Real-time Animation Research Articles

Video-based reconstruction of animatable human characters

We present a new performance capture approach that incorporates a physically-based cloth model to reconstruct a rigged fully-animatable virtual double of a real person in loose apparel from multi-view video recordings. Our algorithm only requires a minimum of manual interaction. Without the use of optical markers in the scene, our algorithm first reconstructs skeleton motion and detailed time-varying surface geometry of a real person from a reference video sequence. These captured reference performance data are then analyzed to automatically identify non-rigidly deforming pieces of apparel on the animated geometry. For each piece of apparel, parameters of a physically-based real-time cloth simulation model are estimated, and surface geometry of occluded body regions is approximated. The reconstructed character model comprises a skeleton-based representation for the actual body parts and a physically-based simulation model for the apparel. In contrast to previous performance capture methods, we can now also create new real-time animations of actors captured in general apparel.

GPU rigid skinning based on a refined skeletonization method

AbstractIn this paper, we present a skeletal rigid skinning approach. First, we describe a skeleton extraction technique that produces refined skeletons appropriate for animation from decomposed character models. Then, to avoid the artifacts generated in previous skinning approaches and the associated high training costs, we develop an efficient and robust rigid skinning technique that applies blending patches around joints. To achieve real time animation, we have adapted all steps of our rigid skinning algorithm so that they are performed efficiently on the GPU. Finally, we present an evaluation of our methods against four criteria: efficiency, quality, scope, and robustness. Copyright © 2010 John Wiley & Sons, Ltd.

A 32-bit floating-point module design for 3D graphic transformations

Nowadays, in computer animations, tens of, even hundreds of animation objects are placed in a scene to form a typical animation scene and thousands of vertices are used to mathematically define each object in the scene. Applying three dimensional (3D) transformations to such scenes requires huge amount of CPU time. As a result, calculation of an animation scene could take a long time. Moreover, in the case of real time animations, it becomes almost impossible to calculate transformations on time. In this presented work, a 32-bit floating-point based hardware module was designed to speed-up 3D graphic transformations using field programmable gate array (FPGA) chips. The module was tested and functional verification of the module was done by comparing the results produced by the module to the results generated by general purpose computers (PCs) for the same set of input data. Module’s data processing speed was compared to various PCs. The results showed that, 3D graphic transformations can be speeded-up by a factor (up to 11.47) employing the designed module. Key words: Field programmable gate array, computer graphics, three dimensional transformation, hardware module.

Comparison of Two Nitroxide Labile Esters for Delivering Electron Paramagnetic Resonance Probes into Mouse Brain

In vivo quantitation of O(2) in brain has been hindered by a lack of suitable imaging modalities. Development of low-frequency electron paramagnetic resonance (EPR) spectrometers that can detect free radicals in animals in real time makes it feasible to image paramagnetic oximetry probes such as nitroxides in brain tissue. We have shown that masking the carboxyl group of 3-carboxy-2,2,5,5-tetramethyl-1-pyrrolidinyloxyl (nitroxide 1) as an esterase-labile acetoxymethyl ester yields 3-acetoxymethoxycarbonyl-2,2,5,5-tetramethyl-1-pyrrolidinyloxyl (nitroxide 2). Nitroxide 2 can cross the blood-brain barrier and is then hydrolyzed in situ by esterases to regenerate nitroxide 1, which becomes entrapped in brain tissue. Seeking to improve the loading of nitroxides into brain, we synthesized the more lipophilic pentanoyloxymethyl ester, 3-pentanoyloxymethoxycarbonyl-2,2,5,5-tetramethyl-1-pyrrolidinyloxyl (nitroxide 3). We report that the higher lipophilicity of nitroxide 3 does not significantly increase its ability to generate EPR signals in the mouse brain. Therefore, irrespective of whether nitroxide 2 or 3 was injected, similar levels of nitroxide were entrapped in brain tissue. These findings suggest that nitroxides 2 and 3 perform comparably well as proimaging agents for measuring O(2) distribution in brain.

Gesture controllers

We introduce gesture controllers , a method for animating the body language of avatars engaged in live spoken conversation. A gesture controller is an optimal-policy controller that schedules gesture animations in real time based on acoustic features in the user's speech. The controller consists of an inference layer, which infers a distribution over a set of hidden states from the speech signal, and a control layer, which selects the optimal motion based on the inferred state distribution. The inference layer, consisting of a specialized conditional random field, learns the hidden structure in body language style and associates it with acoustic features in speech. The control layer uses reinforcement learning to construct an optimal policy for selecting motion clips from a distribution over the learned hidden states. The modularity of the proposed method allows customization of a character's gesture repertoire, animation of non-human characters, and the use of additional inputs such as speech recognition or direct user control.

REAL-TIME ANIMATION OF INTERACTIVE AGENTS: SPECIFICATION AND REALIZATION

Embodied agents are a powerful paradigm for current and future multimodal interfaces yet require high effort and expertise for their creation, assembly, and animation control. Therefore, open animation engines and high-level control languages are required to make embodied agents accessible to researchers and developers. We present EMBR, a new real-time character animation engine that offers a high degree of animation control via the EMBRScript language. We argue that a new layer of control, the animation layer, is necessary to keep the higher-level control layers (behavioral/functional) consistent and slim while allowing a unified and abstract access to the animation engine (e.g., for the procedural animation of nonverbal behavior). We also introduce new concepts for the high-level control of motion quality (spatial/temporal extent, power, fluidity). Finally, we describe the architecture of the EMBR engine, its integration into larger project contexts, and conclude with a concrete application.

Organ Augmented Reality

This paper discusses the Organ Augmented Reality (ORA) project, which considers an audio and visual augmentation of an historical church organ to enhance the understanding and perception of the instrument through intuitive and familiar mappings and outputs. ORA has been presented to public audiences at two immersive concerts. The visual part of the installation was based on a spectral analysis of the music. The visuals were projections of LED-bar VU-meters on the organ pipes. The audio part was an immersive periphonic sound field, created from the live capture of the organ sounds, so that the listeners had the impression of being inside the augmented instrument. The graphical architecture of the installation is based on acoustic analysis, mapping from sound levels to synchronous graphics through visual calibration, real-time multi-layer graphical composition and animation. The ORA project is a new approach to musical instrument augmentation that combines enhanced instrument legibility and enhanced artistic content.

In Vivo Bioluminescent Imaging of Irradiated Orthotopic Pancreatic Cancer Xenografts in Nonobese Diabetic-Severe Combined Immunodeficient Mice: A Novel Met Targeting and Assaying Efficacy of Ionizing Radiation

Adenocarcinoma of the pancreas is a lethal malignancy, and better models to study tumor behavior in vivo are needed forth e development of more effective therapeutics. Ionizing radiation is a treatment modaIitythat is commonly used in the clinical setting, in particular, for locally confined disease; however, good model systems to study the effect of ionizing radiation in orthotopic tumors have not been established. In an attempt to create clinically relevant models for studying treatments directed against pancreatic cancer, we have defined a methodology to measure the effect of varying doses of radiation in established human pancreatic cancer orthotopic xenografts using two different pancreatic cancer cell lines (Panc-1 and BXPC3) infected with a lentiviral vector expressing CMV promoter-driven luciferase to allow bioluminescence imaging of live animals in real time. Quantifiable photon emission from luciferase signaling in vivo correlated well with actual tumor growth. Bioluminescence imaging of the established pancreatic xenografts was used to direct delivery of radiation to the orthotopic tumors and minimize off-target adverse effects. Growth delay was observed with schedules in the range of 7.5 Gy in five fractions to 10 Gy in four fractions, whereas doses 3 Gy or higher produced toxic adverse effects. In conclusion, we describe a model in which the effects of ionizing radiation, alone or in combination with other therapeutics, in orthotopic xenografts, can be studied.

3D Garment Real-Time Simulation in Character Animation

In this paper, a framework of 3D Real-time Garment Simulation System for character animation is presented .For the problem of computational efficiency and stability for cloth physical modeling, we proposed a cloth mass-spring model based on constraint. Take geometry sphere and cylinder as example to explaining the whole strategy which used to dealing with cloth deformable bodies colliding with environment object. We described the procedure of physically based simulation, and illustrated the result and analysis of the experiment. By using the technique of parameterized human body modelling, virtual try-on was realized with the different shape of virtual character. Finally, integrating the techniques of character animation, physically based cloth simulation and non-precise deformable object collision handling, we create the real-time simulation animation of virtual character.

Micro-sensor driven human model for 3D real-time movement

A human model for the human motion capture and reconstruction was set up and the real-time movement of human model controlled by real people's movement was realized. According to the features of the system of the human motion capture and reconstruction,the authors proposed a method of constructing a sensor data-driven layered human motion model and a method of polygon grouping to achieve skin deformation. The methods are based on biomechanics. The joints of human body were categorized according to the motion characteristics. Motion parameters estimated from sensor data were used to control the movement of human skeleton model and the deformation of skin model,and consequently reconstruct the human body motion in real-time animation. The experimental results show that the proposed model is suitable for sensor data-driven virtual-human in real-time animation and has good biomechanics characteristics in representing human motion.

LacZ as a genetic reporter for real-time MRI

Molecular imaging based on MRI is currently hampered by the lack of genetic reporters for in vivo imaging. We determined that the commercially available substrate S-Gal can be used to detect genetically engineered beta-galactosidase expressing cells by MRI. The effect and specificity of the reaction between beta-galactosidase and S-Gal on MRI contrast were determined both in vitro and in vivo. beta-galactosidase activity in the presence of S-Gal resulted in enhanced T(2) and T*(2) MR-contrast, which was amplified with increasing magnetic field strengths (4.7-17.6 T) in phantom studies. Using both lacZ(+) transgenic animals and lacZ(+) tissue transplants, we were able to detect labeled cells in live animals in real time. Similar to phantom studies, detection of the labeled cells/tissues in vivo was enhanced at high magnetic fields. These results demonstrate that the genetic reporter, lacZ, can be used as an in vivo marker gene using high-field-strength MRI.

Melatonin formation in mammals: In vivo perspectives

Melatonin is a hormone secreted from the pineal gland specifically at night and contributes to a wide array of physiological functions in mammals. Melatonin is one of the most well understood output of the circadian clock located in the suprachiasmatic nucleus. Melatonin synthesis is controlled distally via the circadian clock located in the suprachiasmatic nucleus and proximally regulated by norepinephrine released in response to the circadian clock signals. To understand melatonin synthesis in vivo, we have performed microdialysis analysis of the pineal gland, which monitors melatonin as well as the precursor (serotonin) and intermediate (N-acetylserotonin) of melatonin synthesis in freely moving animals in realtime at high resolution. Our data revealed a number of novel features of melatonin production undetected using conventional techniques, which include (1) large inter-individual variations of melatonin onset timing; (2) circadian regulation of serotonin synthesis and secretion in the pineal gland; and (3) a revised view on the rate-limiting step of melatonin formation in vivo. This article will summarize the main findings from our laboratory regarding melatonin formation in mammals.

Decimation of human face model for real-time animation in intelligent multimedia systems

Animating a complex human face model in real-time is not a trivial task in intelligent multimedia systems for next generation environments. This paper proposes a generation scheme of a simplified model for real-time human face animation in intelligent multimedia systems. Previous work mainly focused on the geometric features when generating a simplified human face model. Such methods may lose the critical feature points for animating human faces. The proposed method can find those important feature points and can generate the feature-preserved low-level models busing our new quadrics. The new quadrics consist of basic error metrics and feature edge quadrics. The quality of facial animation with a lower-level model is as good as that of a computationally expansive original model. In this paper, we prove that our decimated facial model is effective in facial animation using a well-known expression-retargeting technique.

In Vivo Bioluminescence Imaging of Furin Activity in Breast Cancer Cells Using Bioluminogenic Substrates

Furin, a proprotein convertases family endoprotease, processes numerous physiological substrates and is overexpressed in cancer and inflammatory conditions. Noninvasive imaging of furin activity will offer a valuable tool to probe furin function over the course of tumor growth and migration in the same animals in real time and directly assess the inhibition efficacy of drugs in vivo. Here, we report successful bioluminescence imaging of furin activity in xenografted MBA-MB-468 breast cancer tumors in mice with bioluminogenic probes. The probes are conjugates of furin substrate, a consensus amino acid motif R-X-K/R-R (X, any amino acid), with the firefly luciferase substrate D-aminoluciferin. In the presence of the luciferase reporter, the probes are unable to produce bioluminescent emission without furin activation. Blocking experiments with a furin inhibitor and control experiments with a scrambled probe showed that the bioluminescence emission in the presence of firefly luciferase is furin-dependent and specific. After furin activation, a 30-fold increase in the bioluminescent emission was observed in vitro, and on average, a 7-8-fold contrast between the probe and control was seen in the same tumor xenografts in mice. Direct imaging of furin activity may facilitate the study of furin function in tumorigenicity and the discovery of new drugs for furin-targeted cancer therapy.

TopoPlan: a topological path planner for real time human navigation under floor and ceiling constraints

AbstractIn this article we present TopoPlan, a topological planner dedicated to real‐time humanoid path‐planning and motion adaptation to floor and ceiling constraints inside complex static environments. This planner analyzes unstructured 3D triangular meshes in order to automatically determine their topology. The analysis is based on a prismatic spatial subdivision which is analyzed, taking into account humanoid characteristics, in order to extract navigable surfaces and precisely identify environmental constraints such as floors, ceilings, walls, steps and bottlenecks. The technique also provides a lightweight roadmap computation covering all accessible free space. We demonstrate the properties of our topological planner within the context of two reactive motion control processes: an on‐the‐fly trajectory optimization and foot print generation process that correctly handles climbing of complex staircases, and a reactive ceiling adaptation process that handles beam avoidance and motion adaptation to irregular floors and ceilings. We further show that the computation cost of these processes is compatible with the real time animation of several dozens of virtual humans.

Effect of glutamine on doxorubicin-induced cardiotoxicity: an echocardiographic assessment.

Abstract Abstract #6143 Background: Doxorubicin (DOX) is a widely used chemotherapeutic agent with a dose-dependent cardiotoxicity. Previous studies showed that dietary glutamine (GLN) reduced cardiac oxidative damages in rats treated with DOX through the increase of cardiac and blood glutathione, reduction of cardiac lipid peroxidation and reducing cardiac apoptosis. The present study aimed to examine further the effect of GLN on DOX-induced cardiac injury and to gain insight into the physiological aspects of this process by using high-resolution micro-ultrasound imaging and Doppler echocardiography.
 Materials and Methods: Female Fisher 344 rats (n=12) were randomized into 2 groups: (i) GLN-supplemented (n=6) and ii) controls (n=6). GLN-supplemented rats received 1g/kg/day GLN via gavage starting 1 week before DOX administration. DOX (12 mg/kg) was injected i.p. in all animals. Each animal was examined before DOX administration, 3 days, 7 days, and 10 days after DOX administration using ultrasound imaging system Vevo 770 (VisualSonics, Toronto, ON, Canada). RMVTM 716 "high frame" scan head, designed for real-time small animal imaging applications, was used. The short-axis imaging was taken in B-mode to view the left ventricle (LV) movement during diastole and systole. Anatomical M-mode was used to obtain LV measurements including LV end-diastolic and systolic inner diameters, LV posterior wall, LV ejection fraction (%EF) and LV fraction shortening (%FS). The LV filling was evaluated by pulsed-Doppler sampling of the mitral valve (MV) inflow. The peak E-wave velocity (E), peak A-wave velocity (A) and the MV E/A ratio were obtained. All data and images were saved and analyzed by Vevo 770 Analytic Software (VisualSonics, Toronto, ON, Canada).
 Results: Ten days after DOX treatment the control animals had: i) increased LV posterior wall end-diastolic thickness of an average from 1.7 mm before DOX administration to 1.8 mm and end-systolic from 2.9 mm to 3.7 mm; ii) reduction of the %EF by 10% and %FS by 14%; and iii) increased MVE by 30% with a resulting MVE/A ratio >2.0; all these suggestive of the development of restrictive cardiomyopathy (RCM). RCM, characterized by thickening and increased rigidity of the endocardium due to infiltration and fibrosis, restrictive ventricular filling with MVE/A >2.0 and in some cases reduction of the EF, has been reported in several clinical studies of patients treated with DOX. In GLN-supplemented rats of this study there was no statistically significant difference between posterior wall thickness before and after DOX administration, MVE/A ratio was maintained between 1.4 and 1.8; and EF was reduced by 2% only.
 Conclusions: The results from this study are in agreement with our previous data showing that GLN is able to reduce cardiac oxidative damages caused by DOX. This data further confirmed the safety of GLN supplementation and its cardioprotective effects during chemotherapeutic treatment with DOX.
 Acknowledgements: This work was supported by a grant from Susan G. Komen to VKT. Citation Information: Cancer Res 2009;69(2 Suppl):Abstract nr 6143.

Simultaneous tracking of movement and gene expression in multiple Drosophila melanogaster flies using GFP and DsRED fluorescent reporter transgenes

BackgroundFluorescent proteins such as GFP (Green Fluorescent Protein) and DsRED (Discosoma sp.Red Fluorescent Protein) are often used as reporter molecules for transgene expression in Drosophila and other species. We have recently reported methods that allow simultaneous tracking of animal movement and GFP expression in real time, however the assay was limited to single animals and a single transgene. Numerous studies would be facilitated by methods that allow for assay of multiple animals and multiple transgenes.FindingsHere we report an improved fly video tracking system that allows multiple transgenic flies to be tracked simultaneously using visible light, GFP fluorescence and DsRED fluorescence. The movement of multiple flies could be accurately tracked at real time rates, while simultaneously assaying the expression level of two different transgenes marked with GFP and DsRED. The individual flies could be accurately tracked and distinguished even during periods when transgene fluorescence was undetected. For example, characteristic patterns of hsp70 and hsp22 transgene induction could be simultaneously quantified and correlated with animal movement in aging flies, and as groups of flies died due to dessication/starvation.ConclusionThe improved methods allow for more efficient assay of the correlation between gene expression, behavior, aging and mortality: multiple animals can be assayed with simultaneous quantification of multiple transgenes using GFP and DsRED fluorescence. These methods should allow for increased flexibility in experimental designs. For example, in the future it should be possible to use gene expression levels to predict remaining life span more accurately, and to quantify gene expression changes caused by interactions between animals in real time.

Real Time Animation of Trees Based on BBSC in Computer Games

That researchers in the field of computer games usually find it is difficult to simulate the motion of actual 3D model trees lies in the fact that the tree model itself has very complicated structure, and many sophisticated factors need to be considered during the simulation. Though there are some works on simulating 3D tree and its motion, few of them are used in computer games due to the high demand for real-time in computer games. In this paper, an approach of animating trees in computer games based on a novel tree model representation—Ball B-Spline Curves (BBSCs) are proposed. By taking advantage of the good features of the BBSC-based model, physical simulation of the motion of leafless trees with wind blowing becomes easier and more efficient. The method can generate realistic 3D tree animation in real-time, which meets the high requirement for real time in computer games.

Human hand motion capture in image sequences for real-time animation systems

This extended abstract details previous methods for motion tracking and capture in 3D animation and in particular that of hand motion tracking and capture. The research aims to enable gesture capture with interpretation of the captured gestures and control of the target 3D animation software. This stage of the project involves the development and testing of a motion analysis system. A motion analysis system is being built from algorithms recently developed. The authors review current software and research methods available in this area and describe current work-in-progress.Motion capture is a technique of digitally recording the movements of real entities, usually humans. It was originally developed as an analysis tool in biomechanics research, but has grown increasingly important as a source of motion data for computer animation. In this context it has been widely used for both cinema and video games. Hand motion capture and tracking in particular has received a lot of attention because of its critical role in the design of new Human Computer Interaction methods and gesture analysis. One of the main difficulties is the capture of human hand motion.

Geometric skinning with approximate dual quaternion blending

Skinning of skeletally deformable models is extensively used for real-time animation of characters, creatures and similar objects. The standard solution, linear blend skinning, has some serious drawbacks that require artist intervention. Therefore, a number of alternatives have been proposed in recent years. All of them successfully combat some of the artifacts, but none challenge the simplicity and efficiency of linear blend skinning. As a result, linear blend skinning is still the number one choice for the majority of developers. In this article, we present a novel skinning algorithm based on linear combination of dual quaternions. Even though our proposed method is approximate, it does not exhibit any of the artifacts inherent in previous methods and still permits an efficient GPU implementation. Upgrading an existing animation system from linear to dual quaternion skinning is very easy and has a relatively minor impact on runtime performance.