LED lights and LED traffic signal are spreading rapidly, and the research and the development of a visible optical communication by modulating the light intensity of the LED light source are advancing at the same time in recent years. In this paper, the characteristics and the application of visible light communication, and activities of standardization are explained.
This technology is the three-dimensional survey system using photogrammetry technique and visible light communication technology, The LED light sources are placed at a position to be measured and stereo-photographed by digital cameras installed in two places. In addition, the relation of same lights in different viewpoints can be automatically done by extracting unique blinking patterns of each light. Experimental results show that this system can provide enough accuracy for construction survey. By using this system, many points can be measured at once, in a short time and in better accurate. For this reason, it can be expected surveyor-saving, suppression of aerial work and improvement of surveying accuracy. In addition, it makes possible to measure three-dimensional coordinates of many points automatically and repeatedly. This system has already been used several bridge construction projects and aluminum dome tank. In this paper, the summary of some projects applied this system are presented.
This article introduces the OCC (Optical Camera Communications) which is a type of Visible Light Communication using camera as a receiving device. At first part, describing the technical overview is shown. And then, as a application example, "Picapicamera" which is implemented as a smart phone app is introduced.
The optical coherence tomography (OCT) system with a near-infrared light source has been used in the clinical site of ophthalmology. Almost all the pigments in the biological tissue are transparent for near infrared light. In order to take a spectroscopic tomographic image of the biological tissue, we developed the OCT system with visible light emitting diodes (LED) with the central wavelengths of 444.6nm (B), 522.6nm (G), and 637.3nm (R). The spectrum-sensitive performance was confirmed by using RGB cellophane phantoms. The internal structure and the dye distribution in the colored goat hairs could be spectroscopically observed by the developed OCT system. The spectral reflectance was quantitatively estimated by the cross-sectional images. As a result, not only the internal structure but also the dye distribution of the colored goat hairs were successfully reconstructed as the tomographic image.
High directional LED lighting has been developed as a parallel light source as a hologram reconstruction. High visibility can be obtained to have the light intensity distribution of the rectangular pseudo-parallel light using an expanded image from the emitter of the light source. It is possible to telecentric lighting by multi-dots pattern formation using a pseudo-parallel light. High stage effects can be obtained by linear pattern formation by oblique irradiation of pseudo-parallel light. It is useful as a safety aided by the linear pattern formation by the refractive optical element and a pseudoparallel light. High directional pattern formation LED lighting are beginning to be put to practical use in the industry various fields such as inspection, stage, building, road, safety, art, sightseeing, communication, laboratory and so on.