Patent ID: 7035430

Claim:
An object detection method for detecting an object present in an image obtained from an imaging device by comparing at least two images, comprising the steps of: generating a first comparison image representing a result of comparison made between a first input image from said imaging device and a reference image stored in a storage device; threshold-processing said first comparison image using a predetermined threshold value, changing said threshold value until a noise level of said threshold-processed image becomes not greater than a predetermined value and setting the threshold value with which the noise level of said threshold-processed image becomes not greater than the predetermined value, as a first threshold value; generating a second comparison image which represents a result of comparison made between a second input image including an object from said imaging device and said reference image stored in said storage device; threshold-processing said second comparison image using a predetermined threshold, changing said threshold until the size of the object in the threshold-processed image becomes not greater than a predetermined value and setting the threshold value with which the size of said object in said threshold-processed image becomes not greater than the predetermined value, as a second threshold value; setting a third threshold value within a range including said first and second threshold values and detecting an object based on said third threshold value.