微光像增强器是微光成像系统的核心部分，其成像质量决定了对微弱光学信号的探测能力。像增强器的调制传递函数（ modulation transfer function，MTF）反映了系统对图像不同频率成分的传递能力，是像质评定的一种客观指标。本文基于狭缝法测试 MTF的原理，进行系统校准和采用分段加权最小二乘拟合实现曲线的平滑去噪，构建了微光像增强器的 MTF测试系统。具体是采用十字狭缝靶标进行测试得到线扩散函数（line spread function，LSF）曲线，然后对其进行去噪处理和离散傅里叶变换得到 MTF曲线，测试结果与德国 OEG-2MTF测试仪比较，误差率低于 5%，为研制高成像质量微光像增强器提供了一种有效评价手段。

A low-light image intensifier is a core part of low-light imaging systems, and the imaging quality of the intensifier determines the ability of the imaging system to detect weak optical signals. The modulation transfer function (MTF) of an image intensifier measures the ability of the imaging system to transmit image components of different frequencies and is an objective indicator of image quality evaluation. In this study, we adopted the slit method to test the MTF, calibrated the system, adopted the segmentation weighted least squares method to achieve the denoising of the curve, and constructed the MTF testing system. In particular, we obtained the line spread function (LSF) curve by testing the cross-slit target, and we processed it using denoising and discrete Fourier transform to achieve the MTF curve. The result was verified using the German OEG-2 and the error rate was found to be less than 5%. Therefore, it is concluded that the MTF is an effective evaluation method to develop high-quality low-light image intensifiers.