Slow Motion Video Research Articles

Smartphone-based video for 3D modelling: Application to infant’s cranial deformation analysis

The use of smartphones cameras for photogrammetric purposes is increasing. However, the suitability of smartphones for 3D modelling for medical purposes in general, and for cranial deformation in particular, is still to be analysed. This paper investigates the suitability of smartphone video cameras to create 3D models for cranial deformation analysis compared to the digital single-lens reflex (SLR) cameras traditionally used in close-range photogrammetry. Two models are obtained, the first one from a slow-motion video recorded with a smartphone, and the second one from SLR camera imagery. The models are compared to evaluate the differences not only between themselves but also through the best fitting ellipsoid that allow the determination of the cranial deformations. The average distance between models is 0.5 mm, and below 1 mm for 86% of the model points. The maximum difference between the two fitted ellipsoid semiaxes is 1 mm. It can be stated that smartphones are a low-cost solution that can provide 3D models with a similar accuracy to that of SLR cameras for non-static objects in close range scenarios. More interestingly, slow-motion videos provide comparable results in real clinical conditions with infants in movement.

Abstract 3924: Single-cell mechanical characteristics of human breast cell lines analyzed by multi-constriction microfluidic channels

Abstract Studies of the mechanical characteristics of single cancer cells have shown that non-metastatic and metastatic cells have significant differences in stiffness. We used a microfluidic multi-constriction channel device to differentiate cancer cells and normal cells based upon differences in their mechanical properties. We fabricated the multi-constriction channels on a silicon wafer with SU-8 photolithography and polydimethylsiloxane (PDMS) soft-lithography, followed by PDMS and glass bonding after plasma treatment. The multi-constriction microfluidic channel contains five constriction channels each 50 μm in length separated by relaxation sections of 50 μm between every constriction channel. We used MDA-MB-231 as the cancer cell line and MCF-10A as the normal cell line, and utilized a smart phone to record video via a microscope. Our measurement by smart phone slow-motion video through microscope reliably collected the velocities of over 200 cells. We focused on comparing the initial velocity change due to cell deformation at the entrance of the first constriction channel and the exiting velocity at the last segment of the final constriction channel, where the cells have experienced sequential deformations. The multiple deformation paradigm tests cells’ resilience towards deformation and shape recovery. Cancer cells recovered back to a round cell shape quickly, and therefore experienced deformation at the entrance to each constriction channel, with a net result of a decrease in velocity. The initial velocities of MDA-MB-231 cells were ~1.1 mm/s, and exiting velocities were ~2.2 mm/s. In contrast, normal cells deformed slower initially, but reached a higher velocity after two or three deformations, because normal cells stay in a rod-like shape without fully recovering back to an original spherical cell shape. The initial velocities of MCF-10A cells were ~0.5 mm/s, and exiting velocities were ~3.8 mm/s. When normal cells enter the fourth and fifth constriction channels, the cells’ shapes were almost fixed. The entrance time of cancer cells into the fourth and fifth channel was longer than the normal cells. After calculating the velocity increments in the fourth channel and fifth channel compared to the initial velocity, the Matlab scatter plot of the velocity data of each MDA-MB-231 (n= 108 cells) and MCF-10A (n= 105 cells) cells showed clear separation of the two cell lines into distinct regions. Algorithms based upon these criteria successfully differentiated ~94.4% of the cancer cells from normal cells. Our experimental results indicated that multi-constriction microfluidic channels can be used to differentiate metastatic MDA-MB-231 and MCF-10A cells at the single cell level and may have further applications in high-throughput cell sorting and analysis. The authors would like to thank National Institute of Health (NIH) R21CA210126 for supporting this research. Citation Format: Xiang Ren, Parham Ghassemi, Hesam Babahosseini, Jeannine S. Strobl, Masoud Agah. Single-cell mechanical characteristics of human breast cell lines analyzed by multi-constriction microfluidic channels [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2017; 2017 Apr 1-5; Washington, DC. Philadelphia (PA): AACR; Cancer Res 2017;77(13 Suppl):Abstract nr 3924. doi:10.1158/1538-7445.AM2017-3924

Authenticity, Captioned: Hashtags, Emojis, and Visibility Politics in Alok Vaid-Menon’s Selfie Captions

Authenticity, Captioned: Hashtags, Emojis, and Visibility Politics in Alok Vaid-Menon’s Selfie Captions

Dynamic Slow Motion Video Endoscopy as an Adjunct to Impedance Audiometry in the Assessment of Eustachian Tube Function.

Introduction Eustachian tube (ET) dysfunction plays an important role not only in the pathophysiology of various middle ear disorders, but also in predicting the outcome of the treatment. As there is no single test that assesses both the anatomic and physiological functions of the ET, a combination of tympanometry and dynamic slow motion video endoscopy may improve the sensitivity of ET function assessment. Objective To find out if there is any correlation between dynamic slow motion nasal video endoscopy and impedance audiometry in assessing ET function in patients with middle ear diseases. Methods Ours was a descriptive study performed with 106 patients attending the Ear, Nose and Throat (ENT) Outpatient Department of a tertiary care center in South India with features suggestive of middle ear disease. All patients underwent impedance audiometry and dynamic slow motion nasal video endoscopy, and were graded based on the severity of the ET pathology. Results A total of 47 out of 97 patients with abnormal endoscopy findings also had abnormal impedance audiometry. The correlation was greater among the patients with higher grades of ET dysfunction. The endoscopy findings of 106 cases, when correlated with middle ear manometry, revealed that 56 cases showed complete agreement, and 50 cases showed disagreement. The nasal endoscopy results, when correlated with middle ear manometry studies by using McNemar's chi-squared (χ 2 ) test, showed a significant association between the 2 tests ( p = 0.017). Conclusion There is a significant alteration in middle ear pressure as the severity of the ET tube dysfunction increases. Impedance audiometry and nasal endoscopy provide a better measure of ET function.

Analysis of Eustachian Tube Dysfunction by Dynamic Slow Motion Video Endoscopy and Eustachian Tube Dysfunction Questionnaire in Chronic Otitis Media.

Objectives Eustachian tube dysfunction has been associated with most cases of middle-ear disease. We aimed to assess the effectiveness of dynamic slow motion video endoscopy (DSVE) as a test of eustachian tube dysfunction. Furthermore, we assessed the correlation of the test with the Valsalva maneuver, the seven-item Eustachian Tube Dysfunction Questionnaire (ETDQ-7), and intraoperative findings of the eustachian tube.Methods We retrospectively reviewed medical records from April to September 2014 to identify patients who were diagnosed with chronic otitis media (COM) at Korea University Ansan Hospital. They all underwent surgery because of COM without cholesteatoma and were assessed via the DSVE and ETDQ-7 to determine eustachian tube function.Results We reviewed 46 COM patients and examined 46 ears with COM and 46 ears on the contralateral side to COM that were thought to be normal. The mean DSVE grade in COM ears was 1.57±0.96, while the mean DSVE grade in contralateral ears was 1.15±0.94. The difference in DSVE between COM ears and normal ears was statistically significant (P=0.006). In the ETDQ-7, a higher score was related to intraoperative obstruction of the eustachian tube (P=0.012).Conclusion DSVE and ETDQ-7 can provide information regarding preoperative status of eustachian tube dysfunction by measuring dynamic structural changes of the eustachian tube in combination with other diagnostic tests.

Using high speed smartphone cameras and video analysis techniques to teach mechanical wave physics

We propose the use of smartphone-based slow-motion video analysis techniques as a valuable tool for investigating physics concepts ruling mechanical wave propagation. The simple experimental activities presented here, suitable for both high school and undergraduate students, allows one to measure, in a simple yet rigorous way, the speed of pulses along a spring and the period of transverse standing waves generated in the same spring. These experiments can be helpful in addressing several relevant concepts about the physics of mechanical waves and in overcoming some of the typical student misconceptions in this same field.

The roles of impact and inertia in the failure of a shoelace knot.

The accidental untying of a shoelace while walking often occurs without warning. In this paper, we discuss the series of events that lead to a shoelace knot becoming untied. First, the repeated impact of the shoe on the floor during walking serves to loosen the knot. Then, the whipping motions of the free ends of the laces caused by the leg swing produce slipping of the laces. This leads to eventual runaway untangling of the knot. As demonstrated using slow-motion video footage and a series of experiments, the failure of the knot happens in a matter of seconds, often without warning, and is catastrophic. The controlled experiments showed that increasing inertial effects of the swinging laces leads to increased rate of knot untying, that the directions of the impact and swing influence the rate of failure, and that the knot structure has a profound influence on a knot's tendency to untie under cyclic impact loading.

Effect of the Man-Weapon System on the Trajectory of a Projectile Fired from a Machine Pistol

The process of burst-firing two projectiles from a Skorpion vz. 61 7.65 mm calibre machine pistol was recorded during a test at a firing range operated by the Polish Police. This experimental test involved Browning 7.65 x 17 mm SR ammunition rounds. The shots were fired by a Police Special Forces operative. The shots were recorded with a Phantom v.9.1 slow-motion video camera, complete with the essential accessories. TEMA, a software suite dedicated to video recording analyses, was used to determine the initial kinematic parameters of flight for each of the two projectiles. By applying the theorem of momentum and spin change, a theoretical projectile flight model was developed with a respective simulation runtime in SciLab. The projectile flight results were verified with the experimental test results to validate the developed model. Having delivered a reliable projectile flight model, an analysis was carried out to study the effectiveness of the shots fired by the Police Special Forces operative towards a target 30 metres away. This paper presents a determined process of burst firing of two projectiles. It is also a representative example of repetitive shooting. The ultimate task of this research is to develop guidelines for the design of machine pistol dynamic properties that reduce the scatter of projectiles shot in series.

FootStriker

In running, knee-related injuries are very common. The main cause are high impact forces when striking the ground with the heel first. Mid- or forefoot running is generally known to reduce impact loads and to be a more efficient running style. In this paper, we introduce a wearable running assistant, consisting of an electrical muscle stimulation (EMS) device and an insole with force sensing resistors. It detects heel striking and actuates the calf muscles during the flight phase to control the foot angle before landing. We conducted a user study, in which we compared the classical coaching approach using slow motion video analysis as a terminal feedback to our proposed real-time EMS feedback. The results show that EMS actuation significantly outperforms traditional coaching, i.e., a decreased average heel striking rate, when using the system. As an implication, EMS feedback can generally be beneficial for the motor learning of complex, repetitive movements.

Testing fine motor coordination via telehealth: Effects of video characteristics on reliability and validity

Background There is limited research about the effects of video quality on the accuracy of assessments of physical function. Methods A repeated measures study design was used to assess reliability and validity of the finger–nose test (FNT) and the finger-tapping test (FTT) carried out with 50 veterans who had impairment in gross and/or fine motor coordination. Videos were scored by expert raters under eight differing conditions, including in-person, high definition video with slow motion review and standard speed videos with varying bit rates and frame rates. Results FTT inter-rater reliability was excellent with slow motion video (ICC 0.98–0.99) and good (ICC 0.59) under the normal speed conditions. Inter-rater reliability for FNT ‘attempts’ was excellent (ICC 0.97–0.99) for all viewing conditions; for FNT ‘misses’ it was good to excellent (ICC 0.89) with slow motion review but substantially worse (ICC 0.44) on the normal speed videos. FTT criterion validity (i.e. compared to slow motion review) was excellent (β = 0.94) for the in-person rater and good (β = 0.77) on normal speed videos. Criterion validity for FNT ‘attempts’ was excellent under all conditions (r ≥ 0.97) and for FNT ‘misses’ it was good to excellent under all conditions (β = 0.61–0.81). Conclusions In general, the inter-rater reliability and validity of the FNT and FTT assessed via video technology is similar to standard clinical practices, but is enhanced with slow motion review and/or higher bit rate.

Low-Cost Smartphone-Based Photogrammetry for the Analysis of Cranial Deformation in Infants

Cranial deformation, including deformational plagiocephaly, brachycephaly, and craniosynostosis, is a condition that affects a large number of infants. Despite its prevalence, there are no standards for the systematic evaluation of the cranial deformation. Usually, the deformation is measured manually by the use of calipers. Experts, however, do not agree on the suitability of these measurements to correctly represent the deformation. Other methodologies for evaluation include 3-dimensional (3D) photography and radiologic scanners. These techniques require either patient's sedation and ionizing radiation or high investment. The aim of this study is to develop a novel, low-cost, and minimally invasive methodology to correctly evaluate the cranial deformation using 3D imagery. A smart phone was used to record a slow motion video sequence on 5 different patients. Then, the videos were processed to create accurate 3D models of the patients' head, and the results were compared with the measurements obtained by the manual caliper. The correspondence between the manual and the photogrammetric 3D model measurements was high as far as head marks are available, with differences of 2 mm ± 0.9 mm; without marks, measurement results differed up to 20 mm. Smartphone-based photogrammetry is a low-cost, highly useful methodology to evaluate cranial deformation. This technique provides a much larger quantity of information than linear measurements with a similar accuracy as far as head marks exist. In addition, a new approach for the evaluation is pointed out: the comparison between the head 3D model and an ideal head, represented by a 3-axis ellipsoid.

Evaluation of Hemodynamic Performance of Aortic Valve Bioprostheses in a Model of Oversizing

The risk of patient-prosthesis mismatch drives most surgeons to select the largest bioprosthesis possible during aortic valve replacement, but interactions between the native aortic annulus and valve prosthesis remain poorly defined. We examined the hemodynamic and functional consequences of oversizing contemporary bioprostheses in an invitro model. Three sizes each (21, 23, and 25 mm) of 5 aortic bioprostheses (Magna, Edwards Lifesciences, Irvine, CA; Trifecta and Epic, St. Jude, St. Paul, MN; and Mosaic and Hancock II, Medtronic, Minneapolis, MN) were tested on a mock annulus in a pulsatile aortic simulator. After the annulus was sized to match each valve, the annulus was decreased by 3 mm and then by 6 mm to simulate oversizing. We measured the effective orifice area and the mean pressure gradient. Changes in prosthetic leaflet behavior and geometric orifice area wereassessed with slow-motion video. Statistical analysis used mixed-effects models for repeated-measures data, allowing comparison within and between groups. For each valve model and size, oversizing resulted in decreased effective orifice areas and geometric orifice areas and increased pressure gradients. This was more pronounced with smaller valve sizes and higher flow rates but varied between valve types. Slow-motion imaging revealed this change in geometric orifice area was a result of an inward shift of the valve leaflet hinge point. Bioprosthetic oversizing impairs hemodynamic performance of aortic valve bioprostheses. The magnitude of this effect varies by valve model and size. Clinically, these data suggest that during aortic valve replacement, placing a valve whose internal orifice closely matches the aortic annulus will provide the optimal hemodynamic performance.

Time-lapse and slow-motion tracking of temperature changes: response time of a thermometer

We propose the use of a smartphone based time-lapse and slow-motion video techniques together with tracking analysis as valuable tools for investigating thermal processes such as the response time of a thermometer. The two simple experimental activities presented here, suitable also for high school and undergraduate students, allow one to measure in a simple yet rigorous way the response time of an alcohol thermometer and show its critical dependence on the properties of the surrounding environment giving insight into instrument characteristics, heat transfer and thermal equilibrium concepts.

A Statically Unstable Passive Hopper: Design Evolution

I have designed a sequence of gravity-powered passive-dynamic toys. These explore locomotion in general and hopping in particular. As with walking, running, crawling, etc., for animals, locomotion in these devices is a horizontal translation by means of approximately periodic patterns of motion. These toys were developed using intuitively guided trial-and-error design iteration based on live viewing, sound sequences, and review of slow motion video. A series of statically stable mechanisms is described. A progression of designs led to the central result: a monopod hopper that repeatedly hops more than 70 steps down a ramp, without conventional feedback control, fast spinning parts, or sensing means, yet unlike the previously statically stable designs, it cannot stand still stably. This free hopping was facilitated by a special mass distribution, and a spring that allowed relative translation and rotation between the body and leg. A retrospective evaluation reveals similarities to the morphology and gaits of hopping bipeds. These toys, interesting dynamical systems in any case, highlight the possibility of a significant role of mechanical structure in locomotion.

Comparison of cyclic fatigue life of nickel-titanium files: an examination using high-speed camera.

ObjectivesTo determine the actual revolutions per minute (rpm) values and compare the cyclic fatigue life of Reciproc (RPC, VDW GmbH), WaveOne (WO, Dentsply Maillefer), and TF Adaptive (TFA, Axis/SybronEndo) nickel-titanium (NiTi) file systems using high-speed camera.Materials and MethodsTwenty RPC R25 (25/0.08), 20 WO Primary (25/0.08), and 20 TFA ML 1 (25/0.08) files were employed in the present study. The cyclic fatigue tests were performed using a dynamic cyclic fatigue testing device, which has an artificial stainless steel canal with a 60° angle of curvature and a 5-mm radius of curvature. The files were divided into 3 groups (group 1, RPC R25 [RPC]; group 2, WO Primary [WO]; group 3, TF Adaptive ML 1 [TFA]). All the instruments were rotated until fracture during the cyclic fatigue test and slow-motion videos were captured using high-speed camera. The number of cycles to failure (NCF) was calculated. The data were analyzed statistically using one-way analysis of variance (ANOVA, p < 0.05).ResultsThe slow-motion videos were indicated that rpm values of the RPC, WO, and TFA groups were 180, 210, and 425, respectively. RPC (3,464.45 ± 487.58) and WO (3,257.63 ± 556.39) groups had significantly longer cyclic fatigue life compared with TFA (1,634.46 ± 300.03) group (p < 0.05). There was no significant difference in the mean length of the fractured fragments.ConclusionsWithin the limitation of the present study, RPC and WO NiTi files showed significantly longer cyclic fatigue life than TFA NiTi file.

A bullet fired in dry water: an investigative activity to learn hydrodynamics concepts

In this paper we report an investigative activity on hydrodynamics, in the context of an inquiry-based learning project. The aim is to analyse the experiment of a bullet shot underwater. Using Tracker, a video analysing and modelling software, the displacement of the bullet was measured as function of time, processing a slow motion video from YouTube. It was found that the displacement of the bullet is well described in the first 20 ms by the inviscid flow regime, where the Newtonian drag force overcomes the viscous drag. This behaviour is discussed in the context of what Richard Feynman’s famous Lectures on Physics describes as ‘The Flow of Dry Water’.

Deictic transformers: Phenomenological analyses of time-shifts in video art installations

Abstract This article seeks to define a phenomenon in video installations that emerged during the 1990s. It is a type of audio-visual architecture that I call deictic transformer. Deictic transformers are not representations, they are events that trigger a specific type of effect, namely, a shift in time-consciousness, which is characterized as total engagement with the present moment in its impermanence, non-substantiality and self-differentiation. The article unfolds in the form of experiment. As a first step, phenomenological accounts of Christian icons are compared to phenomenological readings of Bill Viola’s ultra slow-motion video art installations. The reader is guided to experience how different media (religious paintings, video) generate different engagements with the present moment. The main subject of this article is ‘the now’. The article suggests that there are various ways of engaging with ‘the now’ and these ways trigger specific shifts in present-time consciousness. These shifts are closely related to the formation of subjectivity and thus demonstrate that temporality is not a given, but could be seen as a technology of the self. Christian icons are representative of a metaphysical approach to the present moment, predominant in the arts and philosophy of the western tradition before the twentieth century. Bill Viola’s video installations The Greeting (1995) and The Passions series (2000–2001) represent a new sensitivity towards time brought by electronic media. The dualist experience of time that is deeply embedded in the Christian tradition is recomposed via video and digital manipulation into a dynamically holistic temporality. The second step addresses other video-based examples of deictic transformers such as Gary Hill’s Viewer (1996) and David Claerbout’s Rocking Chair (2003). The third step examines the aesthetic strategies of these video installations and formulates a definition of their modus operandi. This article does not claim that deictic transformers represent the mainstream of video art installations. Deictic transformers, however, are seen as a growing tendency in new media art praxis that demands intensive engagement with the emerging dynamic of embodied presencing; a tendency that is relatively unprecedented in western culture, and that could be considered an (in)direct result of the technological capacities of video and digital media. In other words, the analyses of Viola, Hill, and Claerbout’s audiovisual experiments demonstrate that video and digital technologies of late twentieth century shift our perception of time from attempts to escape everyday impermanence and the search for permanent metaphysical presence towards an entanglement with the non-substantiality of presencing.

Alternative blade materials for technical and ecological optimization of a hydraulic pressure machine

The Hydraulic Pressure Machine (HPM) is an energy converter to exploit head differences between 0.5 and 2.5 m in small streams and irrigation canals. Previous investigations show that efficiencies above 60% are possible. Several case studies indicate good continuity for aquatic life (e.g. fish) and bed load for the technology. The technology is described as an economically and ecologically viable option for small scale hydropower generation. Primary goal of this research is to improve the HPM blade design regarding its continuity properties by maintaining good efficiency rates. This is done by modifying the blade tip and testing within a large physical model under laboratory condition. Blade tips from steel (conventional - reference case) and a combination of EPDM rubber and steel as sandwich construction (rubber, steel, rubber - adhesive layered) are tested and compared. Both materials reach similar values for hydraulic efficiency (approx. 58%) and mechanical power output (approx. 220 W). The variation of different gap sizes pointed out the importance of small clearance gaps to reach high efficiencies. For assessing the two blade tip materials regarding continuity for aquatic life, fish dummies were led through the wheel. Analysis of slow motion video of dummies hit by the blade show significant advantages for the EPDM blade tip. The EPDM rubber allows to bend and thus reduces the shock and the probability for cuts on the fish dummy. It was shown that blade tips from EPDM have certain advantages regarding continuity compared to standard blade tips from steel. No compromise regarding energy production had to be made. These results from the HPM can be transferred to breast shot water wheel and may be applied for new and retrofitting projects.

The Split Second Effect: The Mechanism of How Equinus Can Damage the Human Foot and Ankle.

We are currently in the process of discovering that many, if not the majority, of the non-traumatic acquired adult foot and ankle problems are caused by a singular etiology: non-neuromuscular equinus or the isolated gastrocnemius contracture. There is no question that this biomechanical association exists and in time much more will be uncovered. There are three basic questions that must be answered: why would our calves tighten as we normally age, how does a tight calf, or equinus, actually cause problems remotely in the foot and ankle, and how do the forces produced by equinus cause so many seemingly unrelated pathologies in the foot and ankle? The purpose of this paper is to address the second question: how does a tight calf mechanically cause problems remotely in the foot and ankle? There has been little evidence in the literature addressing the biomechanical mechanisms by which equinus creates damaging forces upon the foot and ankle, and as a result, a precise, convincing mechanism is still lacking. Thus, the mere concept that equinus has anything to do with foot pathology is generally unknown or disregarded. The split second effect, described here, defines exactly how the silent equinus contracture creates incremental and significant damage and injury to the human foot and ankle resulting in a wide variety of pathological conditions. The split second effect is a dissenting theory based on 30 years of clinical and academic orthopedic foot and ankle experience, keen clinical observation along the way, and review of the developing literature, culminating in examination of many hours of slow motion video of normal and abnormal human gait. To my knowledge, no one has ever described the mechanism in detail this precise.

Very large scale integration architecture for block‐matching motion estimation using adaptive rood pattern search algorithm

This study introduces an architecture for motion estimation block of the video encoder using adaptive rood pattern search (ARPS) algorithm. The architecture has been designed for field programmable gate array (FPGA) as well as application specific integrated circuit (ASIC) implementations. Experimental results show that the speed of ARPS algorithm is ahead of several existing fast motion estimation algorithms without compromising the peak signal-to-noise ratio values. The Virtex-4 FPGA implementation of the proposed architecture using Xilinx 14.2 attains a maximum frequency of 103 MHz with <3% usage of slices. ASIC implementation of the proposed architecture with Synopsys design vision tool (0.18 µm) using 100 MHz frequency involves power consumption of 4.54 mW and occupies 0.073 mm2. A maximum frequency of 333 MHz has been achieved for the ASIC implementation with 16 × 16 blocks and it can process 651 frames of slow motion video such as Akiyo and 280 frames of fast motion video such as Football of CIF format (352 × 288 resolution) per second. Moreover, the ASIC implementation can process up to 31 frames of HD (1920 × 1080 resolution) video per second. Hence, the proposed architecture fits well in applications such as video conferencing and video phones.