Kunqian Li

SaCoseg: Object Cosegmentation by Shape Conformability

In this paper, an object cosegmentation method based on shape conformability is proposed. Different from the previous object cosegmentation methods which are based on the region feature similarity of the common objects in image set, our proposed SaCoseg cosegmentation algorithm focuses on the shape consistency of the foreground objects in image set. In the proposed method, given an image set where the implied foreground objects may be varied in appearance but share similar shape structures, the implied common shape pattern in the image set can be automatically mined and regarded as the shape prior of those unsatisfactorily segmented images. The SaCoseg algorithm mainly consists of four steps: 1) the initial Grabcut segmentation; 2) the shape mapping by coherent point drift registration; 3) the common shape pattern discovery by affinity propagation clustering; and 4) the refinement by Grabcut with common shape constraint. To testify our proposed algorithm and establish a benchmark for future work, we built the CoShape data set to evaluate the shape-based cosegmentation. The experiments on CoShape data set and the comparison with some related cosegmentation algorithms demonstrate the good performance of the proposed SaCoseg algorithm.

Unsupervised Co-Segmentation for Indefinite Number of Common Foreground Objects

Co-segmentation addresses the problem of simultaneously extracting the common targets appeared in multiple images. Multiple common targets involved object co-segmentation problem, which is very common in reality, has been a new research hotspot recently. In this paper, an unsupervised object co-segmentation method for indefinite number of common targets is proposed. This method overcomes the inherent limitation of traditional proposal selection-based methods for multiple common targets involved images while retaining their original advantages for objects extracting. For each image, the proposed multi-search strategy extracts each target individually and an adaptive decision criterion is raised to give each candidate a reliable judgment automatically, i.e., target or non-target. The comparison experiments conducted on public data sets iCoseg, MSRC, and a more challenging data set Coseg-INCT demonstrate the superior performance of the proposed method.Co-segmentation addresses the problem of simultaneously extracting the common targets appeared in multiple images. Multiple common targets involved object co-segmentation problem, which is very common in reality, has been a new research hotspot recently. In this paper, an unsupervised object co-segmentation method for indefinite number of common targets is proposed. This method overcomes the inherent limitation of traditional proposal selection-based methods for multiple common targets involved images while retaining their original advantages for objects extracting. For each image, the proposed multi-search strategy extracts each target individually and an adaptive decision criterion is raised to give each candidate a reliable judgment automatically, i.e., target or non-target. The comparison experiments conducted on public data sets iCoseg, MSRC, and a more challenging data set Coseg-INCT demonstrate the superior performance of the proposed method.

Spatial adjacent bag of features with multiple superpixels for object segmentation and classification

In the paper we present a new Spatial Adjacent Bag of Features (SABOF) model, in which the spatial information is effectively integrated into the traditional BOF model to enhance the scene and object recognition performance. The SABOF model chooses the frequency of each keyword and the largest frequency of its neighboring pairs to construct the feature histogram. Using the feature histogram whose dimension is only twice larger than that of the original BOF model, the SABOF model drastically enhances the discrimination performance. Combining the Superpixel Adjacent Histogram (SAH) Fulkerson et al., 2009 [12] with multiple segmentations Pantofaru et al., 2008 [33] and Russell et al., 2006 [36], the SABOF method effectively deals with the segmentation and classification of objects with different sizes. Changing the segmentation scale parameter to obtain multiple superpixel segmentations and correspondingly adjusting the neighbor parameters of the SAH method multiple classifiers are trained so that, the SABOF method can fuse multiple results of these classifiers to obtain better classification performance than any single classifier. The superpixel-based conditional random field (CRF) is used to further improve the classification performance. The experimental results of scene classification and of object recognition and localization on classical data sets demonstrate the performance of the proposed model and algorithm.

Adaptive Optimal Shape Prior for Easy Interactive Object Segmentation

For interactive segmentation approaches, object segmentation in complicated background is cumbersome, and usually needs tedious interactions to refine the incomplete segmentations . In this paper, an adaptive optimal shape prior is proposed for easy interactive object segmentation. Different from the traditional shape priors which only provide loose constraint, our adaptive shape prior gives more accurate and individualized constraint by exploiting the shape information of incomplete segmentation. Moreover, by combining the non-rigid shape registration and a local shape consistency evaluation system presented in this paper, such adaptive optimal shape prior could be achieved automatically. Both of these contributions greatly lighten the burden on users and make interactive segmentation much easier. The comparison experiments on the newly-built TypShape dataset with the related algorithms have demonstrated good performance of the proposed algorithm.

Automatic image segmentation using salient key point extraction and star shape prior

Abstract In this paper, a new unsupervised segmentation method is proposed. The method integrates the star shape prior of the image object with salient point detection algorithm. In the proposed method, the Harris salient point detection is first applied to the color image to obtain the initial salient points. A regional contrast based saliency extraction method is then used to select rough object regions in the image. To restrict the distribution of salient points, an adaptive threshold segmentation is applied to the saliency map to get the saliency mask. And then the salient region points can be obtained by placing the saliency mask on the initial Harris salient points. In order to make sure the salient points which we get are inside the image object thus the star shape constraint can be applied to the graph cuts segmentation, the Affinity Propagation (AP) clustering is employed to find the salient key points among the salient region points. Finally, these salient key points are regarded as foreground seeds and the star shape prior is introduced to graph cuts segmentation framework to extract the foreground object. Extensive experiments and comparisons on public database are provided to demonstrate the good performance of the proposed method.

Iterative image segmentation with feature driven heuristic four-color labeling

A heuristic four color labeling method is proposed to give robust initial foul-phase partition for Multiphase Multiple Piecewise Constant (MMPC) model.A regional adjacency cracking method is proposed to remove unnecessary adjacency constraints which impede the four color labeling.Compared with the random four color labeling, the color map of heuristic coloring shows better consistency for the homogenous regions.The heuristic four color labeling based approach reaches the good or even better segmentation with fewer iterations. Multilabel segmentation is an important research branch in image segmentation field. In our previous work, Multiphase Multiple Piecewise Constant and Geodesic Active Contour (MMPC-GAC) model was proposed, which can effectively describe multiple objects and background with intensity inhomogeneity. It can be approximately solved with Multiple Layer Graph (MLG) methods. To make the optimization more efficient and limit the approximate error, four-color labeling theorem was further introduced which can limit the MLG within three layers (representing four phases). However, the adopted random four-color labeling method usually provides chaotic color maps with obvious inhomogeneity for those semantic consistent regions. For this case, a new and alternative method named heuristic four-color labeling is proposed in this paper, which aims to generate more reasonable color maps with a global view of the whole image. And compared with the random four-color labeling strategy, the whole iterative algorithm based on our method usually produces better segmentations with faster convergence, particularly for images with clutters and complicated structures. This strategy is a good substitute for random coloring method when the latter produces unsatisfactory messy segmentation. Experiments conducted on public dataset demonstrate the effectiveness of the proposed method.

Multivideo Object Cosegmentation for Irrelevant Frames Involved Videos

Even though there have been a large amount of previous work on video segmentation techniques, it is still a challenging task to extract the video objects accurately without interactions, especially for those videos which contain irrelevant frames (frames containing no common targets). In this essay, a novel multivideo object cosegmentation method is raised to cosegment common or similar objects of relevant frames in different videos, which includes three steps: 1) object proposal generation and clustering within each video; 2) weighted graph construction and common objects selection; and 3) irrelevant frames detection and pixel-level segmentation refinement. We apply our method on challenging datasets and exhaustive comparison experiments demonstrate the effectiveness of the proposed method.

Image Co-segmentation by Co-diffusion

AbstractIn this paper, a co-segmentation algorithm based on 3D heat diffusion named co-diffusion is proposed. The image set is considered as a metal cuboid, and the K heat sources with constant temperature, which maximize the sum of the temperature of the system under anisotropic heat diffusion, are found to cluster the image set. The co-diffusion co-segmentation is an intuitive extension of the diffusion segmentation in Kim et al. (Proceedings of ICCV, 2011) while the performance is greatly improved. Comparatively, the proposed algorithm advances in the following three aspects: (1) The proposed algorithm can obtain better optimization because the heat diffusion is directly solved in 3D image set space, while the algorithm in Kim et al. (2011) deals with many independent 2D heat diffusions and solves the optimization by approximate belief propagation. (2) The marginal gain of every candidate heat source is globally determined in the image set, which can effectively compensate the wrong segmentations caused by the locality of the 2D image diffusion (Kim et al. 2011). (3) The K heat sources are chosen in image set while the algorithm (Kim et al. 2011) appoints mandatory K heat sources to each image in set, which will inevitably cause wrong segmentations for some images. The superiority of the proposed co-diffusion segmentation method is examined and demonstrated through a large number of experiments by using some typical datasets.

Automatic Shape Constraint Selection Based Object Segmentation

In this paper, an object segmentation algorithm based on automatic shape constraint selection is proposed. Different from the traditional shape prior based object segmentation methods which only provide loose shape constraints, our proposed object segmentation gives more accurate shape constraint by selecting the most appropriate shape among the standard shape set. Furthermore, to overcome the inevitable differences between the true borders and the standard shapes, the Coherent Point Drift (CPD) is adopted to project the standard shapes to the local ones. A quantitative evaluating mechanism is introduced to pick out the most suitable shape prior. The proposed algorithm mainly consists of four steps: 1) the initial GrabCut segmentation; 2) standard shape projection by CPD registration; 3) rank the standard shapes according to the evaluation scores; 4) refine GrabCut segmentation with the chosen shape constraint. The comparison experiments with the related algorithms on Weizmann_horse dataset have demonstrated the good performance of the proposed algorithm.