体全息光学相关器基于体光栅的布拉格选择性，在记录介质的共同体积中利用角度复用存储多幅图像。相关计算时，输入一幅图像可以并行输出所有的相关点，每个相关点的强度代表输入图像与对应库图像之间的内积值。分析了提高体全息光学相关器运算精度和速度的关键技术。总结了近年来采用散斑调制技术降低相关通道串扰，采用二维随机交错方法消除图案依赖行为，采用多样本并行估计方法提高并行运算精度，采用读写分离结构实观系统小型化集成等体全息光学相关器技术方面的研究进展。目前体全息光学相关器已经实现超过7500通道的并行运算能力，运算速度达到138 GHz。系统在遥感图像匹配、指纹识别等领域的成功应用证明了其高速高精度运算能力。

The volume holographic correlator (VHC) can store multiple images in the common volume of the storage medium by angular multiplexing based on the Bragg selectivity of volume gratings. During the correlation, all the correlation results between the stored images and the input search argument can be simultaneously got. Each correlation result is represented by the intensity of the corresponding correlation spot. The key technologies and constraint factors of the practical utilization of the VHC are analyzed. The research progresses in suppressing the channel crosstalk by speckle modulation, eliminating the impact of pattern dependent behavior, improving the processing accuracy by multi-sample parallel estimation, and system integration of the read-only VHC are summarized. Parallel processing ability with more than 7500 channels and processing speed up to 138 GHz are achieved in the current portable VHC system. The successful applications in remote sensing image matching and biometric recognition have proved the high speed high accuracy abilities of the system.