PhD Thesis - Automated Recognition of 3D CAD Model Objects in ...

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Literature Review 14 (bin size) and sampling (size of the spin image) of spin images; (2) spin images have a low discriminating capability because they map a 3D surface to a 2D histogram, which may lead to ambiguous matches; and (3) although a technique is presented in [64] for accelerating the matching process, matching is done one-to-one so that the recognition time grows rapidly with the sizes of the model library and of the sensed data. Then, Zhang and Herbert [126] present a technique that uses another local (point) surface descriptor, the harmonic shape image. A harmonic shape image is constructed by mapping a local 3D surface patch with disc topology to a 2D domain. Then, the shape information of the surface (curvature) is encoded into the 2D image. Harmonic shape images conserve surface continuity information, while spin images do not, so that they should be more discriminative. Additionally, while the calculation of harmonic shape images requires the estimation of the size of each image, it does not require the estimation of any bin size. The recognition process is then similar to the one use in the spin image approach [64]. The results reported on the performance of this technique with respect to occlusions are limited. In particular, the expected improved performance compared to the spin image approach is not demonstrated. Additionally, similarly to the spin image approach, this technique has two main limitations: (1) harmonic shape images have a limited discriminating capability because they map a 3D surface to a 2D image; and (2) matching is done one-to-one so that the recognition time of this technique grows rapidly with the sizes of the model library and of the sensed data. Finally, Mian et al. [82, 81] have recently presented a technique based on another local shape descriptor: the 3D tensor. A 3D tensor is calculated as follows. A pair of mesh vertices sufficiently far from each other and with sufficiently different orientations is randomly selected. Then a 3D grid is intersected with the meshed data. The pose of the grid is calculated based on the paired vertices and their normals. Each tensor element is then calculated as the surface area of intersection of the mesh with each bin of the grid. The sizes of the grid and of its bins are automatically calculated. They respectively determine the degree of locality of the representation and the level of granularity at which the surface is represented. The recognition is performed by simultaneously matching all the tensors from the sensed data with tensors from the 3D models. Once an object is identified, its sensed range points are segmented from the original data and the process is repeated until no more objects are recognized in the scene. The main advantage of this technique is that 3D tensors are local 3D descriptors, so that they are more discriminative than spin images or harmonic shape images. Experiments were performed and an overall recognition rate of 95% is achieved, and the approach can effectively handle up to 82% occlusion. Experimental comparison with the spin image approach also reveal that this approach is superior in terms of both accuracy, efficiency and robustness. However, similarly to the previous ones, this technique has one main limitation:
Literature Review 15 the recognition time of this technique grows rapidly with the sizes of the model library and the sensed data. Besl [42] reviewed the difficulties in matching free-form objects in range data using local features (point, curve, and surface features). In particular, as seen with the three techniques above, the computational complexity of such matching procedures can quickly become prohibitive. For example, brute-force matching of 3D point sets was shown to have exponential computational complexity. Because of this, all the works using local features have developed techniques to reduce the amount of computation required in their feature matching step. For example, Johnson and Hebert [64] use Principal Component Analysis (PCA) to more rapidly identify positive spin image matches. Similarly, Mian et Al. [81] use a 4D hash table. Nonetheless, these techniques remain limited in the case of large model libraries and range images. The result of this review of 3D object recognition techniques is that techniques based on local shape descriptors are expected to perform better in the context of the problem investigated here. Furthermore, the recent work by Mian et al. [81] seems to demonstrate the best performance with such problems. However, the problem investigated here presents two additional conditions that, with the current assumptions, none of the above techniques can overcome: � Construction models generally contain many objects that have the same shape and typically the same orientation (e.g. columns, beams), so that they cannot be unambiguously recognized, by the methods described above. � Many construction 3D objects present symmetries so that their pose cannot be determined unambiguously. In the next section, some sources of aprioriinformation available within the AEC&FM context are however presented that can be leveraged to remove those constraints. 2.6 A Priori Information Available in the AEC&FM Context Within the context of the AEC&FM industry, two sources of a priori information can be leveraged, that are typically not available in other contexts: project 3D CAD models and 3D registration technologies.
Page 1 and 2: Automated Recognition of 3D CAD Mod
Page 3 and 4: Abstract There is shift in the Arch
Page 5 and 6: Dedication This thesis is dedicated
Page 7 and 8: 3.4 Step 3 - Calculation of the As-
Page 9 and 10: D Construction of the Bounding Volu
Page 11 and 12: 5.4 Progress recognition results fo
Page 13 and 14: 5.2 Example of a model and recogniz
Page 15 and 16: Chapter 1 Introduction 1.1 Backgrou
Page 17 and 18: Introduction 3 Sub-objectives are f
Page 19 and 20: Chapter 2 Literature Review This ch
Page 21 and 22: Literature Review 7 is also often i
Page 23 and 24: Literature Review 9 Figure 2.2: Tot
Page 25 and 26: Literature Review 11 minutes (at mo
Page 27: Literature Review 13 tigated here.
Page 31 and 32: Literature Review 17 recognition of
Page 33 and 34: Literature Review 19 frame of the e
Page 35 and 36: Chapter 3 New Approach 3.1 Overview
Page 37 and 38: New Approach 23 Data: Model, Scan R
Page 39 and 40: New Approach 25 frame. Therefore, f
Page 41 and 42: New Approach 27 The complexity of t
Page 43 and 44: New Approach 29 are tested for inte
Page 45 and 46: New Approach 31 effectiveness of a
Page 47 and 48: New Approach 33 (a) 3D View. (b) To
Page 49 and 50: New Approach 35 Data: PB, BVH Resul
Page 51 and 52: New Approach 37 α, of each as-plan
Page 53 and 54: New Approach 39 Data: Scan,Model Re
Page 55 and 56: New Approach 41 where: α is the as
Page 57 and 58: New Approach 43 Furthermore, the ca
Page 59 and 60: Chapter 4 Experimental Analysis of
Page 61 and 62: Experimental Analysis of the Approa
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Experimental Analysis of the Approa
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Chapter 5 Enabled Applications: Fea
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Enabled Applications: Feasibility A
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Chapter 6 Conclusions and Recommend
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Conclusions and Recommendations 83
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Appendix A Description of the STL F
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Appendix A 87 solid name facet norm
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Appendix B 89 Figure B.1: Spherical
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Appendix B 91 Data: [x, y, z] Resul
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Appendix C 93 (a) 3D View. (b) Top
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Appendix C 95 C.1.1 Bounding Pan An
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Appendix C 97 Figure C.5: Illustrat
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Appendix C 99 Data: ϕmintemp, ϕmi
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Appendix C 101 Figure C.6: Example
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Appendix C 103 Data: {Facet} Result
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Appendix D Construction of the Boun
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Appendix D 107 Figure D.1: Illustra
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Appendix D 109 (a) MSABV not inters
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Appendix D 111 It can be noted that
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Appendix E Containment of a Ray in
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Appendix E 115 Finally, in the case
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Appendix F Calculation of the Range
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Appendix F 119 second plane perpend
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Appendix F 121 included in Algorith
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Appendix G 123 Figure G.1: 3D CAD m
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Appendix G 125 G.2.2 Step 2 - 3D mo
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Appendix G 127 G.2.4 Step 4 - Recog
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Appendix G 129 It can be seen in Fi
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Appendix G 131 Column 7: Whether th
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Appendix G 133 Table G.1 - continue
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Appendix H 143 Table H.1 - continue
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Appendix H 145 Table H.2 - continue
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Appendix H 147 [11] J. Amanatides.
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Appendix H 149 [35] G. S. Coleman a
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Appendix H 151 [57] B. Hofmann-Well
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Appendix H 153 [81] A. S. Mian, M.
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Appendix H 155 [104] L. M. Sheppard
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PhD Thesis - Automated Recognition of 3D CAD Model Objects in ...

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