scholarly journals High-resolution Three-dimensional Surface Imaging Microscope Based on Digital Fringe Projection Technique

2020 ◽  
Vol 20 (3) ◽  
pp. 139-144
Author(s):  
Cheng-Yang Liu ◽  
Tzu-Ping Yen ◽  
Chien-Wen Chen
Keyword(s):  
High Resolution ◽  
Imaging System ◽  
Three Dimensional ◽  
Fringe Projection ◽  
Surface Imaging ◽  
Projection Technique ◽  
Digital Fringe Projection ◽  
Absolute Phase ◽  
The Absolute ◽  
Fringe Patterns

AbstractThe three-dimensional (3-D) micro-scale surface imaging system based on the digital fringe projection technique for the assessments of microfiber and metric screw is presented in this paper. The proposed system comprises a digital light processing (DLP) projector, a set of optical lenses, a microscope, and a charge coupled device (CCD). The digital seven-step fringe patterns from the DLP projector pass through a set of optical lenses before being focused on the target surface. A set of optical lenses is designed for adjustment and size coupling of fringe patterns. A high-resolution CCD camera is employed to picture these distorted fringe patterns. The wrapped phase map is calculated by seven-step phase-shifting calculation from these distorted fringe patterns. The unwrapping calculation with quality guided path is introduced to compute the absolute phase values. The dimensional calibration methods are used to acquire the transformation between real 3-D shape and the absolute phase value. The capability of complex surface measurement for our system is demonstrated by using ISO standard screw M1.6. The experimental results for microfiber with 3 μm diameter indicate that the spatial and vertical resolutions can reach about 3 μm in our system. The proposed system provides a fast digital imaging system to examine the surface features with high-resolution for automatic optical inspection industry.

A New Three-Dimensional Profilometer for Surface Profile Measurement Using Digital Fringe Projection and Phase Shifting

2005 ◽  
Vol 295-296 ◽  
pp. 471-476
Author(s):  
Liang Chia Chen ◽  
S.H. Tsai ◽  
Kuang Chao Fan
Keyword(s):  
High Speed ◽  
Structured Light ◽  
Three Dimensional ◽  
Surface Profile ◽  
Phase Shifting ◽  
Fringe Projection ◽  
Surface Measurement ◽  
Profile Measurement ◽  
Digital Fringe Projection ◽  
Fringe Patterns

The development of a three-dimensional surface profilometer using digital fringe projection technology and phase-shifting principle is presented. Accurate and high-speed three-dimensional profile measurement plays a key role in determining the success of process automation and productivity. By integrating a digital micromirror device (DMD) with the developed system, exclusive advantages in projecting flexible and accurate structured-light patterns onto the object surface to be measured can be obtained. Furthermore, the developed system consists of a specially designed micro-projecting optical unit for generating flexibly optimal structured-light to accommodate requirements in terms of measurement range and resolution. Its wide angle image detection design also improves measurement resolution for detecting deformed fringe patterns. This resolves the problem in capturing effective deformed fringe patterns for phase shifting, especially when a coaxial optical layout of a stereomicroscope is employed. Experimental results verified that the maximum error was within a reasonable range of the measured depth. The developed system and the method can provide a useful and effective tool for 3D full field surface measurement ranging from µm up to cm scale.

FULLY AUTOMATIC DIGITAL FRINGE PROJECTION MEASUREMENT FOR 3D FACIAL SURFACE

2019 ◽  
Vol 19 (02) ◽  
pp. 1940019
Author(s):  
CHENG-YANG LIU ◽  
CHENG-YU WANG ◽  
LI-WEI TENG
Keyword(s):  
High Speed ◽  
Three Dimensional ◽  
Facial Feature ◽  
High Accuracy ◽  
Industrial Applications ◽  
Fringe Projection ◽  
Projection Technique ◽  
Digital Light Processing ◽  
Digital Fringe Projection ◽  
Fully Automatic

Digital fringe projection technique is widely used in industrial applications with high accuracy and measurement speed. In this study, a fully automatic high-speed digital fringe projection technique is presented to profile 3D facial characteristics. The structured light with fringe pattern is used to be the light source in the measurement system and is projected by a digital light processing projector. The distorted fringe patterns from facial surface are captured by the digital camera. The absolute phase maps are calculated by using phase-shifting and quality guided path unwrapping algorithm. A complete, 3D facial feature is obtained by our measurement. We achieved simultaneous phase acquisition, reconstruction and three-dimensional (3D) exhibition at a speed of 0.5[Formula: see text]s. This technique may provide a high accuracy and real-time 3D facial measurement for biometric verification.

scholarly journals Investigation of Phase Pattern Modulation for Digital Fringe Projection Profilometry

2020 ◽  
Vol 20 (1) ◽  
pp. 43-49
Author(s):  
Cheng-Yang Liu ◽  
Chung-Yi Wang
Keyword(s):  
Three Dimensional ◽  
Phase Shifting ◽  
Fringe Projection ◽  
Depth Range ◽  
Digital Fringe Projection ◽  
Great Possibility ◽  
Fringe Patterns ◽  
Pattern Modulation ◽  
Profile Reconstruction ◽  
Fringe Projection Profilometry

AbstractThe fringe projection profilometry with sinusoidal patterns based on phase-shifting algorithms is commonly distorted by the nonlinear intensity response of commercial projector. In order to solve this issue, sinusoidal width modulation is presented to generate binary sinusoidal patterns for defocusing the projection. However, the residual errors in the phase maps are usually notable for highly accurate three-dimensional shape measurements. In this paper, we propose the fringe patterns of the sinusoidal, square, and triangular periodic waveforms with seven-step phase-shifting algorithm to further improve the accuracy of three-dimensional profile reconstruction. The absolute phase values are calculated by using quality guided path unwrapping. We learn that by properly selecting fringe patterns according to the target shape, the undesired harmonics of the measured surface have negligible effect on the phase values. The experiments are presented to verify the imaging performances of three fringe patterns for different testing targets. The triangular fringe patterns are suitable for the shape measurements of complex targets with curved surfaces. The results provide a great possibility for high-accuracy shape measurement technique with wider measuring depth range.

Dynamics range enhancement in digital fringe projection technique

2015 ◽  
Vol 39 ◽  
pp. 243-251 ◽  
Author(s):  
Gelareh Babaie ◽  
Mehrdad Abolbashari ◽  
Faramarz Farahi
Keyword(s):  
Fringe Projection ◽  
Projection Technique ◽  
Digital Fringe Projection

scholarly journals Single-shot detection of 8 unique monochrome fringe patterns representing 4 distinct directions via multispectral fringe projection profilometry

2021 ◽  
Vol 11 (1) ◽  
Author(s):  
Parsa Omidi ◽  
Mohamadreza Najiminaini ◽  
Mamadou Diop ◽  
Jeffrey J. L. Carson
Keyword(s):  
Spatial Resolution ◽  
Fringe Pattern ◽  
Three Dimensional ◽  
Fringe Projection ◽  
Video Frame ◽  
Single Shot ◽  
Shot Detection ◽  
Fringe Patterns ◽  
Fringe Projection Profilometry ◽  
Multispectral Camera

AbstractSpatial resolution in three-dimensional fringe projection profilometry is determined in large part by the number and spacing of fringes projected onto an object. Due to the intensity-based nature of fringe projection profilometry, fringe patterns must be generated in succession, which is time-consuming. As a result, the surface features of highly dynamic objects are difficult to measure. Here, we introduce multispectral fringe projection profilometry, a novel method that utilizes multispectral illumination to project a multispectral fringe pattern onto an object combined with a multispectral camera to detect the deformation of the fringe patterns due to the object. The multispectral camera enables the detection of 8 unique monochrome fringe patterns representing 4 distinct directions in a single snapshot. Furthermore, for each direction, the camera detects two π-phase shifted fringe patterns. Each pair of fringe patterns can be differenced to generate a differential fringe pattern that corrects for illumination offsets and mitigates the effects of glare from highly reflective surfaces. The new multispectral method solves many practical problems related to conventional fringe projection profilometry and doubles the effective spatial resolution. The method is suitable for high-quality fast 3D profilometry at video frame rates.

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