Determination of vehicle speed from recorded video using the open-source software Kinovea

Video devices of different kind often record traffic accidents, including vehicle-pedestrian collisions and hit-and-run accidents. In these cases, the vehicle speed is valuable information because it can assist the investigators in an accident reconstruction. This paper examines the use of Kinovea, an open-source video annotation tool designed for sport analysis, to estimate vehicle speed in forensic videos. Kinovea does not require a complex methodology, and it can be used to make the calculation easily. A series of vehicle driving experiments using an appropriately calibrated speed radar system (so called Scout Speed) were carried out, and measurements were compared with the estimated speed. In controlled conditions, the comparison of Scout reference speed and calculated average vehicle speed by means of Kinovea found an average difference of 0.43 km/h, with a margin of error of ±0.64 km/h. In addition, further preliminary tests were carried out to check the reliability of the measurements under lower resolution conditions. Also, in these cases the calculations were in line with the ground truth. Therefore, in the tested conditions, Kinovea demonstrated to be an easy and reliable tool available for forensic video examiners. Further tests need to be conducted in order to address the applicability of the measurement technique with true CCTV/surveillance video recordings.

A new method for assessing lung tumor motion in radiotherapy using dynamic chest radiography

Dynamic chest radiography (DCR) is a recent advanced modality to acquire dynamic and functional images. We developed a new method using DCR and the free analysis software, Kinovea, to assess lung tumor motion. This study aimed to demonstrate the usefulness of our method. Phantom and clinical studies were performed. In the phantom study, dynamic images of a moving lead sphere were acquired using DCR, and the motion of the phantom was tracked using Kinovea in a DCR video. The amplitude of phantom motion was measured and compared with a predetermined baseline amplitude. In a clinical study, DCR and respiratory‐gated four‐dimensional computed tomography (4D‐CT) were performed on 15 patients who underwent stereotactic body radiation therapy for lung tumors. The amplitudes of tumor motion in DCR and 4D‐CT were measured in the superior‐inferior (SI), left‐right (LR), and anterior‐posterior (AP) directions, and the square root of the sum of squares (SRSS) of the amplitude was calculated in all directions. Spearman's rank correlation and the Wilcoxon signed‐rank test were performed to determine the correlations of the amplitudes of tumor motion obtained using DCR and 4D‐CT. In the phantom study, the absolute mean error between the measured and predetermined amplitudes was 0.60 mm (range: 0.061.53 mm). In the clinical study, the amplitudes of tumor motion obtained using DCR correlated significantly with those of 4D‐CT in the SI and LR directions, as did the SRSS values. The median amplitudes for DCR were significantly higher than those for 4D‐CT in all (SI, LR, and AP) directions, as were the SRSS values. Our proposed method based on DCR and Kinovea is useful for assessing lung tumor motion, visually and quantitatively. Therefore, DCR has potential as a new modality for evaluating lung tumor motion in radiotherapy.

The association and reliability of the frontal plane projection angle during the lateral step down test on knee function in patients with patellofemoral pain

BACKGROUND

The lateral step-down test is used by physical therapists (PT) to identify movement faults in patients with patellofemoral pain (PFP). The FPPA is a measure of knee valgus and PTs have access to open source video analysis software and high quality smart phones and video cameras to implement 2D video analysis into practice. The purpose of our study was to determine the reliability of PTs measuring the frontal plane projection angle (FPPA) during the lateral step-down test, and to determine if the FPPA was associated with pain, self-reported knee function and fear of movement.

METHODS

Twenty-two subjects (mean age[SD] = 27.8 [6.6] years, females n = 14, males n = 8) with PFP were analyzed by six PTs using 2D video analysis software. The FPPA was measured during the lateral step down test. Numeric Pain Rating Scale (NPRS), Anterior Knee Pain Scale (AKPS) and the Tampa Scale of Kinesiophobia (TSK) were collected. Intraclass correlation (ICC) was used to assess for PT measurement reliability. Correlations between outcomes were calculated using Spearman correlation coefficient and standard error of measurement (SEM) and minimal detectable change (MDC) were reported.

RESULTS

Reliability amongst PTs measuring the FPPA was good (ICC [95 %CI] = 0.85 [0.72-0.93]; SEM = 3.33°, MDC = 9.20°). There were no significant correlations (p > 0.05) between FPPA and NPRS(ρ = -0.046), AKPS(ρ = 0.066), or TSK(ρ = -0.204).

CONCLUSIONS

Although reliability measuring FPPA was good, the large SEM and MDC associated with this measurement may limit its clinical utility in those with PFP.

Comparison of flexion relaxation phenomenon between female yogis and matched non-athlete group

BACKGROUND

Trunk flexion is a common exercise during daily activities. Flexion relaxation phenomenon (FRP) occurs during forward bending in which there is a sudden silence of erector spinae (ES) muscles. The pattern of forward bending differs in yoga practitioners. This learned pattern probably predisposes yogis to injuries. The hypothesis of this study was that FRP differs in yogis in comparison to non-yogis individuals.

METHODS

This observational cross-sectional study was performed on 60 women assigned into yogis and non-athlete groups. Each participant was asked to bend forward and then return to the initial position. ES activity was recorded at L3 level, 4 cm from mid line during the trial. Trunk inclination and lumbar flexion angles were calculated at FRP onset and cessation moments.

RESULTS

The FRP occurred in 80% of yoga practitioners in comparison to 96.7% in the control group. Trunk inclination angle was significantly greater at FRP initiation in yogis compared to control group. Lumbar flexion angle was not different between the groups.

CONCLUSIONS

It is concluded that the altered pattern of forward bending observed in yogis may change patterns of ES muscles activity if it becomes part of a person's daily lifestyle which might predispose these muscles to fatigue and subsequent injuries; however, further studies are warranted for clarification.

Development of new 9-ball test protocols for assessing expertise in cue sports

Background

This study aimed to develop new test protocols for evaluating 9-ball expertise levels in cue sports players.

Methods

Thirty-one male 9-ball players at different playing levels were recruited (recreational group, n = 8; university team, n = 15; national team, n = 8). A 15-ball test was administered to indicate overall performance by counting the number of balls potted. Five skill tests (power control, cue alignment, angle, back spin, and top spin) were conducted to evaluate specific techniques by calculating error distances from pre-set targets using 2D video analysis.

Results

Intra-class correlation analyses revealed excellent intra-rater and inter-rater reliability in four out of five skill tests (ICC > 0.95). Significant between-group differences were found in 15-ball test performance (p <  0.001) and absolute error distances in the angle (p <  0.001), back spin (p = 0.006), and top spin tests (p = 0.045), with the recreational group performing worst while the national team performing best. Greater inter-trial variability was observed in recreational players than the more skilled players (p <  0.005).

Conclusions

In conclusion, the 9-ball test protocols were reliable and could successfully discriminate between different playing levels. Coaches and researchers may employ these protocols to identify errors, monitor training, and rank players.

Supplementary Information

The online version contains supplementary material available at 10.1186/s13102-021-00237-9.