生物光学显微镜对生物细胞(组织)厚样本成像时，由于受衍射和散焦成份的共同影响，成像分辨率明显下降。数字共焦显微技术通过三维图像复原方法可以提高图像分辨率。提出了分辨率劣化比和分辨率改善比的指标，并设计了一个包含相互间不同横向和轴向间距的光点和线条的仿真厚样本，采用半峰全宽(FWHM)，对仿真的生物光学显微镜薄样本衍射成像、叠加散焦成份的厚样本成像和数字共焦显微技术复原图像的分辨率进行测定和评价。研究结果表明，数字共焦显微技术具有很高的分辨率改善比，可以有效地恢复厚样本横向和轴向分辨率。

When biological cells or tissue thick specimens are imaged by bio-optical microscopy, image resolution decreased significantly due to the impact of diffraction and defocus. Digital confocal microscopy can improve the image resolution through a three-dimensional image restoration method. The criterions of resolution degradation ratio and resolution improvement ratio are proposed, and a simulation-thick specimen is designed with different lateral and axial spacing of optical points and lines. The full width at half-maximam is used for measurement, evaluation and analysis in the image resolution of thin specimen diffraction imaging, thick specimen imaging containing out-of-focus ingredients, and image by restored digital confocal microscopy. The results show that the digital confocal microscopy has high resolution improve ratio, and can restore lateral and axial resolution of thick specimen effectively.