Rapid 3D measurement technique for colorful objects employing RGB color light projection

Abstract

Three-dimensional (3D) measurement of colorful objects is challenging. As different colors can absorb different wavelengths of projected light, the brightness and contrast of the captured fringe are not uniform when employing single-color light projection, which will lead to measurement error. In this paper, we present a rapid 3D measurement technique for colorful objects employing red, green, and blue (RGB) light projection. According to the research in this paper, for common colors, the pixel with the largest brightness and contrast can be extracted from the three fringes projected by RGB light. Furthermore, we introduce the selection method of exposure time, and then combine the high-speed projection technique with the optimal pixel-extraction algorithm to get the optimal set of fringes for phase calculation. Experiments show that the proposed method improves the measurement accuracy and efficiency.

Investigation on the application of ZnO nanostructures to improve the optical performance of white light-emitting diodes

“…This section demonstrates the scattering coefficient μsca(λ), the scattering phase functions S1(θ) and S2(θ), the reduced scattering coefficient δsca(λ), and the scattering cross-section Csca of ZnO particles. As mentioned above, the Mie-scattering theory [16][17][18] and MATLAB tool are utilized to calculate the light scattering effect when ZnO nanoparticles are added. The computation of ZnO scattering is expressed as:…”

“…In the present, diffuser-loaded encapsulation is a promising method in enhancing the color quality of WLEDs because it can fulfill the requirements of cost-saving and simple fabrication. Adopting this concept, WLED packages with diffuser base that contains metal oxide diffuser materials (TiO2, ZrO2 and SiO2) have been developed [15][16][17][18]. In the research of Chen's group [15], ZrO2 grains whose particle size is 300 nm were integrated to the remote phosphor structure and resulted in the decrease of CCT deviation, from 1000 K to 420 K in the angles from −70° to 70°.…”

“…In the research of Chen's group [15], ZrO2 grains whose particle size is 300 nm were integrated to the remote phosphor structure and resulted in the decrease of CCT deviation, from 1000 K to 420 K in the angles from −70° to 70°. TiO2 diffusers (320 nm) on the phosphor or encapsulation layer were used by Lee and his partners [18]. They reported that the growth of TiO2 concentration caused the CCT deviations to reduce.…”

“…A hybrid ZnO nanostructure with microscopic cylinders and nanorods installed on light-emitting chip that can enhance the light-emitting ability of GaN-based LEDs was demonstrated by Yin's team [26]. The result from the GaN blue LEDs with ZnO nanoparticles implanted to planar indium tin oxide (ITO) film shows a growth in light emission [18]. The ZnO nanorods were used to tune the pattern of light projected from the GaN-LEDs.…”

3-D Shape Reconstruction of Non-Uniform Reflectance Surface Based on Pixel Intensity, Pixel Color and Camera Exposure Time Adaptive Adjustment

“…The reconstruction accuracy of FPP depends on the captured image quality. It is difficult to obtain high-quality images on the surface of colored objects or locally highly reflective objects, which brings great challenges to 3-D shape reconstruction of the objects with non uniform reflectivity [1][2][3][4][5]. Regarding the above problems, many approaches have been proposed, and these methods are generally divided into the following four categories.…”