Design of a Hardware/Software FPGA-Based Driver System for a Large Area High Resolution CCD Image Sensor

A hardware/software field programmable gate array （FPGA）-based driver system was proposed and demonstrated for the KAF-39000 large area high resolution charge coupled device （CCD）. The requirements of the KAF-39000 driver system were analyzed. The structure of ＂microprocessor with application specific integrated circuit （ASIC） chips＂ was implemented to design the driver system. The system test results showed that dual channels of imaging analog data were obtained with a frame rate of 0.87frame/s. The frequencies of horizontal timing and vertical timing were 22.9MHz and 28.7kHz, respectively, which almost reached the theoretical value of 24 MHz and 30kHz, respectively.

Synthetic aperture metalens

Metalenses are ultrathin optical elements that can focus light using densely arranged subwavelength structures.Due to their minimal form factor,they have been considered promising for imaging applications that require extreme system size,weight,and power,such as in consumer electronics and remote sensing.However,as a major impediment prohibiting the wide adoption of the metalens technology,the aperture size,and consequently the imaging resolution,of a metalens are often limited by lithography processes that are not scalable.Here,we propose to adopt a synthetic aperture approach to alleviate the issue,and experimentally demonstrate that,assisted by computational reconstruction,a synthetic aperture metalens composed of multiple metalenses with relatively small aperture size can achieve an imaging resolution comparable to a conventional lens with an equivalent large aperture.We validate the concept via an outdoor imaging experiment performed with a synthetic aperture metalens-integrated near-infrared camera using natural sunlight for target illumination.

Genetic studies of schizophrenia:an update

Schizophrenia（SCZ） is a complex and heterogeneous mental disorder that affects about 1% of global population. In recent years,considerable progress has been made in genetic studies of SCZ. A number of common variants with small effects and rare variants with relatively larger effects have been identifi ed. These variants include risk loci identifi ed by genome-wide association studies,rare copy-number variants identifi ed by comparative genomic analyses,and de novo mutations identified by high-throughput DNA sequencing. Collectively,they contribute to the heterogeneity of the disease. In this review,we update recent discoveries in the fi eld of SCZ genetics,and outline the perspectives of future directions.

Grating coupler efficiency enhancement by double layer interference

A simple method for improving grating couplers' coupling efficiency without any extra microfabrication processes is proposed. This method can improve the coupling efficiency with 1.69 dB by utilizing the combined interference in the cladding layer and air gap between the cladding surface and the paralleled angle polished fiber facet. The proposed method can be applied to various kinds of on-chip grating couplers. Back reflection,1 dB bandwidth, and fiber alignment tolerance have also been improved at the same time.

Review of design principles of 2D photonic crystal microcavity biosensors in silicon and their applications

In this paper, we reviewed the design principles of two-dimensional （2D） silicon photonic crystal microcavity （PCM） biosensors coupled to photonie crystal waveguides （PCWs）. Microcavity radiation loss is con- trolled by engineered the cavity mode volume. Coupling loss into the waveguide is controlled by adjusting the position of the microcavity from the waveguide. We also investigated the dependence of analyte overlap integral （also called fill fraction） of the resonant mode as well as the effect of group index of the coupling waveguide at the resonant wavelength of the microcavity. In addition to the cavity properties, absorbance of the sensing medium or analyte together with the affinity constant of the probe and target biomarkers involved in the biochemical reaction also limits the minimum detection limits. We summarized our results in applications in cancer biomarker detection, heavy metal sensing and therapeutic drug monitoring.

An unsupervised heterogeneous change detection method based on image translation network and post-processing algorithm

The change detection(CD)of heterogeneous remote sensing images is an important but challenging task.The difficulty is to obtain the change information by directly comparing the different statistical characteristics of the images acquired by different sensors.This paper proposes an unsupervised method for heterogeneous image CD based on an image domain transfer network.First,an attention mechanism is added to the Cycle-generative adversarial networks(Cycle-GANs)to obtain a more consistent feature expression by transferring bi-temporal heterogeneous images to the common domain.The Euclidean distance of the corresponding pixels is calculated in the common domain to form a difference map,and a threshold algorithm is applied to get a rough change map.Finally,the proposed adaptive Discrete Cosine Transform(DCT)algorithm reduces the noise introduced by false detection,and the final change map is obtained.The proposed method is verified on three real heterogeneous CD datasets and compared with the current state-of-the-art methods.The results show that the proposed method is accurate and robust for performing heterogeneous CD tasks.