Abstract: The concept of force field to describe intermolecular interaction in physics is adapted to image processing.Ima-ge force field is designed as taking pixels for particles and grey scale for mass.The force field of an image models the discrete information of the image in a more intuitive way and is shown to be isomorphic to the image itself.Based on the image force field,an image copy detection algorithm called Clock algorithm was presented.In Clock algorithm,features of an image force field map are represented by three lines with the same endpoint like hour,minute and second hands of a clock,hence its name.The Clock algorithm was tested with images in an image database.The experiment results show that it can detect both noise-like distortions and geometric distortions with very high accuracy.In addition,the type and intensity of the distortion can also be determined,maintaining high rate at both recall and precision ratio in the same time.

Key words: Image copy detection algorithm,Content-based copy detection,Force field,Noise and geometric distortion,Molecular computing