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3D Model-based Object Recognition and Segmentation in Cluttered Scenes

Abstract
Viewpoint independent recognition of free-form objects and their segmentation in the presence of clutter and occlusions is a challenging task. We present a novel 3D model-based algorithm which performs this task automatically and efficiently. A 3D model of an object is automatically constructed offline from its multiple unordered range images (views). These views are converted into multidimensional table representations (which we refer to as tensors). Correspondences are automatically established between these views by simultaneously matching the tensors of a view with those of the remaining views using a hash table based voting scheme. This results in a graph of relative transformations used to register the views before they are integrated into a seamless 3D model. These models and their tensor representations constitute the model library. During online recognition, a tensor from the scene is simultaneously matched with those in the library by casting votes. Similarity measures are calculated for the model tensors which receive the most votes. The model with the highest similarity is transformed to the scene and if it aligns accurately with an object in the scene, that object is declared as recognized and is segmented. This process is repeated until the scene is completely segmented. Experiments were performed on real and synthetic data comprised of 55 models and 610 scenes and an overall recognition rate of 95 percent was achieved. Comparison with the spin images revealed that our algorithm is superior in terms of recognition rate and efficiency.

Ajmal Mian, M. Bennamoun and R. Owens, "3D Model-based Object Recognition and Segmentation in Cluttered Scenes", IEEE Trans. on Pattern Analysis and Machine Intelligence (PAMI), vol. 28(10), pp. 1584--1601, 2006. [pdfCopyright © IEEE.

On the Repeatability and Quality of Keypoints for Local Feature-based 3D Object Retrieval from Cluttered Scenes

Abstract
Abstract 3D object recognition from local features is robust to occlusions and clutter. However, local features must be extracted from a small set of feature rich keypoints to avoid computational complexity and ambiguous features. We present an algorithm for the detection of such keypoints on 3D models and partial views of objects. The keypoints are highly repeatable between partial views of an object and its complete 3D model. We also propose a quality measure to rank the keypoints and select the best ones for extracting local features. Keypoints are identified at locations where a unique local 3D coordinate basis can be derived from the underlying surface in order to extract invariant features. We also propose an automatic scale selection technique for extracting multi-scale and scale invariant features to match objects at different unknown scales. Features are projected to a PCA subspace and matched to find correspondences between a database and query object. Each pair of matching features gives a transformation that aligns the query and database object. These transformations are clustered and the biggest cluster is used to identify the query object. Experiments on a public database revealed that the proposed quality measure relates correctly to the repeatability of keypoints and the multi-scale features have a recognition rate of over 95% for up to 80% occluded objects.

Ajmal Mian, M. Bennamoun and R. Owens, "
On the Repeatability and Quality of Keypoints for Local Feature-based 3D Object Retrieval from Cluttered Scenes", International Journal of Computer Vision (IJCV), to appear 2009. Copyright © Springer Science+Business Media.

Data (along with ground truth) is also available for download below. Data is provided without any warranty and for research purposes only. If you use the data, cite the above two papers.

3D Models in PLY format

Chef [download 3.6MB]    Parasaurolophus [download 3.6MB]    T-rex [download 3.5MB]    Chicken [download 2.7MB]    Rhino [download 1.6MB]

The above objects were placed in a scene causing occlusions and clutter. The scene was then scanned with the Minolta Vivid 910 scanner to get a 2.5D view of the scene. The scenes are available for download below. File sizes vary from 1.5 to 2.2 MB.

2.5D Scenes in PLY format (zip files). A snapshot of the first 10 sences is shown rendered with plyview.

scene1

scene2 

scene3

scene4

scene5

scene6

scene7

scene8

scene9

scene10
scene11 scene12 scene13 scene14 scene15 scene16 scene17 scene18 scene19 scene20
scene21 scene22 scene23 scene24 scene25 scene26 scene27 scene28 scene29 scene30
scene31 scene32 scene33 scene34 scene35 scene36 scene37 scene38 scene39 scene40
scene41 scene42 scene43 scene44 scene45 scene46 scene47 scene48 scene49 scene50

NEW!  Ground truth locations of the objects and percentage occlusion in the above 50 scenes [download]