LOCATING METHOD, LOCATING DEVICE, DEPTH DETERMINING METHOD AND DEPTH DETERMINING DEVICE OF OPERATING BODY

A locating method, a locating device, a depth determining method, and a depth determining device of an operating body are provided. The locating method includes following steps: deriving an image that includes an operating body; scanning the image transversely according to each of scan lines of the image, and deriving each of width values of the operating body in each of the scan lines according to the bright dot information in each of the scan lines of the image; calculating a relative variation level between each of the width values in the adjacent scan line sequentially; when the relative variation level is less than a threshold, determining a locating point of the operating body according to one of the scan lines and one of the width values corresponding to the relative variation level.