Motion Analysis

We live in an age of movement. More than at any other time in history , people and things move longer distances, more frequently, and faster than ever before. All that was solid melted into air long ago and is now in full circulation around the world like dandelion seeds adrift on turbulent winds. We find ourselves, in the early twenty-first century, in a world where every major domain of human activity has become increasingly defined by motion. 1 We have entered a new historical era defined in large part by movement and mobility and are now in need of a new historical on-tology appropriate to our time. The observation that the end of the twentieth century and the beginning of the twenty-first was marked by an increasingly " liquid " and " mobile modernity " is now something widely recognized in the scholarly literature at the turn of the century. 2 Today, however, our orientation to this event is quite different. Almost twenty years into the twenty-first century we now find ourselves situated on the other side of this heralded transition. The question that confronts us today is thus a new one: how to fold all that has melted back up into new solids. 3

Multimedia data is generally stored in compressed form in order to efficiently utilize the available storage facilities. Access to archives is dependent on our ability to browse compressed multimedia information-retrieval and tracking from coded video databases. In this paper, a novel visual search engine for video retrieval and tracking from compressed multimedia databases is proposed. The goal of the project is the implementation of a visual browser that operates in a distributed environment where users initiate video searches and retrieve relevant video information simultaneously from multiple video archives. Being presented with a query in the form of template images of objects, the system operates on the compressed video to find the images or video sequences where those objects are present and their positions in the image. Upon user's request, the system will decompress and display only the video sequences of interest.

The aim of this study was to analyse the kinematic sequencing in the penalty-corner drag-flicks of elite male and female field hockey players of international calibre. Thirteen participants (one skilled male drag-flicker and six male and six female elite players) participated in the study. An optoelectronic motion analysis system was used to capture the drag-flicks with six cameras, sampling at 250 Hz. Select ground reaction force parameters were obtained from a force platform which registered the last support of the front foot. Twenty trials were captured from each subject. Both player groups showed significantly (p < 0.05) smaller ball velocity at release, peak angular velocity of the pelvis, and negative and positive peak angular velocities of the stick than the skilled subject. Normalised ground reaction forces of the gender groups were also smaller than that of the skilled drag-flicker. By comparing these players we established that the cues of the skill level are a wide sta...

Prezentowany rozdział otwierał drugą część popularnonaukowej książki "Inżynieria Biomedyczna". Część ta miała tytuł "Diagnostyka elektroniczna: Jak z pomocą maszyny śledzić procesy życiowe". Prezentowany tu rozdział wskazywał na to, jakie (ogólnie) sygnały można pozyskiwać z organizmu człowieka i co przy ich pomocy można osiągnąć w zakresie wspomagania diagnostyki medycznej i monitorowania terapii.

Purpose: The Purpose of this study was to investigate ball velocity of instep and inside foot kicks of university level soccer players. Method: The participants sample consisted twenty university soccer players from Fiji National University, Fiji. All participants have minimum of four years playing experience. The participants delivered instep and inside foot kicks using the right leg. Participants wore a complete soccer kit. Two cameras were used for this study. The cameras intersected each other perpendicularly on sagittal and frontal plans. Motion Analysis Tools (MAT) software was used to determine the ball velocity and IBM SPSS 30 was used to calculate pair t-test involving two tail tests to determine the significant difference of the ball velocity of university soccer players. Results: The results of the study indicate that the mean velocity of instep soccer kick is higher than the mean velocity of the inside foot soccer kicks. A significant difference also exists at the .05 level between the instep and the inside foot soccer kicks of the participants. Conclusion: It can be concluded that the inside foot kick resulted in a lower ball velocity than the instep kick on the part of the university level players.

In this paper, we derive a principal component regression (PCR) method for estimating the optical flow between frames of video sequences according to a pel-recursive manner. This is an easy alternative to dealing with mixtures of motion vectors due to the lack of too much prior information on their statistics (although they are supposed to be normal). The 2D motion vector estimation takes into consideration local image properties. The main advantage of the developed procedure is that no knowledge of the noise distribution is necessary. Preliminary experiments indicate that this approach provides robust estimates of the optical flow. KEY WORDS Motion estimation, principal component regression, and surveillance. 1.

Dynamically changing background ("dynamic background") still presents a great challenge to many motion-based video surveillance systems. In the context of event detection, it is a major source of false alarms. There is a strong need from the security industry either to detect and suppress these false alarms, or dampen the effects of background changes, so as to increase the sensitivity to meaningful events of interest. In this paper, we restrict our focus to one of the most common causes of dynamic background changes: that of swaying tree branches and their shadows under windy conditions. Considering the ultimate goal in a video analytics pipeline, we formulate a new dynamic background detection problem as a signal processing alternative to the previously described but unreliable computer vision-based approaches. Within this new framework, we directly reduce the number of false alarms by testing if the detected events are due to characteristic background motions. In addition, we introduce a new dataset suitable for the evaluation of dynamic background detection. It consists of real-world events detected by a commercial surveillance system from two static surveillance cameras. The research question we address is whether dynamic background can be detected reliably and efficiently using simple motion features and in the presence of similar but meaningful events such as loitering. Inspired by the tree aerodynamics theory, we propose a novel method named local variation persistence (LVP), that captures the key characteristics of swaying motions. The method is posed as a convex optimization problem whose variable is the local variation. We derive a computationally efficient algorithm for solving the optimization problem, the solution of which is then used to form a powerful detection statistic. On our newly collected dataset, we demonstrate that the proposed LVP achieves excellent detection results and outperforms the best alternative adapted from existing art in the dynamic background literature.

The aim of this study was to examine the effect of playing formation on high-intensity running and technical performance during elite soccer matches. Twenty English FA Premier League games were analysed using a multiple-camera computerized tracking system (n = 153 players). Overall ball possession did not differ (P < 0.05) between 4-4-2, 4-3-3 and 4-5-1 formations (50%, s = 7 vs. 49%, s = 8 vs. 44%, s = 6). No differences were observed in high-intensity running between 4-4-2, 4-3-3 and 4-5-1 formations. Compared with 4-4-2 and 4-3-3 formations, players in a 4-5-1 formation performed less very high-intensity running when their team was in possession (312 m, s = 196 vs. 433 m, s = 261 vs. 410 m, s = 270; P 5 0.05) but more when their team was not in possession (547 m, s = 217 vs. 461 m, s = 156 vs. 459 m, s = 169; P < 0.05). Attackers in a 4-3-3 performed ~30% more (P < 0.05)…

Background: Virtual reality (VR) simulators now have the potential to replace traditional methods of laparoscopic training. The aim of this study was to compare the VR simulator with the classical box trainer and determine whether one has advantages over the other. Methods: Twenty four novices were tested to determine their baseline laparoscopic skills and then randomized into the following three group: LapSim, box trainer, and no training (control). After 3 weekly training sessions lasting 30-min each, all subjects were reassessed. Assessment included motion analysis and error scores. Nonparametric tests were applied, and p < 0.05 was deemed significant. Results: Both trained groups made significant improvements in all parameters measured (p < 0.05). Compared to the controls, the box trainer group performed significantly better on most of the parameters, whereas the LapSim group performed significantly better on some parameters. There were no significant differences between the LapSim and box trainer groups. Conclusions: LapSim is effective in teaching skills that are transferable to a real laparoscopic task. However, there appear to be no substantial advantages of one system over the other.

— In this paper, the accuracy evaluation of the Kinect v2 sensor is investigated in a rehabilitation scenario. The accuracy analysis is provided in terms of joint positions and angles during dynamic postures used in low-back pain rehabilitation. Although other studies have focused on the validation of the accuracy in terms of joint angles and positions, they present results only considering static postures whereas the rehabilitation exercise monitoring involves to consider dynamic movements with a wide range of motion and issues related to the joints tracking. In this work, joint positions and angles represent clinical features, chosen by medical staff, used to evaluate the subject's movements. The spatial and temporal accuracy is investigated with respect to the gold standard, represented by a stereophotogrammetric system, characterized by 6 infrared cameras. The results provide salient information for evaluating the reliability of Kinect v2 sensor for dynamic postures.

Visual motion is sensed by low-level (energy-based) and high-level (feature-based) mechanisms. Ocular following responses (OFR) were elicited in humans by applying horizontal motion to vertical square-wave gratings lacking the fundamental (&quot;missing fundamental stimulus&quot;). Motion consisted of successive 1/4-wavelength steps, so the features and 4n+1 harmonics (where n=integer) shifted forwards, whereas the 4n-1 harmonics--including the strongest Fourier component (the 3rd harmonic)--shifted backwards (spatial aliasing). Initial OFR, recorded with the electromagnetic search coil technique, were always in the direction of the 3rd harmonic, e.g., leftward steps resulted in rightward OFR. Thus, the earliest OFR were strongly dependent on the motion of the major Fourier component, consistent with early spatio-temporal filtering prior to motion detection, as in the well-known energy model of motion analysis.

The aim of this study was to compare match performance in professional soccer players across two major European championships: Spanish La Liga and English FA Premier League (FAPL). Data were collected using a computerized match analysis system. A total of 5938 analyses were recorded during the 2006–2007 season. The players were classified into six positional roles: central defenders, full backs,

Our aim is to estimate the perspective-effected geometric distortion of a scene from a video feed. In contrast to most related previous work, in this task we are constrained to using low-level, spatio-temporally local motion features only. This particular challenge arises in many semi-automatic surveillance systems which alert a human operator to potential abnormalities in the scene. Low-level, spatio-temporally local motion features are sparse (and thus require comparatively little storage space) and sufficiently powerful in the context of video abnormality detection to reduce the need for human intervention by more than 100-fold. This paper introduces three significant contributions: (i) we describe a dense algorithm for perspective estimation which uses motion features to estimate the perspective distortion at each image locus and then polls all such local estimates to arrive at the globally best estimate, (ii) we also present an alternative coarse algorithm which subdivides the image frame into blocks, and uses motion features to derive block-specific motion characteristics and constrain the relationships between these characteristics, with the perspective estimate emerging as a result of a global optimization scheme, and (iii) we report the results of an evaluation using nine large sets acquired using existing close-circuit television (CCTV) cameras, not installed specifically for the purposes of this work. Our findings demonstrate that both of the proposed methods are successful, their accuracy matching that of human labelling using complete visual data (by the constraints of the setup unavailable to our algorithms).

It is often postulated that an increased hip to shoulder differential angle (`X-Factor') during the early downswing better utilises the stretch-shorten cycle and improves golf performance. The current study aims to examine the potential relationship between the X-Factor and performance during the tee-shot. Seven golfers with handicaps between 0 and 10 strokes comprised the low-handicap group, whilst the high-handicap group consisted of eight golfers with handicaps between 11 and 20 strokes. The golfers performed 20 drives and three-dimensional kinematic data were used to quantify hip and shoulder rotation and the subsequent X-Factor. Compared with the low-handicap group, the high-handicap golfers tended to demonstrate greater hip rotation at the top of the backswing and recorded reduced maximum X-Factor values. The inconsistencies evident in the literature may suggest that a universal method of measuring rotational angles during the golf swing would be beneficial for future studies, particularly when considering potential injury.

"...Process cycle time reduction to increase Productivity, Quality and Efficiency of G-435cc diesel engine assembly line at Greaves cotton Ltd...'

The project was successful as the required target was achieved.
Some of the achievements are listed below:-
1]2nd shift was successfully eliminated.
2]Productivity improved by 16%.
3]Monthly saving of Rs.46, 500 (as second shift is eliminated).
4]Cycle time reduced by 13 sec.