PEA265: Perceptual Assessment of Video Compression Artifacts

The most widely used video encoders share a common hybrid coding framework that includes block-based motion estimation/compensation and block-based transform coding. Despite their high coding efficiency, the encoded videos often exhibit visually annoying artifacts, denoted as Perceivable Encoding Artifacts (PEAs), which significantly degrade the visual Qualityof- Experience (QoE) of end users. To monitor and improve visual QoE, it is crucial to develop subjective and objective measures that can identify and quantify various types of PEAs. In this work, we make the first attempt to build a large-scale subjectlabelled database composed of H.265/HEVC compressed videos containing various PEAs. The database, namely the PEA265 database, includes 4 types of spatial PEAs (i.e. blurring, blocking, ringing and color bleeding) and 2 types of temporal PEAs (i.e. flickering and floating). Each containing at least 60,000 image or video patches with positive and negative labels. To objectively identify these PEAs, we train Convolutional Neural Networks (CNNs) using the PEA265 database. It appears that state-of-theart ResNeXt is capable of identifying each type of PEAs with high accuracy. Furthermore, we define PEA pattern and PEA intensity measures to quantify PEA levels of compressed video sequence. We believe that the PEA265 database and our findings will benefit the future development of video quality assessment methods and perceptually motivated video encoders.Comment: 10 pages,15 figures,4 table

A Review: Solder Joint Cracks at Sn-Bi58 Solder ACFs Joints

In this chapter, solder joint cracks at Sn-Bi58 solder ACF joints were investigated in conventional thermal compression bonding and ultrasonic bonding. It was found that resin storage modulus is the crucial for solder joint morphology regardless of bonding pressures. At high temperature, polymer resin tends to rebound above Tg and break the molten solder morphology. We proposed two useful methods to keep off solder joints cracks during bonding process. One is to remain bonding pressure until room temperature, the other is to use fillers to increase resin thermal mechanical property. The thermal cycling reliability was significantly enhanced when solder joint morphology was modified using 10 wt% 0.2 μm SiO2 fillers in acrylic based Sn-Bi58 solder ACF joints

Saliency-Aware Spatio-Temporal Artifact Detection for Compressed Video Quality Assessment

Compressed videos often exhibit visually annoying artifacts, known as Perceivable Encoding Artifacts (PEAs), which dramatically degrade video visual quality. Subjective and objective measures capable of identifying and quantifying various types of PEAs are critical in improving visual quality. In this paper, we investigate the influence of four spatial PEAs (i.e. blurring, blocking, bleeding, and ringing) and two temporal PEAs (i.e. flickering and floating) on video quality. For spatial artifacts, we propose a visual saliency model with a low computational cost and higher consistency with human visual perception. In terms of temporal artifacts, self-attention based TimeSFormer is improved to detect temporal artifacts. Based on the six types of PEAs, a quality metric called Saliency-Aware Spatio-Temporal Artifacts Measurement (SSTAM) is proposed. Experimental results demonstrate that the proposed method outperforms state-of-the-art metrics. We believe that SSTAM will be beneficial for optimizing video coding techniques

Geometry-based spherical JND modeling for 360∘^\circ display

360$^\circ$ videos have received widespread attention due to its realistic and immersive experiences for users. To date, how to accurately model the user perceptions on 360$^\circ$ display is still a challenging issue. In this paper, we exploit the visual characteristics of 360$^\circ$ projection and display and extend the popular just noticeable difference (JND) model to spherical JND (SJND). First, we propose a quantitative 2D-JND model by jointly considering spatial contrast sensitivity, luminance adaptation and texture masking effect. In particular, our model introduces an entropy-based region classification and utilizes different parameters for different types of regions for better modeling performance. Second, we extend our 2D-JND model to SJND by jointly exploiting latitude projection and field of view during 360$^\circ$ display. With this operation, SJND reflects both the characteristics of human vision system and the 360$^\circ$ display. Third, our SJND model is more consistent with user perceptions during subjective test and also shows more tolerance in distortions with fewer bit rates during 360$^\circ$ video compression. To further examine the effectiveness of our SJND model, we embed it in Versatile Video Coding (VVC) compression. Compared with the state-of-the-arts, our SJND-VVC framework significantly reduced the bit rate with negligible loss in visual quality

Wetting and Brazing of YIG Ceramics Using Ag–CuO–TiO2 Metal Filler

The wetting and brazing of Y3Fe5O12 (YIG) ceramics with a Ag–8CuO–2TiO2 filler was investigated for the first time. For comparison, the wettability of a Ag–10CuO filler on YIG ceramics was similarly investigated. The Ag–8CuO–2TiO2 filler has an equilibrium contact angle of approximately 31 °C on the YIG substrate at 1000 °C; thus, its wettability is excellent. Moreover, its wettability exceeds that of Ag–10CuO. The microstructure and the interfacial structure between the filler and the substrate were determined using scanning electron microscopy, X-ray diffraction, EPMA and transmission electron microscopy. The liquid Ag–8CuO–2TiO2 filler can react with the YIG substrate by forming continuous Y2Ti2O7 layers with dotted CuFe2O4 and promote the wetting behavior and bonding performance. The average shear strength could exceed 30 MPa for the joints at a brazing temperature of 1000 °C. As rupture occurred adjacent to the seam at the ceramic side, the strengths of the interfaces were characterized via nanoindentation. The hardness of the interface with doped TiO2 exceeds that of Ag–10CuO, which is strengthened by the dotted CuFe2O4 among Y2Ti2O7

Joining ferrite at a relatively low temperature using 43SnO-15ZnO-35P₂O₅-7SiO₂ phosphate glass braze

Joining ferrite to itself is of great interest for applications in electronic field. Despite the importance, glass joining techniques have been developed to produce reliable joints. In this work, phosphate glass, 43SnO-15ZnO-35P2O5-7SiO2 (in mol.%), was designed and employed to braze ferrite directly in an atmospheric environment at a relatively low temperature (550 ℃, 10 min). The typical microstructure of the ferrite joints was investigated, and the products formed in the joint domain were characterized. The research results indicated that Zn2Mg(PO4)2 phases were produced in the joint domain, and the typical microstructure was ferrite/ Zn2Mg(PO4)2 + glassy phase + Zn2Mg(PO4)2/ferrite. In addition, mechanical properties of the joints were also investigated. The shear test was performed on six brazed samples, and the results showed the joints possessed average strength of 90.2 MP under the joining parameters. Subsequent ffracture analysis indicated the fracture mainly took place at the ferrite side. The present work provides a channel of using phosphate glass for brazing ferrite at low temperatures.The authors gratefully acknowledge financial support from the China Scholarship Council (CSC) (contract 201906295008)

Wetting behavior of SnO-ZnO-P₂O₅-SiO₂ glass on 60 vol% SiCₚ/Al composites and characterization of the interfacial phases

The phosphate glass having a chemical composition of 49SnO-19ZnO-32P2O5-3SiO2 (mol.%) was prepared in the present work. Then, the wettability of the glass on 60 vol/% SiCp/Al composites was investigated at 550 °C for 20 min. The results verified potential brazibility of high volume SiCp/Al composites with glass. Average contact angle of 26.3° was reached, performing good wettability of the glass on the surface of 60 vol% SiCp/Al composites. The interfacial products were characterized in detail, and the results showed the ZnPO4 layer was formed adjacent to the composites due to the crystallization in the glass braze.This research was supported by the Natural Science Foundation of Shaanxi Province, China (Grant No. 2021JQ-103) ; State Key Laboratory of Advanced Welding and Joining, Harbin Institute of Technology;China Postdoctoral Science Foundation (Grant No. 2018 M643733) ; China Scholarship Council (CSC) (Contract No. 201906295008)

Investigation on the High-Temperature Oxidation Resistance of Ni-(3~10) Ta and Ni-(3~10) Y Alloys

Ni-(3~10) Ta and Ni-(3~10) Y alloys were fabricated by vacuum arc melting. The oxidation resistance of the alloys was studied by cyclic and isothermal oxidation tests at 800 °C in static air. The present work focused on the investigation of the effects of the alloying elements (Ta and Y) on the oxidation behavior of Ni-based alloys. The oxidation behavior of alloys was evaluated by mass gain, composition, as well as the microstructure of oxidized products. The experimental results indicated that Ta at a low content (3 wt %) had a positive role in enhancing oxidation resistance by decreasing the oxygen vacancy concentration of the oxide layer to prevent the inward diffusion of oxygen during oxidation, and the mass gain decreased from 2.9 mg·cm−2 to 1.7 mg·cm−2 (800 °C/200 h), while Y (3~10 wt %) degraded the oxidation resistance. However, it is worth mentioning that the pinning effect of Y2O3 increased the adhesion between the substrate and oxide layer by changing the growing patterns of the oxide layer from a plane growth to fibrous growth. Among the results, the bonding of the substrate and oxide layer was best in the Ni-3Y alloys