Fig. 1. Comparison of images acquired by microscope systems using 4× and 20× objectives.（a）Grayscale image of a USAF acquired with a 4× objective，（a1）is an enlarged view of the corresponding position in（a）；（b）Grayscale image of a USAF acquired with a 20× objective.

Fig. 2. Example of two types of freeform designs.（a）High-resolution wide-FOV photolithographic objective lens^［2］；（b）Design solutions and experiment result of hemispherical electronic eye camera^［5］；（c）SST array and it’s process^［6］.

Fig. 3. Scanning method^［10］ and intrinsic drawbacks^［80］ of conventional digital pathologic scanners

Fig. 4. SAR and FPM.（a）Working principle and real image of SAR；（b）Space-time bandwidth product extended by FPM；（c）System construction and imaging experiment of FPM；（d）Flow chart of FPM reconstruction^［13］.

Fig. 5. Roadmap on FPM

Fig. 6. Principle and experimental results of CFFPM.（a）Match color and color transfer^［34］；（b）Imaging system of CFPM and FPM^［34］；（c）Color space of CFPM and CFFPM^［34］；（d）Schematic diagram of CFFPM method and it’s imaging results^［59］.

Fig. 7. SIM and SSIM.（a1~a4）Concept of resolution enhancement by SIM^［60］；（b1~b3）Resolution extension through the Moire˙ effect^［61］；（c1~c5）Resolution extension by nonlinear structured illumination^［61］；（d）SIM imaging of organism cells^［63］；（e）SSIM imaging of organism cells^［63］.

Fig. 8. High SBP is achieved by establishing a microfluidic channel.（a）Structure，working principle and imaging results of on-chip OFM，（a1）OFM scheme design section display，（a2）The physical picture of OFM on the chip，The microfluidic motion of a Giardia cyst when（a3）driven by pressure and（a4）driven by DC electrokinetics^［64］；（b）Lensless ultra-wide-field cell monitoring array platform based on shadow imaging^［65］；（c）Time-lapse imaging of HeLa cell culture on the ePetri platform^［66］.

Fig. 9. Lensless super-resolution imaging with phase recovery.（a）System composition and imaging experiment of high-resolution on-chip lensless imaging by laterally moving light source^［67］；（b）Schematic diagram of the multi-height pixel super-resolution based lensfree on-chip imaging set-up and phase image of a Pap test^［68］；（c）Structure of lensless on-chip microscopy using a fiber-optic array and imaging of red blood cells infected with malaria parasites^［69］；（d）Structure of LISA and imaging of breast cancer tissue^［70］；（e）Optical setup of wavelength-scanning pixel-super resolution and Lens-free imaging of a Papanicolaou（Pap）smear^［71］.

Fig. 10. Imaging principle and experimental results of SAP.（a）Comparison between conventional ptychography and SAP；（b）Experimental validation of the transmission configuration of SAP^［90］.