针对远距离数字全息成像中波前畸变和散斑噪声对成像质量的影响，实验研究了基于图像指标优化的波前校正技术，以及基于孔径分割的多帧图像平均散斑噪声抑制方法。建立了数字离轴全息实验装置，针对系统自身像差，采用梯度下降算法，以图像清晰度为优化指标进行了波前校正实验；在此基础上通过孔径分割，重构出多帧散斑噪声分布各异的目标图像，进行平均运算。结果表明，基于图像清晰度优化的波前校正技术能够有效消除波前畸变，提高成像分辨率；采用基于孔径分割的多帧图像平均方法能够在一定程度上消除目标图像的散斑噪声，获得更高的成像质量。

Considering the wavefront aberration and speckle noises in long distance digital holography, the wavefront correction based on image metric optimization and speckle noise reduction based on multi-image averaging are studied, in which the multi-images are generated with aperture dividing technique. A digital off-axis holography experimental setup is established, and the wavefront aberration correction experiments are performed, in which the gradient descent algorithm is used to optimize the image sharpness metric. Multi-images with different speckle noises are reconstructed by dividing aperture into certain small parts, and average operation is performed among those multi images. The results show that the image resolution is improved effectively while the aberration is corrected with image metric optimization method, and a higher quality image is obtained after multi-images averaging.