Abstract: In consideration of gray level characteristics of SAR images, a new contrast enhancement method based on the Minimum Fuzzy Offset（MFO） principle is proposed. The Gaussian membership function is adopted, and the Fuzzy Contrast Intensification（INT） operator is settled based on the MFO principle. Then it obtains the adaptive S-shape transformation function for image enhancement, which is capable of expanding the value of the medium gray-level range in the image, suppressing speckle noise, and increasing target brightness. The Tenengrad（TEN） principle  and Measure of Enhancement（EME） are used to evaluate the quality of the algorithm.

Key words: SAR image, contrast enhancement, membership function, fuzzy offset

摘要： 针对SAR图像灰度特性，提出最小模糊偏移自动对比度增强算法（MFO）。该算法基于模糊理论，利用高斯型隶属度函数将图像灰度信息模糊化，以模糊偏移度最小准则确定模糊对比度增强操作数（INT），得到该准则下最优的S形灰度映射函数，增强SAR图像对比度。利用TEN、EME两种评估参数评价增强结果，验证了算法的有效性。

关键词: SAR图像, 对比度增强, 隶属度函数, 模糊偏移度