将传统光学显微镜和CCD、计算机相结合，实现对标本的无损显微观察。在介绍系统硬件组成的同时，着重说明了图像清晰度评价与图片重建的核心算法，并用VC++加以验证和实现。清晰度评价函数采用自行设计的类灰度方差算法，即采用图像的灰度值方差作为图像的清晰度。无损显微分析仪通过精密位置控制机械结构上下移动载物台，采集样本和显微物镜在不同距离时的多幅局部清晰的图像，通过清晰度评价算法找到满足清晰度要求的局部图像，再对多个清晰的局部图像进行合成，得到清晰的整体图像。

A CCD, a computer and a traditional microscope are combined to realize the non-destructive microscope observation of specimens. The hardware and the software of the system are introduced, with focus on the assessment of image definition and the key algorithm of image reconstruction, and VC++ program is used to validate and implement. The definition evaluation function is specified by gray variance algorithm, and the definition of the image is indicated by gray variance. The non-destructive analysis instrument collects a lot of images of the specimen in different distances by moving the plate controlled by accurate mechanism. It finds the clear parts of the image by using definition evaluation function, and synthesizes them into a complete clear image.