Color gamut extension algorithm for various images based on laser display.

In pursuit of enhancing the display performance of gamut extension algorithms across diverse image types while minimizing image dependency, this study introduces a dynamic gamut extension algorithm. The algorithm is designed to extend the sRGB source gamut towards the wide gamut of a laser display. To evaluate its effectiveness, psychophysical experiments were conducted using four distinct image categories: complexions, scenery, objects, and color blocks and bars. The performance of the proposed algorithm was benchmarked against four established color gamut mapping algorithms. The comparative analysis revealed that our algorithm excels in handling wide color gamuts, outperforming the alternatives in terms of preference and the preservation of detail richness.

Inverse design of chiral functional films by a robotic AI-guided system.

Artificial chiral materials and nanostructures with strong and tuneable chiroptical activities, including sign, magnitude, and wavelength distribution, are useful owing to their potential applications in chiral sensing, enantioselective catalysis, and chiroptical devices. Thus, the inverse design and customized manufacturing of these materials is highly desirable. Here, we use an artificial intelligence (AI) guided robotic chemist to accurately predict chiroptical activities from the experimental absorption spectra and structure/process parameters, and generate chiral films with targeted chiroptical activities across the full visible spectrum. The robotic AI-chemist carries out the entire process, including chiral film construction, characterization, and testing. A machine learned reverse design model using spectrum embedded descriptors is developed to predict optimal structure/process parameters for any targeted chiroptical property. A series of chiral films with a dissymmetry factor as high as 1.9 (gabs ~ 1.9) are identified out of more than 100 million possible structures, and their feasible application in circular polarization-selective color filters for multiplex laser display and switchable circularly polarized (CP) luminescence is demonstrated. Our findings not only provide chiral films with the highest reported chiroptical activity, but also have great fundamental value for the inverse design of chiroptical materials.

Research on the color gamut volume and light efficiency in four-primary laser display systems.

The color gamut volume (CGV) and light efficiency of a four-primary display system were theoretically simulated with different wavelength configuration. Given the wavelengths of the blue and red primaries, we optimized the other two primary colors; the wavelength set with the largest CGV was chosen. The maximum CGV, 2.346 × 106, was obtained at (660, 530, 507, 465) nm. The maximum light efficiency was also determined. A trade-off between CGV and light efficiency should be made according to the requirement of the devices. This study provides guidance for the construction of a four-primary laser display system and the optimization of the CGV in multi-primary display systems.

Potential application of a green fiber laser in laser display systems.

This study explores the application of optical fiber lasers in display systems by integrating a P r3+-doped green all-fiber laser into a laser projection display system. As a control group to compare the results, a 520 nm semiconductor green laser diode module was integrated, similar to the experimental group. The color gamut and speckle performances were studied and compared. The results showed that the experimental group performed slightly better in the color gamut volume. The speckle contrast decreased rapidly in the experimental group when power increased. To our knowledge, this is the first study to apply a fiber laser to a laser display system. The results shed light on developing laser display systems with fewer or no speckle reduction elements.

Renal Insufficiency Increases the Combined Risk of Left Ventricular Hypertrophy and Dysfunction in Patients at High Risk of Cardiovascular Diseases.

BACKGROUND: The identification of asymptomatic structural and functional cardiac abnormalities can help us to recognize early and intervene in patients at pre-heart failure (HF). However, few studies have adequately evaluated the associations of renal function and left ventricular (LV) structure and function in patients at high risk of cardiovascular diseases (CVD). METHODS: Patients undergoing coronary angiography and/or percutaneous coronary interventions were enrolled from the Cardiorenal ImprovemeNt II (CIN-II) cohort study, and their echocardiography and renal function were assessed at admission. Patients were divided into five groups according to their estimated glomerular filtration rate (eGFR). Our outcomes were LV hypertrophy and LV systolic and diastolic dysfunction. Multivariable logistic regression analyses were conducted to investigate the associations of eGFR with LV hypertrophy and LV systolic and diastolic dysfunction. RESULTS: A total of 5610 patients (mean age: 61.6 ± 10.6 years; 27.3% female) were included in the final analysis. The prevalence of LV hypertrophy assessed by echocardiography was 29.0%, 34.8%, 51.9%, 66.7%, and 74.3% for the eGFR categories >90, 61-90, 31-60, 16-30, and ≤15 mL/min per 1.73 m2 or for patients needing dialysis, respectively. Multivariate logistic regression analysis showed that subjects with eGFR levels of ≤15 mL/min per 1.73 m2 or needing dialysis (OR: 4.66, 95% CI: 2.96-7.54), as well as those with eGFR levels of 16-30 (OR: 3.87, 95% CI: 2.43-6.24), 31-60 (OR: 2.00, 95% CI: 1.64-2.45), and 61-90 (OR: 1.23, 95% CI: 1.07-1.42), were significantly associated with LV hypertrophy. This reduction in renal function was also significantly associated with LV systolic and diastolic dysfunction (all P for trend <0.001). In addition, a per one unit decrease in eGFR was associated with a 2% heightened combined risk of LV hypertrophy and systolic and diastolic dysfunction. CONCLUSIONS: Among patients at high risk of CVD, poor renal function was strongly associated with cardiac structural and functional abnormalities. In addition, the presence or absence of CAD did not change the associations. The results may have implications for the pathophysiology behind cardiorenal syndrome.

Color-speckle assessment in multi-primary laser-projection systems based on a 3D Jzazbz color space.

We propose and demonstrate a color-speckle assessment method based on a three-dimensional Jzazbz color space, which is appropriate for both three-primary and multi-primary systems. In the proposed scheme, new physical quantities are defined to describe the color-speckle characteristics, which provides a general and intuitive color-speckle evaluation for different laser projectors. Experimental verification is also performed using three-primary and six-primary laser projectors. The simulation and measurement results are consistent.

Evaluation of gamut enhancement in yellow regions and a choice of optimal wavelength for a RGBY four-primary laser display system.

To improve the color rendering ability in yellow color regions, the inclusion of yellow among the primary colors is commonly proposed. In this study, an algorithm for evaluating gamut enhancement in yellow regions is developed. The performance of different wavelength sets of RGBY four-primary system is studied theoretically in terms of various aspects, including the color gamut volume, gamut coverages, and gamut enhancement ratio in yellow regions. The optimal wavelength set and its optimal luminance ratio are then determined. This research provides strong guidance for the construction of practical four-primary-laser display systems.

Upper limit of gamut volumes in multi-primary display systems.

Based on the difference between multi-primary displays (MPDs) and three-primary displays, we propose a new definition for evaluating the color gamut volume (CGV) to explore the upper limit of MPDs, which could theoretically represent all colors that MPDs can display. The proposed definition corrects the defects in the L*a*b* color space that arise when calculating the CGV of MPDs. In view of the high computational complexity of this method, we propose a simplified scheme with a small margin of error. Additionally, we verify the new definition with experiments on a six-primary projector. This method is helpful in guiding the selection of light sources and the evaluation of MPDs, and also has great reference value to calculate the target gamut for gamut mapping in MPDs.

Resolution-preserving passive 2D/3D convertible display based on holographic optical elements.

We propose and demonstrate a resolution-preserving passive 2D/3D convertible display by two individual wavelengths. It uses a holographic optical element to generate two images and passively separate the exit pupils for these two wavelengths, which forms two viewpoints for each of the observer's eyes. Due to Bragg-mismatched reconstruction of two similar but distinct wavelengths, the images are separated in space. They can be fused into one through the convergence function of human eyes. By switching the input image source, the conversion between 2D and 3D mode can be realized. This method is resolution-preserving and 2D/3D convertible with no extra active components. For experimental verification, a proof-of-concept projection-type prototype is assessed.

Tailoring the spectrum and spatial mode of Yb-doped random fiber laser.

In this paper, we make a comprehensive study on tailoring the spectrum and transverse mode of random fiber lasers (RFLs). By simply temperature tuning, the mode gain profile of RFL can be flexibly and precisely manipulated. The spectrum of laser output can be easily tailored in single-wavelength, dual-wavelength, and three-wavelength, respectively. Meanwhile, the operating transverse mode is also optional among LP01 mode, LP11 mode, and hybrid mode. The slope efficiency of 17.9% and 27.3% are obtained for LP11 mode and LP01 mode operation, respectively. Besides, the coherence control can be confirmed by making speckle contrast measurements. This high-efficiency RFL with the customizable spectrum and spatial mode would have unique applications in wavelength or mode division multiplexing systems, speckle-free imaging, secure communication, and information encryption.