公开(公告)号：EP3264361A1

公开(公告)日：2018-01-03

申请号：EP16748536.6

申请日：2016-01-05

Applicant: BYD Company Limited

Inventor： ZHENG, Li ,  XU, Kunping ,  YANG, Yun

IPC: G06T7/00

CPC classification number: G06K9/0008 ,  G01B11/14 ,  G06T5/002 ,  G06T7/13 ,  G06T7/60 ,  G06T7/73 ,  G06T2207/20021 ,  G06T2207/30196

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 and 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.

Abstract translation: 本公开公开了一种计算行距的方法和装置。 该方法包括：获取原始图像并进行灰度处理生成灰度图像; 根据灰度图像生成基础图像和切向图像; 根据所述切向图像对所述灰度图像执行滤波以生成平滑图像并将所述平滑图像转换为二值图像; 将所述二值图像分块，根据所述径向图确定各个块的中心点的径向方向; 遍历每个块的中心点的自由基方向上的像素，以计算每个块内的两个相邻像素的像素值在第一像素值和第二像素值之间改变的次数，并且计算坐标和子像素 与变化点对应的边界点的值; 根据所述变化次数以及与所述变化点对应的边界点的坐标和子像素值生成所述线距离。 该方法通过寻找指纹棱线和指纹谷线的边界点，根据边界点的坐标和子像素值计算出行距，提高了准确性，增强了抵抗噪声的能力。