Keywords

1 Introduction

Due to the development of technology, the functions of cameras have become more and more diverse as the operation of products has become more and more complicated, which also attributes to the lack of availability of most camera products. With the usability research methods, it is convenient to find some problems in the digital camera interaction design, and then the designer can gradually solve these problems, which can bring a better operating experience to the users.

This study aims to investigate whether the functions of GR II cater to all the users and whether this digital camera exists any usability issues. GR II is not only high-quality enough to take good pictures, but also is convenient and portable, which means it is easy to carry with travelers. But this digital camera occupies a much less market amount than Canon and Nikon, in China. So, we plan to carry out usability experiment investigation, related theoretical research and technical analysis on it, and try to find some aspects imperatively to improve.

2 Experiment Method

The study is based on the user experience measurement and usability metrics [6]. According to the international organization for standardization [7, 8], it is mentioned that the usability of something should be measured in three dimensions: effectiveness, efficiency and satisfaction.

According to ISO 9241. Ergonomics of human-system interaction [9]—(ISO International Organization for Standardization).

The definition of effectiveness refers to whether the user task is completed or not, and whether the task is completed is valid. Efficiency is defined as the speed at which a user’s task is completed. Satisfaction is defined as the satisfaction of the user’s process of completing related tasks.

We try to measure the main functions of the camera and identify whether the goal is combined well with the function, if not, we will put forward the improvement proposal with the reference to the participants’ data.

2.1 Materials

In the experiment, the common type of GR II available on the market was selected, as shown in Fig. 1. Since the images saved in the camera can be displayed on/imported to a communication device by directly connecting both the devices via Wi-Fi and using the dedicated application “Image Sync”, a cellphone was needed in this process.

Fig. 1.
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GR II

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We used video camera to record the behavior of the participants and wrote down what they spoke during the tasks.

2.2 Participants

Eight participants were enrolled from Hunan University and Hunan Normal University, after they signed the Informed Consent Form, we used the user information form to distinguish them into three groups: novice, normal and expert. We used task book to guide them to finish the tasks. After that, they were asked to fill the questionnaires immediately. We used these self-reporting questionnaires to collect subjective & qualitative data.

2.3 Questionnaire Design

In the course of the experiment, the participants need to complete three kinds of questionnaires: the user information table questionnaire, the post-mission satisfaction questionnaire, and the product icon recognition questionnaire [10].

User Information Table.

The purpose of the questionnaire is to understand the basic situation of the participants, the background of the camera and the experience of using the camera to ensure a balanced group. Through the understanding of the basic information, we divided the participants into three groups, namely novices, ordinary users, and expert groups;

Post-mission Satisfaction Questionnaire.

The post-mission questionnaire was based primarily on the SUS System Usability Questionnaire [11], which was used to collect feedback from participants after completing each task, including scoring camera interfaces, icons, and subjective impressions of GR II used in the experiment;

Product Icon Cognitive Questionnaire.

The product icon cognition is mainly used to collect the participant’s cognition of the camera interface, icons, and button identification, and is conducted by means of interviews and questionnaires [12].

2.4 Task Analysis

Referring to different categories, we defined camera operation into three steps, including 1) getting ready, 2) adjusting parameters and shooting, 3) downloading into the cellphone. Understanding the user’s tasks at both a high and a detailed level [13, 14], we decomposed them into the detailed subtasks defining them and developed a hierarchical breakdown, as shown in Fig. 2.

Fig. 2.
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Flowchart of the ordinary activity of the task of “Using GR II”

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2.5 Think Aloud

Think aloud method was used to let the user speak while thinking about what he wants [14]. During the operation, the user can say “I think the following should be done like this…”. In this way, we can grasp which part of the user’s attention, what he thinks, and what kind of operation is taken. This is a very effective evaluation method that can figure out why it leads to bad results.

The focus of think aloud observation:

  • Has the user completed the task independently? If the task cannot be completed independently, the product has a validity problem.

  • Did the user perform an invalid operation or be at a loss during the process of achieving the goal? If there is, the product has efficiency issues.

  • Does the user have feelings of dissatisfaction? If there is, there is a problem with the satisfaction of the product.

Then, we quantitatively and statistically evaluated the effectiveness, efficiency and satisfaction of Think aloud, study the cognitive process of users, explore the cognitive factors and variables that affect GR II, and analyze the different stages of the user’s use process according to the analysis results. Cognitive features, thus incorporating the user’s cognitive characteristics into the user-use process model based on problem-solving theory, to form a more complete model.

Sometimes, there is a problem in the user test, but for some reason we are not convenient to interrupt the user to ask questions in depth, or the user would miss some information by thinking aloud. At this point, after the test is completed, the tester will ask questions about the problems that occurred during the test.

3 Analysis

Behavioral and subjective data were collected to measure the usability of each task. Average and variance were used to compare whether there is significant difference between different tasks; and Chi-square test method were employed to whether performances vary significantly among normal, expert and novice group [15].

3.1 Qualitative Data

Qualitative data includes user’s feelings and words. They all are objective comments and reveal the basic problems.

This part is the “Think aloud”, we gathered the words and ranked them to get the highest frequent problems, as shown in Table 1. We can find that there exist some problems of the battery cover, mode dial, and some parts of the camera do not conform to users’ habits according to the result.

Table 1. The most frequent problems
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3.2 Quantitative Data

Quantitative data includes finish time and accurate rate under each task for three groups, as well as the self-report questionnaires.

Usability Characteristics.

We collected and analyzed the mistakes during the three tasks, and calculated the data to describe the effectiveness (As shown in Table 2). We recorded the time consumed during tasks and calculated the the reciprocal to describe the efficiency (As shown in Table 3). We also analyzed the result of post-mission satisfaction questionnaire to arrive at the conclusion of satisfaction (Table 4).

Table 2. Experiment result of the effectiveness of the 3 tasks
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Table 3. Experiment result of the efficiency of the 3 tasks
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Table 4. Experiment result of the satisfaction of the 3 tasks
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The record of the task time frequency is used to compare the efficiency of the task, after calculating the reciprocal of the time. From the histogram (Fig. 3) above, we can conclude that task 2 is the most time-consuming, which indicates there remain the most issues during task 2 and we will pay much attention to this part in the analysis of the camera interface design (Fig. 4).

Fig. 3.
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Histogram for comparison of task time frequency

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Fig. 4.
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Chart for comparison of average and variance

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The three tasks’ availabilities vary a little, but the variance of task 2 is much higher, which means task 2 may lead to cognitive errors of new users. And task 2 takes a lot of time to learn. The situations of novice, normal and professional in task 3 vary least of all. So we come to a conclusion that the usability of task 2 is the lowest [13].

Performance Measurement.

We analyzed the task of each participant in 5 dimensions: task success, finish time, errors, efficiency and learnability [10]. And then we got the average mark of each step to compare with each other, with a chart (Fig. 5) ranking the figure, finally found the most severe task or step. We selected one of the participant’s measurement results as an example (as shown in Table 5).

Fig. 5.
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Chart for average data of performance measurement

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Table 5. Measurement of each step’s performance (User 01)
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  • Observed = Observations refer to the number of participants who successfully completed the task for each group of participants.

  • expected = Average number of successful completions in each group of participants chi-test = (observed value, expected value)

The table above (Fig. 6) shows the three results of Chi-square Test are lower than “Significance level P = 0.05”, so our observation experiment result is close to the theoretical inference. Through inspection, it is necessary to know that the improvement of the problems in task 2 is urging. It will be easy for novices to learn, if the company try to achieve the expected efficiency.

Fig. 6.
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Result of the Chi-square Test

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4 Findings

4.1 Preliminary Ideas

Quantitative data reveals that task 2 (Adjusting parameters and shooting) remains the most usability problems, and then we pay attention to the subjective data of task 2 to get to know how do the functions not fit with the user objectives.

Through the videos we recorded during the tasks, we can get to know the position and design of some icons confused the participants, and most of novices get stuck. They tend to make mistakes at that step.

We also use intensive interview to get more details, and experts expressed their experience of using it and gave some opinion of the design.

4.2 Problems and Improvements

Five users think they can close the battery/card cover directly so we will change this structure into a new one that when the users close the cover, they needn’t slide the release lever to lock it.

Playback is an important function in camera design, but when a user holds the camera, this button is hidden, so we would like to change its location.

The menu and ok button’s function’s misleading so we will change it to ok button and then add a new menu button in the top right corner.

And we will change normal screen to touch screen. There are several ways to interact: click; slide switch; double click to enlarge; double fingers to zoom in or out and so on.

For the mode dial, there are two problems: 1. Users can’t rotate directly, they need to press the mode dial lock release button firstly; 2. The mode dial makes confusions, because users think it is the mark of shooting mode.

For the Wi-Fi button, users may think it is a Wi-Fi button, but only try to have a short press, which is set for effect.

As for its interface, it not perfect, either. There are only three classification, and functions are numerous, so users can’t find the function they need quickly. Users can’t classify them clearly and the icon meaning is blurred. So, we will add a new navigation bar to subdivision, which can help users find the information which they need.

We will add a new menu button in the top right corner and change the playback button’s location. The menu and ok button are changed into the ok button. The Effect/Wi-Fi button is changed to the Wi-Fi button, and don’t need to press and hold to turn on/off the Wi-Fi function. Finally, when you close the card/battery cover, it can be closed directly. And all the improvement suggestions are shown in Fig. 7.

Fig. 7.
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Improvement of GR II

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5 Conclusions

This paper explores the usability of digital camera interaction design, and the work is as follows:

  • First: The paper designs a task list of usability tests based on user operation characteristics. It ensures the usability test method and the credibility of the task chain, and conducts targeted usability tests and questionnaires;

  • Second: The paper analyzes the data from the usability test to finds out the problems in the digital camera interaction design and summarizes the reasons and types;

  • Third: We gets the improvement points of the GR II camera based on the analysis data and determines how to improve it.

The conclusions and innovations obtained in this paper are mainly as follows:

  • First: The analysis shows that the camera’s button layout is the most relevant to the screen interface and usability. The camera’s usability is based on simple symbols and daily operation.

  • Second: In the course of the research, the user’s perception of the symbols on the camera was tested innovatively.

Due to the limited research time and the ability of the group members, there are still many deficiencies in this paper, which need to be slowly supplemented and improved.

  • First: Ricoh is a good brand. Because of the limited conditions, GRIII has been on the market for a long time when we tested GR II;

  • Second: The problem of usability of GR II in this paper is still need more deeper investigation.

  • Third: The research is a summative evaluation and we are supposed to obtain a large representative sample, but we failed to recruit enough participants for the test. The result would be more accurate if we had had adequate samples.

Although the research method of this paper is not a new theoretical method system, it is based on the research results of predecessors, and draws on the successful experience of predecessors and strengthens the research in depth. We hope that the research of this paper can be used for subsequent related design. It can provide new design ideas and technical means for the staff. The study of usability needs to be taken seriously, and we hope that through our own efforts, we can make a contribution to usability research.

With the development of technology, cameras will gradually add new features and new usability issues. This requires our team members to continue to pay attention to new developments in such issues, making research more and more perfect and satisfying more users’ needs.