Light-field fluorescence microscopy (LFM) is a powerful elegant compact method for long-term high-speed imaging of complex biological systems, such as neuron activities and rapid movements of organelles. LFM experiments typically generate terabytes of image data and require a substantial amount of storage space. Some lossy compression algorithms have been proposed recently with good compression performance. However, since the specimen usually only tolerates low-power density illumination for long-term imaging with low phototoxicity, the image signal-to-noise ratio (SNR) is relatively low, which will cause the loss of some efficient position or intensity information using such lossy compression algorithms. Here, we propose a phase-space continuity-enhanced bzip2 (PC-bzip2) lossless compression method for LFM data as a high-efficiency and open-source tool that combines graphics processing unit-based fast entropy judgment and multicore-CPU-based high-speed lossless compression. Our proposed method achieves almost 10% compression ratio improvement while keeping the capability of high-speed compression, compared with the original bzip2. We evaluated our method on fluorescence beads data and fluorescence staining cells data with different SNRs. Moreover, by introducing temporal continuity, our method shows the superior compression ratio on time series data of zebrafish blood vessels.

为实现包装盒纸质基底层和透明膜层缺陷的同步检测，开展了对纸和膜缺陷的同步成像研究。首先，分别建立了标准球面积分光场、椭球面积分光场和弧面积分光场模型，并利用COMSOL Multiphysics 5.6对3类光场进行射线仿真，对比分析了球面积分光场下射线角度均匀性及辐照均匀性，通过正交仿真优化椭球面积分光场参数；其次，在椭球面积分光场环境、亮场前打光环境、暗场前打光环境下对包装盒成像。与此同时，对包装盒的油污、抵触、开口、泡皱、破损5项常见缺陷依次进行物理检测和机器视觉检测，验证缺陷成像的有效性。试验结果表明，在椭球面积分光场下成像，图像对纸质基底层缺陷特征、透明膜层缺陷特征均有较好的呈现效果，图像上油污、抵触、开口、泡皱、破损的物理检出率分别为96.2%、92.5%、100%、95%、92%，异常检出率分别为98.6%、97.5%、100%、100%、98.4%，缺陷类别检出率分别为97.6%、96%、100%、97%、96%。研究结果表明，椭球面积分光场光路角度和辐照强度均匀，覆透明膜包装盒的缺陷特征呈现清晰，满足工业生产的检测要求。