Detection of Changed Symbol Images Based on Revised Histogram Invariant Moments

As the Hu’s invariant moments cannot deal with the changed gray during detecting changed image, a revised histogram invariant moment’s algorithm is put forward based on the histogram invariant moments. The invariant moments of image histogram filtered is calculated and revised with the related coefficient of the two images. Two symbol images, a reference image and an aim image, are tested to detect the change. The experiment shows that the method can resist the effect of the brightness and the contrast change of images.