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2 results about "Otsu's method" patented technology
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In computer vision and image processing, Otsu's method, named after Nobuyuki Otsu (大津展之 Ōtsu Nobuyuki), is used to perform automatic image thresholding. In the simplest form, the algorithm returns a single intensity threshold that separate pixels into two classes, foreground and background. This threshold is determined by minimizing intra-class intensity variance, or equivalently, by maximizing inter-class variance. Otsu's method is a one-dimensional discrete analog of Fisher's Discriminant Analysis, is related to Jenks optimization method, and is equivalent to a globally optimal k-means performed on the intensity histogram. The extension to multi-level thresholding was described in the original paper, and computationally efficient implementations have since been proposed.
Real-time comprehensive quality evaluation method and adaptive optical parameter adjustment system for outdoor iris recognition scene
This invention relates to outdoor iris image processing technology, providing a real-time comprehensive quality assessment method and an adaptive optical parameter adjustment system. The assessment method includes: locating the eye boundary based on grayscale projection and local normalization; generating dual thresholds using an improved Otsu algorithm and dynamic grayscale subspace search; calculating a sharpness index based on second-order gradient entropy change; locating the pupil through a reliable edge point fitting mechanism, detecting the outer circle of the iris using an improved integral-differential operator, and evaluating segmentation accuracy using the ratio of the local standard deviation of the edge to the standard deviation of the target region; fusing gradient fitting and grayscale distribution to achieve eyelid and eyelash detection; and finally outputting a quality score based on 18 weighted indicators. The optical adjustment system senses the environment and initializes optical parameters, dynamically adjusting parameters based on weighted voting from multiple frames of images, and achieving rapid convergence with environmental consistency verification. This invention improves the speed and stability of pupil localization, sharpness assessment, eyelash detection, and illumination adjustment in low-computing-power scenarios.
Owner:HUAZHONG UNIV OF SCI & TECH
Anti-intermittent sampling interference method based on Otsu's method of random orthogonal subpulses
This invention discloses a method for combating intermittent sampling interference based on Otsu's method for random orthogonal subpulses. The method includes: establishing intra-pulse and inter-pulse randomly coded orthogonal frequency modulated waveform models; encoding and orthogonally frequency modulating intra-pulse and inter-pulse subpulses to obtain compressed subpulses; obtaining the inter-class variance of the compressed subpulses according to a multi-level Otsu algorithm; obtaining an optimal threshold based on the inter-class variance of the compressed subpulses; and determining the difference between the target signal and three types of intermittent sampling interference signals based on the optimal threshold. This invention can improve the accuracy of identifying and distinguishing the target signal and the three types of intermittent sampling forwarding interference signals, effectively combating intermittent sampling forwarding interference.
Owner:SUN YAT SEN UNIVERSITY SHENZHEN +1