关键词: 小波变换, 模极大值去噪, 交替投影法

Abstract: Aiming at the high cost of the AP algorithm’s computation in the signal processing ，an improved method has been proposed in this paper.Firstly the modulus maximum of the signal is calculated by the Ad hoc algorithm in the improved method，then the signal estimated coefficients of wavelet can be obtained from the parabola’s inserted value of subsection between the points of modulus maximum，finally the purpose of denoising can be achieved by the signal reconstruction based on these coefficients.The simulation results show that the method can filter noises effectively and the principle of the method is more simple and which makes the program can be completed more easily and the speed of denoising is higher and the method is more practical compared with AP algorithm，especially more convenient to realize it by hardware.

Key words: wavelet transform, denoising of modulus maximum, Alternating Projection（AP） algorithm