Key Frame Technique Research Articles

A Novel Real-Time Reference Key Frame Scan Matching Method.

Unmanned aerial vehicles represent an effective technology for indoor search and rescue operations. Typically, most indoor missions’ environments would be unknown, unstructured, and/or dynamic. Navigation of UAVs in such environments is addressed by simultaneous localization and mapping approach using either local or global approaches. Both approaches suffer from accumulated errors and high processing time due to the iterative nature of the scan matching method. Moreover, point-to-point scan matching is prone to outlier association processes. This paper proposes a low-cost novel method for 2D real-time scan matching based on a reference key frame (RKF). RKF is a hybrid scan matching technique comprised of feature-to-feature and point-to-point approaches. This algorithm aims at mitigating errors accumulation using the key frame technique, which is inspired from video streaming broadcast process. The algorithm depends on the iterative closest point algorithm during the lack of linear features which is typically exhibited in unstructured environments. The algorithm switches back to the RKF once linear features are detected. To validate and evaluate the algorithm, the mapping performance and time consumption are compared with various algorithms in static and dynamic environments. The performance of the algorithm exhibits promising navigational, mapping results and very short computational time, that indicates the potential use of the new algorithm with real-time systems.

Artist-directed dynamics for 2D animation

Animation artists enjoy the benefits of simulation but do not want to be held back by its constraints. Artist-directed dynamics seeks to resolve this need with a unified method that combines simulation with classical keyframing techniques. The combination of these approaches improves upon both extremes: simulation becomes more customizable and keyframing becomes more automatic. Examining our system in the context of the twelve fundamental animation principles reveals that it stands out for its treatment of exaggeration and appeal. Our system accommodates abrupt jumps, large plastic deformations, and makes it easy to reuse carefully crafted animations.

An Energy-Driven Motion Planning Method for Two Distant Postures.

In this paper, we present a local motion planning algorithm for character animation. We focus on motion planning between two distant postures where linear interpolation leads to penetrations. Our framework has two stages. The motion planning problem is first solved as a Boundary Value Problem (BVP) on an energy graph which encodes penetrations, motion smoothness and user control. Having established a mapping from the configuration space to the energy graph, a fast and robust local motion planning algorithm is introduced to solve the BVP to generate motions that could only previously be computed by global planning methods. In the second stage, a projection of the solution motion onto a constraint manifold is proposed for more user control. Our method can be integrated into current keyframing techniques. It also has potential applications in motion planning problems in robotics.

The Population-Based Optimization Algorithms for Role Modelling and Path Generation in Group Animation

Traditional animation by key frame techniques takes animators lots of time and vigour to model and simulate behaviours of crowds. For solving this problem, this paper presents a novel group animation generation approach based on population-based optimization algorithms. It is mainly divided into two parts. First, it puts forward a role modelling approach based on dynamic self-adaptive genetic algorithm and NURBS technology. Second, following the introduction to PSO (Particle Swarm Optimization) algorithm, a group path generative approach is presented. It simulates group behaviours, including cohesion and separation, dynamic object tracking and collision avoidance. Finally, a group of shark modelling and path generation images are exhibited as examples.

Research on virtual actor action editing and movement control

To directly use a virtual surface model for action editing and movement control, a general method for creating virtual actor skeleton models and controlling movement is presented. The method includes judging borderlines of the block virtual surface model, calculating the joints, confirming the above block, and using the block hierarchical layout to create the skeleton model. Then, according to the virtual actor model and movement restriction, the study focuses on the generation of movement animation using the key frame technique and smoothing movement technique by automatically adding animation and adjusting the actor’s pose by different weights on movement amplitude. Finally, movement control of the actor in the virtual environment is implemented by real-time control and path point control, which achieve a good result.

지면의 미끄러운 정도에 따른 캐릭터의 걷기 동작 생성

3차원 가상현실 내에서 캐릭터 움직임 동작의 기술은 기존 방식인 키프레임 기법에 의존하던 것이 점차 동작 제어 기법을 활용하고, 보다 사실적이고 자연스러운 움직임을 생성해 내고자 하는 방향으로 발전해 가고 있다. 그러나 이러한 동작 제어 기법을 통해 가상현실의 지형 성질에 따라 적응적인 캐릭터의 동작을 표현하는데 한계가 있다. 즉, 대부분의 가상환경에서 캐릭터의 걷는 움직임은 일정하고 단조로운 동작만을 반복하여 표현하고 있어 관찰자로 하여금 지루함을 느끼게 하고, 지형의 조건이나 형태에 맞지않게 캐릭터의 발끝이 지면에 스며들거나 떠있는 등의 부자연스러운 동작으로 인해 사실감을 저하시킨다. 본 논문에서는 적은 매개변수들과 역운동학 방법을 적용하여 기본 걷기 동작을 표현하고, 지면의 성질을 마찰계수로 대표시켜 지면에 적응적인 걷기 동작의 생성 방법을 제안한다. 제안된 방법에서는 구심력과 마찰계수를 결합한 후, 이를 근거로하여 한 주기 동안의 걷는 동작을 분석하고 이를 기반으로 동작에 필요한 매개변수를 조정하여 지질에 따른 적응적인 캐릭터의 걷기 동작을 생성한다. In 3D virtual environment the description of character' s movement that has utilized the conventional key-frame technique is gradually being developed toward the application of motion control method to generate more realistic and natural motion. Even the motion control method, however, has the limitation for expression of character's motion adapted to the ground properties of virtual world. That is, the walking motions of character are not only, for the most part, so uniform simple and repeated often as to feel to be tedious, but also the unnatural motion in which the tips of the toes soak through a plane or float in the air discording with the conditions of terrain lowers the semblance of reality. This paper proposes an adaptive motion control method for human figure locomotion in virtual environments or games, in which the walking motion is dynamiccally adapted to the ground's sliding properties. We compute an optimal parameters for one cycle of walking motion adapted to the ground properties by combining the coefficient of friction and centripetal force, and therefrom we induce a set of nonskid speed corresponding to various sliding properties of the ground.

Towards a balanced 3D kinematic model of a faulted domain - the Bergheim open pit mine, Lower Rhine Basin

AbstractIn the context of the investigation of the sedimentary and structural evolution of the Cenozoic Lower Rhine Basin, the construction of a volume-balanced kinematic model of a small faulted domain with detailed spatial information on strata and fault geometry from a set of parallel geological sections is under development. A 3D geometry model is built that allows for relative movements of blocks at fault surfaces. Rouby’s method of restoration in the map plane is used to determine horizontal displacement fields. The 3D and 3D(t) geometry models are supported by the object-oriented geometry database tool GeoToolKit for storage and retrieval of selected parts of the model using queries referring to spatial and temporal criteria, while visualization is based on key frame technique.

Dynamics and unification of animation control

We present an analysis of unified animation control processes. The design of an animation system is strongly coupled with the considered application. Most of the existing systems are specialized. For example, in audiovisual production or in C.A.D., only a few systems specialized in mechanical computation have capabilities in the image synthesis field. We are working on the design of a general animation system, including generation of motion defined by use of mechanical laws, in an audiovisual environment. Our system is built around a structured graph in which we store a hierarchical description of the objects and mechanical joints. The joints may be used to link the objects together to allow the building of multibody mechanical systems. For objects which are not submited to mechanical laws, motion control can be specified by key-framing techniques or explicit trajectories. We use a dynamical formalism based upon the principle of virtual work associated with LAGRANGE's multipliers and that takes into account holonomic and nonholonomic constraints. The generation of the differential motion equations system is automatically built by performing symbolic derivations. These equations are then solved for each time step and give object locations and orientations.

Inbetweening for computer animation utilizing moving point constraints

This paper presents an approach to computerized inbetweening which allows the animator more control over an interpolation sequence than existing keyframe techniques. In our approach, the animator specifies in addition to a set of keyframe constraints, a set of new constraints called moving points . Moving points are curves in space and time which constrain both the trajectory and dynamics of certain points on the keyframes. The sets of keyframes and moving points form a constraint or patch network specification of the desired dynamics. Several algorithms are presented for inbetweening or completing such a patch network. By measuring these algorithms with respect to a set of evaluation criteria, the algorithm which best meets our interpolation needs is selected.