Optical Microscopy Imaging And Its Application In Bio-sample Display And Measurement

To a great degree, the breakthrough in the field of life science depends on various novel and powerful measurement systems. The microscopy apparatus is the most widely used and important device for magnifying imaging. However, the conventional microscope cannot meet the rapid development of the scientific research. Therefore, it is necessary to grope for innovative microscopic imaging tools that can realize real-time, non-invasive and quantitative analysis. In this dissertation, two kinds of optical microscopy imaging techniques are developed based on interferometry and lensfree holography, to realize bio-sample display and measurement. The detailed contents can be generalized as:A interferometric phase microscopy imaging system is proposed based on extensive research literature on bio-microscopy techniques. Red blood cells (RBCs) are samples and used for phase imaging. The captured interferograms are processed via fast Fourier transform based phase retrieval method and2D discrete cosine transform unweighted least-squares algorithm based phase unwrapping method. The phase distributions of RBCs are recovered quantitatively, which agree with the literature findings.Infection of cells by metallic ions leads to both biochemical and structural modifications, and interferometric phase microscopy is adopted for the first time to detect such effects. The phase distributions of RBCs damaged by the lithium and lead ions are recovered in a real-time, quantitative and whole-process analytical manner, which are identical with the cell shape and qualitative phase distribution observation under differential interference contrast (DIC) microscopy. Furthermore, accurate phase area and phase volume values could be calculated. The results could be used for damage estimation and trend assessment of infected cells.A slightly-off-axis interferometry is further discussed to acquire more details on biosamples. Hilbert phase microscopy (HPM) method is developed as a phase retrieval approach in the post-processing with more information about the cells edge and high frequency components. Slightly-off-axis interferometry based HPM is evaluated by parameters such as diameter, phase area, phase volume and phase distribution histogram. The experimental results show that the proposed method owns fine spatial details and real-time imaging capability, which are useful for cells detection.Field of view (FOV) of system is one of the key parameters in the microscopic imaging. In this system, FOV is the same size as the effective photosensitive imaging area of the image sensor. For each lensfree hologram, the pixel size of sensor chip limits the spatial resolution of the reconstructed image. To circumvent this limitation, a sub-pixel shifting super-resolution algorithm is implemented to improve the resolution. Gigapixel imaging is achieved based on such a platform with a FOV of～18cm2and2.19μm half-pitch resolution.Wide FOV provides a platform for tracking bio-samples trajectories. Dual-view lensfree on-chip imaging technique that can track3D trajectories of thousands of individual human sperms is demonstrated. The large statistics provided by this lensfree imaging platform reveal that rare motile human sperms swim along well-defined helices. Furthermore, among these observed helical human sperms, approximately90%prefer right-handed helices over left-handed ones. What’s more, some parameters such as helical rotation speed and linear speed can be determined. The portable lab-on-a-chip device is manufactured with unique features like compactness and light weight. It could in general be quite valuable for telemedicine.