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Transcript: Computational performance: (orders of magnitude relatively to HY) QUESTION: Can we extract the number of distinct motion models from a dense flow field? The correlated histogram and the decay ratio of the normalized entropy weight vector Videos: Temporal contribution Outline of presentation Refining: Decomposes the flow field into a set of clusters that represent different motion (affine) models. 1. The Polar representation makes the data more distributed over space which facilitates the analysis. 2. Initial partitioning of the flow field into a set of non-overlapping clusters: LSQ computes of the affine model for each cluster using samples; MOTIVATION Motion perception plays an important role on human daily interactions: drive or walk in a street. Infers about the intrinsic motion features of elements in a scene and based on the visual field. Direction and Speed of moving objects are the most critical skills: Indications of danger Visual motion perception can be divided into: Detection, Measurement and Cognitive. Techniques for motion perception are related to the movement of the observer: stationary observation; moving observation. Architecture for visual motion perception: ARCHITECTURE 3D Median filter The static perception mode detects and extracts motion information based on conventional motion analysis techniques (background subtraction). The dynamic perception mode extracts and analyze motion information when the robot is moving along the rail and based on dense flow fields. The research Wise Optical Flow Segmentation (WOFS) Main properties: Pixel-wise method formed by two phases: Evaluating and Resetting; A guided-based segmentation; Extract and enhance the edges of the moving objects. F1-score: - geometric spatial closeness: Weights the distance between the focal pixel and each neighbor; Spatial coherence assumption - photometric similarity of the domain contribution: Measures the similarity intensity difference between the focal pixel and its neighbors, using robust techniques; - temporal range for the focal pixel at different time instants; Temporal coherence assumption - photometric similarity of the temporal contribution. The photometric similarities are computed using the weight function of M-estimators: RESULTS: Specific databases: http://vision.middlebury.edu/flow/eval/ http://visual.cs.ucl.ac.uk/pubs/flowConfidence/supp/ AAE (average angular error): frequency of values higher than a threshold [1]- A. Bruhn, J. Weickert and C. Schnorr. "Lucas/Kanade meets Horn/Schunk: combining local and global optical flow methods", International Journal of Computer Vision (IJCV), 61(3):211–231, 2005. Incorporating high level information in the optical flow estimation is advantageous: Mimics the human motion detection based on different layers of visual details; Focus on regions that have the most complex and relevant motions; Balance the computational efficiency and the accuracy of the flow field. Stages 3 and 4 are executed until convergence or a maximum number of iterations. Visual Motion Analysis based on a Robotic Moving System 3D Gaussian filter ratio of values higher than a threshold similarity distance Produce satisfactory estimations about the number of clusters: 18ms to compute; depends on the quality of the flow field (parallax, textureless regions,...); movement of persons has more than a single model. penalize the model complexity which discourages the overfitting Log-Likelihood: using k-means for efficiency. Normalized entropy: using the log-likelihood. Conventional approach: model selection is the lowest NEC value. The model is overestimated in our situation. Decay ratio: model with higher confidence has the highest decay. I1 - Gaussian noise (STD = 50) I2 - Salt-Pepper noise (50%) K-means Detect and treat violations of the spatial and temporal coherence assumption Preventing the smoothing across motion boundaries; Denoise image sequences with low SNR Mahalanobis squared distance of samples RBLT filter GPU: NVidia GT750M 384 @ 967MHz CPU: Intel I7 2.2GHz Spatial contribution The majority of related works about motion detection and analysis resort to fixed cameras. Is a non-trivial research field and wide diversity of methods can be found: Temporal differencing; Background subtraction; Optical flow. Expectation: Extracts high level information about the sequence to guide the computation of the optical flow. Tree-based structure with split and merge procedures based on descriptive properties: Splitting: brightness gradient and absolute temporal derivative; Merging: spatial information, dominant color, absolute temporal derivative and gradient of brightness and texture. Division criteria is a discriminative function of 2 features: Publications Motion perception and analysis Motivation The objectives Vision-based robotic system Concept Architecture The research A spatiotemporal filtering Optical flow Motion Analysis Conclusion Future Work / Applications OBJECTIVES The big question: "How the robot

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Transcript: Direction of Arrival Estimation using MultiKernel Sparse Learning Method Guide : Dr.S M Shashidhara Presented by: Awab H Fakih ( 5VX15PEJ73 ) Abstract To develop the Multi kernel Sparse learning (MKSL) algorithm for Direction of Arrival estimation(DOAE) in antenna arrays. DOAE is carried out using multiple sparse learning techniques. Matlab based implementation is carried out and the outcome are compared with the previous literatures and the outcome are pronouncing better performance in the proposed work. Abstract The necessity of Direction Of Arrival (DOA) is important in many applications like the radar systems, wireless communication, radio astronomy, tracking moving objects, sonar etc[1]. The increasing over usage of the low end of the spectrum has lead the people to start discover the higher frequency band for these applications, where larger spectrums is available [1-3]. 5G communication which works with higher frequencies, higher data rate and higher user density, multipath fading and cross- interference become more serious issues, resulting in the degradation of bit error rate (BER). Signal processing aspects of smart antenna systems has lead to development of effective algorithms for Direction-of-Arrival (DOA) estimation and adaptive beam forming. Introduction The DOA estimation methods have reached newer heights by having different fast estimation methods and low energy consumption based methods introduced recently. Dynamic dictionary based methods for signal and image processing are popping up with the idea of early detection process which increases the speed of estimation and reduces the memory and processing time. The traditional DOA estimation is mainly divided into two classes. One is non-parameterized method including beam forming, Capon spatial spectrum estimation and subspace methods such as MUSIC and ESPRIT. These methods have some constrains in noise power and correlation between signal sources to achieve high precision. The other is parametric methods mainly including deterministic maximum likelihood estimation method and stochastic maximum likelihood estimation method. But they have some limitation on the initial value and convergence. Lit. Survey As a solution to the off-grid effect. The statistic information of covariance matrix under the uncorrelated sources condition is utilized and a simple sparse representation model is given. Then the cross iteration and series expansion approximation are introduced to update the dynamic dictionary. Compared with the conventional sparse representation method, it has better performance and lower computation complexity. Fast covariance matrix sparse representation for DOA estimation based on dynamic dictionary Tong Qian, Jin Zhi Xiang & Wei Cui 2016 IEEE 13th International Conference on Signal Processing (ICSP). This paper proposes a novel sparse representation method for direction of arrival estimation based on dynamic dictionary and negative exponent penalty. The dynamic dictionary can eliminate the off-grid effect and the negative exponent penalty is capable of strengthening the sparse constraint to improve the performance. The basis is regarded as a part of the optimal target and the cross iteration is utilized to jointly update the dictionary and sparse support in this method. Based on the propositions of the penalty function, the penalty function is designed to replace of ℓ1 norm because of its unbiasedness and stronger sparse constraint. The regularization parameter is simplified as a constant due to pre-white process, which greatly extends the application range of the proposed method. Sparse Reconstruction Method for DOA Estimation Based on Dynamic Dictionary and Negative Exponent Penalty Tong Qian, Wei Cui and Qing Shen Chinese Journal of Electronics ( Volume: 27, Issue: 2, 3 2018 ), 386 – 392. Vector-valued dictionary elements are formed for specific parameter values. A linear combination of a subset of dictionary elements is used to represent the model The dictionary elements are dynamically adjusted to improve parameter estimation performance. We examine the performance of both static and dynamic algorithms in terms of probability of correct model order selection and the root mean-squared error of parameter estimates. Dynamic Dictionary Algorithms for Model Order and Parameter Estimation C. D. Austin, J. N. Ash & R. L. Moses, IEEE Trans. Signal Process., vol. 61, no. 20, pp. 5117-5130, Oct 2013. Sparse signal priors help in a variety of modern signal processing tasks. For instance, sparse approximation of a signal with an overcomplete dictionary or reconstruction of a sparse signal from a small number of linear measurements. The reconstruction problem typically requires solving an ℓ1 norm minimization problem. We also discuss a case where these ideas can be extended to accommodate for more general changes in the system matrix. Sparse signal recovery and dynamic update of the underdetermined system M. Asif and J. Romberg, in Signals, The

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