## 4 Experiments  
### Experimental Prototype  
Our imaging system consists of a high-performance cooled CCD (Belfast, UK, Apogee Alta F16000 Compact, 15.8 Megapixel CCD) coupled with a 180 mm Nikon photographic lens (Tokyo, Japan, AF NIKKOR 180 MM F/2.8, IF-ED), which was mounted on a motorized 2D stage (Shanghai, China, GCD-20330M, see Figure 8). The total travel of the 2D stage was 300 mm with an accuracy of 0.1 \(\upmu\)m. The object was located 2 m away from the pupil plane of the lens and illuminated by a 808 nm laser with a multimode fiber near-infrared  
Figure 6: Image reconstruction effect of the original image under different degrees of overlap ratio. (**a**) The ideal original image; (**b1**) the synthetic aperture under 70% overlap ratio; (**b2**) the synthetic aperture under 50% overlap ratio; (**b3**) the synthetic aperture under 30% overlap ratio; (**c1**) the system PSF image under 70% overlap ratio; (**c2**) the system PSF image under 50% overlap ratio; (**c3**) the system PSF image under 30% overlap ratio; (**d1**) the intensity image with high-resolution under 70% overlap ratio; (**d2**) the intensity image with high-resolution under 50% overlap ratio; (**d3**) the intensity image with high-resolution under 30% overlap ratio.  
Figure 7: Effect of varying overlap between adjacent images on RMSE and resolution of HR image. (**a**) the RMSE plot of HR intensity image; (**b**) the resolution plot of the different overlap ratio.  
semiconductor (Changchun, China, CNI, MDL-III-808 nm-1W-19121367). The coherent light beam emitted by the laser light source directly illuminated the focusing lens (\(f_{1}=150\) mm) and was imaged to the variable pupil plane of the Nikon imaging lens after passing the object with 20 mm \(\times\) 20 mm (Shanghai, China, RealLight, RT-GBA1-TNS001). In addition, the object image and the corresponding data chart are shown in Figure 9. As shown in Figure 9, the object of the experiment, which is shown on the left and tagged with No. 1 to No. 25, had a total of 25 groups of stripes, and the line width and frequency of each group that indicate the resolution increases in turn are shown in the chart. The camera sensor received a series of LR intensity images, which was the inverse Fourier transform of the object spectrum at different locations.  
The purpose of our fiber laser is to ensure that the object has a sufficient illumination range. The laser source with less than 1% intensity fluctuation was used in our experiments. Therefore, we were able to obtain a uniform illumination image without correcting the laser illumination intensity, as was evident from the images collected. The focusing lens  
Figure 8: Laboratory hardware configuration for images obtained.  
Figure 9: The object image and the corresponding data chart.  
converges the illumination and forms a Fourier transform of the object on the imaging plane of the lens, which means that the laser source is imaged at the pupil position of the imaging lens.  
To simulate a cheap lens with a long focal length and small aperture, we stopped the lens down to a focal length of 180 mm and f-number \(F/22\), creating an 8.2 mm diameter aperture. A set of images was acquired by moving the camera to different positions in the synthetic aperture plane via the translation stage. At every grid position, we captured multiple images with different exposures time to form a high-dynamic-range reconstructive image. By translating the camera, the shift in perspective causes the captured images to be misaligned. The translation stage is sufficiently precise enough to allow the calibration step to be performed immediately before or after data capture.