Self-supervised phase unwrapping in fringe projection profilometry

Fast-speed and high-accuracy three-dimensional (3D) shape measurement has been the goal all along in fringe projection profilometry (FPP). The dual-frequency temporal phase unwrapping method (DF-TPU) is one of the prominent technologies to achieve this goal. However, the period number of the high-frequency pattern of existing DF-TPU approaches is usually limited by the inevitable phase errors, setting a limit to measurement accuracy. Deep-learning-based phase unwrapping methods for single-camera FPP usually require labeled data for training. In this letter, a novel self-supervised phase unwrapping method for single-camera FPP systems is proposed. The trained network can retrieve the absolute fringe order from one phase map of 64-period and overperform DF-TPU approaches in terms of depth accuracy. Experimental results demonstrate the validation of the proposed method on real scenes of motion blur, isolated objects, low reflectivity, and phase discontinuity

Deep Learning-enabled Spatial Phase Unwrapping for 3D Measurement

In terms of 3D imaging speed and system cost, the single-camera system projecting single-frequency patterns is the ideal option among all proposed Fringe Projection Profilometry (FPP) systems. This system necessitates a robust spatial phase unwrapping (SPU) algorithm. However, robust SPU remains a challenge in complex scenes. Quality-guided SPU algorithms need more efficient ways to identify the unreliable points in phase maps before unwrapping. End-to-end deep learning SPU methods face generality and interpretability problems. This paper proposes a hybrid method combining deep learning and traditional path-following for robust SPU in FPP. This hybrid SPU scheme demonstrates better robustness than traditional quality-guided SPU methods, better interpretability than end-to-end deep learning scheme, and generality on unseen data. Experiments on the real dataset of multiple illumination conditions and multiple FPP systems differing in image resolution, the number of fringes, fringe direction, and optics wavelength verify the effectiveness of the proposed method.Comment: 26 page

Exploration on flotation behavior of galena in seawater and related mechanism

The utilization of seawater in mineral flotation is the future development trend because of the shortage of fresh water resources. However, at present, the flotation behavior and mechanism of galena in seawater are not clear. Therefore, this paper comprehensively carried out the effect mechanism of seawater on the flotation of galena. Micro-flotation results illustrated that the recovery of galena was higher in deionized water than that in 5×10-2 mol/L MgCl2 solution, 1×10-2 mol/L CaCl2 solution and seawater. Contact angle determination and Zeta potential distribution measurements showed that hydrophilic substances adsorbed on the surface of galena under alkaline conditions. X-ray photoelectron spectroscopy (XPS) analysis further indicated that these substances were hydroxides precipitates, carbonate precipitates and hydroxyl complexes formed by divalent magnesium and calcium ions, which prevented the adsorption of collector on mineral surface. As a result, the galena recovery declined in 5×10-2 mol/L MgCl2 solution, 1×10-2 mol/L CaCl2 solution and seawater

Identification of microRNAs and mRNAs associated with multidrug resistance of human laryngeal cancer Hep-2 cells

Multidrug resistance (MDR) poses a serious impediment to the success of chemotherapy for laryngeal cancer. To identify microRNAs and mRNAs associated with MDR of human laryngeal cancer Hep-2 cells, we developed a multidrug-resistant human laryngeal cancer subline, designated Hep-2/v, by exposing Hep-2 cells to stepwise increasing concentrations of vincristine (0.02-0.96'µM). Microarray assays were performed to compare the microRNA and mRNA expression profiles of Hep-2 and Hep-2/v cells. Compared to Hep-2 cells, Hep-2/v cells were more resistant to chemotherapy drugs (&#8764;45-fold more resistant to vincristine, 5.1-fold more resistant to cisplatin, and 5.6-fold more resistant to 5-fluorouracil) and had a longer doubling time (42.33±1.76 vs 28.75±1.12'h, P<0.05), higher percentage of cells in G0/G1 phase (80.98±0.52 vs69.14±0.89, P<0.05), increased efflux of rhodamine 123 (95.97±0.56 vs 12.40±0.44%, P<0.01), and up-regulated MDR1 expression. A total of 7 microRNAs and 605 mRNAs were differentially expressed between the two cell types. Of the differentially expressed mRNAs identified, regulator of G-protein signaling 10, high-temperature requirement protein A1, and nuclear protein 1 were found to be the putative targets of the differentially expressed microRNAs identified. These findings may open a new avenue for clarifying the mechanisms responsible for MDR in laryngeal cancer