Distance In 3D Space Research Articles

Object-Wise Video Editing

Beyond time frame editing in video data, object level video editing is a challenging task; such as object removal in a video or viewpoint changes. These tasks involve dynamic object segmentation, novel view video synthesis and background inpainting. Background inpainting is a task of the reconstruction of unseen regions presented by object removal or viewpoint change. In this paper, we propose a video editing method including foreground object removal background inpainting and novel view video synthesis under challenging conditions such as complex visual pattern, occlusion, overlaid clutter and variation of depth in a moving camera. Our proposed method calculates a weighted confidence score on the basis of normalized difference between observed depth and predicted distance in 3D space. A set of potential points from epipolar lines from neighbor frames are collected, refined, and weighted to select a few number of highly qualified observations to fill the desired region of interest area in the current frame from video. Based on the background inpainting method, novel view video synthesis is conducted with arbitrary viewpoint. Our method is evaluated with both a public dataset and our own video clips and compared with multiple state of the art methods showing a superior performance.

Early autologous cranioplasty: complications and identification of risk factors using virtual reality visualisation technique

Background: Cranioplasty (CP) of autologous bone flap after decompressive craniectomy (DC) is known to be associated with a high complication rate, particularly bone flap resorption (BFR). In a retrospective study, we used a novel virtual reality (VR) visualisation technique to identify and evaluate risk factors associated with CP.Method: Twenty-five patients underwent early autologous CP. All complications were recorded. Cranial computed tomography scans were visualised via the VR software to access the fitting accuracy of the bone flap (bone flap size, gap width at trepanation cutting edge, extent of osteoclastic extension).Results: An overall complication rate of 44% was seen, and BFR was the most common (36%). Only ‘osteoclastic extension of trepanation’ (p = .04) was a significant risk factor for BFR. The factors ‘indication for DC’ (p = .09) and ‘size of bone flap’ (p = .09) had a tendency towards influencing the rate of BFR, while ‘age’ (p = .68), ‘time interval between DC and CP’ (p = 1.00), and ‘gap width’ (p = .50) were not considered to influence the BFR rate.Conclusions: DC and subsequent CP is a complication-prone procedure. Therefore, it is relevant to identify and quantify probable risk factors for the most common complications, such as BFR. Here, we found that the extent of osteoclastic extension may impair the patient’s healing process. Our investigation was made considerably easier by using the novel VR visualisation technique, which allows parallax free measurements of distances in 3D space.

Real-time tumor tracking using fluoroscopic imaging with deep neural network analysis

PurposeTo improve respiratory gating accuracy and treatment throughput, we developed a fluoroscopic markerless tumor tracking algorithm based on a deep neural network (DNN). MethodsIn the learning stage, target positions were projected onto digitally reconstructed radiography (DRR) images from four-dimensional computed tomography (4DCT). DRR images were cropped into subimages of the target or surrounding regions to build a network that takes input of the image pattern of subimages and produces a target probability map (TPM) for estimating the target position. Using multiple subimages, a DNN was trained to generate a TPM based on the target position projected onto the DRRs. In the tracking stage, the network takes in the subimages cropped from fluoroscopic images at the same position of the subimages on the DRRs and produces TPMs, which are used to estimate target positions. We integrated the lateral correction to modify an estimated target position by using a linear regression model. We tracked five lung and five liver cases, and calculated tracking accuracy (Euclidian distance in 3D space) by subtracting the estimated position from the reference. ResultsTracking accuracy averaged over all patients was 1.64 ± 0.73 mm. Accuracy for liver cases (1.37 ± 0.81 mm) was better than that for lung cases (1.90 ± 0.65 mm). Computation time was <40 ms for a pair of fluoroscopic images. ConclusionsOur markerless tracking algorithm successfully estimated tumor positions. We believe our results will provide useful information to advance tumor tracking technology.

Design and verification of a simple 3D dynamic model of speed skating which mimics observed forces and motions

Advice about the optimal coordination pattern for an individual speed skater, could be addressed by simulation and optimization of a biomechanical speed skating model. But before getting to this optimization approach one needs a model that can reasonably match observed behaviour. Therefore, the objective of this study is to present a verified three dimensional inverse skater model with minimal complexity, which models the speed skating motion on the straights. The model simulates the upper body transverse translation of the skater together with the forces exerted by the skates on the ice. The input of the model is the changing distance between the upper body and the skate, referred to as the leg extension (Euclidean distance in 3D space). Verification shows that the model mimics the observed forces and motions well. The model is most accurate for the position and velocity estimation (respectively 1.2% and 2.9% maximum residuals) and least accurate for the force estimations (underestimation of 4.5–10%). The model can be used to further investigate variables in the skating motion. For this, the input of the model, the leg extension, can be optimized to obtain a maximal forward velocity of the upper body.

Trajectory tracking with obstacle avoidance of redundant manipulator based on fuzzy inference systems

In presence of the uncertainties in robot dynamics, model-based control law can easily fail. In our paper, this important question is tackled by using fuzzy adaptive control to drive with obstacle avoidance an industrial redundant manipulator under the hypothesis of uncertain dynamics. This hypothesis makes our controller an original one, since the problem of the tracking trajectory in the presence of obstacles and assuming that the robot dynamics are unknown has not been discussed before in the literature. Besides, the proposed obstacle avoidance is achieved by generating a self-motion. Furthermore, the usual procedure related to the obstacle avoidance based on Euclidean distance in 3D space is made easier since this one includes only the parameters of 2D space. This self-motion is directly incorporated into the adaptive fuzzy control scheme via the filtered tracking errors. The proposed method is tested by simulations in the case of redundant robot (PUMA 560) operating in 3D space in presence of obstacles. Despite that the robot dynamics are assumed to be uncertain, the proposed control performance is satisfactory. Indeed, the trajectory tracking control, incorporating self-motion obstacle avoidance, operates effectively with weak tracking control errors and bounded actuator torques evolving in admissible range.

Three‐dimensional gamma criterion for patient‐specific quality assurance of spot scanning proton beams

The purpose of this study was to evaluate the effectiveness of full three‐dimensional (3D) gamma algorithm for spot scanning proton fields, also referred to as pencil beam scanning (PBS) fields. The difference between the full 3D gamma algorithm and a simplified two‐dimensional (2D) version was presented. Both 3D and 2D gamma algorithms are used for dose evaluations of clinical proton PBS fields. The 3D gamma algorithm was implemented in an in‐house software program without resorting to 2D interpolations perpendicular to the proton beams at the depths of measurement. Comparison between calculated and measured dose points was carried out directly using Euclidian distance in 3D space and the dose difference as a fourth dimension. Note that this 3D algorithm faithfully implemented the original concept proposed by Low et al. (1998) who described gamma criterion using 3D Euclidian distance and dose difference. Patient‐specific proton PBS plans are separated into two categories, depending on their optimization method: single‐field optimization (SFO) or multifield optimized (MFO). A total of 195 measurements were performed for 58 SFO proton fields. A MFO proton plan with four fields was also calculated and measured, although not used for treatment. Typically three different depths were selected from each field for measurements. Each measurement was analyzed by both 3D and 2D gamma algorithms. The resultant 3D and 2D gamma passing rates are then compared and analyzed. Comparison between 3D and 2D gamma passing rates of SFO fields showed that 3D algorithm does show higher passing rates than its 2D counterpart toward the distal end, while little difference is observed at depths away from the distal end. Similar phenomenon in the lateral penumbra was well documented in photon radiation therapy, and in fact brought about the concept of gamma criterion. Although 2D gamma algorithm has been shown to suffice in addressing dose comparisons in lateral penumbra for photon intensity‐modulation radiation therapy (IMRT) plans, results here showed that a full 3D algorithm is required for proton dose comparisons due to the existence of Bragg peaks and distal penumbra. A MFO proton plan with four fields was also measured and analyzed. Sharp dose gradients exist in MFO proton fields, both in the middle of the modulation and toward the most distal layers. Decreased 2D gamma passing rates at locations of high dose gradient are again observed as in the SFO fields. Results confirmed that a full 3D algorithm for gamma criterion is needed for proton PBS plan's dose comparisons. The 3D gamma algorithm is implemented by an in‐house software program. Patient‐specific proton PBS plans are measured and analyzed using both 3D and 2D gamma algorithms. For measurements performed at depths with large dose gradients along the beam direction, gamma comparison passing rates using 2D algorithm is lower than those obtained with the full 3D algorithm.PACS number: 87.53.Bn, 87.53.Jw, 87.55.de, 87.55.kd, 87.55.ne, 87.55.Qr

The Water Molecule with Conjoint Translational, Rotational and Spin Degrees of Freedom in the Gas and Liquid Phases

The theoretical model of water molecule is created which gives an opportunity to understand what happen with translational, rotational and spin degrees of freedom when molecule makes transitions from gas into liquid phase and vice versa. Translational degrees of freedom are considered classically but rotational and spin degrees of freedom are treated according to quantum-mechanical rules. The model is based on the mathematical techniques of geometric algebras over the field of real numbers. Unusual properties of water molecules with conjoint degrees of freedom compared to usual or free molecules are predicted and denoted as latent in future. The latent molecules have not the full rotational spectrum but possess three isolated rotational levels only. The latent molecules are capable of moving along straight lines at finite distances in 3D-space. The latent molecules conserve all their degrees of freedom during the transition from gas into liquid phase.

Tracking and replication of hand movements by teleguided intelligent manipulator robot

SUMMARYIn this paper, a new method is presented that allows an intelligent manipulator robotic system to track a human hand from far distance in 3D space and estimate its orientation and position in real time with the goal of ultimately using the algorithm with a robotic spherical wrist system. In this proposed algorithm, several image processing and morphology techniques are used in conjunction with various mathematical formulas to calculate the hand position and orientation. The proposed technique was tested on Remote teleguided virtual Robotic system. Experimental results show that proposed method is a robust technique in terms of the required processing time of estimation of orientation and position of hand.

A top-down positioning scheme for underwater wireless sensor networks

In order to increase the localization coverage while keeping the localization error small in a unique network architecture in which there are not evenly distributed anchor nodes with great ability of communication or additional infrastructure, a Top-down Positioning Scheme (TPS) for underwater acoustic sensor networks is proposed. By defining node’s confidence reasonably, TPS insures the quality of the new reference nodes. TPS also refines the nodes which have just been positioned via the gradient method and helps non-localized nodes search for more reference nodes via the new scheme for 3D Euclidean distance estimation. By comparing the new scheme for 3D Euclidean distance estimation with the existing scheme, the new scheme is shown to have greater ability to estimate two-hop Euclidean distance in 3D space. Simulation results show that TPS which integrates node’s confidence defined reasonably, the gradient method, and the new scheme for 3D Euclidean distance estimation can increase the localization coverage ratio, while keeping the localization error small.

Detailed analysis of consumption of the transport device by the mobile device

This paper deals with the gathering of GPS data and other personal information that iares used to calculate the consumption of motor vehicles. To create a basic test application for the measurement consumption (Microsoft Visual Studio, 2008), C # programming language was used. The application is designed for devices based on Windows Mobile. For testing, a few PDA devices with integrated GPS module were used. The application calculated the consumption of refuel liters (yet entered by the user) with regard to mileage, which was determined from the read coordinates of a GPS module. This information is then stored in a SQL database for further analysis. To minimize errors will aid in using the algorithms to calculate the distance in 3D space. The application reached accuracy using a suitably chosen sampling interval. The result is a relatively simple test application for the Windows Mobile platform. Key words: GPS NMEA, distance calculation, windows mobile, measurement consumption.

Tomographic quantification of branching morphogenesis and renal development

Branching morphogenesis is a central process in renal development, but imaging and quantifying this process beyond early organogenesis presents challenges due to growth of the kidney preventing ready imaging of the complex structures. Current analysis of renal development relies heavily on explant organ culture and visualization by confocal microscopy, as a more developmentally advanced native tissue is too thick for conventional microscopic imaging. Cultured renal primordia lack vascularization and a supportive matrix for normal growth, resulting in tissue compression and distortion of ureteric branching. To overcome this, we used optical projection tomography to image and reconstruct the branching ureter epithelium of ex vivo embryonic kidneys and developed software to quantify these three-dimensional (3D) data. Ureteric branching was assessed by measuring tree and terminal branch length, tip number, branching iterations, branch angles, and inter-tip distances in 3D space. To validate this approach for analyzing genetic influences on renal development, we assessed branching and organ morphology in Tgfbeta2(+/-) embryos from E12.5 through E15.5. We found decreased branching, contrary to previous findings using organ culture, and quantified a primary defect in renal pelvic formation. Our approach offers many advantages from improved throughput, analysis, and observation of in vivo branching states, and has demonstrated its utility in studying the basis of renal developmental disease.

Acoustic mirror effect increases prey detection distance in trawling bats

Many different and phylogenetically distant species of bats forage for insects above water bodies and take insects from and close to the surface; the so-called 'trawling behaviour'. Detection of surface-based prey by echolocation is facilitated by acoustically smooth backgrounds such as water surfaces that reflect sound impinging at an acute angle away from the bat and thereby render a prey object acoustically conspicuous. Previous measurements had shown that the echo amplitude of a target on a smooth surface is higher than that of the same target in mid-air, due to an acoustic mirror effect. In behavioural experiments with three pond bats (Myotis dasycneme), we tested the hypothesis that the maximum distances at which bats can detect prey are larger for prey on smooth surfaces than for the same prey in an airborne situation. We determined the moment of prey detection from a change in echolocation behaviour and measured the detection distance in 3D space from IR-video recordings using stereo-photogrammetry. The bats showed the predicted increase in detection distance for prey on smooth surfaces. The acoustic mirror effect therefore increases search efficiency and contributes to the acoustic advantages encountered by echolocating bats when foraging at low heights above smooth water surfaces. These acoustic advantages may have favoured the repeated evolution of trawling behaviour.

Comparison between traditional 2-dimensional cephalometry and a 3-dimensional approach on human dry skulls

The cephalogram is the standard used by orthodontists to assess skeletal, dental, and soft tissue relationships. This approach, however, is based on 2-dimensional (2D) views used to analyze 3-dimensional (3D) objects. The purpose of this project was to evaluate and compare a 3D imaging system and traditional 2D cephalometry for accuracy in recording the anatomical truth as defined by physical measurements with a calibrated caliper. Thirteen skeletal landmarks were located by both radiographic methods on 9 dry human skulls. Intraclass correlation (0.995), variance (0.054 mm 2), and standard deviation (SD) (0.237 mm) were averaged over 76 measurements and derived from precision calipers to establish these physical measurements as a reliable gold standard to make comparisons of the 2D and 3D radiographic methods. The results showed great variability of the 2D from the gold standard, with the range varying from −17.68 mm (underestimation of Gn-Zyg R) to +15.52 mm (overestimation of Zyg L-Zyg R). In contrast, the 3D method (Sculptor, Glendora, Calif) indicated a range of the SD from −3.99 (underestimation) mm to +2.96 mm (overestimation). The 3D evaluation was much more precise, within approximately 1 mm of the gold standard. These results indicate that, when the actual distance is measured on a human skull in its true dimensions of 3D space, the Sculptor program, by using a 3D method, is more precise and 4 to 5 times more accurate than the 2D approach. Evaluating distances in 3D space with a 2D image grossly exaggerates the true measure and offers a distorted view of craniofacial growth. There is an inherent problem of representing a linear measure occupying a 3D space with a 2D image.

Two-dimensional effects in the edge sound of vortices and dipoles

Edge sound consists of the pressure waves generated by the fast modification of the local velocity field when a flow inhomogeneity passes near an edge. The modifications take place in the near field; they locally allow a description in terms of incompressible flow. The incompressible disturbances are referred to as pseudosound. The disturbances progress into the far field as diffraction waves that, in 3D space, dominate the pseudosound. In 3D space the diffraction waves have a 2D character in their time history; they behave as the halfth time derivative of the pseudosound. This latter effect is not manifest in the analogous, purely 2D diffraction problem where the diffracted wave in the far field has the form of retarded pseudosound. In this paper, an answer is presented to the intriguing question: what is the rationale behind this difference in behavior? The analysis is based on time integral representations having as a kernel the closed form of Green’s functions for half-plane problems in 2D and in 3D space. The Green’s functions are presented in this paper. The integral representations inherently represent the relations between wave-sound and incompressible pseudosound. After performing an integration by parts, appropriate approximations reveal the incompressible near-field behavior or the far-field wave behavior. Examples are given of the edge sound of moving vortices and dipoles in 2D and in 3D space. In free 2D space the potential field of a vortex is proportional to the logarithm of the distance; the field of a dipole is proportional to the inverse of the distance. However, the edge sound pressure of vortices and of dipoles does not show a difference in far field behavior. It falls off with the square root of distance in 2D space and linear with distance in 3D space.

Visualization and quantitation of cellular and tissue anatomy by 3D light microscopy

Many areas of biomedical research require the visualization and quantitation of 3D micro- and tissue level anatomy. Both are possible by utilizing confocal or wide-field light microscopy in combination with computational methods, including deblurring and 3D image analysis. The three-dimensionality of the specimen, required image resolution, and parameters to be quantitated dictate the methods of choice. Applications under study by our group range from automatically quantitating a few cell layers in cervical/vaginal smears, or hundreds of cell nuclei or immunologically labeled cells in thick brainslices, to tracing individual neurons for long distances in 3D space. Examples of our wide-field deconvolution methods and automated detection and counting of nuclei in thick tissue are shown.Image restoration by blind deconvolution of portions of the axonal fields of two rat hippocampal pyramidal cells injected with biocytin and contrasted with horseradish peroxidase and diaminobenzidine6 is shown in Figure 1. The original data is projected along and perpendicular to the optic axis in Fig. 1a while 1b is a similar set of restored image projections.