tasks, which were carried out in
two city centers in Finland, during summer 2006. The study
consisted of two phases, referred to in the following as A
(Oulu) and B (Tampere), which had identical set-ups. In
addition, in study B some additional details were asked in
order to verify assumptions made based on study A. The
interviews took place in an outdoor pedestrian shopping
mall, a library, and a market place. Participants were chosen
from those present on the street, aiming to achieve a
balance of male and female, with ages ranging from
teenager to middle aged (50+).
Figure 1. The poster used in the study. Above, the complete
poster with the visual tag, and below, the lower part of the
RFID poster (tag is behind the paper).
During the interview, each participant was shown two
posters, one employing an RFID tag and one a visual tag
(Figure 1). Participants were first asked about their
familiarity with a particular tag technology, then given a
brief easy-to-understand explanation of how the tag works,
and shown the tags. However, they were not told how to
interact with it. The participants were asked what kind of
information they would expect to receive from the tag, and
then given a properly-equipped mobile phone and asked to
demonstrate how they would interact with the tag (Figure
2). Answers to the interview questions, as well as
observations on usage were recorded by the researchers.
After the user had tried to use the tag and was shown the
proper usage scenario, he or she was asked to reflect on the
intuitiveness and ease-of-use of the experience. For each
participant, this process was repeated with both types of
tags. To avoid bias the order was altered so that half of the
participants started with RFID, half with visual tags.
Figure 2. A study participant reading RFID tag with a phone
The study included 50 participants (A: 11 female, 15 male;
B 13 female, 11 male). Participants’ background
information about mobile phone usage is presented in Table
1 (information from one female participant in study A is
missing, as she had to leave before completing the last
questions of the interview).
Table 1. Mobile phone usage of the study participants
Yes No
Currently carrying
a phone:
49
(A:25, B:24)
0
Owned a camera
phone:
19
(A:12, B:7)
30
(A:13, B:17)
RESULTS
In the study it was found that although the participants were
enthusiastic and open towards the presented information
acquisition methods, a large majority of the interviewed
were not familiar with the concept of either the RFID or
visual tag (see Figure 3). For some, RFID tags were known
from security tags on clothing or compact discs, but they
were not aware of their usage in the current context. Few of
the participants were able to associate the visual tag
(semacode) to the barcodes used in product packages.
As the participants did not have prior experience on which
to base their interactions with this technology, they applied
a diverse range of mental models governing what kind of
information the tags could store, and how that information
could be transferred to their mobile phone. For the visual
tag, based on its printed nature most users deduced it was
accessed with the camera. Some users suggested taking a
picture of the visual tag, while others pointed the camera at
the tag and waited for it to register automatically. For the
RFID tag, given its invisibility (i.e. hidden behind the
paper), and more advanced technology, the appropriate
CHI 2007 Proceedings • Tags, Tagging & Notetaking April 28-May 3, 2007 • San Jose, CA, USA
992
interaction technique proved slightly more elusive for
participants. The interaction techniques proposed for RFID
tags included, for example, utilizing Bluetooth, manually
typing up the visible URL to a mobile browser, reading the
tag via an infrared port, calling a stored number to hear pre-
recorded information, and taking a picture of the visual
icon.
Figure 3. Participants’ answers to if they recognized what the
tags were, or if they had seen them earlier.
Figure 4. Participants’ preferences for the tags.
For many of the participants the storage location and the
nature of the content was not clear. Many users correctly
assumed that the tag would contain some band-related
information, and some suggested specifically that it might
contain an mp3 file. The information was, in most of the
cases, considered to be in the tag itself; it was not perceived
as a reference to the actual information. This was quite
evident, as many of the participants did not even expect the
mobile phone to contain web browsing functionality.
Implicit in many participants’ responses was that the phone
would read and just store the information from the tag for
later use.
Thirty-one out of the fifty study participants preferred the
interaction paradigm of the RFID tag, while fifteen
preferred the visual tag (Figure 4). The RFID swipe was
viewed as being quicker, requiring less effort, and generally
feeling more natural than explicitly taking the picture of a
visual tag. Those that favored RFID also liked that it did not
require opening any additional application but the
interaction was instant. Those that preferred the visual tag
considered the physical action of taking a photo to be more
familiar and socially acceptable than waving the phone on
the wall.
There were also differing opinions with respect to the
aesthetics of the two different types of tags. Some people
disliked the way the visual tag looked, saying that it was too
official, vague or technological looking, while others
praised it for its sleek look, and said that they thought it
made the poster look cooler. Based solely on the
appearance of the visual tag, one participant claimed not to
be able to use the visual tag because of not being “a
mathematical person”.
Interestingly, several participants thinking from the
perspective of information producers preferred the visual
tags because they were cheaper to create and caused less
waste. However, the reliability of the tags was found to be
problematic. Participants pointed out that, as the tags were
accessible in public places, they were vulnerable to
vandalism. Visual tags could be visually manipulated and
this way their content might be altered. Also overlaying
water and dirt affects their readability. RFID can be ripped
off or changed with other tags containing information or
pointers to harmful material. Also the perceived active
nature of RFID tags caused concerns about picking up
harmful information accidentally while passing the tag.
As an answer to our hypothesis, the study showed that the
RFID and visual tags are perceived differently with respect
their nature as data storages and the way they transfer data.
The RFID was conceived to have a more active nature and
wider spatial range of functionality. Also, taking a picture
with a camera is considered to be familiar, but it does not
directly imply that it is intuitive as an interaction method.
The camera was expected to work like a continuously
sensing scanner rather than explicitly triggered reader.
DISCUSSION
User perceptions on interacting with tags have not been
extensively studied by earlier research. If user studies on
the interaction paradigm have been performed, they have
typically been used for confirming the interaction paradigm
selected for a certain application. These studies have
commonly employed only a small amount of people, and
have typically been performed in a laboratory environment,
university campus, or with IT students or professionals.
Often user studies are carried out to gain proof of concept,
in the manner of approving and justifying the research and
implementation. The results gained this way often have a
tendency to be positively biased and may not give realistic
feedback on the usability risks of the design. In our study,
we concentrated on the perceptions ‘a man on the street’
had about visual and RFID tags, and aimed to have a
sample large enough for realistic and reliable understanding
of the phenomenon.
The study results reveal that there are potential usability
risks with the mobile interaction with RFID and visual tags.
When a user is faced with any unfamiliar situation (s)he
CHI 2007 Proceedings • Tags, Tagging & Notetaking April 28-May 3, 2007 • San Jose, CA, USA
993
attempts to make sense of the world by developing a mental
model based on any prior relevant experience [2].
Currently, the mental model that people have on the
technologies is still very vague.
Characteristics that affected participants’ interactions with
the RFID and visual tags were their range of function and
visibility. The range of the RFID tags is typically less than
10 centimeters. Due to this short range of function the user
needs to be informed precisely of the location of the tag,
although the tag itself does not need to be visible. In the
study, the RFID was attached to behind the poster and its
location was indicated with visual icon. The visual icon
utilized (two concentric circles) was not a commonly
known indicator for RFID and did not therefore provide any
previously known cues for interaction. As the usage of
RFIDs or other invisible near-field communication (NFC)
becomes more common, it will be important to develop
standardized visual cues, enabling users to easily recognize
the presence of an NFC, and execute the known interaction
method.
The interaction required for triggering the tag reading was
not evident to the users. Although participants had used
cameraphones before and were used to the idea of snapping
a photo, many expected the visual tag to be recognized by
pointing at it with the camera, without initiating an explicit
capture action. This implies that the users expected the
system to be able to detect the presence of a tag. The
semacode reader application used in the study required the
user to trigger the tag reading. However, it should be noted
that there are existing applications able to detect the tag
automatically.
Both of the tags were expected to contain direct, mostly
textual information related to the band presented in the
poster. This leads us to assume that the device and
application were considered as a “lens” to view their
information content, being otherwise in an
incomprehensible, encrypted form. The users were
surprised when the recognized identifier triggered a
browser which then retrieved information from the internet.
They did not expect the identifier to act as reference or
trigger for other applications. In addition, the information
display was expected quite often to be dependent on the
proximity with the tag. The tag was held in the scope of the
device, either within the viewfinder of the camera or in the
proximity of the RFID module even after the actual tag
recognition occurred. This observation also supports the
concept of the device as a lens to view local information.
However, as the nature of the tag may vary in different
contexts between local storage and a reference to the actual
remote resource, it is challenging to provide a mental model
fitting to each context.
As the study was conducted in two cities within a single
country, it is therefore somewhat limited by the
geographical and cultural environment. However, we
believe that it reflects the general situation in industrial,
urban environment in a western culture.
CONCLUSIONS
In this paper, we presented a study of user perceptions on
mobile interaction with visual and RFID tags. The study
was conducted for 50 participants in two Finnish cities as
semi-structured interviews accompanied with interaction
tasks. In the study we found that the large majority of the
participants were not familiar with the concept of either the
RFID or visual tag and did not have clear knowledge of
their application prior to the interview. Together with the
lack of prior experience, minimal visual interaction cues
caused misconceptions and usability problems while
interacting with the tags. Their range of function and
methods for accessing the data were often unclear and
misconceived. The tags were assumed to contain direct
information in encrypted form in contrast to acting as
references to networked data resources.
In the future, conducting a similar study in another regional
location and culture would offer valuable insight into the
stage of local development and the cultural variables
affecting the usage of the tags. In addition, the evaluation of
metaphors and visual design of physical tags affecting the
user’s perception of the interaction with the tags would
require further study.
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