A cost-effective interactive 3D virtual reality system applied to military live firing training

Virtual Reality (2016) 20:127–140 DOI 10.1007/s10055-016-0284-x ORIGINAL ARTICLE A cost-effective interactive 3D virtual reality system applied to military live firing training Kaushal Kumar Bhagat1 • Wei-Kai Liou2 • Chun-Yen Chang1,2,3 Received: 23 May 2015 / Accepted: 14 April 2016 / Published online: 27 April 2016 Ó Springer-Verlag London 2016 Abstract The goal of the present study was to develop a 1 Introduction cost-effective, man–machine digital interface, to improve students’ real-world firing range training, results, and This work integrated invisible laser infrared technology, achievement scores. A serious game-based learning envi- 1:1 real-scale rifle guns with recoil effects, and 3D inter- ronment was developed, integrating invisible laser infrared active virtual reality (VR) military training digital infor- technology, 1:1 real-scale rifle guns with recoil effects, as mation content. The use of digital information technology well as 3D interactive virtual reality (VR) military training in education has given birth to a new generation of edu- digital information content, to train students in military live cational design patterns. However, compared to other firing. To evaluate the effectiveness of the proposed design, subjects, the use of military training courses, which com- students’ performance, in terms of their learning achieve- bine research and digital information technology, is still ment and learning motivation, was examined. One hundred lacking. The goal of this study was to develop a prototype and sixty high school students from Taiwan were divided simulation-based training concept, to improve users’ real- into four individual groups of 40 students each, with one world firing range skills and results. control group and three experimental groups (EG1, EG2, The challenge for such a simulation is how to provide and EG3). The data were analyzed by one-way analysis of the learner with experience in real-world firing range skills. variance. The results of this cost-effective 3D VR showed Currently, most digital real-world firing range systems significantly better learning motivation, learning outcomes, implement the use of visible laser tracking technology as and positive impacts on users’ actual live firing achieve- their core technology (Hagman 2000). Although different ment scores. from the actual trajectory path of a bullet, a laser light’s straight-line property is, nevertheless, suitable in simulat- Keywords Serious games Virtual reality (VR) Military ing the resulting trajectory in live firing training (US training Learning outcome Learning motivation Department of Defense 2013) as shown in Fig. 1. In this study, we only focus on basic live firing training. Dynamic influences such as rain, wind, and sunlight effects will be Kaushal Kumar Bhagat and Wei-Kai Liou have contributed equally to this work. presented in future stages of this study. The main problem of a visible laser point is that it & Chun-Yen Chang provides unnecessary reference coordinates for the learner

to correct their trajectory (Liou and Lee 2012). Likewise, 1 Graduate Institute of Science Education, National Taiwan the reality of gun recoil is an important factor the learner Normal University, Taipei, Taiwan, ROC must deal with during actual shooting (Wolff et al. 2003). 2 Hence, we adopt invisible lasers, 1:1 real-scale guns with Science Education Center, National Taiwan Normal University, 88 Section 4, Ting-Chou Road, Taipei 116, the recoil effect devices, and totally immersive 3D VR Taiwan, ROC technology in this work; these units, together with a 3D VR 3 Department of Earth Sciences, National Taiwan Normal real-world firing range program, supply learners with an University, Taipei, Taiwan, ROC immersive training exercise. By combining the three 123 128 Virtual Reality (2016) 20:127–140 Fig. 1 Laser light has a straight-line property, suitable for simulating the resulting trajectory of live firing training technologies, invisible laser image acquisition, gun recoil, outcome (Hummel et al. 2011; Ku et al. 2014; Sa´nchez and and 3D VR, we have succeeded in developing an economic Olivares 2011; Sung and Hwang 2013; Sung et al. 2015), and effective digital real-world firing range system (suit- enhance students’ learning motivation (Hwang and Wu able for any basic-level training unit utilizing rifle and live 2012; Kebritchi et al. 2010; Lim 2008; Papastergiou 2009; firing training). To evaluate the effectiveness of the pro- Sung and Hwang 2013; Sung et al. 2015; Wijers et al. posed design, students’ performances, in terms of their 2008), help in the development of skills (Garris et al. learning achievement and learning motivation, are 2002), and promote student engagement (Huizenga et al. examined. 2009; Hung et al. 2014; Lim 2008; Wang and Chen 2010). It can be seen that serious games encompass a wealth of potential to be integrated into formal and informal learning 2 Serious game and its effectiveness settings. Many research studies and reports advocate the use of With the recent advancement in technology, serious games, serious games for military training purpose. For example, also known as digital game-based learning, have attracted Lim and Jung (2013) stated that virtual military training is much attention to the field of education. Serious games one of the major objectives of military serious games; attempt to deliver engaging learning environments using they advocate for military serious games as they save gaming interfaces that are familiar to the end users (Csete resources in terms of time and costs. Hsu (2010) men- et al. 2004; Van Der Spek et al. 2011). According to Marsh tioned that serious games, when aligned with military (2011), ‘‘serious games are digital games, simulations, training, enhanced the fighting skills of US military virtual environments and mixed reality/media that provide recruits and also protected them from mental stress. opportunities to engage in activities through responsive Simulation games in military training can provide a real- narrative/story, gameplay or encounters to inform, influ- life experience, without harming any life or equipment. In ence, for well-being, and/or experience, to convey mean- addition, they can save many millions of dollars for ing. The quality or success of serious games is training purposes (Kennedy 1999). The US Army’s Future characterized by the degree to which purpose has been Holistic Training Environment Live Synthetic program fulfilled. Serious games are identified along a continuum has adopted a new approach to providing cheaper and from games for purpose at one end, through experiential more effective training for the future soldiers by inte- environments with minimal or no gaming characteristics grating combat training with various simulations (Szondy for experience at the other end’’ (p. 63). In another defi- 2014). National Post (2013) reported that the Canadian nition, Miller et al. (2011) defined serious games as military adopted video simulations, including commercial ‘‘games primarily focused on education rather than enter- games such as call of duty for enhancing shooting skills tainment’’ (p. 1425). Hummel et al. (2011) mentioned that and also for cost-cutting purposes. Whitney et al. (2014) serious games are purposively designed to educate and reviewed the effectiveness of game-based training for train for learning. soldiers. They concluded that empirical evidence involv- Many empirical research studies point out the positive ing the effectiveness of computer game-based training for outcomes of serious games as they improve learning soldiers was very limited. 123 Virtual Reality (2016) 20:127–140 129 From the above literature review, two conclusions can the opportunity to execute simulations of live firing train- be drawn. First, serious games have great underlying ing. Although those systems provided valuable assistance potentials and thus may be integrated in formal and for training needs, their price and volume are a major informal settings for teaching and training purposes. Sec- concern for many users; a common digital real-world firing ond, although there have been studies that included serious range system, with basic functions, costs upwards of games for military training purposes, they are limited and 100,000 US dollars and is not portable. Therefore, how to need to be explored further in terms of education and real- make an economical and convenient solution for digital life results. Thus, in the present study, we developed a real-world firing range systems is an attractive topic for serious game-based learning environment by integrating a many researchers. This work develops an economic and 3D interactive VR and military training course with digital effective digital real-world firing range system for any information content to train the students for live firing. basic-level training unit utilizing rifle and live firing training. 3 System design 3.2 Totally immersive effect This work integrates infrared technology, 1:1 real-scale Important factors, such as gun recoil effect, cannot be rifle guns with recoil effects, and 3D interactive VR mili- included in most traditional simulation shooting practice tary training digital software to develop an economical and (such as US Patent No. 4050166 A). However, the reality effective technique for rifle real-world firing range as of gun recoil is a very important factor the learner must shown in Fig. 2. deal with during actual shooting (Wolff et al. 2003). Hence, in this work, we adopt 1:1 real-scale guns, with the 3.1 An economical and convenient solution recoil effect device on simulation rifle gun. This unit, together with a 3D VR real-world firing range program, Today, traditional shooting practice is being replaced by supplies learners with a simulation-based training exercise. real-world firing range systems, which combine digital information technology/simulation gun systems. Digitally 3.3 Invisible laser infrared (ILI) technology simulated real-world firing range systems use human–sys- tem interfaces, for interactive operations, to replicate live Invisible laser infrared tracking technology may help firing training. learners to adopt actual shooting techniques to hit targets The armed troops of many countries have succeeded in more precisely. Previously, most digital real-world firing the development of large-scale computer simulations of range systems implemented the use of visible laser tracking live firing training. These provide those armed troops with technology as their core technology (Hagman 2000). The Fig. 2 A concept of an innovative 3D interactive VR system 123 130 Virtual Reality (2016) 20:127–140 main problem of a visible laser point is that it provides 4.1.2 The internal coordinates with external coordinate unnecessary reference coordinates for the learner to correct convert operation their trajectory (Liou and Lee 2012). Thus, training uti- lizing a visible laser practice system will have a negative The ILI emission unit is for emitting an invisible laser impact on shooting essentials. Learners, utilizing an infrared spot image on the screen. Based on the coordinates invisible laser, can be better prepared for essential and of the ILI spot (detected through the image capture unit and basic real-world firing. the coordinate converter operation), the internal coordi- nates may be turned into external coordinates on the data processing unit. The location of the ILI spot, through image 4 Technical characteristics acquisition calibration, as well as an internal and external coordinate converter operation, can guide the cursor output By combining three technologies (invisible laser image by the data processing unit, via on-screen imaging to acquisition, gun recoil, and 3D VR), we have attempted to launch synchronous coordinates with the ILI spot. demonstrate a useful technique for military live firing training. This research technology is divided into three 4.1.3 Calibration technology sections, described below. The calibration utilizes an automatic four-corner localiza- 4.1 Invisible laser infrared (ILI) technology tion method to adjust the coordinates of the mouse cursor on the screen (mathematical matrix transformation). This This work developed and incorporated an auto-positioning automatic calibration only takes a few seconds each time. and ILI spot tracking method for the purpose of feasibility The coordinate of the mouse cursor is followed by a to use in various human–machine interface system opera- defined sequence for completing the calibration. When a tions. We proposed a method to achieve a quick auto-cal- corner is captured by the camera, the tracking process can ibration, which gives a fast positioning and tracking for be started; at this time, the cursor tracking is set up com- solving an ILI tracking problem, by utilizing a common pletely. Once the calibration stage is completed, the system webcam. This method is developed by coordinating the starts its main loop. The main loop consists of a series of projector’s screen with the computer’s screen, and works image manipulations that are performed on each frame and between two coordinate systems. By combining a common result in an array of coordinates pertaining to coordinate webcam with visual identification and geometry conver- points on the screen. After image processing and computer sion, we can capture a snapshot of a projector’s screen. software program operations, the movement of an image After a quick analysis and vertices calculation, a conver- can be transformed by a cursor command to guide the sion matrix can be obtained, which is an important pro- invisible laser infrared spot precisely as shown in Fig. 3. cedure for the conversion of the ILI spot from external After the image acquisition and automatic four-corner coordinate to internal coordinate. ILI tracking technology localization methods are complete, the system can adjust promotes the learner to adopt shooting essentials to hit the the coordinates of the internal coordinates with external target precisely. coordinate conversion operation, as shown in Fig. 4. Then, the ILI spot on the screen, emitted from muzzle, can be 4.1.1 Image acquisition directly transformed into a mouse cursor position and click command to guide the bullet impact precisely as shown in The ILI unit emits an invisible laser infrared spot on the Fig. 5. screen. The ILI spot is then detected by a data processing unit through an image capturing unit. The image is utilized 4.2 Simulation rifle gun to display the output image from the data processing unit. The image acquisition technology, utilized in this study, is The second technology involves installing an invisible a 390–700-nm-visible-light filter. This light filter lens may laser infrared emitter source on the muzzle, and a recoil effectively filter the 390–700-nm-visible-light on the effect device on simulation T91 rifle gun. The T91 assault screen image. The wavelength of the invisible laser infra- rifle is produced by 205th Armory in Taiwan. It incor- red spot is higher than the 390–700-nm visible-light. This porates features from the M16 and AR-18. The T91 is allows the optics photography function to trace the ILI lighter and shorter with modern features. This rifle has a emitter spot on the screen image. Utilizing this spot 6-position telescopic stock, allowing for the installation of tracking provides the coordinates of the ILI spot with good different kinds of equipment depending on individual precision. requirements. 123 Virtual Reality (2016) 20:127–140 131 Fig. 3 a A red visible-light filter lens transforms the whole image, four-corner localization method, d by the four-corner localization and the background turns into a full red view, b the four white corners method, and the control cursor can launch precise and synchronous are captured by the camera, c the calibration comes from an automatic movement with the laser spot Fig. 4 By means of image acquisition, the system can adjust the coordinates of the internal coordinates with the external coordinate conversion operation The recoil effect device is made possible through a gas scenario to achieve a true simulation of a real-world firing power system. Before shooting, the gas is filled into the gas range, as shown in Fig. 6. magazine. During shooting, the gas inside the magazine will drive barrel firing recoil. By linking invisible laser 4.3 3D VR real-world firing range software infrared emitter source on the muzzle, and a recoil effect device on simulation T91 rifle gun, a true shooting expe- The 3D VR real-world firing range software in this study, rience is provided. This gives the learner a realistic as shown in Fig. 7, utilizes the Unity game engine. Unity is 123 132 Virtual Reality (2016) 20:127–140 Fig. 5 ILI spot on the screen may be directly transformed into a simulated bullet impact point a powerful game development engine. We selected this 4.3.2 Combat training mode software because it is cross-platform software well sup- ported by a vast ecosystem of art and design resources. For In our combat training mode, we have two shooting independent developers, this software breaks time and cost training modes. The first is a moving enemy attack mode barriers for creating works as needed. (see Fig. 11). The purpose of this mode, for the learner, is to establish the basics of shooting skills, become familiar 4.3.1 Real-world firing range training mode with shooting essentials, and increase the learner’s moti- vation on learning. The digital real-world firing range software is divided into The second mode is a fixed enemy attack mode (see five training modes as follows: Fig. 12). The purpose of this mode is for the learner to Training modes 1–3 are 25-, 75-, and 175-m fixed target practice shooting essentials and hit the target precisely. The training mode, respectively. Each training mode, 1–3, has a fixed enemy attack distance was designed as per the fixed different shooting range for the learner to practice live target training mode, 25-, 75-, and 175-m. The purpose of firing at different distances. These distances and scenarios this fixed enemy attack mode is almost the same as the were designed based on true live firing ranges. Learner can fixed target training mode as mentioned above. The learner be trained in these practice modes as if he were in a true needs to concentrate on their shooting essentials to hit the firing range as shown in Fig. 8. enemy precisely. It was found that most learners are will- Training modes 4 and 5 are mobile target training ing to practice and practice on their own without any modes. The training purpose on these modes is for the coercion. learner to practice advanced shooting skill as the target is not fixed in position (i.e., the target is moving). These modes include 75 and 175 m targets for training. All sce- 5 Methods narios in these modes are also designed based on true firing range training as shown in Fig. 9. 5.1 Research design and sample The other important function in this software is that the system can record the bullet impact points automatically, The present study followed a post-test only quasi-experi- as shown in Fig. 10a, b. Based on this function, trainers can mental design. A total of 160 (males = 90, females = 70) observe information about the learner’s learning status and Taiwanese high school students, aged 15–16 years, were learning outcomes. Following the records stored by the divided into four individual groups of 40 students, system, trainers may develop teaching strategies, correct including: one control group (CG) and three experimental the learner’s weak point(s) on shooting, and improve the groups (EG1, EG2, and EG3). All the participants in this learner’s shooting and essential skills. study had previous gaming experience. The independent 123 Virtual Reality (2016) 20:127–140 133 Fig. 6 Invisible laser infrared emitter source and a recoil effect device on a simulation T91 rifle gun variable in the present study was the training mode (i.e., projector screen were used as hardware. The learner’s ordinary real-world firing range vs. real-world firing range learning outcome was taken from the shooting scores, mode in 3D interactive VR vs. combat training mode vs. from a true real-world firing range, as shown in Fig. 13. In both real-world firing range mode and combat training order to measure learner’s motivation, a questionnaire mode). The dependent variables were learning outcome was developed. To maintain the content validity, a group and motivation. of experts from the field of educational technology reviewed the items. The questionnaire was constructed 5.2 Instruments based on the reviewer’s comments and suggestions. A pilot test of the questionnaire was conducted with 70 In the present study, we used OpenCV and Unity as participants. The resulting questionnaire consisted of ten software to develop automatic calibration and 3D real- items, which is included as ‘‘Appendix’’ section. The world firing range, respectively. In addition, a simulation overall Cronbach’s a (internal consistency) for the ques- T91 gun, a laptop (with webcam), a projector, and a tionnaire was 0.796. 123 134 Virtual Reality (2016) 20:127–140 Fig. 7 3D VR real-world firing range software 5.3 Procedure using the statistical package for the social sciences version 21 (SPSS 21). The statistical significance level was set at Classes were 8 h (2 h per week) in length, for a total of p \ 0.05. 4 weeks in the experimental course with different didac- tics. In the first stage, teacher started the automatic cali- bration software as mentioned above. As the calibration 6 Results and discussion stage was completed, the movement of bullet impact points could be transformed by a cursor command to guide the ILI 6.1 Learning outcome spots precisely. The students utilized firearms installed with ILI emitter sources, on the muzzles, and recoil effect As shown in Table 1, there was a statistically significant devices on said simulation T91 guns. In the next stage, difference between the groups for learning outcome as teacher started the 3D VR live firing training software, indicated by one-way ANOVA [F (3156) = 58.10, utilizing the Unity game engine. p \ .05] due to different modes of training. The calculated The CG adopted ordinary real-world firing range effect size (eta squared, g2) is 0.52, which is considered to didactics. The other three experimental groups adopted ILI be a large effect (Cohen 1988). Furthermore, a post hoc tracking technology, 1:1 real-scale guns with recoil effects least significant difference (LSD) analysis was also con- and 3D interactive VR digital information software in ducted to evaluate the pairwise differences among the class. The difference between the three experimental means. The results showed that students in EG3 scored groups was that the first experimental group (EG1) adopted significantly (p \ .01) higher than EG1, EG2, and CG (as only the real-world firing range mode in 3D interactive VR shown in Table 2). This indicated that the experimental digital information; the second experimental group (EG2) group (EG3), which adopted both real-world firing range adopted only combat training mode; and the third experi- mode in 3D VR and combat training mode, performed mental group (EG3) adopted both real-world firing range better in the post-test than the students of the other groups mode and combat training mode. The classes focused on (EG1, EG2, and CG). In addition, there were differences in serious game-based learning strategies for teaching activi- the means among the different modes of VR training we ties designed to create a human–machine interactive tested. Similar to the previous research findings, Hummel learning environment for learners by using digital learning; et al. (2011), Ku et al. (2014), and Sung et al. (2015), the after which, users experienced a real-world firing range. present study concluded that serious game-based learning improved the learning outcome of the learners. 5.4 Data analysis 6.2 Learning motivation One-way analysis of variance (ANOVA) was used to test for statistically significant differences between the experi- As shown in Table 3, there was a statistically significant mental group and the CG. All analyses were conducted difference between the groups for learning motivation as 123 Virtual Reality (2016) 20:127–140 135 Fig. 8 25-, 75-, and 175-m fixed target training mode (from top to bottom, respectively) indicated by one-way ANOVA [F (3156) = 160.015, EG3 scored significantly (p \ .01) higher than those in p \ .05] due to different modes of training. The calculated EG1 and CG (as shown in Table 4). This indicated that the effect size (eta squared, g2) is 0.75, which is considered to experimental group (EG2), which adopted only combat be a large effect (Cohen 1988). Furthermore, a post hoc training mode, and the experimental group (EG3), which least significant difference (LSD) analysis was also con- adopted both real-world firing range mode in 3D VR and ducted. The results showed that students in both EG2 and combat training mode, were more highly motivated than 123 136 Virtual Reality (2016) 20:127–140 Fig. 9 75- and 175-m mobile target training modes (from top to bottom, respectively) the students of the other groups. The outcomes of this study traditional live firing training. This study presents a useful are consistent with the studies by Hwang and Wu (2012), and cost-effective system for the military live firing train- Kebritchi et al. (2010), and Wijers et al. (2008), which ing. The real-world firing range mode not only helps the highlighted that serious game-based learning promoted learner to immerse in the scenario, via the execution sim- students’ learning motivation. ulation of live firing training, but can, likewise, store bullet impact point records. Following these records, the trainer 6.3 Relationship between learner’s learning may develop teaching strategies, correct the learner’s weak outcome and learning motivation point on shooting, and improve the learner’s shooting skill and essentials. There is still more research that needs to be We also calculated the correlation between learner’s done. As we look toward the future, we are starting by learning outcome and learning motivation, which was providing a cost-effective interactive 3D VR real-world 0.509. This showed a strong positive significant relation- firing range system to schools, which can easily add this ship between the two measures. innovation with a projector, screen, and PC equipment, already found in most classrooms. The other interesting phenomenon is that the students 7 Conclusions prefer to be educated in the combat training mode, as this mode is very interesting to the learner. Users were often We found learner’s learning outcomes, learning motivation found practicing and enjoying themselves, in this mode, and final performance, when utilizing the innovative 3D without any coercion or suggestions. As we continue to interactive virtual system, were better than those in investigate, this stated self-motivation may be the reason 123 Virtual Reality (2016) 20:127–140 137 Fig. 10 System records bullet impact points automatically for a 25 m, b 75 m target Fig. 11 Combat training mode on a moving enemy attack 123 138 Virtual Reality (2016) 20:127–140 Fig. 12 Combat training mode on a fixed enemy attack Fig. 13 Learner’s learning outcomes (shooting scores) taken from a real-world firing range Table 1 One-way ANOVA result of the learning outcome post-test for the improvement in students’ shooting essential and basic skills imperceptibly. Source df SS MS F p Future research, already in progress, examines the Between groups 3 99 33 58.10 .000* relationships between motivation and learning outcomes in Within groups 156 88.6 .56 real-world firing ranges. The present study only focuses on Total 159 187.6 basic real-world fire training mode. Dynamic influences, * p \ 0.05 including rain, wind, and sunlight effects, need to be 123 Virtual Reality (2016) 20:127–140 139 Table 2 Post hoc test results of Group Mean SD CG EG1 EG2 the learning outcome post-test CG 2 .75 EG1 3.55 .72 (-1.88, -1.21*) EG2 3.10 .77 (-1.43, -.76*) (-.11, -.78*) EG3 4.15 .69 (-2.48, -1.81*) (-.93, -.26*) (-1.38, -.71*) An asterisk indicates that 95 % confidence interval does not contain zero, and therefore, the difference in means is significant at the .05 significance level Table 3 One-way ANOVA result of the learning motivation post- software. In addition, this study uses a simulation, 1:1 real-scale questionnaire gun, with actual recoil effects. The outcomes show there is Source df SS MS F p significantly better learning motivation, learning outcomes, and positive impacts on learner’s live firing achievements. This Between groups 3 318.8 106.2 160.015 .000* system succeeds as an economical and effective training tech- Within groups 156 103.6 .66 nique for military live firing training. These results provide Total 159 422.4 important references for further studies related to the future * p \ 0.05 conduct of military training curriculum design and digital learning teaching models for 3D interactive VR courses. presented in the next stage of study. Another limitation of Acknowledgments This research is parti2ally supported by the the current research is that the study pool focused on high ‘‘Aim for the Top University Project’’ of National Taiwan Normal school students, and does not touch upon the subject of University (NTNU), sponsored by the Ministry of Education, Taiwan, how well it may motivate or improve the military skills of R.O.C. and the ‘‘International Research-Intensive Center of Excel- someone who has joined the military. These shortcomings lence Program’’ of NTNU, and National Science Council, Taiwan, R.O.C. under Grant No. NSC 103-2911-I-003-301. and concerns should be included in future research. As mentioned above, real-world firing range mode can increase learning performances, and combat training mode Appendix A: Motivation questionnaire can increase learning motivation. To take advantage to make up for the shortcomings of both training modes, this study also adopts both real-world firing range mode and combat training mode in class. VR training mode was 1. Are you satisfied with this teaching method? better than the non-VR training mode, and even that our 2. Do you agree this teaching method benefited for hybrid training model had the best performance scores and your shooting skills? was one of the best for improving learner’s motivation. 3. Do you agree this teaching method help you to learn In this study, we use invisible laser infrared technology, to easier? develop its interaction and application on a real-world firing 4. Do you agree this teaching method increases your range system. It is demonstrated that the system’s performance motivation for learning shooting skills? positively impacts a students’ achievement in military training 5. Do you agree this teaching method makes you courses. Our solution is constructed with simple and cheap spontaneous to learn? devices, including a charge-coupled device (CCD) camera, 6. Do you agree this teaching method allows you to invisible laser infrared source, a camera carriage, a special concentrate better? camera lens, a webcam (with a resolution of 1280 9 1024 7. Do you agree this teaching method makes you more pixels or above), and invisible laser infrared point tracking actively involved? Table 4 Post hoc test results of Group Mean SD CG EG1 EG2 the learning motivation post- questionnaire CG 5.40 .75 EG1 7.50 .72 (-2.45, -1.74*) EG2 8.90 .77 (-3.85, -3.14*) (-1.75, -1.04*) EG3 8.80 .69 (-3.75, -3.04*) (-1.65, -.94*) (-.25, .45) An asterisk indicates that 95 % confidence interval does not contain zero, and therefore, the difference in means is significant at the .05 significance level 123 140 Virtual Reality (2016) 20:127–140 8. Do you agree this teaching method enhances the Lim CP (2008) Global citizenship education, school curriculum and interaction between you and instructor? games: learning Mathematics, English and Science as a global citizen. Comput Educ 51(3):1073–1093 9. Do you agree this teaching method has positive Lim C-W, Jung H-W (2013) A study on the military serious game. influence on your learning achievement? Adv Sci Technol Lett 39:73–77 10. Do you agree this teaching method builds self- Liou W-K, Lee S-C (2012) Application of laser guide and wireless confidence in the true live firing range exam? control method on military training and the FPS game system. In: 2012 IEEE 4th international conference on paper presented at the digital game and intelligent toy enhanced learning (DIGITEL) Marsh T (2011) Serious games continuum: between games for purpose and experiential environments for purpose. 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