Number Of Light Emitting Diodes Research Articles

Robotic measurement system based on cooperative optical profiler integrating fringe projection with photometric stereo for highly reflective workpiece

Robotic measurement has emerged as a prominent method for the quality control of large-scale metal workpieces. However, it faces two significant challenges: optical measurement of homogeneous high-reflective metal surfaces and point cloud registration on local featureless surfaces. To address these challenges, this study presents a cooperative optical profiler that integrates a certain number of light-emitting diodes into a conventional fringe projection profiler. This integration enables the use of photometric stereo, providing comprehensive and accurate surface normals of machined metal surfaces with intricate details such as tool marks. The surface normal was then fused with the initial point cloud from the fringe projection profiler to yield complete local measurement results. In addition, a geometry descriptor incorporating the surface normal was designed to improve data registration accuracy. Experiments based on six small workpieces with the combination of three shapes and two materials and a large freeform workpiece demonstrated that the proposed method achieved measurement accuracy close to that of a coordinate measuring machine.

Tweaking Light-Emitting Diodes: A Multiobjective Optimal Design for New Luminaires

In this article, a Pareto multiobjective optimization is performed to design new luminaires. The effort involves finding the optimal forward current, the number of light-emitting diodes (LEDs), and a proper heat sink by taking into account the cost, energy consumption, and environmental impact (carrying out a cradleto-grave life-cycle analysis). Three commercial white LEDs were studied and modeled in terms of their optical, electrical, thermal, and aging performance. The multiobjective methodology was also applied to other lamps (incandescent, halogen, and fluorescent), which indicated that LED lighting has great potential for energy and cost savings, with minimal long-term environmental impact.

Optimized LEDs Footprinting for Indoor Visible Light Communication Networks

Indoor access to the Internet via visible light communication (VLC) technology is becoming an issue and in this sense system planning requires to look at the number of light-emitting diodes (LEDs) to be used. This task can be accomplished by looking at different performance metrics. We consider the problem of optimal footprint mapping by taking into account the achievable user rate when handover procedures take place due to user mobility. This problem is equivalent to the optimal LEDs placement. In this regard, it is shown that several parameters influence system performance starting from the data rate of download, the speed of the user in the room as well the handover time. In this context, we derive a mathematical tool for VLC network planning and show the performance that can be achieved as a function of different parameters.