Can the new "nano-satellite system" get better images at lower cost?

Researchers at Ben-Gurion University have developed a new satellite imaging system, which can completely change the economy and images provided by space cameras and even earth telescopes. Angika Bulbul, a doctoral student under the guidance of Joseph Rosen, a professor of electronics and computer engineering at BGU, said: This invention has completely changed the cost of space exploration, astronomy, aerial photography and other fields. In a paper published in Optics magazine, researchers proved that spherical (annular) nanosatellites the size of milk cartons can capture images with the same resolution as full frames, lenses or concave mirror systems used in today's telescopes.

Some previous assumptions about long-distance photography are incorrect, and it is found that only a small part of the telescope lens is needed to obtain high-quality images. Even if the aperture around the lens is as low as 0.43%, the image resolution is close to the full aperture area of the imaging system based on mirror/lens. Therefore, the huge cost, time and materials required by the huge traditional optical space telescope and large curved mirror can be reduced. In order to demonstrate the ability of the rotating telescope (SMART) system to synthesize the edge aperture, the research team established a miniature laboratory model with a circular sub-aperture array, studied the image resolution, and compared it with full lens imaging.

Introduction to the study:

The imaging resolution of space and ground telescopes is often limited by the limited aperture of the optical system. A new imaging system based on synthetic aperture is proposed. The two physical sub-apertures of the imaging system are only distributed around the synthetic aperture. It is proved that the smallest sub-aperture area only accounts for 0.43% of the total synthetic aperture area. The inspiration for proposing the optical structure comes from a device in which two synchronous satellites only move along the boundary of synthetic aperture and capture some light patterns from the observed scene. The light reflected by these two satellites will interfere with the image sensor located on the third satellite. After processing the sum of all interference modes, the image quality of the scene can be comparable to that obtained by full synthetic aperture.

Based on incoherent coded aperture holography, the system uses pseudo-random coded phase mask to modulate the diffracted light of the target. The modulated light is recorded and digitally processed to produce a three-dimensional image of the object. In this paper, an experimental model of dual synchronous subaperture imaging is proposed. The experimental results show that sampling along the synthetic aperture boundary is enough to produce images with complete synthetic aperture resolution. Unlike other synthetic aperture schemes, there is no need to sample any other part outside the aperture boundary. Therefore, in the process of data acquisition, time and/or equipment can be greatly saved.

Boko Park-Popular Science | Research/From: Ben Gurion University

Refer to periodical literature: "optics"

Paper doi:10.1364/optica.5.0438+0607.

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