FDMA-CDMA Mode CAOS Camera Demonstration using UV to NIR Full Spectrum

TL;DR

This paper introduces a novel FDMA-CDMA mode for the CAOS camera, enabling faster, high dynamic range imaging across UV to NIR spectra with improved signal-to-noise ratio and simultaneous dual image capture.

Contribution

It demonstrates the first hybrid FDMA-CDMA mode for CAOS cameras, combining spectrum analysis and high SNR detection, with experimental validation across UV to NIR wavelengths.

Findings

Faster camera operation with P=4 channels compared to previous modes.

High-quality HDR image recovery of 64 dB dynamic range.

Successful dual image capture across UV to NIR spectrum.

Abstract

For the first time, the hybrid Frequency Division Multiple Access (FDMA) Code Division Multiple Access (CDMA) mode of the CAOS (i.e., Coded Access Optical Sensor) camera is demonstrated. The FDMA CDMA mode is a time frequency double signal encoding design for robust and faster linear High Dynamic Range (HDR) image irradiance extraction. Specifically, it simultaneously combines the strength of the FDMA-mode linear HDR Fast Fourier Transform (FFT) Digital Signal Processing (DSP) based spectrum analysis with the CDMA mode provided many simultaneous CAOS pixels high Signal to Noise Ratio (SNR) photo-detection. The FDMA CDMA mode with P FDMA channels provides a faster camera operation versus the linear HDR Frequency Modulation (FM) CDMA mode. Visible band imaging experiments using a Digital Micromirror Device (DMD) based CAOS camera demonstrate a P equal to 4 channels FDMA CDMA mode high quality image recovery of a calibrated 64 dB 6 patches HDR target versus the CDMA and FM CDMA CAOS modes that limit dynamic range and speed, respectively. Simultaneous dual image capture capability of the FDMA-CDMA mode is also demonstrated for the first time in Ultraviolet (UV) to Near Infrared (NIR) 350 to 1800 nm full spectrum using Silicon (Si) and Germanium (Ge) point photo-detectors.