Computational temporal ghost imaging based on complementary modulation

We report an experimental demonstration of temporal ghost imaging in which a digital micromirror device(DMD)and+1/-1 binary modulation have been combined to give an accurate reconstruction of a nonperiodic time object.Compared to the 0/1 modulation,the reconstruction signal can be improved greatly by+1/-1 binary modulation even with half of the measurements.Experimental results show that 0/1 binary temporal objects up to 4 kHz and sinusoidal time objects up to 1 kHz can be reconstructed by this method.The influences of modulation speed and array detector gray levels are also discussed.

Signal transmission of 4 GHz beyond the system bandwidth in UV-C LED communication based on temporal ghost imaging

Due to the bandwidth limitation of the ultraviolet-C(UV-C) optical communication system and strong channel attenuation, it is difficult to transmit high-frequency signals. In this paper, the temporal ghost imaging(TGI) algorithm was first applied to the UV-C communication experimentally, and we realized the transmission of a 4 GHz signal through 95.34 MHz system bandwidth. The study indicates that the TGI algorithm can significantly improve the signal-to-noise ratio(SNR) compared with the on–off keying method. Our research provides a new approach for alleviating transmission frequency limitation due to poor SNR and insufficient hardware bandwidth.

Improving the resolution temporal in quantum and classical imaging

The point-spread function of an optical system determines its optical resolution for both spatial and temporal imaging. For spatial imaging, it is given by a Fourier transform of the pupil function of the system. For temporal imaging based on nonlinear optical processes, such as sum-frequency generation or four-wave mixing, the pointspread function is related to the waveform of the pump wave by a nonlinear transformation. We compare the point-spread functions of three temporal imaging schemes： sum-frequency generation, co-propagating four-wave mixing, and counter-propagating four-wave mixing, and demonstrate that the last scheme provides the best temporal resolution. Our results are valid for both quantum and classical temporal imaging.

Planning for selective amygdalohippocampectomy involving less neuronal fiber damage based on brain connectivity using tractography

Temporal lobe resection is an important treatment option for epilepsy that involves removal of potentially essential brain regions. Selective amygdalohippocampectomy is a widely performed temporal lobe surgery. We suggest starting the incision for selective amygdalohippocampectomy at the inferior temporal gyrus based on diffusion magnetic resonance imaging（MRI） tractography. Diffusion MRI data from 20 normal participants were obtained from Parkinson＇s Progression Markers Initiative（PPMI） database（www.ppmi-info.org）. A tractography algorithm was applied to extract neuronal fiber information for the temporal lobe, hippocampus, and amygdala. Fiber information was analyzed in terms of the number of fibers and betweenness centrality. Distances between starting incisions and surgical target regions were also considered to explore the length of the surgical path. Middle temporal and superior temporal gyrus regions have higher connectivity values than the inferior temporal gyrus and thus are not good candidates for starting the incision. The distances between inferior temporal gyrus and surgical target regions were shorter than those between middle temporal gyrus and target regions. Thus, the inferior temporal gyrus is a good candidate for starting the incision. Starting the incision from the inferior temporal gyrus would spare the important（in terms of betweenness centrality values） middle region and shorten the distance to the target regions of the hippocampus and amygdala.

A PRELIMINARY STUDY OF FOURIER SERIES ANALYSIS ON CLOUD TRACKING WITH GOES HIGH TEMPORAL RESOLUTION IMAGES

Fourier series analysis is proposed as a new technique to address the problem of“sub-pixel motion”in deriving cloud motion winds(CMW)from high temporal resolution images.Based on a concept different from that of maximum correlation matching technique,the Fourier technique computes phase speed as an estimate of cloud motion.It is very effective for tracking small cellular clouds in 1-min interval images and more efficient for computation than the maximum correlation technique because only two templates in same size are involved in primary tracking procedure. Moreover it obtains not only CMW vectors but potentially also velocity spectrum and variance.A practical example is given to show the cloud motion winds from 1-min interval images with the Fourier method versus those from traditional 30-min interval images with maximum correlation technique.Problems that require further investigation before the Fourier technique can be regarded as a viable technique,especially for cloud tracking with high temporal resolution images,are also revealed.