Method and apparatus for measuring rotation characteristics of rotating body

摘要

Disclosed are a method and apparatus for measuring rotation characteristics such as rotation rate, rotation axis, and rotation angle of a rotating body. A method of measuring rotation characteristics includes extracting a rotating-body region from an image of the rotating body; extracting a surface pattern of the rotating body on the basis of brightness values of the extracted rotating-body region and acquiring rotation characteristics of the rotating body on the basis of change in the extracted surface pattern. Accordingly, it is possible to accurately measure rotation characteristics regardless of variation in brightness values of a surface region of the rotating body depending on illumination of a lamp, sensitivity of a camera, and exposure time of a camera.

主权项

1. A method of measuring rotation characteristics, the method comprising:
extracting a rotating-body region from an image of a rotating body; extracting a surface pattern of the rotating body on the basis of brightness values of pixels included in the extracted rotating-body region; and acquiring rotation characteristics of the rotating body on the basis of change in the extracted surface pattern, wherein the extracting of the surface pattern comprises:
normalizing a brightness range of the rotating-body region on the basis of a minimum brightness value and a maximum brightness value among the brightness values of the pixels included in the extracted rotating-body region;creating an integration image by adding brightness values of pixels included in a certain portion of the normalized rotating-body region; andextracting the surface pattern of the rotating body on the basis of the integration image,wherein the integration image for the certain portion has a value D(x1, y1, x2, y2) that is calculated using the following equations:D⁡(x1,y1,x2,y2)=I⁡(x2,y2)-I⁡(x2,y1-1)-I⁡(x1-1,y2)+I⁢(x1-1,y1-1),⁢⁢a⁢⁢n⁢⁢d⁢⁢I⁡(x,y)=∑u=x0x⁢∑v=y0y⁢G⁡(u,v), wherein G (u, v) is a brightness value of a pixel located at coordinate (u, v), I(x, y) is a value obtained by adding brightness values of all pixels located in a region from coordinate (x0, y0) to coordinate (x, y), coordinate (x0, y0) is a coordinate of a specific point outside a surface region of the rotating body, and the certain portion is defined by coordinate (x1, y1) and coordinate (x2, y2).