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This work focuses on the generation of three-dimensional (3D)-scene information as well as the fusion of real and virtual 3D scene information for the full-parallax holographic stereogram based on the effective perspective images’ segmentation and mosaicking (EPISM) method. The improved depth-image-based rendering (DIBR) method was used to generate the virtual viewpoint images of the real 3D scene, and the regularization and densification processing models of the degraded light field were established; as a result, the real sampling-light field was reconstructed. Combined with the computer-rendered virtual 3D scene information, a “real + virtual” light-field fusion method based on a pixel-affine-projection was proposed to realize the fusion of the real and virtual 3D scene. The fusion information was then processed by the EPISM encoding and was then holographically printed. The optical experiment results showed that the full-parallax holographic stereogram with the real–virtual scene-fused 3D scenes could be correctly printed and reconstructed, which validated the effectiveness of our proposed method.

The smart pseudoscopic-to-orthoscopic conversion (SPOC) algorithm can synthesize a new elemental image array (EIA) using the already captured EIA, but the algorithm only relies on one simulated ray to establish the mapping relationship between the display pixels and the synthetic pixels. This paper improves the SPOC algorithm and proposes the average SPOC algorithm, which fully considers the converging effect of the synthetic lens on the ray. In the average SPOC algorithm, the simulated rays start from the synthetic pixel, pass through the upper and lower edges of the corresponding synthetic lens, and intersect the display lenses, respectively. Then, the value of the synthetic pixel is equivalent to the average value of display pixels, which correspond to the display lenses covered by the rays. Theoretical analysis points out that the average SPOC algorithm can effectively alleviate the matching error between the display pixels and the synthetic pixels, thereby improving the accuracy of the synthetic elemental image array (SEIA) and the reconstruction effect. According to the experimental results we get, the superiority of the average SPOC algorithm is verified.

A novel inverter hybrid cascaded LCC-MMC UHVDC system is studied in this paper. The rectifier of the system is consisted of LCC; the inverter is consisted of LCC and parallel MMCs. Based on the analysis of the coordinated control strategy of LCCs and MMCs, a detailed startup control strategy for the inverter hybrid cascaded LCC-MMC UHVDC system is proposed. The startup control strategy is divided into 4 periods: MMC uncontrolled charging period, MMC unlocking period, DC loop closing period and power boosting period. In order to verify the performance of the proposed startup strategy, a model of the inverter hybrid cascaded LCC-MMC UHVDC system based on detailed engineering parameters was established in the PSCAD/EMTDC environment. The simulation results show that the system has a good dynamic performance except that MMCs may exchange power during power boosting period. However, after adopting the optimized startup strategy, the power exchange between MMCs has been significantly suppressed.

To improve the performance of the protection scheme for HVDC lines, a novel distance backup protection scheme is proposed in this paper. First, it is proved that the DC line model can be equivalent to lumped parameter model during the steady-state. Based on the equivalent model, the fault distance can be calculated, and the criterion of the distance relay is implemented. Secondly, a directional relay based on the transient currents is added to solve the dead zone problem of distance protection. Finally, a ± 800 kV HVDC system is built in PSCAD/EMTDC simulation environment to test the performance of the protection. Comprehensive test studies show that the proposed protection scheme can correctly distinguish internal faults from external faults. Besides, the proposed protection has a clear setting principle, low requirements of the calculation amount and sampling rate.

The fifth generation mobile communication (5G communication) technology provides new ideas for current differential protections of distribution networks by virtue of its advantages in bandwidth, transmission capacity, transmission rate and delay. This paper firstly introduces the characteristics of 5G communication technology and tests the 5G communication delay characteristics in a laboratory environment. The test results show that the 5G communication delay can meet the requirements of current differential protections in distribution networks. On this basis, an adaptive current differential protection is proposed, which includes the use of a distribution management system to realize the automatic topology identification of the distribution network and the automatic establishment of communication links. Finally, simulations on the RTDS platform are implemented to verify the effectiveness of the proposed protection scheme. Moreover, the protection scheme can still play a protective role when a single terminal of the distribution network fails or its communication fails, which greatly improves the reliability of the current differential protection of the distribution networks based on 5G communication.

Different light-fields information collection methods will cause different light-fields information cannot be fused and recorded into the holographic stereogram. In order to print the holographic stereogram recording information of virtualreal fusion, the depth-image-based rendering (DIBR) technology is applied to the holographic stereogram fabricated by effective perspective images’ segmentation and mosaicking method (EPISM). This method firstly obtains matching real scene sampling parameters according to the virtual scene, and combines with the improved DIBR technology to draw the initial perspective images without holes or crack problems. After EPISM processing, the synthetic perspective images of real and virtual scenes with the same parameters are fused. Finally, the fused perspective images are recorded into holographic stereogram. The experimental results demonstrate this proposed method obtain high quality virtual-real fusion display.

In this paper, image processing technology is used to simulate the reconstructed images of holographic stereogram in different depth planes. The quality of the reconstructed image of a single hogel at different depths is analyzed firstly. The size of the hogel, the distance between the holographic stereogram and the LCD and the distance between the holographic stereogram and the imaging plane are all factors affecting the quality of the reconstructed image. By dividing the hogel into many sub-parts, the reconstructed images of each sub-parts are analyzed one by one, and by superimposing the reconstructed images of each sub-parts, the reconstructed images of the hogel at different depths can be obtained. Then, the relationship between the reconstructed images of each hogel is analyzed, and the reconstructed images of all hogels are translated and superimposed to obtain the reconstructed images of the holographic stereogram in different depth. The synthetic parallax images generated by using the effective perspective image segmentation and mosaicking (EPISM) algorithm proposed by our group are used to print the holographic stereogram. The experiment results show that the reconstructed images of the stereogram in different depth planes are consistent with the simulation results, which verifies the validation of the simulation.