Abstract：Equalization algorithm can effectively reduce the correlation between ultrasonic image samples; improve the performance of despeckling methods. But acquiring equalization filter parameters based on in vivo images requires a large amount of calculation which is not conducive to realtime processing. Aiming at superficial ultrasonic images, this paper gives an effective equalization method that avoids lots of realtime calculation. Based on the ultrasonic RF imaging formation model, this paper analyzed the spectrum of ultrasonic phantom echo signals, filtered the spectral component of the tissue reflectivity function, obtained the pointspread function and constructed the equalization filter to analyze its effect for superficial images. With the parameters acquired from the phantom the equalization filter used for superficial ultrasonic images can reduce the correlation. Compared with direct despeckling methods, the speckle SNR of preprocessed de-speckling methods has been improved about 19.2%, the performance of de-speckling methods gets improved. For superficial ultrasonic images, parameters of equalization filter can be acquired through ultrasound phantom in advance，it can reduce the calculation of despeckling process and easy to realize realtime processing.
［1］李敏，张自友，卢林菊. 基于形态Haar小波的SAR图像斑点噪声抑制方法 ［J］. 计算机应用,2012, 32(3):746-748.
［2］冯若，刘忠齐，姚锦钟,等.超声诊断设备原理与设计 ［M］.北京:中国医药科技出版社,1993.
［3］侯涛. 医学超声图像斑点噪声去除的研究 ［D］.上海: 复旦大学，2011.
［4］姜三平. 基于小波变换的图像降噪 ［M］. 北京：国防工业出版社,2009:94-95.
［5］Iraca D, Landini L, Verrazzani L. Power spectrum equalization for ultrasonic image restoration ［J］. IEEE Trans Ultrason Ferroelect Freq Contr, 1989,32: 216-222.
［6］Michailovich O, Tannenbaum A. Despcckling of medical ultrasound images ［J］. IEEE Trans Ultrason Ferroelect Freq Contr, 2006,53(1): 64-78.
［7］Michailovich O, Adam D. A novel approach to the 2-D blind in medical ultrasound ［J］. IEEE Trans Med Imag, 2005,24(1): 86-94.
［8］Georgiou G, Cohen F. Statistical characterization of diffuse scattering in ultrasound images ［J］. IEEE Ultrasoun Ferroelect, 1998,45:57-64.
［9］于黎耘，白净，杨福生. 超声回波信号的解卷 ［J］. 国外医学生物医学工程分册,1993,16(3):125-128.
［10］Jensen JA, Leeman S. Nonparametric estimation of ultrasound pulses ［J］. IEEE Trans Biomed Eng, 1994, 41:929-936.
［11］Michailovich O, Adam D. Robust estimation of ultrasound pulses using outlierresistant denoising ［J］. IEEE Trans Med Imag, 2003, 22: 368-392.
