Fast and Effective Dynamic Mesh Completion · animated mesh is required before the execution of the...

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Fast and Effective Dynamic Mesh Completion Gerasimos Arvanitis Aris S. Lalos Konstantinos Moustakas Nikos Fakotakis Dept. of Electrical and Computer Engineering University of Patras, Rio, Patras, Greece {arvanitis, aris.lalos, moustakas}@ece.upatras.gr, [email protected] ABSTRACT We introduce a novel approach to support fast and efficient completion of arbitrary animation sequences, ideally suited for real-time scenarios, such as immersive tele-presence systems and gaming. In most of these applications, the reconstruction of 3D animations is based on dynamic meshes which are highly incomplete, stressing the need of completion approaches with low computational requirements. In this paper, we present a new online approach for fast and effective completion of 3D animated models that estimates the position of the unknown vertices of the current frame by exploiting the connectivity information and the current motion vectors of the known vertices. Extensive evaluation studies carried out using a collection of different incomplete animated models, verify that the proposed technique achieves plausible reconstruction output despite the constraints posed by arbitrarily complex and motion scenarios. Keywords 3D animated meshes, missing vertices, weighed iterative function 1 INTRODUCTION Recently, there has been increasing interest in real-time 3D capture enabling the acquisition of dynamically de- forming shapes at sustained ”video” rates. Although resolution and accuracy of 3D scanners are constantly improving, they are still unable to capture the full sur- face at once. Even in scenarios where multiple sensors are placed around the subject, most scanned shapes are likely to exhibit large holes, noise and outliers due to occlusions [BTSAL14], limited sensor range capabili- ties, high light absorption and low surface albedo. Although a large number of prior works [SGP03] has investigated the problem of completion in static geometries, resulting in excellent filled static meshes, their direct application to every frame separately usually causes incorrect topologies and temporally incoherent surfaces. A fast and efficient approach for reconstructing surfaces from a set of known points have been proposed in [SC04] where the authors reconstruct meshes with a prescribed connectivity that approximate a set of control points in a least-squares sense. Building on this direction, in this work we introduce a novel technique for reconstruction of highly incomplete Permission to make digital or hard copies of all or part of this work for personal or classroom use is granted without fee provided that copies are not made or distributed for profit or commercial advantage and that copies bear this notice and the full citation on the first page. To copy otherwise, or re- publish, to post on servers or to redistribute to lists, requires prior specific permission and/or a fee. dynamic meshes 1 , by exploiting a known connectivity and set of motion vectors corresponding to the known points in an online setting. In this setting the animation sequence in not known a priori and at each time our method exploits information that has been presented so far. An extensive analysis has demonstrated that the high-frequency details of the animated model can be adequately recovered from a highly incomplete geome- try dataset at very fast execution times. 2 RELATED WORKS & CONTRIBU- TIONS In recent years, a lot of research has been carried out into the field of 3D mesh reconstruction, having pre- sented excellent results applied to incomplete static meshes. However, little attention has been given to the reconstruction of animated meshes. Traditional methods usually cause temporally incoherent surfaces when they are directly applied to each frame individu- ally. These methods do not take advantage of previous frames knowledge, as a result they basically deal with n individual meshes instead of a sequence of tempo- rally coherent meshes. A common approach to produce a temporal consistent dynamic mesh is to use a tem- plate prior [ZA04], however, this approach is not ideal for real-time applications because the entire captured animated mesh is required before the execution of the process. The authors in [ACSTD07] focus on reconstructing watertight surfaces from unoriented point sets using a 1 A dynamic mesh is a common term defined as a series of static, mainly triangular, meshes representing a 3D animation. ISSN 2464-4617(print) ISSN 2464-4625(CD) CSRN 2701 Computer Science Research Notes http://www.WSCG.eu Full Papers Proceedings 125 ISBN 978-80-86943-49-7

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Fast and Effective Dynamic Mesh Completion

Gerasimos Arvanitis Aris S. Lalos Konstantinos Moustakas Nikos FakotakisDept. of Electrical and Computer Engineering

University of Patras, Rio, Patras, Greece{arvanitis, aris.lalos, moustakas}@ece.upatras.gr, [email protected]

ABSTRACTWe introduce a novel approach to support fast and efficient completion of arbitrary animation sequences, ideallysuited for real-time scenarios, such as immersive tele-presence systems and gaming. In most of these applications,the reconstruction of 3D animations is based on dynamic meshes which are highly incomplete, stressing the needof completion approaches with low computational requirements. In this paper, we present a new online approachfor fast and effective completion of 3D animated models that estimates the position of the unknown vertices ofthe current frame by exploiting the connectivity information and the current motion vectors of the known vertices.Extensive evaluation studies carried out using a collection of different incomplete animated models, verify that theproposed technique achieves plausible reconstruction output despite the constraints posed by arbitrarily complexand motion scenarios.

Keywords3D animated meshes, missing vertices, weighed iterative function

1 INTRODUCTION

Recently, there has been increasing interest in real-time3D capture enabling the acquisition of dynamically de-forming shapes at sustained ”video” rates. Althoughresolution and accuracy of 3D scanners are constantlyimproving, they are still unable to capture the full sur-face at once. Even in scenarios where multiple sensorsare placed around the subject, most scanned shapes arelikely to exhibit large holes, noise and outliers due toocclusions [BTSAL14], limited sensor range capabili-ties, high light absorption and low surface albedo.

Although a large number of prior works [SGP03]has investigated the problem of completion in staticgeometries, resulting in excellent filled static meshes,their direct application to every frame separatelyusually causes incorrect topologies and temporallyincoherent surfaces. A fast and efficient approach forreconstructing surfaces from a set of known points havebeen proposed in [SC04] where the authors reconstructmeshes with a prescribed connectivity that approximatea set of control points in a least-squares sense.

Building on this direction, in this work we introduce anovel technique for reconstruction of highly incomplete

Permission to make digital or hard copies of all or part ofthis work for personal or classroom use is granted withoutfee provided that copies are not made or distributed for profitor commercial advantage and that copies bear this notice andthe full citation on the first page. To copy otherwise, or re-publish, to post on servers or to redistribute to lists, requiresprior specific permission and/or a fee.

dynamic meshes1, by exploiting a known connectivityand set of motion vectors corresponding to the knownpoints in an online setting. In this setting the animationsequence in not known a priori and at each time ourmethod exploits information that has been presented sofar. An extensive analysis has demonstrated that thehigh-frequency details of the animated model can beadequately recovered from a highly incomplete geome-try dataset at very fast execution times.

2 RELATED WORKS & CONTRIBU-TIONS

In recent years, a lot of research has been carried outinto the field of 3D mesh reconstruction, having pre-sented excellent results applied to incomplete staticmeshes. However, little attention has been given tothe reconstruction of animated meshes. Traditionalmethods usually cause temporally incoherent surfaceswhen they are directly applied to each frame individu-ally. These methods do not take advantage of previousframes knowledge, as a result they basically deal withn individual meshes instead of a sequence of tempo-rally coherent meshes. A common approach to producea temporal consistent dynamic mesh is to use a tem-plate prior [ZA04], however, this approach is not idealfor real-time applications because the entire capturedanimated mesh is required before the execution of theprocess.

The authors in [ACSTD07] focus on reconstructingwatertight surfaces from unoriented point sets using a

1 A dynamic mesh is a common term defined as a series ofstatic, mainly triangular, meshes representing a 3D animation.

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Voronoi-based variational approach, while the methodin [SLS07] tries to handle the missing points by try-ing to infer topological structures in the original sur-face at the potential expense of retaining geometric fi-delity. The researchers in [DGQ12] perform recon-struction only on the available information, effectivelypreserving the boundaries from the scan. Recently, anew signal processing technique known as matrix com-pletion (MC) [CAN12] has been successfully appliedto several computer vision problems, including the re-covery of occluded faces/dynamic meshes [DDZ11],[VLMB07], [SWG08] and the face image alignment[PGWXM12]. It has been also used for the fusion ofpoint clouds from multiview images of the same object[DDZW12]. In [RPMR13], it is applied on RGB-D datafor the simultaneous tracking and reconstruction of 3Dobjects.

The common limitation of all the aforementioned ap-proaches is the high computational complexity that sig-nificantly affects the execution time and renders theminappropriate for real time applications. These limi-tations motivated us to search for a fast and effectiveapproach that can satisfy the reconstruction efficiencysupporting at the same time real time applications. Insummary, the main contributions of our work are:

• A general out-of-core approach to dynamic meshcompletion ideally suited for fast and accurate filling(in spatial or temporal space) of incomplete arbitrarymesh sequences.

• An extensive experimental evaluation under differ-ent configurations and mesh animations showingthat our approach achieves the highest reconstruc-tion quality offering at the same time faster execu-tion times as compared to previous methods.

The rest of this paper is organized as follows: Section2 includes a detailed summary of prior art. Section 3presents an overview of our method. Section 4 presentsour experimental results and discusses the advantagesand limitations of the proposal method. Section 5 drawsconclusions and identifies future directions.

3 OVERVIEW OF OUR METHODInitial Assumptions and PreliminariesIn this section we present the basic assumptions andpreliminaries related to animated meshes. Firstly, a dy-namic mesh is defined A = [M1; M2; . . . Mn] as a se-quence of n static meshes consisting of k vertices. Eachone of these meshes can be represented by two differ-ent sets M = (V ,F ) corresponding to the vertices (V )and the indexed faces (F ) of the mesh. Each vertexcan be represented as a point in the Euclidean space.Let us define with v = [ x, y, z ] a vector of vertices

in a 3D coordinate space denoted as x,y,z ∈ ℜk×1,v = [v1, v2, ... vk] ∈ ℜk×3 and V = {v1, v2, ... vk} isthe corresponding set of vertices. Additionally, eachface is represented as a set of 3 connected verticesfi = [vi1, vi2, vi3] ∀ i = 1,m where m > k and the corre-sponding set of faces is denoted by F = { f1, f2, ... fm}.The set of edges E can be directly derived from V andF , corresponds to the connectivity information.

Let us assume that A′ is a highly incomplete dynamicmesh. In other words, each mesh of the animationhas only a subset of known vertices while the resthave been removed. The incomplete animated modelis represented by a sequence of incomplete meshesA′ = [M1; M′2; . . . M′n] where M′i ⊂Mi ∀ i = 2,n. Eachincomplete dynamic mesh is described by a matrix ofdimension 3k×n:

A′=

M1M′2M′3M′4...

M′n

=

v11 v12 v13 v14 ... v1k−1 v1k0 v22 0 0 ... 0 0

v31 0 0 v34 ... 0 00 0 v43 0 ... v4k−1 v4k...

......

......

......

0 vn2 0 0 ... vnk−1 0

The incomplete meshes are created by randomlyremoving points from the original ones. Fig. 1 depictssome indicative frames (meshes) assuming differentdensities of known points.

Adjacency and Laplacian MatrixTo estimate the coordinates of the missing points, weinitially use a prescribed connectivity information (i.e.,adjacency matrix), constructed from the faces of themesh. Despite the fact that the position of vertices ischanging, the adjacency matrix remains fixed over time,since we assume that every mesh has the same connec-tivity [WJHB07]. This observation allows us to esti-mate the adjacency matrix only once and use it repeat-edly for any subsequent mesh of the same model. More-over, we assume that we have full knowledge of the firstmesh M1 of the sequence. We define as R ∈ ℜk×k theadjacency matrix which is estimated as described be-low:

Ri j =

{1 i f i, j ∈ E0 otherwise (1)

The matrix R is binary and it is used for the creation ofthe Laplacian matrix defined as:

L = D−R (2)

D = diag{d1, . . . ,dk} is a diagonal matrix with di =

∑kj=1 ri j, being the degree of its node.

Spatial Classification of Each Frame Ver-ticesWe create k cells of nodes ci ∀ i = 1,k using the knowl-edge of the adjacency matrix R. Each cell ci rep-

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(a) (b) (c) (d) (e)

Figure 1: Indicative incomplete frames of the animated sequence: (a) original mesh (10002 points), (b) 10% oforiginal points, (c) 30% of original points, (d) 50% of original points, (e) 70% of original points

resents the first ring area of each vertex i. We de-fine as C = [c1 c2 . . . ck] the set of k cells whereci = [ci1 ci2 . . . ci j] ∀ i = 1,k. However, it is worthmentioning here that each cell has different connectiv-ity valence denoted by j. The element cip represents theindex of p-th connected vertex with the vertex i. The setC remains fixed for every frame (mesh) and it is usedfor recovering the missing points. Fig. 2 illustrates anexample of two connected cells c1,c2 with their relatedconnections, cell c1 has j = 6 connected neighbors (va-lence), while c2 has a valence j = 5.

𝑐1c2

ሶ𝑐11

ሶ𝑐12

ሶ𝑐13

ሶ𝑐14

ሶ𝑐15

ሶ𝑐16

ሶ𝑐21

ሶ𝑐22

ሶ𝑐23

ሶ𝑐24

ሶ𝑐25

Figure 2: Representation of two connected cells

After the definition of cells we focus on the classifica-tion of vertices for each frame M′i ∀ i = 2,n. This pro-cess is executed in a sequential manner for each meshstarting from the second mesh until the end of the ani-mation sequence. We assume three different classes foreach vertex:

• Anchor vertices are the known vertices of the mesh.

• Satellites vertices are those belonging to a cell of analready known vertex. If a vertex belong to a cell ofan anchor vertex then is defined as first generationsatellite otherwise is defined as second generationsatellite and so on.

• Unknown vertices are the vertices that do not be-long to a cell of an already known vertex. Thosevertices will be recovered and placed in the mesh ata future iteration.

The classification procedure is an iterative process thattries to eliminate any remaining unknown vertex so thatthe mesh will be composed of only anchor or satel-lite vertices. This means that the coordinates of anunknown vertex are evaluated in a following iteration.This method has been proved to be robust and all themissing vertices are always recovered. The methodstarts with the assumption that if the position of a vertexis known then it is called anchor point, i ∀ i = 1,k′ k′ <k . All the vertices that belong to the cell ci are classi-fied as satellite vertices (first generation satellite). Therest vertices are classified as unknown. At the follow-ing iteration the position of the satellite points are takeninto account and their cells are used for identifying newsatellites (second generation satellites).

(a) (b)

(c) (d)

Figure 3: (a) Part of mesh with unknown points, (b) An-chors are indicated with red (Iteration 1), (c) First gen-eration satellites identified based on anchors cells (Iter-ation 2), (d) Second generation satellites are set basedon first generation satellites cells (Iteration 3).

Fig. 3 illustrates the aforementioned classification pro-cedure. Red points represent the known vertices (an-chor points). Blue points represent the satellites (firstgeneration) which are connected with the anchor points,and correspondingly green point represent the satellites

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∀ 𝑡 = 2, 𝑛

Temporal process for the animation reconstruction

𝑀𝑡′

𝑀𝑡−1

Reconstructed Animated Mesh

Spatial iterative process for the

mesh reconstruction

𝑀𝑡Reconstructed

Mesh

Figure 4: The animation is reconstructed frame byframe (temporal process) taking into account the pre-vious reconstructed mesh and the current incomplete(spatial iterative process).

(second generation) that are connected with the firstgeneration satellites. It is important to mention here,that a satellite point can be also a satellite point of morethan one anchor point while, an anchor point can be asatellite point for another neighbor anchor point.

A cell ci can indicate the existence of satellite verticesin a first ring area of vertex i, nevertheless it does notspecify their real position. The classification procedureis used for assigning weights and then estimating theunknown vertex position using a weighted filtering ap-proach based on their previous position and the motionvector of the anchor points. A detailed description ofthe method is provided in the following section.

Geometry Completion Based on Topologi-cal CharacteristicsIn this section we present the main steps of our interpo-lation procedure which is divided in two stages. In thefirst stage, a spatial iterative process is executed for re-constructing the mesh using only the known vertices ofthe current mesh. In the second stage, a temporal pro-cess tries to reconstruct the entire animated mesh us-ing knowledge of the previous frame. Fig. 4 presentsthe process while the reconstruction takes place gradu-ally, starting from the second mesh and continues untilthe end of the animation sequence rendering the methodappropriate for online setups.

As mentioned earlier, a cell c represents the first ringarea where points (satellite vertices) are connected withan anchor vertex. Therefore we decided to build uponthe assumption that the satellite vertices are expected tomove towards the direction of an anchor keeping their

Figure 5: Example of large and small variations in cellmovements.

common topological characteristics (e.g., distances be-tween each other) unchanged. However, some satellitesare connected with more than one anchors, meaningthat their new position will be affected by the motionvectors of every connected anchor.

For making the estimation of coordinates more accuratewe suggest a weighted reconstruction function which isdefined by exploiting the following observations. Asit was mentioned earlier, when a satellite is connectedwith more than one anchors then its new position is af-fected by the motion vectors of all the anchors. How-ever, each anchor contributes with a different weightthat is related to the relative distance between anchorsand satellites. Smaller cells are more rigid so that theirsatellite points are expected to follow the motion vec-tors of the closest anchor, as shown in Fig. 5.

The second rule that we apply, is based on the fact thatsome points are more trustworthy than others. In otherwords we give more emphasis on the anchor points in-stead of the satellites due to their known position. Sub-sequently, we give more emphasis in the first genera-tion satellites rather than the next generation becausethey are connected directly with the anchor points sothat their estimated position is expected to be more ac-curate. According to the aformentioned observations,we distinguish two different weighted factors:

(a) the weighting factor si j that represents the inversedistance between points j (new discovered satellite) andi (already known point) such as si j = 1/||vi−v j||22.

(b) the weighting factor wi that represents the prioriti-zation weight of vertex i. More specifically, anchorsprioritization weights have the highest value while thelast generation satellites have the smallest one.

For each vertex v j∀ j = 1,k− k′ we define a weightedmatrix S j = [s1 j s2 j · · · sn j] that consists of n′ elementsthat represent the distance between the current vertexand the known vertices that are connected with the ver-tex v j. The matrix W = [w1 w2 · · · wk′ ] is universal andcan be used by every vertex v j. However, in each itera-tion the values of their elements increase by one, whilein every new element we assign a unit weight. For eachsatellite j we estimate its new coordinates in the (p+1)

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v(p)i v(p+1)iM(p) M(p+1)

v(p)j v(p+1)j

1/s(p)ij

dp(p+1)j

dp(p+1)i1/s(p+1)ij

Figure 6: Anchor and satellites movement in a cell oftwo sequential meshes.

mesh, by updating its previous coordinates in (p) mesh,based on the following equation:

v(p+1) j = v(p) j +dp(p+1) j (3)

where

dp(p+1) j =∑

ni=1 si jwidp(p+1)i

∑ni=1 |si jwi|

(4)

The dp(p+1) j represents the motion vector of vertex vifrom (p)-th mesh to (p + 1)-th mesh (see Fig. 6), irepresents the known vertex vi (anchors and satellites)and d = [dx = |x(p+1)− x(p)| dy = |y(p+1)− y(p)| dz =|z(p+1)− z(p)|] is a distance vector. An overview of theproposed method is briefly presented in the followingAlgorithm 1.

Algorithm 1: Reconstruction of 3D animated modelFunction: 3D mesh reconstruction based on previous

complete meshInput : Animated 3D model A′ with missing data.Output : A reconstructed animated model A.

1 Find the connectivity R of M1;2 for i≤ n do3 while Number of known vertices < k do4 Search for satellate points using the connectivity of

C;5 Estimate the wighted distance via Eq. (4);6 Update vertex based on its previous frame

coordiantes via Eq. (3) ;7 end8 end9 return Reconstructed animated model A;

4 RESULTSIn this section, we present an experimental analysisof the proposed completion approach on different dy-namic meshes. The evaluation of both the executiontime and the reconstruction quality shows the effective-ness of our method even in complex motion scenariothat include rapid changes between sequential framesor in cased with a small percentage of known points.

Experimental SetupIn all the experiments we have used a PC Intel core i7-4710HQ CPU @ 2.50GHz 2.50GHz, 8 GB RAM. Thealgorithms have been implemented using the Julia sci-entific language.

MetricsThe quality of the reconstructed results are evaluatedusing the metrics that are briefly presented below:

NMSVE. Normalized mean square visual error is usedin order to evaluate the reconstruction quality of results,by capturing the average distortion between the originaland the approximated frame [CG04]:

NMSV E =12k

k

∑j=1

(‖vi − vi‖2+‖GL(vi)−GL(vi)‖

2) (5)

GL(vi) = vi−∑ j∈Ni d−1

i j v j

∑ j∈Ni d−1i j

(6)

di j denotes the Euclidean distance between i and j.

Heatmap. To efficiently highlight the visual differ-ence between reconstructed and original mesh we useheatmap visualization of |Mi− Mi| ∀ i = 1,n.

DatasetTwo types of 3D animated models were used in our ex-periments. These models represent different case stud-ies because of their inherent properties and the factthat they target on different applications (e.g., immer-sive tele-presence systems, gaming). Specifically, (a)Handstand has many smooth areas, while there are noabrupt temporal changes (175 frames, 10002 verticesand 20000 triangles). (b) Ocean on the other hand is fullof repetitive abrupt changes (1500 frames 2500 verticesand 4802 triangles).

Comparison MethodsFor comparison purposes, we have also employed con-ventional techniques for the reconstruction of the ani-mation models, namely the least-square meshes (LSM)algorithm [SC04] and the Laplacian interpolation ap-proach (LIA) [OOH89]. LSM is described as the solu-tion of an extended system of equations [LT IT

n×k′ ]T xp =

[0T ,xk′,k], for p = 1, · · · ,n, for k′ known (anchor) ver-tices in the p-th frame. Laplacian interpolation is de-scribed as a fast and effective method with a lot of sim-ilarities with LSM. According to [OOH89] a way to in-terpolate a triangulated mesh is by putting constraintson the Laplacian ∆ f of the function and trying to mini-mize its Euclidean norm.

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Experimental ResultsThe processing time is related to the number of ini-tial known vertices. Specifically, the execution time in-creases linearly with the number of unknown vertices.In Fig. 7 we present the processing time for the recon-struction of each mesh of the animated sequence us-ing different initialization schemes. The required num-ber of iterations for a complete mesh reconstruction de-pends on the percentage of known vertices. Addition-ally, we can observe that the two models have a similarbehavior.

Number of Iterations0 1 2 3 4 5 6

Num

ber

of P

oint

s

0

2000

4000

6000

8000

10000

0.98 sec. !

0.56 sec. !

0.32 sec. !

0.29 sec. !

Handstand (10002 points per mesh)

10% of initial points30% of initial points50% of initial points70% of initial points

Number of Iterations0 1 2 3 4 5 6

Num

ber

of P

oint

s

0

500

1000

1500

2000

2500

0.27 sec. !

0.17 sec. !

0.12 sec. !

0.07 sec. !

Ocean (2700 points per mesh)

10% of initial points30% of initial points50% of initial points70% of initial points

Figure 7: Number of iteration and processing time fora full mesh reconstruction.

In Fig. 8 the missing vertices are visualized with redcolor and the known vertices with blue (1st and 3rdrow). A heatmap visualization is also offered present-ing the squared difference between original and recon-structed mesh for different numbers of known vertices(2nd and 4th row). The compared results of our ap-proach and LIA are presented in Fig. 9 showing that ourmethod outperforms LIA in both reconstruction qualityand execution time. A major disadvantage of LIA isthe smoothed results even in cases with a high percent-age of remaining points. In terms of execution time, ourmethod becomes faster when more remaining points areused, because of the less iterations that are required,contrary to LIA where the execution time increases be-cause of the larger matrix operations. Fig. 10 illustratessome indicative reconstructed frames of the Handstandmodel after using the aforementioned approaches. Ourmethod seems to outperform the others while LIA andLSM have similar performance. Fig. 11 presents someindicative reconstructed frames of different animated

(a) (b) (c) (d)

Figure 8: Visualized missing data and heatmap visual-ization for different density of points (a) 10% of origi-nal points, (b) 30% of original points, (c) 50% of orig-inal points, (d) 70% of original points. (Handstandframe 110, Ocean frame 1500).

Percentage of remaining points (%)0 10 20 30 40 50 60 70

NM

SV

E (

dB)

-62

-60

-58

-56

-54

-52

-50

-48

-46

-44

-42

0.98 sec. !

0.56 sec. !

0.32 sec. !

0.29 sec. !

2.83 sec. # 4.48 sec. #

5.66 sec. #

7.09 sec. #

Handstand (mesh 55)

Proposed methodLaplacian Interpolation

Figure 9: NMSVE and processing time results for thetwo compared methods.

models. For the sake of completeness, the NMSVE val-ues are also illustrated under each reconstructed mesh.Finally, it should be noted that despite the high motionvariance of animated trajectories, the perceptual qualityof the reconstructed dynamic meshes when the densityof the known point is higher than > 30% is consider-ably high. This totally satisfies the main goal of thiswork which is the design and implementation of fastand effective dynamic mesh reconstruction approaches.

5 CONCLUSIONS AND FUTURES EX-TENDS

In this work we introduced a fast and effective methodfor reconstructing animated 3D models with missingdata. The proposed method takes advantage of the adja-cency matrix information in order to identify the coor-dinated of the missing vertices. After that a weighted

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30

% o

f th

e o

rigi

nal

po

ints

(a) (b) (c)

50

% o

f th

e o

rigi

nal

po

ints

Figure 10: Handstand with 30% of original points(Frames 150 & 80) and with 50% of the original points(Frames 55 & 120) (a) our method, (b) LIA, (c) LSM.

iterative procedure estimates the position of missingvertices based on their previous position and the mo-tion vectors of the connected anchors. An extensiveevaluation study using a collection of different 3D an-imation models verified that the proposed techniqueachieve plausible reconstruction output and fast execu-tion times.

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[SGP03] P. Liepa. 2003. Filling holes in meshes. InProceedings of the 2003 Eurographics/ACM SIG-GRAPH symposium on Geometry processing(SGP ’03). Eurographics Association, Aire-la-Ville, Switzerland, Switzerland, 200-205

[OOH89] Thom F Oostendorp, Adriaan van Oosteromand Geertjan Huiskamp, Interpolation on a tri-angulated 3D surface. Journal of ComputationalPhysics, 80: 331-343, 1989.

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Full Papers Proceedings 131 ISBN 978-80-86943-49-7

Page 8: Fast and Effective Dynamic Mesh Completion · animated mesh is required before the execution of the process. The authors in [ACSTD07] focus on reconstructing watertight surfaces from

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Figure 11: Reconstructed meshes for different density of remaining points (a) 10% of original points, (b) 30% oforiginal points, (c) 50% of original points, (d) 70% of original points, (e) original mesh. (Handstand & Ocean)

ISSN 2464-4617(print) ISSN 2464-4625(CD) CSRN 2701 Computer Science Research Noteshttp://www.WSCG.eu

Full Papers Proceedings 132 ISBN 978-80-86943-49-7