Coded aperture imaging with uniformly redundant arrays.

Area of Science:

• Astronomy
• Optics
• Signal Processing

Background:

• Traditional random arrays suffer from inherent noise limitations, restricting signal-to-noise ratio (SNR) and imaging capabilities for faint sources.
• Nonredundant pinhole arrays offer flat sidelobes but lack the high-transmission characteristics of random arrays.

Purpose of the Study:

• To introduce and evaluate the performance of Uniformly Redundant Arrays (URAs) for imaging low-intensity, low-contrast astronomical sources.
• To demonstrate the advantages of URAs over traditional random array techniques, particularly in noisy conditions.

Main Methods:

• Theoretical analysis of autocorrelation functions for URAs, focusing on sidelobe properties.
• Computer simulations comparing URA performance against random array techniques under various noise conditions (shot and background noise).

Main Results:

• URAs exhibit perfectly flat sidelobes, a significant improvement over other array types.
• Simulations show URAs are vastly superior to random arrays in the presence of significant shot and background noise.
• URA implementation allows for a smaller detector size compared to random array systems.

Conclusions:

• Uniformly Redundant Arrays provide a powerful new capability for imaging faint and low-contrast sources.
• The flat sidelobe characteristic and noise resilience of URAs overcome key limitations of existing imaging techniques.
• URAs offer practical advantages, including improved SNR and reduced detector size, making them suitable for advanced astronomical observations.