CIRCULAR OBJECT MATTER DETECTING DEVICE

摘要

PURPOSE:To provide a circular object matter detecting device whose position detecting accuracy of a circular object matter is not affected by the image noises. CONSTITUTION:In regard of an image for which the position of a circular object matter should be detected, an inner circular window 21 and an outer circular window 22 are arranged in a circular window diameter 14 approximately equal to the diameter of the image of the circular object matter. Then the plural windows 17a-17h consisting of plural measuring points having the coefficients of different + or - signs are set at the prescribed positions of both windows 21 and 22 respectively. Then a circular window 20 to scan the images together with a correlative value calculation means which obtains the sum total of products of the coefficients and the image density at each measuring point of plural windows as the correlative value between the circular object matter and the window 20 at each scanning position, and a maximum correlative value position detector means which detects a scanning position with the absolute correlative value maximized as the position of the circular object matter are provided.