Phase diagram evolution at finite coupling in strong coupling lattice QCD

We investigate the chiral phase transition in the strong coupling lattice QCD at finite temperature and density with finite coupling effects. We adopt one species of staggered fermion, and develop an analytic formulation based on strong coupling and cluster expansions. We derive the effective potential as a function of two order parameters, the chiral condensate sigma and the quark number density $\rho_q$, in a self-consistent treatment of the next-to-leading order (NLO) effective action terms. NLO contributions lead to modifications of quark mass, chemical potential and the quark wave function renormalization factor. While the ratio mu_c(T=0)/Tc(mu=0) is too small in the strong coupling limit, it is found to increase as beta=2Nc/g^2 increases. The critical point is found to move in the lower T direction as beta increases. Since the vector interaction induced by $\rho_q$ is shown to grow as beta, the present trend is consistent with the results in Nambu-Jona-Lasinio models. The interplay between two order parameters leads to the existence of partially chiral restored matter, where effective chemical potential is automatically adjusted to the quark excitation energy.Comment: 17 pages, 9 figure

Polyakov loop effects on the phase diagram in strong-coupling lattice QCD

We investigate the Polyakov loop effects on the QCD phase diagram by using the strong-coupling (1/g^2) expansion of the lattice QCD (SC-LQCD) with one species of unrooted staggered quark, including O}(1/g^4) effects. We take account of the effects of Polyakov loop fluctuations in Weiss mean-field approximation (MFA), and compare the results with those in the Haar-measure MFA (no fluctuation from the mean-field). The Polyakov loops strongly suppress the chiral transition temperature in the second-order/crossover region at small chemical potential, while they give a minor modification of the first-order phase boundary at larger chemical potential. The Polyakov loops also account for a drastic increase of the interaction measure near the chiral phase transition. The chiral and Polyakov loop susceptibilities have their peaks close to each other in the second-order/crossover region. In particular in Weiss MFA, there is no indication of the separated deconfinement transition boundary from the chiral phase boundary at any chemical potential. We discuss the interplay between the chiral and deconfinement dynamics via the bare quark mass dependence of susceptibilities.Comment: 17 pages, 17 figure

Image segmentation and object extraction based on geometric features of regions

We propose a method for segmenting a color image into object-regions each of which corresponds to the projected region of each object in the scene onto an image plane. In conventional segmentation methods, it is not easy to extract an object-region as one region. Our proposed method uses geometric features of regions. At first, the image is segmented into small regions. Next, the geometric features such as inclusion, area ratio, smoothness, and continuity, are calculated for each region. Then the regions are merged together based on the geometric features. This merging enables us to obtain an object-region even if the surface of the object is textured with a variety of reflectances; this isn't taken into account in conventional segmentation methods. We show experimental results demonstrating the effectiveness of the proposed method

Correcting distortion of image by image registration

Fifth Asian Conference on Computer Vision (ACCV2002), Slide ; Place : Melbourne, Australia ; Date : January 22-25, 200

Correcting distortion of image by image registration with the implicit function theorem

We propose a method for correcting image distortion due to camera lenses by calibrating intrinsic camera parameters. The proposed method is based on image registration and doesn't require point-to-point correspondence. Parameters of three successive transfor-mations –view change, radial distortion and illumination change– are estimated using the Gauss-Newton method. Estimating all 19 unknowns simultaneously, we introduce the implicit function theorem for calculating the Jacobian. To avoid local minima, we first estimate parameters for view change and employ coarse-to-fine minimization. Experimental results using real images demonstrate the robustness and the usefulness of the proposed method

Unified approach to image distortion

We propose a new unified approach to deal with two formulations of image distortion and a method for estimating the distortion parameters by using the both formulation. Although all of conventional researches are based on the same distortion model proposed in an early study in photogrammetry, two different formulations have been used and developed by different papers separately, and this has caused a confusion for developing calibration methods. The proposed method is based on image registration and consists of nonlinear optimization to estimate parameters including view change and radial distortion.16th International Conference on Pattern Recognition, poster ; Place : Quebec, Canada ; Date : 11-15 August, 200

Extracting human limb region using optical flow and nonlinear optimization

Fifth Asian Conference on Computer Vision (ACCV2002), Poster ; Place : Melbourne, Australia ; Date : January 22-25, 200