Heterodyne 3D ghost imaging

Performance analysis of ghost imaging lidar in background light environment

“…Rectt∕T chirp , where s chirp t is a chirped-AM waveform with bandwidth B chirp and duration T B T C T chirp , and m is the modulation depth [14,15]. To obtain equivalent range resolution, we set B chirp 1∕T A .…”

“…For lidar system (B), the backscattered light is converted into an intensity-modulated photocurrent i B t. Then de-chirping is processed by mixing the photocurrent with a local chirp signal s LO s chirp . After a proper bandpass filter, fast Fourier transform (FFT) is used to find the beating frequency f z and accumulate the signal energy [14]. The amplitude spectrum can be denoted as…”

“…As shown by Eqs. (10), (14), and (18), the three lidar systems have different responses to signal and background light, thus leading to different image SNRs when the three systems share the same signal power to background power ratio σ. We will compare them explicitly in the next section.…”

“…Ghost imaging (GI) is a novel non-scanning imaging method to obtain a target's image with a single-pixel bucket detector [1][2][3][4][5][6]. Due to its capacity for high detection sensitivity, GI has aroused increasing interest in remote sensing, and a new imaging lidar system called GI lidar has gradually developed [7][8][9][10][11][12][13][14][15]. Up to now, there have been three types of three-dimensional GI lidars, namely narrow pulsed GI lidar, heterodyne GI lidar, and pulse-compression GI lidar via coherent detection [12][13][14][15].…”

“…The structure of pulsed GI lidar is simple, but its imaging quality is subject to a low-detection signal-to-noise ratio (SNR). Heterodyne GI lidar employs a spatiotemporal modulated light generated by temporal chirped amplitude modulation (chirped-AM) and transverse random modulation [14]. Using a de-chirping method, a high-range resolution can be obtained even with the use of a long pulse.…”