The Validity of a Global Navigation Satellite System for Quantifying Small-Area Team-Sport Movements

Delaney, JA, Wileman, TM, Perry, NJ, Thornton, HR, Moresi, MP, and Duthie, GM. The validity of a global navigation satellite system for quantifying small-area team-sport movements. J Strength Cond Res XX(X): 000–000, 2019—The recent development of global navigation satellite systems (GNSS) has improved the availability and signal strength of surrounding satellites compared with traditional global positioning systems, although their ability to quantify rapid changes in speed may still be limited. This study aimed to evaluate the validity of GNSS to quantify the mean speed (m·s−1) and acceleration (m·s−2) of movements typical to team sports. One participant completed 9 periods of 4 minutes of activity, separated by 2-minute rest periods, which involved walking, jogging, and running in a variety of directions and patterns, aimed to simulate a team-sport movement profile. Speed and acceleration were quantified from a 10-Hz GNSS unit and compared with a 10-camera, 3-dimensional motion capture system (VICON), from which the movement of both the participant’s center of mass (COM) and the location of the GNSS unit (e.g., C7 vertebrae) were calculated. Practical estimates of speed were associated with small differences from both the criterion COM (effect size; ±90% confidence limits = 0.19–0.25; ± ∼0.21) and criterion C7 (0.14–0.22; ± ∼0.13). The corresponding estimates of acceleration derived from raw data were classified as small (0.16–0.22; ± ∼0.15) and small to moderate (0.25–0.35; ± ∼0.24) for the COM and C7, respectively. Software-exported acceleration values exhibited very large mean bias compared with both criterion measures (−3.81 to −3.77; ± ∼0.24). This study demonstrates that 10-Hz GNSS possess acceptable validity for assessing the average demands of movements typical of team-sports training and competition, although caution is recommended when using software-exported measures of acceleration.
Address correspondence to Jace A. Delaney, jace.delaney@live.vu.edu.au.
Copyright © 2019 by the National Strength & Conditioning Association.

Electrically Assisted 3D Printing

Applying an electric field during 3D printing [Source: ScienceAdvances]

Researchers have developed an incredibly ingenious new method of 3D printing very strong structures using techniques analogous to nature.

Researchers at the University of Southern California were inspired by the material known as “nacre”. You haven’t heard of nacre? More than likely, you have, as it is simply the formal name for “mother of pearl”. That’s the substance that mollusks use to construct their very tough shells.

Why are they so tough? It turns out the secret is in the microscopic structure of the material. Nacre is composed of small “bricks” of calcium carbonate joined together with proteins. These are set in a sophisticated brick-and-mortar style arrangement that provides tremendous strength.

The question is, how could you do this with 3D printing?

Apparently some research has previously been done on generating this type of material in 2D environments. However, according to the researchers, the methods of doing so were quite complex and unlikely to be commercialized.

The researchers came up with an ingenious approach that used the familiar photopolymer resin 3D printing process. The difference was that they first mixed the resin with tiny graphene nanoplatelets. This would normally provide some additional strengths to the resin print, but there was another difference.

Concept for aligned 3D printed graphene nanoplatelets [Source: ScienceAdvances]

Concept for aligned 3D printed graphene nanoplatelets [Source: ScienceAdvances]

An electric field was employed during 3D printing. This field caused the graphene nano platelets to simultaneously align with each other according to the electric field. When the resin and graphene nanoplatelet mixture solidified, the resulting object had a much stronger microstructure.

The researchers found that this printed substance had a strength more or less equal to that of natural nacre. They also found that the substance had an anisotropic electrical property that is not found in nature.

They explain:

”The bioinspired BM architecture enhances the mechanical strength and electrical conduction by aligning GN in each layer to maximize their performance by crack deflection under loading. The electrically assisted 3D-printing method can build a multifunctional lightweight and strong 3D structure with electrically self-sensing capability.”

A 3D printed helmet that senses when it is cracked [Source: ScienceAdvances]

A 3D printed helmet that senses when it is cracked [Source: ScienceAdvances]

In other words, this material could electrically detect when it cracks! This is an incredibly interesting feature with countless practical applications. One application that the researchers suggest is a helmet, which could inform you when it is damaged.

Significant mechanical testing was done on sample prints, and they explained their results:

“The 3D-printed structure with aGNs shows significantly enhanced toughness, impact, and compression resistances due to the synergistic effect and crack deflection. The 3D-printed nacre displays lightweight property with comparable specific fracture toughness to the natural nacre. In addition, the alignment of GNs leads to the anisotropic electrical property, presenting a feasible direction for building protective wearable sensors that can self-sense the crack.”

A very interesting aspect of their process was that they were able to change the alignment of the graphene nanoplatelets for each individual layer of the print. One could easily imagine a sophisticated FEA System being used to devise the optimum alignment strategy for a given part. That would be a very different approach to part design.

Hopefully this approach will be commercialized so that all of us can make good use of it.

Via ScienceAdvances

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Timea Tihanyi: Rule-Making And Rule-Breaking Is My Focus

Timea Tihanyi [Source: Women in 3D Printing]

Timea Tihanyi is a Hungarian born cross-disciplinary artist and ceramist living and working in Seattle, United States.

Timea earned an MD (Semmelweis University, Budapest, Hungary, 1993) in neurology/neuropsychology, a BFA (Massachusetts College of Art, Boston, 1998) and an MFA (University of Washington, Seattle, 2003) in ceramics, where she currently teaches as a senior lecturer in the Interdisciplinary Visual Arts program.

Tihanyi’s installations with slipcast porcelain and participatory works has been exhibited in Brazil, Australia, Denmark, the Netherlands, and in the USA, including Shepparton Art Museum, Henry Art Gallery, Bellevue Art Museum, Mint Museum of Art and Design, Society for Contemporary Craft in Pittsburg, Clay Center for the Arts and Sciences, Foundry Art Center, and International Museum of Surgical Science.

She has participated in artist residencies at Kohler Arts/Industry, Sundaymorning@EKWC (formerly, European Ceramic Workcenter), European Ceramic Context 2010 and Museum of Glass, Tacoma. She is a recipient of the Bergstrom Award in Art and Science and the winner of the 2018 Neddy Award in Open Media.

Timea is the founder and director of Slip Rabbit, an experimental research and education studio focused on the advancement of ceramic 3D printing and digital ceramics.

Nora Toure: Timea, you were one of the first people on the West Coast, USA to order, build, learn, and work with your ceramics 3D printers – what excites you about this process?

Timea Tihanyi: What excites me is the potential to combine a real physical/corporal and emotional material (clay) with abstract and immaterial logic that is a code or an algorithm. As an artist, the content of my work has always revolved around the relationship between the mind and the body as well as around questions about the origins of knowledge (whether it is through the mind or through the body).

I find a beautiful metaphor for this dualistic relationship in digital ceramics. I work with mathematicians on self-organizing patterns that show critical behavior (dynamic systems), which look insanely complex yet clearly having some rule-based logic.

These systems come into play when explaining and predicting the behavior of sandpiles, earthquakes, forest fires, electric breakdowns, the formation of water droplets and other growing surfaces, and human brains.

Rule-making and rule-breaking, by accident or by intention, is my focus in the emerging area of ceramic 3D printing. Following the prescribed path of the digital design or an algorithm-generated code, the ceramic 3D printer extrudes a thin coil of soft porcelain and creates each object layer by layer, line by line.

The form it makes is dependent on the “materialness” of clay and would not exist and cannot stand without the skilled human hand. In between design and serendipity lies the resulting object, consistent yet unique.

Clay, with its own unique materiality challenges all logical and predictable outcomes of the gcode. My work reinterprets technical, formal and conceptual aspects of the ceramic vessel tradition and reasserts them in the realm of the cognitive experience of the human body.

Read the rest at Women in 3D Printing

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Effect of COL5A1, GDF5, and PPARA Genes on a Movement Screen and Neuromuscular Performance in Adolescent Team Sport Athletes

Stastny, P, Lehnert, M, De Ste Croix, M, Petr, M, Svoboda, Z, Maixnerova, E, Varekova, R, Botek, M, Petrek, M, Lenka, K, and Cięszczyk, P. Effect of COL5A1, GDF5, and PPARA genes on a movement screen and neuromuscular performance in adolescent team sport athletes. J Strength Cond Res 12XX(2X): 000–000, 2019—The risk of injury increases with adolescents’ chronological age and may be related to limited muscle function neuromuscular, genetic, and biomechanical factors. The purpose of this study was to determine whether COL5A1, PPARA, and GDF5 genes are associated with muscle functions and stretch-shortening cycle performance in adolescent athletes. One hundred forty-six youth players (14.4 ± 0.2 years) from various team sports (basketball n = 54, soccer n = 50, handball n = 32) underwent a manual test for muscle function, maturity estimation, functional bend test (FBT), passive straight leg raise (SLR) test, leg stiffness test, test of reactive strength index (RSI), and gene sampling for COL5A1, PPARA, and GDF5. The χ2 test did not show any differences in allele or genotype frequency between participants before and after peak height velocity. Multivariate analysis of variance showed that COL5A1 rs12722 CT heterozygotes had worse score in FBT (p < 0.001), worse score in SLR (p = 0.003), and lower maturity offset (p = 0.029, only in females) than TT homozygotes. Male GDF5 rs143383 GG homozygotes showed better score in SLR than AA and AG genotypes (p = 0.003), and AA and AG genotypes in both sex had greater RSI than GG homozygotes (p = 0.016). The PPARA rs4253778 CC homozygotes had greater RSI than GG and GC genotypes (p = 0.004). The CT genotype in COL5A1 rs12722 is possible predictor of functional movement disruption in the posterior hip muscle chain, causing shortening in FBT and SLR, which includes hamstrings function. CT genotype in COL5A1 rs12722 should be involved in programs targeting hamstring and posterior hip muscle chain.
This is an open-access article distributed under the terms of the Creative Commons Attribution-Non Commercial-No Derivatives License 4.0 (CCBY-NC-ND), where it is permissible to download and share the work provided it is properly cited. The work cannot be changed in any way or used commercially without permission from the journal.
Address correspondence to Dr. Stastny Petr, stastny@ftvs.cuni.cz.
Copyright © 2019 by the National Strength & Conditioning Association.

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Specific activation of HIV-1 by a bromodomain inhibitor from monocytic cells in humanized mice under ART in vivo [Virus-Cell Interactions]

The combination antiretroviral therapy (cART) effectively suppresses HIV-1 replication and enables HIV-infected individuals to live long productive lives. However, the persistence of HIV-1 reservoirs of both T and myeloid cells with latent or low-replicating HIV-1 in patients under cART makes HIV-1 infection an incurable disease. Recent studies have focused on the development of strategies to activate and purge these reservoirs. Bromodomain and extraterminal domain proteins (BETs) are epigenetic readers involved in modulating gene expression. Several bromodomain inhibitors (BETi) are reported to activate viral transcription in vitro in HIV-1 latency cell lines in a P-TEFb (CDK9/cyclin T1)-dependent manner. Little is known about the BETi efficacy in activating HIV-1 reservoir cells under cART in vivo. In this study, we report that a BETi (I-BET151) efficiently activated HIV-1 reservoirs under effective cART in humanized mice in vivo. Interestingly, I-BET151 during suppressive cART in vivo activated HIV-1 gene expression only in monocytic cells, but not in CD4+ T cells. We further demonstrate that BETi preferentially enhanced HIV-1 gene expression in monocytic cells than in T cells and, whereas CDK9 was involved in activating HIV-1 by I-BET151 in both monocytic and T cells, CDK2 enhanced HIV-1 transcription in monocytic cells but inhibited it in T cells. Our findings reveal a role of CDK2 in differential modulation of HIV-1 gene expression in myeloid cells and in T cells, and provides a novel strategy to reactivate monocytic reservoirs with BETi during cART.

IMPORTANCE Bromodomain inhibitors have been reported to activate HIV-1 transcription in vitro but their effect on activation of HIV-1 reservoirs during cART in vivo is unclear. We found that BETi (I-BET151) treatment reactivated HIV-1 gene expression in humanized mice during suppressive cART. Interestingly, I-BET151 preferentially reactivated HIV-1 gene expression in monocytic cells, but not in CD4 T cells in cART-treated mice. Furthermore, I-BET151 significantly increased HIV-1 transcription in monocytic cells, but not in HIV-1 infected CD4 T cells, via CDK2-dependent mechanisms. Our findings suggest that BETi can preferentially activate monocytic HIV-1 reservoir cells, and a combination of reservoir activation agents targeting different cell types and pathways is needed to achieve reactivation of different HIV-1 reservoir cells during cART.

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Characterization of Novel Reoviruses [Wad Medani virus (Orbivirus) and Kundal (Coltivirus)] collected from Hyalomma antolicum ticks in India during CCHF surveillance [Genetic Diversity and Evolution]

In 2011, ticks were collected from livestock following an outbreak of Crimean Congo Hemorrhagic fever (CCHF) in Gujarat state, India. CCHF-negative Hyalomma anatolicum tick pools were passaged for virus isolation, and two virus isolates were obtained, designated Karyana virus (KARYV) and Kundal virus (KUNDV) respectively. Traditional RT-PCR identification of known viruses was unsuccessful, but a next-generation sequencing approach identified KARYV and KUNDV as viruses in the Reoviridae family, Orbivirus, and Coltivirus genera, respectively. Viral genomes were de novo assembled, yielding 10 complete segments of KARYV and 12 nearly complete segments of KUNDV. The VP1 gene of KARYV shared a most recent common ancestor with Wad Medani virus (WMV), strain Ar495, and based on nucleotide identity we demonstrate that it is a novel WMV strain. The VP1 segment of KUNDV shares a common ancestor with Colorado tick fever virus, Eyach virus, Tai Forest reovirus and Tarumizu tick virus from the Coltivirus genus. Based on VP1, VP6, VP7, and VP12 nucleotide and amino acid identity, KUNDV is proposed to be a new species of Coltivirus. Electron microscopy supported the classification of KARYV and KUNDV as reoviruses and identified replication morphology consistent with other Orbi– and Colti– viruses. The identification of novel tick-borne viruses carried by the CCHF vector is an important step in the characterization of their potential role in human and animal pathogenesis.

Importance Ticks, mosquitoes, as well Culicoides, can transmit viruses in the Reoviridae family. With the help of next-generation sequencing (NGS), previously unreported reoviruses such as equine encephalosis virus, Wad Medani virus (WMV), Kammanvanpettai virus (KVPTV) and with this report, KARYV and KUNDV have been discovered and characterized in India. The isolation of KUNDV and KARYV from Hyalomma anatolicum, which is a known vector for zoonotic pathogens, such as Crimean Congo Hemorrhagic Fever virus, Babesia, Theileria and Anaplasma species, identifies arboviruses with the potential to transmit to humans. Characterization of these KUNDV and KARYV isolated from Hyalomma ticks is critical for the development of specific serological and molecular assays that can be used to determine the association of these viruses with disease in humans and livestock.

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Automated Quoting, eCommerce, and Custom Orthotics

However, that’s not what clients want. At the era of Amazon, people desire things when they want them, and then that usually means currently . ECommerce is currently changing the way business is done, supplementing traditional brick-and-mortar and social business, just as additive is reshaping the way.
Founded to make custom instruments, iOrthotics spent into the MJF 3D printers of HP in 2017. MJF has been demonstrated to grow the reach of their installment — and to be a fantastic match for orthotics, iOrthotics turned into its dollar 3D printing investment into a organization that was new.
“DigiFabster’s solution has profited i3DPS in a number of different methods,” said Hartley. “Among the would be that the low time it can take to get orders out. Our work flow improved with this comes a decrease in cost and significantly. We’re probably saving anywhere from 30 to 60 minutes each order by reducing lots of the administrative tasks that go along with each order, both at the front and rear end of this process.”
Service bureaus are doing a business in 3D printing as use is seen by the tech in orders of various sizes. Small businesses looking for replacement parts , or one time, custom may get industrial equipment that is expensive without investing the money time, or training necessary.
This appearance right into where automation will help that its own fit has been seen by a Australian small business operation in curbing its work flow for custom orthotics.

“i3DPS was made therefore other kinds of organizations can gain access to our capabilities. They use our site from prototypes and replacement parts, to production parts where they need even or 100 1,000 pieces. We now have an entire array of industries arriving at us, getting quotes and placing orders for 3D printed parts,” explained Dean Hartley, Founder and General Manager, iOrthotics.

3D printing fits into a manufacturing setting, and also afield the work flow for many is a goal for many companies these days. Automation is responsible for streamlining front- and – backend surgeries, and choosing the right software is important for creating the brand new solutions that are ideal.
The agencies themselves create programs for clients get and to explore their personal information, requiring significant experience to end. Because of its applications needs, i3DPS looked to get an online quoting solution for easy ordering to DigiFabster. Quoting could prove an bottleneck from the ordering process, because these may expect a person.

Implementing solutions from DigiFabster allowed i3DPS to offer quoting, as well as track and manage orders.

Via DigiFabster

The spinoff, i3DPS, features a digital manufacturing chain with online ordering and quoting.

I3DPS eases the quoting for customers and use of the CRM system of DigiFabster keeps those customers upgraded on status. Payment and shipping are also automated in their installation.

IOrthotics has established a new branch for practice orthotics, filled with a digital workflow.

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Total Sleep Deprivation and Recovery Sleep Affect the Diurnal Variation of Agility Performance: The Gender Differences

Address correspondence into Mohamed Romdhani, romdhaniroma@gmail.com.
Copyright © 2019.
J Strength Cond Res XX(X): 000–000, 2018–This study aimed to research the results of Timeofday, 24 and 36 hours of sleep deprivation (TSD), and healing sleep (RS) on repeated-agility performances. Twenty two physical education students (11 male and 11 female students) completed 5 repeated modified agility t test (RMAT) sessions (i.e., two later normal sleep nighttime [NSN] [in 07:00 and 17:00 hours], 2 later TSD [in 07:00 hrs, i.e., 24-hour TSD and in 17:00 hours, i.e., 36-hour TSD], and 1 after R S at 17:00 hours). The RMAT index dropped from the afternoon into the afternoon after NSN (p < 0.05, d = 1.05; p < 0.01, d = 0.73) and after TSD (p < 0.001, d = 0.92; d = 1.08), respectively, to get total time (TT) and summit time (PT). This finding implies a variation. However, the abrupt increase in PT was less marked in the female group after NSN (2.98 vs. 6.24%). More over, TT and PT increased, respectively, after 24hour TSD (p < 0.001; d = 0.84, Id = 0.87) and also 36-hour TSD (p < 0.001, d = 1.12; p < 0.01, d = 0.65). Female participants' PT was less affected by 24-hour TSD (1.76 vs. 6.81%) compared with male participants' PT. After 36-hour TSD, the amount of decrease was not different between classes, which increased the diurnal amplitude of PT just for participants. Overall sleep deprivation raised that the amplitude of fever in women and suppressed PT's growth. Nevertheless, RS normalized the sleep-loss. Conclusively, repeated-agility performance of men and women affect during your afternoon. Sleep extension postdeprivation could have potent restorative influence on performances that are repeated-agility, and greater benefits could be extracted by female participants.

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3D Printing versus Smartphone Security

darkshark using the 3D printed fingerprint to open a Galaxy S10 [Image via Imgur]

Yes, 3D printed fingerprints can fool smartphone scanners. No, that shouldn’t keep you up at night.

Hackers love a good hack, and often that falls into “because I could” territory. So it was for Imgur user “darkshark” whose latest attempt has been making the rounds of internet tech news this week. Darkshark poses a simple claim:

“I attempted to fool the new Samsung Galaxy S10’s ultrasonic fingerprint scanner by using 3d printing. I succeeded.”

The Galaxy S10 is the latest smartphone from Samsung, equipped with a high-tech ultrasonic fingerprint scanner — said to be much more secure than typical optical scanners. With this newfangled scanner, fingerprints are examined in 3D as the phone looks into not just patterns but ridges to ensure that the right finger is trying to access the phone.

But is it infallible? Does it have to be the right finger? Such questions keep the curious up at night, and no one can say darkshark isn’t the curious sort.

So off went a bit of work with a wine glass, smartphone camera, software manipulation and modeling, and a 3D printer.

Darkshark captured a photo of their fingerprint on a wine glass, then increased the contrast in Photoshop to create an alpha mask. That in turn went into 3ds Max to create a full 3D model “of every last detail of the fingerprint.”

“I popped that model into the 3D printing software and began to print it. This was printed using an AnyCubic Photon LCD resin printer, which is accurate down to about 10 microns (in Z height, 45 microns in x/y), which is more than enough detail to capture all of the ridges in a fingerprint,” darkshark reports. “Printed perfectly. Print time was only around 13 minutes.”


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[“I distorted my fingerprints in photoshop before posting this, so that you guys can’t steal it lol. I don’t trust any of you.” / Images via Imgur]

It took a bit of tweaking to get it right, but not much. Three reprints, including mirroring the fingerprint, ensured the ridge height hit right, and the resin print was usable as seen in the full Imgur post.

There have been fears for years about 3D printed hand replicas being used in identity theft, and new smartphone releases with the most advanced facial/fingerprint scanners continue to be targets for new attempts. Many of those attempts succeed, with 3D printed fingerprints and 3D printed masks unlocking phones. More of the attempts fail, of course; we don’t hear about those so much. There’s not much Imgur street cred for “I attempted to do this hack-y thing and failed and gave up.”

Still, that some of them succeed and are highly publicized lends credibility to fears about just how secure our phones are. Phones are our portal to everything these days: bank accounts, mortgages, contact lists, calendars, perhaps sensitive photos or documents.

Those who are proving the vulnerabilities are not unaware of the issues they raise; darkshark notes:

“This brings up a lot of ethics questions and concerns. There’s nothing stopping me from stealing your fingerprints without you ever knowing, then printing gloves with your fingerprints built into them and going and committing a crime.

If I steal someone’s phone, their fingerprints are already on it. I can do this entire process in less than 3 minutes and remotely start the 3d print so that it’s done by the time I get to it. Most banking apps only require fingerprint authentication so I could have all of your info and spend your money in less than 15 minutes if your phone is secured by fingerprint alone.”

So, yes, it can be done… but, really, will it?

Phones, especially expensive new models, are certainly targets for thieves. But how many pickpockets are going to actually first swoop in for a high-res snapshot of your fingerprints at the bar where they lift your phone and be ready with software, hardware, and the patience to try and retry the design to delete the calendar reminder for Billy’s piano recital before deleting all your information and turning the phone into profit?

A lot of things are technically possible, but that doesn’t mean they’re going to be regular occurrences. For most people, common sense is a good enough protective measure.

Via Imgur

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What is 3D Scanning?

A common trope in spy and heist movies is for the protagonist to scan the face of an opposing agent or any valuable item and create a perfect replica out of the scanned model. These movies probably take a few liberties for the sake of storytelling, but technology in the real world isn’t that far off from what these cinematic spies can do. Specifically, 3D scanning technology has been around for decades and is widely used across several different industries. How does this seemingly magical technology work? What can be achieved with 3D scanning and how much potential does it have?

What is 3D scanning?

3D scanning refers to any form of technology or technique that collects data from real-world objects or environments and uses this data to construct digital 3D models. Development of 3D scanning technology started as far back as the 1960s in the field of research and design. Early 3D scanners used a rudimentary setup of a combination of lights, cameras, and projectors to accurately recreate the surface of various objects and places.

After 1985, developments in 3D scanning technology allowed for the use of scanners that utilized white light and lasers to capture a given surface. Still, the time and effort needed to create an accurate model proved to be difficult hurdles for the acceptance of 3D scanning technology.

The advent of computers with vast data processing capabilities revolutionized the field of 3D scanning. Fast and accurate scanning of very detailed objects became possible, which led to the development of different 3D scanning techniques.

Nowadays, 3D scanning technology has become heavily used in the entertainment industry in the production of animation, movies, and video games. Consumer-level products that feature motion capture and gesture recognition capabilities have also benefited from the strides that 3D scanning technology has taken in the past decades. 3D scanning has become very useful in industrial design, rapid prototyping, and reverse engineering.

How does 3D scanning work?

Over the years, different techniques have been developed to generate the unique data needed to create 3D models. In a nutshell, all 3D models are essentially “data clouds” – conglomerations of data points arranged in three-dimensional space. Listed below are the different techniques used to create these data clouds:

1. Contact-based

One of the earliest methods of 3D scanning, contact-based 3D scanners rely on very precise measurements of the object made by an articulated arm equipped with high precision sensors. In this method, the object needs to be on a precision flat surface or held in place by a precisely measured fixture. Contact-based 3D scanners are fairly simple and inexpensive. However, they are also relatively slow compared to other scanners.

Another limitation of contact-based scanners comes from the very fact that the probe needs to come into direct contact with the object. This might not be advisable when scanning valuable objects such as historical artifacts. Contact-based scanners are also limited in terms of the size of objects that it can scan since it relies on a platform and articulated arm that has spatial limitations.

2. Photogrammetry

Photogrammetry is a very common method to create 3D models due to its simplicity and versatility. This is a passive method – meaning that it relies only on the energy emitted by the object being scanned. In this case, photogrammetry relies on the visible colors being reflected off the object. Simply put, photogrammetry relies on a series of overlapping photos to come up with a 3D model.

By combining images of an object captured at different angles and matching points between different images to identify features, a 3D model can be constructed without any sophisticated equipment. This level of accessibility is the biggest advantage of photogrammetry as any high-quality camera can be used, even the one on your smartphone. This technique instead relies on an intelligent software algorithm to find the edges of the object, identify matching features, and reconstruct the pixels in 3D space.

Another huge benefit of photogrammetry is that it can capture surface data on top of spatial data. This means that 3D models can be constructed that retain the color or patterns on the surface of the original object. Photogrammetry can also be used to scan huge objects – one of its most common applications is in creating 3D topographical maps of entire landscapes or cityscapes.

The limitation of photogrammetry comes from the fact that it relies on visible colors. Thus, it cannot be used reliably in dark areas or areas with a lot of canopy cover. Reflective surfaces or objects with features that do not have a high contrast can also be particularly problematic. Moreover, photogrammetry is known to be less consistent and accurate compared to other non-contact 3D scanning methods.

3. Laser triangulation

Laser triangulation is only one of several active 3D scanning methods that use laser emissions in various inventive ways. In laser triangulation, a laser is aimed at the subject while a camera records the location of the emitted laser. As the laser hits different features of the subject, the emitted point appears in different locations from the perspective of the camera.

By combining the geometrical data related to the position of the laser emitter and the subject and the angle of the camera with respect to the laser dot as it appears on the subject, the features and dimensions of the subject can be recreated in a digital model. The technique is called “triangulation” because the position of the laser emitter, the camera, and the laser dot on the subject forms a triangle which acts the basis of all spatial measurements. A laser stripe can also be used instead of a single laser point to speed up the process.

Laser triangulation is one of the most accurate 3D scanning methods, able to achieve an accuracy in the order of tens of micrometers. Since laser triangulation also uses a camera, the visual data can be combined with the data cloud to come out with full-color 3D models.

The technology behind laser triangulation is fairly simple, allowing the development of handheld 3D scanners. These desktop-scale DIY models also come fairly cheap – just about a few hundred bucks. Combined with the accuracy and rate of data acquisition of laser triangulation scanners, their level of accessibility has made them extremely popular.

The limitation of laser triangulation lies in the distance. Since the camera needs to see the position of a very small laser dot or a thin laser stripe, laser triangulation cannot be used to scan objects more than a few meters away. Since the method relies on a reflected laser dot, subjects with reflective or transparent surfaces can be particularly problematic.

4. Structured light

Structured light 3D scanners project an image with a pre-determined pattern on the subject. Depending on the features of the subject, the pattern will then be distorted in a number of different ways. A camera records the image of the projected pattern and uses the data on the distortions to calculate the dimensions of the individual features.

One strength of the structured light method is that it does not rely on any sophisticated equipment. The light pattern can be projected on the subject using a standard LCD projector, while images can be captured using any high-quality camera. The speed of data acquisition using structured light is almost unmatched since it can scan multiple points or an entire field of view at once. Resolution is also excellent – typically in the range of 1 micrometer.

As with any 3D scanning method that relies on optical properties, reflective or transparent surfaces can be challenging for structured light 3D scanners. In some cases, this limitation can be overcome by painting over these surfaces with a thin opaque lacquer.

More recent developments in the field of structured light 3D scanning have focused on coming up with algorithms by re-designing the illumination patterns that come up when scanning optically complex subjects. The results of these efforts have been promising for scanning difficulty objects such as reflective metals or translucent surfaces.

5. Time-of-flight

Time-of-flight 3D scanning is another active method that uses a laser emitter to fire off successive pulses of laser light. These pulses are reflected off the surface of the subject, upon which a separate lase sensor receives them. The time interval between the emission of the laser and the reception of the reflected beam is used to measure the dimension of individual features on the surface of the subject.

Time-of-flight 3D scanners have the distinct advantage of being usable over large distances. Light Detection and Ranging (LiDAR) sensors that are founded on the principle of time-of-flight 3D scanning have been extensively used to create 3D topographical maps using an aircraft-mounted sensor. Large structures, such as building and other geographical features, are also commonly scanned using time-of-flight methods. Since time-of-flight 3D scanners don’t rely on visible light, they can be used to scan objects and environments even in darkness.

Data acquisition rate is one of the areas where time-of-flight 3D scanners suffer. Since they only detect the distance of one point at a time, it can take millions of data points to come up with an accurate model of a moderately-sized subject. Some time-of-flight 3D scanners have solved this problem by extending the field of the view of the range finder.

While there are other 3D scanning methods beyond those included in this list, the ones listed above are the most common. Each method has a set of strengths and limitations in terms of data scope, quality, accuracy, acquisition speed, and applicability.

Applications of 3D scanning

As you can imagine, 3D scanning has a lot of potential to change the way things are done across different industries. The applications of 3D scanning in today’s world are incredibly diverse and showcase just how useful and versatile the technology is.

1. Industrial design

Designing new products and prototype has never been easier before the dawn of 3D scanning and modeling. Often, products need to be designed to work around existing objects or environments. By capturing accurate measurements of these objects, prototypes can be created that fit perfectly to their applications.

Reverse engineering a physical object has also become much easier with 3D scanning technology. A digital model of an object can be generated with extremely high accuracy, allowing for mass-scale reproduction. The 3D model can even be tweaked to implement easy improvements.

2. Entertainment

Motion capture and recreation of real-world objects in a digital space have become incredibly common in movies and video games. This is made possible by a variety of different 3D scanning techniques that can capture motion paths or even recreate human faces. Computer-animated models typically begin with hand-sculpted physical models that are then scanned and manipulated in a digital environment.

3. Manufacturing

3D scanning has allowed manufacturing and production firms to monitor the quality of tools and manufactured products with utmost precision. “Hand-tuned” products can be 3D scanned to generate a model that will act as the basis for mass production. Tool and equipment wear can also be monitored at a high level of detail, giving firms a chance to reduce the likelihood of equipment failure.

4. Construction and civil works

The construction industry may be one of the biggest beneficiaries of 3D scanning technology. From site modeling to monitoring of progress and quality control, 3D scanning can be used in a huge number of ways to model and assess any major construction work. 3D scanning can also be used to establish a “benchmark” for a newly constructed building, making it much easier to identify deformations in the structure as a result of extreme conditions.

5. Archeology and geology

The technology of 3D scanners has been used in combination with drones to create topographical models of unexplored lands. With the ability of some 3D scanning methods to penetrate foliage and other canopy cover, 3D scanners have even uncovered networks of cities and roads that are invisible to the naked eye. For geologists planning expeditions and surveys into the unknown, 3D scanning has proven to be an invaluable tool for planning and reconnaissance.

6. Real estate

Some enterprising real estate agents have come up with the bright idea of using 3D scanning technology to offer virtual tours of their property to prospective buyers. This is a level of immersive marketing that beats anything that photos and videos can offer, all without the hassle of driving over to the actual property.

7. Preservation of art and artifacts

3D scanning has allowed archeologists, historians, and museum curators the ability to preserve historical artifacts in a digital environment. The technology has even provided them the opportunity to intimately analyze these artifacts without risking permanent damage. Some museums have leveraged the use of 3D scanning to allow visitors to interact and view art pieces and artifacts like never before.

The future of 3D scanning

1. Mobile photogrammetry

One of the most exciting frontiers in 3D scanning is the possibility of being able to do 3D scans using your typical smartphone. Since it’s impractical and expensive to equip a smartphone with additional dedicated sensors, photogrammetry seems to be the most sensible way to go. Software-driven photogrammetry certainly sounds feasible but taking the right photographs from the right angles requires a certain level of skill which might be off-putting to the casual smartphone user. Most smartphones are also not equipped with enough processing power to handle pixel matching of what could potentially be dozens of individual photographs.

However, it’s only a matter of time before camera and mobile processing technologies catch up to the demands of on-the-go photogrammetry. In fact, iPhone users have been able to do mobile photogrammetry for a few years now through the Trnio app. By providing basic tracking guidance to the user and taking advantage of cloud-based data processing, this simple app has been able to generate basic 3D models, albeit after a lot of waiting due to multiple file transfers.

2. Integration with artificial intelligence

Even with all the sophistication of 3D scanning, it is still a method that relies heavily on human intervention. In particular, the use of 3D scanning for quality in the manufacturing industry still relies on human-decided “pass” or “fail” conditions. This is because letting a part or tool pass the quality standards of the process can be very subjective and can be too complex for a computer to process.

This can all change by integrating artificial intelligence (AI) into the 3D scanning process. A carefully-designed AI can make rapid decisions on quality control using a highly complex set of parameters. This can help streamline the manufacturing processes across several industries and provide a more accurate and less labor-intensive alternative to human-based decision making.

3. Portable, accurate, and affordable 3D scanners

Handheld and portable 3D scanners are actually already available today, but the cheapest models typically fall short in terms of performance. Most 3D scanners in the below $500 range are inaccurate, unreliable, and generally clunky for average users. If you want a high-quality desktop 3D scanner, you are going to have to fork over more than $2000.

If you are dreaming of owning a reliable 3D scanner at a price that won’t break the bank, then the bad news is that the technology isn’t quite there yet. However, the mainstream success of desktop-scale 3D printing means that there is a viable market for casual 3D modelers and DIY creators. With a huge following, it should be only a matter of time before 3D scanners enter the casual or hobbyist market.

Final thoughts

Although 3D scanning technology has been around for decades, it is only recently that huge industries have started to take notice. 3D scanning has a huge number of applications across different industries: prototyping, industrial design, manufacturing, entertainment, construction, and artifact preservation. The existing techniques for 3D scanning are just as varied, with each method having its set of strengths and limitations that make it apt for different circumstances.

There is no doubt that 3D scanning will continue to be a relevant technology and will receive focus in terms of innovation and advancement. 3D scanning technology might even soon be available on the phone in your hand. We believe that 3D scanning still has a lot of untapped potential, and the future is looking very bright for this particular technological marvel.

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