Identification and Tracking of Vehicles between Multiple Cameras on Bridges Using a YOLOv4 and OSNet-Based Method.

The estimation of vehicle loads is a rising research hotspot in bridge structure health monitoring (SHM). Traditional methods, such as the bridge weight-in-motion system (BWIM), are widely used but they fail to record the locations of vehicles on the bridges. Computer vision-based approaches are promising ways for vehicle tracking on bridges. Nevertheless, keeping track of vehicles from the video frames of multiple cameras without an overlapped visual field poses a challenge for the tracking of vehicles across the whole bridge. In this study, a method that was You Only Look Once v4 (YOLOv4)- and Omni-Scale Net (OSNet)-based was proposed to realize vehicle detecting and tracking across multiple cameras. A modified IoU-based tracking method was proposed to track a vehicle in adjacent video frames from the same camera, which takes both the appearance of vehicles and overlapping rates between the vehicle bounding boxes into consideration. The Hungary algorithm was adopted to match vehicle photos in various videos. Moreover, a dataset with 25,080 images of 1727 vehicles for vehicle identification was established to train and evaluate four models. Field validation experiments based on videos from three surveillance cameras were conducted to validate the proposed method. Experimental results show that the proposed method has an accuracy of 97.7% in terms of vehicle tracking in the visual field of a single camera and over 92.5% in tracking across multiple cameras, which can contribute to the acquisition of the temporal-spatial distribution of vehicle loads on the whole bridge.

Spatial separation of azimuthally and radially polarized beams from non-polarized light waves based on the electrically controlled birefringence effect.

Based on the electrically controlled birefringence effect in liquid crystal materials, an effective method for spatially separating azimuthally and radially polarized beams from non-polarized incident light waves is proposed. The radially polarized beam was highly converged by using a microhole-patterned electrode and a planar photo-alignment layer to shape the initial liquid-crystal radial alignment and a gradient refractive index distribution with central axial symmetry after applying a voltage signal. Due to the intrinsic polarization sensitivity of nematic liquid-crystal materials, the shaped gradient refractive index only applies to extraordinary light waves, which then converge into a spot. Thus, the azimuthally and radially polarized beams are effectively separated. The proposed method demonstrates some advantages, such as low cost, miniaturization, and easy fabrication and integration with other functional devices. Thanks to the wideband electrically controlled birefringence of liquid-crystal materials, this light-wave manipulation to spatially separate azimuthally and radially polarized beams can also be performed over a wide wavelength range.

All-In-Focus Polarimetric Imaging Based on an Integrated Plenoptic Camera with a Key Electrically Tunable LC Device.

In this paper, a prototyped plenoptic camera based on a key electrically tunable liquid-crystal (LC) device for all-in-focus polarimetric imaging is proposed. By using computer numerical control machining and 3D printing, the proposed imaging architecture can be integrated into a hand-held prototyped plenoptic camera so as to greatly improve the applicability for outdoor imaging measurements. Compared with previous square-period liquid-crystal microlens arrays (LCMLA), the utilized hexagonal-period LCMLA has remarkably increased the light utilization rate by ~15%. Experiments demonstrate that the proposed imaging approach can simultaneously realize both the plenoptic and polarimetric imaging without any macroscopic moving parts. With the depth-based rendering method, both the all-in-focus images and the all-in-focus degree of linear polarization (DoLP) images can be obtained efficiently. Due to the large depth-of-field advantage of plenoptic cameras, the proposed camera enables polarimetric imaging in a larger depth range than conventional 2D polarimetric cameras. Currently, the raw light field images with three polarization states including I0 and I60 and I120 can be captured by the proposed imaging architecture, with a switching time of several tens of milliseconds. Some local patterns which are selected as interested target features can be effectively suppressed or obviously enhanced by switching the polarization state mentioned. According to experiments, the visibility in scattering medium can also be apparently improved. It can be expected that the proposed polarimetric imaging approach will exhibit an excellent development potential.

Arrayed dual-mode integrated liquid crystal microlens driven jointly by both independent signal voltages.

A new type of liquid crystal microlens array (LCMLA) constructed by a single-layered LC material is proposed. The basic dual-mode integrated LC microlens includes a concentric microhole electrode and a central plate electrode. Compared with traditional LC microlenses driven electrically, the dual-mode integrated LC microlens presents a better light control effect, such as being flexibly adjusted between the beam convergence and divergence modes, enlarging both the tunable range of the signal voltage and the focal length and also reducing the focal spot assisted by a convex electric-field generated by the central plate electrode, acquiring a sharper beam diverging microring formed by the concave LC microlens assisted by a concave electric-field generated by the microhole electrode. At the same time, we have also verified that the electric-field filling factor of the dual-mode integrated LCMLA can be obviously increased through jointly tuning the signal voltages applied independently over both the microhole electrode and the central plate electrode. This research has laid a solid foundation for continuously developing LCMLA technology.

Mechanism of tumor­derived extracellular vesicles in regulating renal cell carcinoma progression by the delivery of MALAT1.

Renal cell carcinoma (RCC) is a major healthcare burden globally. Tumor­derived extracellular vesicles (EVs) contribute to the formation of a pro­metastatic microenvironment. In the present study, we explored the role and mechanism of RCC cell 786­O­derived EVs (786­O­EVs) in RCC. First, 786­O­EVs were extracted and identified, and EV internalization of RCC cells was observed. RCC cell malignant behaviors and long noncoding RNA (lncRNA) metastasis­associated lung adenocarcinoma transcript 1 (MALAT1) expression patterns were detected before and after 786­O­EV treatment. MALAT1 was intervened to evaluate RCC cell behaviors. The downstream mechanism involving MALAT1 was predicted. In addition, the relationship among MALAT1, transcription factor CP2 like 1 (TFCP2L1) and ETS proto­oncogene 1, transcription factor (ETS1) was analyzed. TFCP2L1 expression patterns were measured after 786­O­EV exposure. Tumor xenograft formation assay and lung metastasis model were adopted to verify the role of 786­O­EVs in vivo in RCC. It was found that 786­O­EVs could be internalized by RCC cells. 786­O­EVs promoted RCC cell malignant behaviors, accompanied by elevated MALAT1 expression levels. The 786­O­EVs with MALAT1 knockdown attenuated the promotive effect of sole 786­O­EVs on RCC cells. MALAT1 located ETS1 in the TFCP2L1 promoter and negatively regulated TFCP2L1, and ETS1 protein could specifically bind to MALAT1. 786­O­EVs enhanced the binding of ETS1 and the TFCP2L1 promoter and decreased TFCP2L1 expression. In vivo, 786­O­EVs promoted tumor growth and RCC lung metastasis, which was suppressed following inhibition of MALAT1. Our findings indicated that 786­O­EVs promoted RCC invasion and metastasis by transporting MALAT1 to promote the binding of transcription factor ETS1 and TFCP2L1 promoter.

Circ_0039569 promotes renal cell carcinoma growth and metastasis by regulating miR-34a-5p/CCL22.

Circular RNAs (circRNAs) belong to non-coding RNAs and are known as key regulators in gene regulation. CircRNAs involve in the various biological processes of cancer. However, the functions of circRNAs in renal cell carcinoma (RCC) are still not clear. In this study, the circRNA expression profile was performed in the RCC tissues by microarray. There were 35 significantly expressed circRNAs with more than 5 folds from microarray analysis. Hsa_circ_0039569 (circ_0039569) was verified to be up-regulated in RCC and cells compared with the controls by real time RT-PCR. The assays of cellular functions showed that circ_0039569 down-regulation suppressed the proliferation and metastasis of RCC cells. The molecular mechanism of circ_0039569 in RCC cells showed that circ_0039569 promoted RCC progression by up-regulating CCL22 expression via down-regulating miR-34a-5p. Taken together, the study indicated that circ_0039569 played an important role in RCC cell survival and metastasis, which suggested that an oncogenic role of circ_0039569 in RCC progression.