Jaferzadeh Keyvan, Gholami Samaneh, Moon Inkyu
Appl Opt. 2016 Dec 20;55(36):10409-10416. doi: 10.1364/AO.55.010409.
In this paper, we evaluate lossless and lossy compression techniques to compress quantitative phase images of red blood cells (RBCs) obtained by an off-axis digital holographic microscopy (DHM). The RBC phase images are numerically reconstructed from their digital holograms and are stored in 16-bit unsigned integer format. In the case of lossless compression, predictive coding of JPEG lossless (JPEG-LS), JPEG2000, and JP3D are evaluated, and compression ratio (CR) and complexity (compression time) are compared against each other. It turns out that JP2k can outperform other methods by having the best CR. In the lossy case, JP2k and JP3D with different CRs are examined. Because some data is lost in a lossy way, the degradation level is measured by comparing different morphological and biochemical parameters of RBC before and after compression. Morphological parameters are volume, surface area, RBC diameter, sphericity index, and the biochemical cell parameter is mean corpuscular hemoglobin (MCH). Experimental results show that JP2k outperforms JP3D not only in terms of mean square error (MSE) when CR increases, but also in compression time in the lossy compression way. In addition, our compression results with both algorithms demonstrate that with high CR values the three-dimensional profile of RBC can be preserved and morphological and biochemical parameters can still be within the range of reported values.
在本文中，我们评估了无损和有损压缩技术，以压缩通过离轴数字全息显微镜（DHM）获得的红细胞（RBC）定量相位图像。红细胞相位图像从其数字全息图进行数值重建，并以16位无符号整数格式存储。在无损压缩的情况下，评估了JPEG无损（JPEG-LS）、JPEG2000和JP3D的预测编码，并相互比较了压缩率（CR）和复杂度（压缩时间）。结果表明，JP2k通过具有最佳的压缩率可以胜过其他方法。在有损情况下，研究了具有不同压缩率的JP2k和JP3D。由于一些数据以有损方式丢失，通过比较压缩前后红细胞的不同形态和生化参数来测量降解水平。形态参数包括体积、表面积、红细胞直径、球形指数，生化细胞参数是平均红细胞血红蛋白（MCH）。实验结果表明，在有损压缩方式下，JP2k不仅在压缩率增加时的均方误差（MSE）方面优于JP3D，而且在压缩时间方面也更优。此外，我们使用这两种算法的压缩结果表明，在高压缩率值下，红细胞的三维轮廓可以保留，形态和生化参数仍可在报告值范围内。
