Search

A thousand-unit scalable wave-front detector based image restoration technology was proposed.The wave-front detection and image restoration were combined to eliminate the effect of atmospheric disturbance and system aberration on the image resolution and to meet the requirements of large ground-based telescopes for high-resolution imaging.First,the wave-front detection was used to obtain the wave-front aberration and then degenerated images were restored based on obtained aberration amounts.The core component,a wave-front processor,used a wave-front host Printed Circuit Board(PCB) combined with a wave-front sub PCB to implement wave-front processing for optical systems with different sizes and it could reach thousand magnitude unit outputs.An image restoration experiment for a laser source was performed in an experimental laboratory,which shows the laser energy concentration has increased by 50%.And the binary source of 0.6 arc-second experiments was carried out in a telescope,and its Full Width at Half Maximum(FWHM) has decreased by 80%.By using a large-scale Field Programming Gate Array(FPGA) as the core processing device,the system achieves the high resolution image restoration for a degenerated image from the ground-based telescope.

In order to overcome the wave-front distortion caused by atmosphere turbulence and optical system aberration,the Phase-Diverse Speckle(PDS) method was used to collect simultaneouslly two or more short-exposure optical images formed by focusing or defocusing to estimate both the object and the wave-front phases.To verify the improvement of image resolution and phase estimation of PDS method,a comparison experiment on high-resolution imaging and phase estimation comparison was carried out based the PDS method and a Shack-Hartmann sensor.By shifting the high accurate translation stage at a certain distance,the focusing and defocusing images were obtained,then the wavefront phase based on the image was camparied with that from the Shack-Hartmann sensor.Experiment results indicate that the estimated wave-front phase is highly according with that detected by Shack-Hartmann and the resolution of the restored image can increase by 12% compared with the origin image formed by focus plane.In conclustion,the proposed method can be used to restore the degradative images in large aperture telescopes.

Image capaturing and image restoration implentmented by Phase-diverse Speckle(PDS) were researched in this paper.A PDS experimental platform with two cameras was designed for the extended object in our lab.Two cameras were taken to capture the short-expose images in focus and defocus simultaneously and a deformable mirror was used to construct optics system error.Then an electrical dryer was used to simulate the atmosphere turbulence.The problems from the two cameras were compared with that from single camera.Furthermore,the PD destination function was derived when the two cameras have different readout noises and how to solve the image rotation between the multi-channels was given.Finally,the capability of PDS method for image resolution improvement was validated.The PDS processes by single frame,3 frames and 10 frames were execussed,respectively,and results show that the PDS technique can generate images with highly improved quality compared with the traditional PD method.