ABSTRACT
Existing classification methods tend not to work well on various error diffusion patterns. Thus a novel classification method for halftone image via statistics matrices is proposed. The statistics matrix descriptor of halftone image is constructed according to the characteristic of error diffusion filters. On this basis, an extraction algorithm is developed based on halftone image patches. The feature modeling is formulated as an optimization problem and then a gradient descent method is used to seek optimum class feature matrices by minimizing the total square error. A maximum likelihood method is proposed according to priori knowledge of training samples. In experiments, the performance evaluation method is provided and comparisons of performance between our method and seven similar methods are made. Then, the influence of parameters, performance under various attacks, computational time complexity and the limitations are discussed. From our experimental study, it is observed that our method has lower classification error rate when compared with other similar methods. In addition, it is robust against usual attacks.
Subject(s)
Color , Computer Graphics , Image Enhancement/methods , Image Interpretation, Computer-Assisted/methods , Models, Statistical , Signal Processing, Computer-Assisted , Algorithms , Computer Simulation , Models, Biological , Numerical Analysis, Computer-Assisted , Reproducibility of Results , Sensitivity and SpecificityABSTRACT
<p><b>OBJECTIVE</b>To study the methods and therapeutic effect of repairing deformity of nasal columella and tip by anastomosing its blood vessels with those of the great/second toe web flap.</p><p><b>METHODS</b>The donor site was the great/second toe web flap. Sewing the great/second toe web flap and nasal columella and tip together by using 5-0 silk thread, anatomizing facial artery and facial vein for three centimeters long behind submaximal, protecting lower jaw branch of facial nerve, separating a subcutaneous layer tunnel between nasal columella and one of facial artery and facial vein behind submaximal. Dorsal artery of foot, saphenous vein in the flap were anastomosed with the facial artery and facial vein behind submaximal through the tunnel under the subcutaneous layer.</p><p><b>RESULTS</b>All flaps survived, satisfactory therapeutic effect was obtained. Postoperative follow-up was 0.5-1 year. The reconstructed columella showed satisfactory contour, good texture and color, and good resistance to injury.</p><p><b>CONCLUSIONS</b>Great/second toe web flap is a ideal skin flap for repairing deformity of nasal columella and tip.</p>
