IMAGE POSITION DETECTING DEVICE

An image position detecting device for detecting relative positions of images of an object on a pair of image sensors. A pair of image data groups are derived from the pair of image sensors. The image position detecting device includes window-size designating means, correlative value calculating means, and highest-correlation detecting means. The window-size designating means determines the number of data to be contained in windows, which define partial data groups from the image data groups depending on an optical parameter of the optical instrument. The correlative value calculating means calculates a correlative value representing the correlation between a pair of partial data groups defined by the windows. The highest-correlation detecting means detects the combination of the partial data groups with a correlative value which represents the highest correlation, and changes the combination of the partial data groups by successively displacing the windows for both the image data groups. With such an arrangement, an index is obtained from the positions of the windows for the combination of the partial data groups with the highest correlation to indicate the relative positions of the images on the pair of image sensors.