SWIR AOTF Imaging Spectrometer Based on Single-pixel Imaging.

An acousto-optic tunable filter (AOTF) is a new type of mono-wavelength generator, and an AOTF imaging spectrometer can obtain spectral images of interest. However, due to the limitation of AOTF aperture and acceptance angle, the light passing through the AOTF imaging spectrometer is weak, especially in the short-wave infrared (SWIR) region. In weak light conditions, the noise of a non-deep cooling mercury cadmium telluride (MCT) detector is high compared to the camera response.

Chromatic aberrations correction for imaging spectrometer based on acousto-optic tunable filter with two transducers.

The acousto-optic tunable filter (AOTF) with wide wavelength range and high spectral resolution has long crystal and two transducers. A longer crystal length leads to a bigger chromatic focal shift and the double-transducer arrangement induces angular mutation in diffracted beam, which increase difficulty in longitudinal and lateral chromatic aberration correction respectively. In this study, the two chromatic aberrations are analyzed quantitatively based on an AOTF optical model and a novel catadioptric dual-path configuration is proposed to correct both the chromatic aberrations.

Calibration of AOTF-based 3D measurement system using multiplane model based on phase fringe and BP neural network.

A specifically designed imaging system based on an acousto-optic tunable filter (AOTF) can integrate hyperspectral imaging and 3D reconstruction. As a result of the complicated optical structure, the AOTF imaging system deviates from the traditional pinhole model and lens distortion form, causing difficulty to achieve precise camera calibration. The influencing factors leading to the deviation are discussed and a multiplane model (MPM) is proposed with phase fringe to produce dense mark points and a back propagation neural network to obtain subpixel calibration.

Improvement in the synchronization between the radio frequency signal and the image detector in an acousto-optic tunable filter imaging spectrometer.

An improved synchronization between the radio frequency (RF) signal and the image detector in an acousto-optic tunable filter (AOTF) imaging spectrometer is proposed to optimize power consumption and eliminate image smear. The RF signal is controlled on and off alternately to match the exposure of the image sensor. This scheme reduces the RF power and rejects the light illumination on the image sensor in the interval of charge transfer.