Augmented Reality:Applications in Manufacturing and Maintenance

SUN Jing (A0120104J)Aela GOURLAOUEN (A0146994L)QIU Zhi (A0077961R)Francois LEROY (A0148144H)Rostislav DOGANOV (A0107966U)Thomas Joseph Traviño SEVILLA (A0079294N)

Outline• Introduction• AR in Manufacturing

• AR in Product Design• Production Planning and Spatial Organization• AR in Assembly

• AR in Maintenance• Improvements in Maintenance• First steps and applications in AR for maintenance

• Future trends in AR application in Manufacturing and Maintenance • Technological Challenges and Developments

• Algorithms and Processing• Transparent displays• Novel content development

• Conclusion: Drivers, Bottlenecks and Opportunities

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IntroductionWhat is Augmented Reality (AR) ?

“The basic goal of an AR system is to enhance the user’s perception of and interaction with the real world

through supplementing the real world with 3D virtual objects that appear to coexist in the same space as

the real world.” [1]

Augmented Reality vs Virtual Reality

[1] R. Azuma, “Recent Advances in Augmented Reality”, Computers and Graphics, November 2001 3

Realizations of AR

Smart glasses for training and hands-free work

iPhone/iPad-based applications providing live

data

Head-mounted displays Handheld displays Spatial displays

Project virtual items in the environment to plan a

plant’ layout, to design,...

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AR in Manufacturing

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Evolution of Manufacturing

• Limitation of current computer-aided system:– Not easy to fully and accurately model the actual working environment

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Evolution of Manufacturing

• The advantages of AR now and in the future:– provide a natural approach for modelling the actual working environment instead of modelling the real world– enhances an existing environment rather than replacing it– Reduce cost and avoid time-consuming

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AR applications in Manufacturing

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Product Design &

Prototyping

Production

Planning & Spatial

Organization

Training &

Assembly

• AR can be applied to all parts of the value chain：

Product Design and Prototyping• Developed by Volkswagen, 2013. • Virtual technologies

– reduce time & costs– Problem: data is scaled down in size

and not an accurate reflection; data skewed

• Spatial AR– Ensure the data is visualized with

actual proportions and size– Assess data more effectively by the

designer– Shows virtual data on a real model

http://www.volkswagenag.com/content/vwcorp/content/en/innovation/Virtual_technologies/Use_of_spatial_augmented_reality_in_the_automotive_industry.html 9 9

Product Design and Prototyping• Advantage:

– Analyze the virtual data straight away in reality in a familiar environment

MARTA spatial AR system developed by Volkswagen

http://www.volkswagenag.com/content/vwcorp/content/en/innovation/Virtual_technologies/Use_of_spatial_augmented_reality_in_the_automotive_industry.html

Projector

Life-sized Dashboard Platform

Panel

Final design

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Production Planning and Spatial Organization

• Previous Issues

Manual assembly design and planning is a complex and time-consuming process as besides technical and economic factors, human factors have to be considered

• With spatial AR

• a physically existing production environment can be superimposed with virtual planning objects and planning tasks can thus be validated without modelling the surrounding

• highly immersive and intuitive environment to evaluate the virtual prototypes of new product designs or the assembly sequence

• reduce re-designing and re-planning activities

Source: http://www.intechopen.com/books/augmented-reality/using-augmented-reality-to-cognitively-facilitate-product-assembly-process 11

AR In Training and Assembly• Previous issues:• Time spent in forming the workers• Possibility of making errors

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• With AR:

- Reduce formation time and cost as direct information can be provided on the field

- Real-time data reduces errors

- Devices like smart glasses enable hands-free work

Example: Augmented reality helmet developed by Miller, 2013.

“Time spent per aircraft (...) is divided by six with an error rate reduced to zero” in cabins assembly at Airbus

Jets assembly goes “30% faster” during trials at Lockheed Martin’s using smart glasses

Training and Assembly - Welding

Applied by Miller, 2013• Old Mask

– Keep flip up and down, really time consuming• Current Mask:

– Automatically dim a panel in front of the user’s eyes with sensors

– Do not work well caused by low contrast ratio of human eye

• AR Mask– Identify welding apparatus, the weld point,

and the molten metal – Assist-display help the welder keep the joint in

view using temperatures and best-fit scenarios to make sure that it welds properly

Old Masks

Modern Marks

Welding mask with AR

Source: http://www.roadtovr.com/augmented-reality-welding-mask/Visualization of the Welder

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Training and Assembly - “Duplo Blocks” Case Study

14Tang, A., et al. Performance Evaluation of Augmented Reality for Directed Assembly. Virtual and Augmented Reality Applications in Manufacturing, ed. by Ong and Nee. 2004.

Subjects were asked to complete an assembly task of arranging 56 Duplo blocks using:

1. Printed manual 2. Computer assisted instruction (CAI) on an LCD monitor3. CAI on head mounted device4. Spatially registered AR on head mounted device

Training and Assembly - “Duplo Blocks” Case Study

15Tang, A., et al. Performance Evaluation of Augmented Reality for Directed Assembly. Virtual and Augmented Reality Applications in Manufacturing, ed. by Ong and Nee. 2004.

Use of AR decreases task completion time and reduces errors.

Figure 16.6 illustrates the mean time of the completion for the assembly task. The graph indicates that treatment 4 had the shortest time of completion and treatment 1 had the longest time of completion. Figure 16.7 indicates the average number of errors for the task. The descriptive statistics reveal that treatment 4 has significantly lower error rates in all categories. They also indicated that the majority of errors in treatment 4 are independent errors, whereas treats 1,2 and 3 exhibition a majority proportion of dependent errors.

Training and Assembly - “Duplo Blocks” Case Study

Use of AR reduces the mental load on the worker

• The NASA Task Load Index (TLX) for each task performed was measured for both AR and non-AR set-ups.

16Tang, A., et al. Performance Evaluation of Augmented Reality for Directed Assembly. Virtual and Augmented Reality Applications in Manufacturing, ed. by Ong and Nee. 2004.

The table 16.1 indicates the mean rating of the NASA TLX. The statistics show that subjects in

treatment 1 have the highest mental workload, whereas subjects in treatment 4 have the lowest

mental workload.

AR in Maintenance

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Types of Maintenance Activities

● Preventive (Planned)

○ Routine tasks, sequential steps

● Corrective (Unplanned)

○ Tasks range from simple & sequential types to complex ones.

○ Require expert on-site → Costly Solution

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Current Maintenance Practices

● Hundred billions are spent annually in maintenance around the world. Companies

want to achieve maximum availability at minimum cost.

● The process to fully train a maintenance staff takes a long time.

Courses (theoretical+hands-on) → On the Job Training → Fully Training

3 months + 3 months = 6 months

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1. From Paperback Manual to AR Assisted Maintenance

Primitive Form Ultimate Form

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Currently Available

2. Improvement In Efficiency and Effectiveness

1. F. LAMBERTI, F. MANURI, A. SANNA, G. PARAVATI, P. PEZZOLLA,, P.MONTUSCHI Challenges, Opportunities, and Future Trends of Emerging Techniques for Augmented Reality-Based

Maintenance IEEE TRANSACTIONS ON EMERGING TOPICS IN COMPUTING,Vol. 2, No. 4, DECEMBER 2014

2. A. Sanna, F. Manuri, F. Lamberti, G. Paravati, P. Pezzolla Using Handheld Devices to Support Augmented Reality-based Maintenance and Assembly Tasks IEEE International Conference on

Consumer Electronics, 2015

Assemble/ Disassemble Computer Parts

Type of Participants Parameters Paperback Manual AR with Pre-set Instruction

Experienced

Time 1 50%

Error 1 30%

Standard Deviation

Poor Knowledged

Time 1 94%

Error 1 37.5%

Standard Deviation 1 0.6

Assemble/ Disassemble Computer Parts (Poor Knowledged)

Parameters Video/Text (Tele-com) AR with Remote Audio

Time 1 83%

Error 1 1

Standard Deviation 1 0.85

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3. Financial ImpactDisplaying useful information such as

Part, Status, Working Hours, etc. to

find and fix problem more effectively

and accurately.

SGD 180 Million/Nightin Saving

Maintenance Worker’s Hour Rate = SGD 30

Engineering Hour = 4 hours/ night AR → saves 50% of Time = 2 hours/night

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Teardown Cost of Google Glass at 150 SGD. Breakeven in 5 days!

First steps in Augmented Reality for Maintenance And RepairARMAR project (2005)

Experimentation of a prototype to be used for maintenance aiding on military equipment both during training

and in the field.

Scope: How real time computer graphics overlaid with the equipment being maintained, can significantly

increase the productivity, accuracy and safety of maintenance personnel?

Use of head-mounted displays (HMDs) showing a set of virtual instructions (computer graphics overlaid on the

real view of the system to repair)

• Augment a mechanic’s natural view with text, arrows and animated sequences

• Labelling of components

• Real time diagnostic data

• Gesture tracking

• Safety warnings

• Allows off-site collaboration

Research from Steve Feiner, Professor of Computer Science at Columbia University and his team, in collaboration with US army.23

Research from Steve Feiner, Professor of Computer Science at Columbia University and his team, in collaboration with US army.

Comparison between a fixed flat panel display (LCD) and see-

through head-worn display to complete some common tasks.

Benefits for task localization and performance: ability for the mechanics to spot the components and the task, and

improve the psychomotor aspects of the assembly task

Tasks are located 47% quicker

37% less overall head movements

More intuitive

Challenges and limits:Take into consideration the environment.

● Constraints in freedom of motion and interferent luminosity

● Avoid interferences with others devices (electromagnetic, ultrasonic echoes)

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● Both hands are always free● Greater accuracy ● Provide dynamic, prescriptive and overlaid

instructions

● Assessing airframe damage resulting from combat or environmental hazards to prolong

equipment life and maximize the aircraft’s operational availability

● Replace the cumbersome method of using a transparent film over the damaged area to

measure the distance of a hole from supporting structures or the depth of a scratch and then

cross-referencing it with a database to see the impact of the damage

● Use of a powerful 3D volumetric rendering engine: voxels (3D pixels)

■ Provide accuracy within 1/10th of an inch

■ Visualize and represent aircraft damage on a 3D model

Preventive Maintenance Virtual Damage Assessment & Repair Tracking for F-35 and F-22 Aircraft

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1. Increase Operational Availability of EquipmentReduce the maintenance time-to-flight hour ratio

2. Work More Efficiently with Fewer PersonnelBetter documentation and access to historical damage and repair data for each aircraft

3. Capture Data More Accurately3D model closer to reality, reducing the probability of maintainers making mistakes

Maintenance becomes accessible to everyone

● No specific knowledge or skills needed, replace the

user manual

● By simply owning an iPad and downloading the right

application, beginners or DIY lovers would be able to

repair their own car, smartphone, washing machine

by following step-by-step audio and visual instructions,

thus diminishing the costs of a professional

intervention.

https://www.youtube.com/watch?v=EUmNbNa3RYY

● In case of difficulties, an expert can remotely help solving

the problem. 27

Future Trends and Challenges of AR Application in Manufacturing and Maintenance

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Applications* per types of AR devices*includes tests and implementations

Future trends in AR applications in Manufacturing and Maintenance

➔ Head-Mounted devices will be the leading AR device:

- No problem of social acceptance in the framework

- Currently used at 64% in Assembly, 36% in Maintenance

- Being tested by pioneering company

- High expected growth in the use of mobile devices (Global Heads Up Display

Market in 2014 $1.76 billion -> $7.05 billion in 2022)

- The development of HMD will could from the research in the automotive,

aviation and military industries for drivers assistance

➔ Still a long way to go?- Experts expect the glasses to have taken off within 2025...- … but so far, no communication on the tests performed in the companies HMD are at an early stage -> being tested- Handheld devices are currently more functional, but their use is of restricted

interestCompanies testing HMDs

Challenges of AR Application in Manufacturing and Maintenance

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• Reliability• Interactive in Real time (rapidity in processing, comparing, gathering the data)

High bandwidth, connection to the cloud, compression of data

• Ability to detect defaults in the shape, the size, the color, the temperature…

• Scalability• Recognition of the parts of a system and ability to memorize new components

• Ability to learn new way to repair by recording the mechanics movement

• Adaptive level of detail (Components -> Sub-components)

• Import and deploy content and data of all kinds with a user-friendly graphic interface (pictures, data, sheets..)

• Scaling it to a large business, using multiple devices and hardware

• User-friendliness • Head Mounted Device Versus Handheld Device

• End of the user manual “dictionary sized”

• Available for almost everyone through portable devices: tablets, phones...

Technological Challenges and Developments

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Required improvements for Mainstream AR

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1. Highly-efficient tracking and registration → CRUCIAL

2. High-resolution transparent displays → VITAL for glasses

3. Efficient and user-friendly AR content development → CRUCIAL

Kato, Zoltan. Linear and Nonlinear Shape Alignment without Correspondences. Computer Vision, Imaging and Computer Graphics: 7th International Joint Conference,

VISIGRAPP 2012. Rome, Italy, February 2012. Springer-Verlag Berlin Heidelberg: 2013 33

1 - Tracking and Registration

Main obstacles to accurate and reliable AR: 1. Instant object tracking and image registration.2. This requires high-end graphic processing on a wearable device.

Enabled by:1. Improvements in computer vision algorithms. → DEV UNDER WAY

(registration, 3D sensing, tracking, feature detection, etc.)2. Improvements in processing power of of mobile devices. → DEV UNDER WAY

3. Leverage on cloud computing. → NOT TOO FAR AWAY

Object Registration• In order to work effectively, the AR device

must recognize and register objects immediately.s.

Tracking and Occlusion• The device must be able to recognize and

track objects even as the user moves and superimpose virtual content on a moving background.

3D depth sensing• 3D depth sensing is required to accurately

superimpose content

[1] Kato, Zoltan. Linear and Nonlinear Shape Alignment without Correspondences. Computer Vision, Imaging and Computer Graphics: 7th International Joint Conference, VISIGRAPP 2012. Rome, Italy, February 2012. Springer-Verlag Berlin Heidelberg: 2013

[2] Kalkofen, D. et al.. Visualization Techniques for Augmented Reality. Handbook of Augmented Reality. Edited by Borko Furht. eBook. Springer: 2011

[3] Ko, Dong-Ik, and Agarwal, Gaurav. Gesture recognition: Enabling natural interactions with electronics. White Paper, Texas Instruments. Texas Instruments: 2012. Available from http://www.ti.com/lit/wp/spry199/spry199.pdf.

[4] Handa, A., et al. Real-Time Camera Tracking: When is High Frame Rate Best? Department of Computing, Imperial College London, U.K. 2012: 12th European Conference on Computer Vision.34

1 - Tracking and Registration Algorithms

1 - Hardware processing improvements

• Improvements in mobile processors performance (Are mobile units going to catch up with high-power processors?).

• Integrated graphic performance has increased 75x in about 8 years!

[1] Limer, Eric. May 1, 2013. Intel Iris: Integrated Graphics Are Finally Awesome. Gizmodo. Available from: http://gizmodo.com/intel-iris-integrated-graphics-are-finally-awesome-486483980. [2] Shimpi, Anand Lal. July 17, 2013. The ARM Diaries Part 2: Understanding the Cortex AI2. ANANDTECH. Available from: http://www.anandtech.com/show/7126/the-arm-diaries-part-2-understanding-the-cortex-a12. [3] Anand Lal Shimpi et al. “The iPhone 5 review” Available at: http://www.anandtech.com/show/6330/the-iphone-5-review/9

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1 - Software processing improvements

Open CV:

• Developments in computer vision and AI lead to improvements in image processing algorithms.

• OpenCV- open source project by Intel for advanced programming functions aimed at real-time computer vision.

[1] Coombs, Joseph, and Prabhu, Rahul. OpenCV on TI’s DSP+ARM platforms: Mitigating the challenges of of porting OpenCV to embedded platforms. Texas Instruments. Available from: http://www.ti.com/lit/wp/spry175/spry175.pdf. [2] Kartoshkin, Vadim. Performance promise of OpenCV 3.0 and Intel INDE OpenCV. Intel Developer Zone. Available from: https://software.intel.com/en-us/articles/performance-promise-of-opencv-30-and-intel-inde-opencv.

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Kato, Zoltan. Linear and Nonlinear Shape Alignment without Correspondences. Computer Vision, Imaging and Computer Graphics: 7th International Joint Conference,

VISIGRAPP 2012. Rome, Italy, February 2012. Springer-Verlag Berlin Heidelberg: 2013 37

2 - High Resolution Transparent Displays

Main obstacles to realistic and reliable AR glasses: 1. The resolution and brightness of current see-through displays is insufficient.2. Transparent display technology is still at an early stage.

Enabled by:1. Improvements in transparent LCD displays. → DEV UNDER WAY2. Improvements in transparent OLED displays → EARLY DEV STAGES

2 - Transparent Display Technology

Improvements in transparent display technology are key to the realization of head-mounted AR devices:

•High resolution

•High brightness and contrast

•Transparent and lightweight

Burns, Chris. Jan 12, 2012. Lumus DK-32 wearable display hands-on. Slash Gear. Available from http://www.slashgear.com/lumus-dk-32-wearable-display-hands-on-12208896/.SGI News. April 09 2015. The Future of Home Display Made Possible By Transparent Display. Available from http://www.news-sgi.globalprintmonitor.org/en/news/industry-news/digital-signage/27995-the-future-of-home-display-made-possible-by-transparent-display. Dedezade, Ezat. This stunning smartwatch blends traditional mechanical innards with a transparent OLED display. Stuff.tv. Available from http://www.stuff.tv/news/stunning-smartwatch-blends-traditional-mechanical-innards-transparent-oled-display.

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2 - Transparent displays projection

Projected transparent display market.• Transparent displays are expected to overtake opaque displays.

• LCD technology to dominate the early stages. -> BLU problem

[1] Displaybank “Transparent Display Market to Reach $87.2 Bln in 2025”. Available from http://www.displaybank.com/_eng/share/press_view.html?id=218792&[2] Mertens, Ron. Oct. 22, 2014. Nanomarkets: LCD to dominate transparent display market in the next few years, but OLED adoption will rapidly pick up. OLED-info. Available from: http://oleds6.rssing.com/browser.php?indx=9721861&item=44.

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Kato, Zoltan. Linear and Nonlinear Shape Alignment without Correspondences. Computer Vision, Imaging and Computer Graphics: 7th International Joint Conference,

VISIGRAPP 2012. Rome, Italy, February 2012. Springer-Verlag Berlin Heidelberg: 2013 40

3 - Efficient and User-Friendly AR Content Development

Main obstacles to the widespread use of AR: 1. Conceptually new software development, which involves reality.2. Difficulty of AR content development.

Enabled by:1. Development of novel user-friendly AR Authoring tools. → NOT TOO FAR AWAY

3- Novel AR Authoring Tools

• Augmented Reality authoring tools, such as SUGAR, are currently developed for people without programming skills to create their own AR guides for industrial purposes.

• These can be used to create prototype AR models to aid in assembly, design and manufacturing.

Gimeno, et al. An Easy-to-Use AR Authoring Tool for Industrial Applications. Computer Vision, Imaging and Computer Graphics: 7th International Joint Conference,

VISIGRAPP 2012. Rome, Italy, February 2012. Springer-Verlag Berlin Heidelberg: 201341

3 - Novel AR Authoring Tools - Case Study

PROC 1 - Replacement of the cut heading within a lathe machine (metal machining area)PROC 2 - Computer assembly starting from basic componentsPROC 3 - Repair of the admission system in a mobile lighting towerPROC 4 - Review of the spark plugs and the ignition coils on a BMW M3 E92 (420CV)

S1 - Printed manualS2 - Computer-Assisted Instructions (CAI) using a TabletPC displayS3 - CAI using a Head-Mounted Display (HMD)

[1] Gimeno, et al. An Easy-to-Use AR Authoring Tool for Industrial Applications. Computer

Vision, Imaging and Computer Graphics: 7th International Joint Conference, VISIGRAPP 2012. Rome,

Italy, February 2012. Springer-Verlag Berlin Heidelberg: 2013

SUGAR was used to create AR guides using HMDs and a TabletPC for 4 processes, and their efficiency was tested using four tasks.

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3 - Novel AR Authoring Tools - Case Study

Team 1 - used the classic AR development approach for developing AR toolsTeam 2 - used SUGAR for developing AR tools for the four processes

Parameters: SLOC - number of Source Lines Of Code produced

FPS - frame rate in Frames Per Second

CT - Coding Time in working days

DT - Debugging Time in working days

TT - Total Time for development, in working days

Gimeno, et al. An Easy-to-Use AR Authoring Tool for Industrial Applications. Computer Vision, Imaging and Computer Graphics: 7th International Joint Conference, VISIGRAPP 2012.

Rome, Italy, February 2012. Springer-Verlag Berlin Heidelberg: 2013

The use of SUGAR greatly decreased the development time of AR guides for different tasks.

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3 - Novel AR Authoring Tools

Other tools for AR development in mobile apps.

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Product Company License Supported Platforms

ARPA SDKs Arpa

Solutions

Commercial* Android, iOS (ARPA SDKs), Google Glass (ARPA GLASS SDK), Android, iOS, Windows PC

(ARPA Unity Plugin)

ARLab SDKs ARLab Commercial Android, iOS

DroidAR – Free and Commercial Android

Metaio SDK Metaio Free and Commercial Android, iOS, Windows PC, Google Glass, Epson Moverio BT-200, Vuzix M-100, Unity

Vuforia SDK Qualcomm Free and Commercial Android, iOS, Unity

Wikitude SDK Wikitude

GmbH

Commercial* Android, iOS, Google Glass, Epson Moverio, Vuzix M-100, Optinvent ORA1, PhoneGap,

Titanium, Xamarin

[1] Katerina Roukounaki “Top 5 Tools for Augmented Reality in Mobile Apps”. Available at: http://www.developereconomics.com/top-5-tools-for-augmented-reality-in-mobile-apps/

Conclusion: Drivers, Bottlenecks, and Opportunities

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AR in Maintenance and Manufacturing -drivers and bottlenecks

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Visualization during design and planning.

Reduction in completion time for complex tasks.

Reduction in human errors.

Reduction in workers’ mental load.

Technical assistance during maintenance.

Reduction in training time for new tasks/personnel.

Intrinsically complex algorithms and processes.

Sophisticated processing on a mobile device.

Limits to currently achievable speed and accuracy.

Transparent display technology not mature yet.

Challenging content development.

Drivers: Bottlenecks:

AR in Maintenance and Manufacturing -Opportunities

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AR software platforms and apps for hand-held devices.

AR glasses - product design & components assembly.

Transparent displays for AR glasses.

AR software for glasses and head-mounted displays.

Strategic Market Position Map

Increase of Efficiency for User

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System Adaptability

ARMAR*

2012 2011

2005

2003, acquired by Apple in 2015

20082013

2007

2010

AR - projections

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[1] Tractica, “Installed Base of Mobile Augmented Reality Apps to Reach 2.2 Billion by 2019”. Available at: https://www.tractica.com/newsroom/press-releases/installed-base-of-mobile-augmented-reality-apps-to-reach-2-2-billion-by-2019/[2] Tractica, “Smart Augmented Reality Glasses Shipments to Surpass 12 Million Units between 2015 and 2020” May 2015. Available at: https://www.tractica.com/newsroom/press-releases/smart-augmented-reality-glasses-shipments-to-surpass-12-million-units-between-2015-and-2020/

Response from Prof Andrew. Y.C. Nee, ME Dept. NUS

• What do you think would be the most important potential benefits of using AR in

manufacturing and maintenance applications?

o Realistic simulation and guidance in situ with display of text, animation and graphics.

o Bi-directional interaction and authoring with experts located remotely.

• What do you think are the biggest technological obstacles to mainstream use of AR in

manufacturing/maintenance at the present time?

o Hands-free light weight high resolution display tools. Google glass resolution insufficient.

o Highly efficient tracking and registration algorithms to provide real-time information

display.

o Efficient and clear content development for manufacturing applications rather time-

consuming.

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Response from Prof Andrew. Y.C. Nee, ME Dept. NUS

• In your opinion, what emerging technologies are being developed to address these

technological obstacles and to improve AR products?

o Next generation Google glass.

o Better client-server communication and leverage of cloud.

• Given the improvements in AR and its component technologies, when do you think AR will

become widely used in manufacturing and maintenance?

o Acceptance by the workforce is important. They need to be trained and to overcome

the inconvenience of wearing headsets.

o AR wearables should be light, non-intrusive, and conducive to use.

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Q&A

Thank you!52

ReferencesHanda, A., et al. Real-Time Camera Tracking: When is High Frame Rate Best? Department of Computing,

Imperial College London, U.K. 2012: 12th European Conference on Computer Vision.Herold, Rigo; Vogel, Uwe; Richter, B.; Kreye, D.; Reckziegel, S.; Scholles, M.; Lakner, H., "OLED-on-CMOS

integration for augmented-reality systems," in Photonics and Microsystems, 2008 International Students and Young Scientists Workshop - , vol., no., pp.19-22, 20-22 June 2008. doi: 10.1109/STYSW.2008.5164134. Available from http://ieeexplore.ieee.org/xpl/articleDetails.jsp?reload=true&arnumber=5164134.

Gimeno, et al. An Easy-to-Use AR Authoring Tool for Industrial Applications. Computer Vision, Imaging and Computer Graphics: 7th International Joint Conference, VISIGRAPP 2012. Rome, Italy, February 2012. Springer-Verlag Berlin Heidelberg: 2013

Kalkofen, D. et al.. Visualization Techniques for Augmented Reality. Handbook of Augmented Reality. Edited

by Borko Furht. eBook. Springer: 2011.

F. LAMBERTI, F. MANURI, A. SANNA, G. PARAVATI, P. PEZZOLLA,, P.MONTUSCHI Challenges, Opportunities, and Future Trends of Emerging Techniques for Augmented Reality-Based Maintenance IEEE TRANSACTIONS ON EMERGING TOPICS IN COMPUTING,Vol. 2, No. 4, DECEMBER 2014

A. Sanna, F. Manuri, F. Lamberti, G. Paravati, P. Pezzolla Using Handheld Devices to Support Augmented Reality-based Maintenance and Assembly Tasks IEEE International Conference on Consumer Electronics, 2015

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ReferencesKato, Zoltan. Linear and Nonlinear Shape Alignment without Correspondences. Computer Vision, Imaging and

Computer Graphics: 7th International Joint Conference, VISIGRAPP 2012. Rome, Italy, February 2012. Springer-Verlag Berlin Heidelberg: 2013

Ko, Dong-Ik, and Agarwal, Gaurav. Gesture recognition: Enabling natural interactions with electronics. White Paper, Texas Instruments. Texas Instruments: 2012. Available from http://www.ti.com/lit/wp/spry199/spry199.pdf.

Panasonic. PanaCIM. Brochure. Available from https://www.panasonicfa.com/sites/default/files/pdfs/MaintenanceAR_Panasonic.pdf. Logo from https://www.panasonicfa.com/content/maintenance-augmented-reality-panacim%C2%AE-enterprise-edition.

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