公开(公告)号：US20180018497A1

公开(公告)日：2018-01-18

申请号：US15548688

申请日：2016-01-05

Applicant: BYD COMPANY LIMITED

Inventor： Li ZHENG ,  Kunping XU ,  Yun YANG

IPC: G06K9/00 ,  G06T7/60 ,  G06T5/00 ,  G01B11/14

Abstract: The present disclosure discloses a method and device for calculating a line distance. The method includes: obtaining an original image and performing grayscale processing to generate a grayscale image; generating a radical image and a tangential image according to the grayscale image; performing filtering on the grayscale image according to the tangential image to generate a smoothened image and converting the smoothened image into a binary image; dividing the binary image into blocks acid determining a radical direction of a center point of each block according to the radical image; traversing pixels in the radical direction of the center point of each block to calculate a number of times pixel values of two adjacent pixels within the each block change between a first pixel value and a second pixel value, and to calculate a coordinate and sub-pixel value of a boundary point corresponding to a changing-point; and generating the line distance according to the number of times of the change, and the coordinate and the sub-pixel value of the boundary point corresponding to the changing-point. The method seeks the boundary point of the fingerprint ridge lines and the fingerprint valley lines and calculates the line distance according to the coordinates and the sub-pixel value of the boundary point, improving accuracy, strengthening the ability to resist noise