Abstract: The threshoding method based on moment preserving (MP) is a simple and effective image segmentation method.However there are some drawbacks,such as over and under thresholding.This paper presents an image thresholding method based on combing the discrete cosine transform (DCT) and moment preserving.Firstly,the rough threshold of MP is analyzed to obtain the condition of thepossible problems in order to decide the improved ways.Then,DCT coefficients oftheimage histogram are calculated through DCT.Since the low-frequency coefficients can reflect the ensemble,the sum of a few of them is used as an modifying amplitude.Finally,comparison of the first order moment and the rough threshold istaken for an modifying direction to modify the rough threshold adaptively.Experimental results show that the proposed method can not only get better segmentation result and better generalization,but also maintain the high speed of MP.

Key words: image segmentation, thresholding, moment preserving principle (MPP), discrete cosine transform (DCT), histogram