A Robust Rigid Registration Framework of 3D Indoor Scene Point Clouds Based on RGB-D Information

Rigid registration of 3D indoor scenes is a fundamental yet vital task in various fields that include remote sensing (e.g., 3D reconstruction of indoor scenes), photogrammetry measurement, geometry modeling, etc. Nevertheless, state-of-the-art registration approaches still have defects when dealing with low-quality indoor scene point clouds derived from consumer-grade RGB-D sensors. The major challenge is accurately extracting correspondences between a pair of low-quality point clouds when they contain considerable noise, outliers, or weak texture features. To solve the problem, we present a point cloud registration framework in view of RGB-D information. First, we propose a point normal filter for effectively removing noise and simultaneously maintaining sharp geometric features and smooth transition regions. Second, we design a correspondence extraction scheme based on a novel descriptor encoding textural and geometry information, which can robustly establish dense correspondences between a pair of low-quality point clouds. Finally, we propose a point-to-plane registration technology via a nonconvex regularizer, which can further diminish the influence of those false correspondences and produce an exact rigid transformation between a pair of point clouds. Compared to existing state-of-the-art techniques, intensive experimental results demonstrate that our registration framework is excellent visually and numerically, especially for dealing with low-quality indoor scenes.

Consequences of Choosing Different Settings When Processing Hip-Based Accelerometry Data From Older Adults: A Practical Approach Using Baseline Data From the SITLESS Study

Accurately measuring older adults’ physical activity (PA) and sedentary behavior (SB) using accelerometers is essential, as both are important markers of health. This study aimed to highlight how steps taken during data processing may affect key hip-based accelerometry outcomes in older adults, using a selection of baseline accelerometry data (n = 658) from the SITLESS study. Different analytical parameters tested included wear-time algorithms, use of low-frequency extension (LFE) filter, epoch length, and minimum and maximum daily wear-time thresholds. These were compared against vertical axis counts per minute (CPM), vector magnitude (VM) CPM, SB, light PA, moderate-to-vigorous PA, step counts, and wear-time percentage. Differences in settings across the analytical parameters were assessed using paired sample t-tests and repeated measures ANOVAs using Bonferroni correction. Using the “Choi” versus “Troiano” wear-time algorithm resulted in a higher percentage wear-time. Most SB and PA outcomes were significantly different across wear-time algorithms (p < .001). This was similar when using the LFE filter versus normal filter (p < .001). Using 10-second epoch length increased daily SB time (between +75.7 and +79.2 minutes) compared to 60-second. Most SB and PA outcomes significantly changed comparing minimum-wear-time thresholds of 360, 480, 600, and 720 minutes per day (p < .001). Applying a log-diary with a ≥1140-minute threshold had a significant impact on vertical axis CPM, VM CPM, SB, and light PA outcomes (p < .001). This study demonstrates the potential variability in the number of participants being included in studies and reported SB and PA levels when processing older adults’ accelerometry data dependent on the analytical procedures utilized.

Real-Time and Low-Power HEVC Deblocking Filter Architecture Targeting 8K UHD @ 60fps Videos

This paper presents a low-power and high-throughput Deblocking Filter (DBF) hardware architecture for the High Efficiency Video Coding (HEVC) standard. The architecture implements the three HEVC deblocking filtering modes, namely: (i) normal filter, (ii) strong filter and (iii) chroma filter. The designed DBF architecture is able to process 64 samples per clock cycle, considering luminance and chrominance components. The architecture was described in VHDL and synthesized targeting the CMOS standard-cell TSMC 40nm library. The power results were reached with real input samples extracted from the HEVC reference software. Synthesis results show that the DBF design, when running at 124.4MHz, can reach a throughput of 60 frames per second (fps) for a 7680×4320 (8K UHD) video resolution. At this frequency, the DBF design presented a low power dissipation of 4.73mW. The presented DBF hardware surpasses all related works in terms of throughput and power dissipation and is the unique solution able to real-time processing of 8K UHD videos at 60 frames per second.

Penyisipan Citra pada Audio dengan Kode PN Terdistribusi Gaussian

ABSTRAKPada makalah ini, perancangan audio watermarking memanfaatkan kode PN yang terdistribusi Gaussian atau Normal dengan menggunakan citra sebagai watermark yang disisipkan pada audio. Watermark yang berupa citra biner diubah ke dalam vektor 1 dimensi, kemudian dijumlahkan dengan kode PN terdistribusi normal yang disaring dengan filter psikoakustik. Setelah itu, sinyal dikalikan dengan faktor gain α sebelum dijumlahkan dengan host audio untuk mendapatkan watermarked audio. Hasil dari simulasi menunjukkan bahwa sistem memiliki kapasitas watermark yang tinggi pada 689.06 bps, imperseptibilitas yang baik pada SNR>26 dB, dan tahan terhadap serangan LPF mulai frekuensi cut off 6 kHz keatas, serangan Additive Noise mulai 40 dB keatas, resampling pada rate 16 kHz, LSC 1% - 10%, dan kompresi MP3 untuk rate 192 kbps.Kata kunci: Audio Watermarking, Kode PN, distribusi normal, filter sikoakustik ABSTRACTIn this paper, the design of audio watermarking utilizes PN code that is Gaussian or Normal distributed by using the image as a watermark inserted in the audio. The watermark in the form of binary images is converted into a 1-dimensional vector, then summed up with a normally distributed PN code filtered by a psychoacoustic filter. After that, the signal is multiplied by α gain factor before adding it to the audio host to get the watermarked audio. The result of the simulation shows that the system has a high watermark capacity at 689.06 bps, good imperceptibility at SNR> 26 dB, and withstand LPF attacks starting from 6 kHz cut-off frequency and above, Additive Noise attacks from 40 dB up, resampling at 16 kHz , LSC 1% - 10%, and MP3 compression for 192 kbps rate.Keywords: Audio Watermarking, PN code, normal distribution, psychoacoustic filter

The practical implementation of DIN EN ISO 16891 “Test methods for evaluating the degradation of characteristics of cleanable filter media“/Die praktische Umsetzung der Norm DIN EN ISO 16891 „Prüfmethode zur Ermittlung der Abnahme der Wirksamkeit von abreinigbaren Filtermedien“

Summary DIN EN ISO 16891:2016 “Test methods for evaluating the degradation of characteristics of cleanable filter media“ is the first standard in Germany that takes into account the thermal and chemical ageing of the filter media and stipulates how they are to be tested. These normative specifications were to be implemented as part of a research project. However, the boundary test conditions proved to be general conditions and many other details were not described in the standard. This is why, as well as there being many safety aspects, the filter testing has so far only been partially implemented. Uniform loading of several samples at the normal filter flow velocities used in practice could not be implemented. Doubt exists with regard to the comparability of the results of the tests that were based on the standard in its current form at different test institutes.

Defining Accelerometer Nonwear Time to Maximize Detection of Sedentary Time in Youth

Purpose: The present study examined various accelerometer nonwear definitions and their impact on detection of sedentary time using different ActiGraph models, filters, and axes. Methods: In total, 61 youth (34 children and 27 adolescents; aged 5–17 y) wore a 7164 and GT3X+ ActiGraph on a hip-worn belt during a 90-minute structured sedentary activity. Data from GT3X+ were downloaded using the Normal filter (N) and low-frequency extension (LFE), and vertical axis (V) and vector magnitude (VM) counts were examined. Nine nonwear definitions were applied to the 7164 model (V), GT3X+LFE (V and VM), and GT3X+N (V and VM), and sedentary estimates were computed. Results: The GT3X+LFE-VM was most sensitive to movement and could accurately detect observed sedentary time with the shortest nonwear definition of 20 minutes of consecutive “0” counts for children and 40 minutes for adolescents. The GT3X+N-V was least sensitive to movement and required longer definitions to detect observed sedentary time (40 min for children and 90 min for adolescents). VM definitions were 10 minutes shorter than V definitions. LFE definitions were 40 minutes shorter than N definitions in adolescents. Conclusion: Different nonwear definitions are needed for children and adolescents and for different model-filter-axis types. Authors need to consider nonwear definitions when comparing prevalence rates of sedentary behavior across studies.

Preparation of Nano-Co3O4 by Direct Thermal Decomposition of Cobalt(II) Nitrate Hexahydrate for Electrochemical Water Oxidation

Background: Nano-Co3O4 has been used in various technological areas and applications such as electrochemical sensors and electrochemical water splitting. Even though many efforts have been expended to prepare nano-Co3O4, the development of novel methods to prepare Co3O4 using simple processes and at low cost remain a topic of interest. Besides, it could be economic and useful if the synthesized nanoparticle could be applied as efficient electrocatalyst upon its immobilization on a cheap base electrode material by very simple method for various practical applications including renewable energy. Method: We prepared nano-Co3O4 by a direct thermal decomposition of an inexpensive, simple and widely available cobalt inorganic precursor, such as Co(NO3)2·6H2O without any type of prereaction or processing. The nano-Co3O4 was immobilized on filter-paper-derived carbon electrode by drop-drying method for applying as electrode materials toward water electrooxidation. Results: The X-ray diffraction, field emission scanning electron microscopy, and transmission electron microscopy analysis confirmed the formation of short nanorods of single-phase Co3O4 upon thermal decomposition of Co(NO3)2·6H2O at 520°C. The electrocatalytic properties of the nano- Co3O4 were evaluated after immobilizing it on a cheap carbon electrode derived from normal filter paper. The modified electrode showed good electrocatalytic properties toward water oxidation in an alkaline solution. Conclusion: In conclusion, we developed a very simple, straight-forward and economic method for preparation of nano-Co3O4 and immobilized it on very cheap carbon electrode for evaluating its electrocatalytic properties. Due to the high electrocatalytic properties, the prepared nano-Co3O4 could potentially play an important role in various practical fields.

A simple photoluminescent strategy for pH and amine vapors detection based on Eu(iii)-complex functionalized material

A simple luminescence sensing strategy has been designed for pH and amine vapors detection after loaded luminescent compound Eu(DBM)3Phen (LMOF-1), Eu(DBM)3BPY (LMOF-2) on portable matrices such as neutral silica plate and normal filter paper.