scholarly journals A Calibration Method for System Parameters in Direct Phase Measuring Deflectometry

2019 ◽  
Vol 9 (7) ◽  
pp. 1444
Author(s):  
Xiaoting Deng ◽  
Nan Gao ◽  
Zonghua Zhang
Keyword(s):  
Liquid Crystal Display ◽  
Three Dimensional ◽  
Calibration Method ◽  
Concave Mirror ◽  
System Parameters ◽  
Dimensional Shape ◽  
Phase Map ◽  
Specular Objects ◽  
Fringe Patterns ◽  
Three Dimensional Shape

Phase measuring deflectometry has been widely studied as a way of obtaining the three-dimensional shape of specular objects. Recently, a new direct phase measuring deflectometry technique has been developed to measure the three-dimensional shape of specular objects that have discontinuous and/or isolated surfaces. However, accurate calibration of the system parameters is an important step in direct phase measuring deflectometry. This paper proposes a new calibration method that uses phase information to obtain the system parameters. Phase data are used to accurately calibrate the relative orientation of two liquid crystal display screens in a camera coordinate system, by generating and displaying horizontal and vertical sinusoidal fringe patterns on the two screens. The results of the experiments with an artificial specular step and a concave mirror showed that the proposed calibration method can build a highly accurate relationship between the absolute phase map and the depth data.

Calibration Method of Three-Dimensional Shape Measurement System Based on iGPS Positioning and Tracking

2019 ◽  
Vol 46 (1) ◽  
pp. 0104003
Author(s):  
马国庆 Ma Guoqing ◽  
刘丽 Liu Li ◽  
于正林 Yu Zhenglin ◽  
曹国华 Cao Guohua ◽  
王强 Wang Qiang
Keyword(s):  
Measurement System ◽  
Three Dimensional ◽  
Calibration Method ◽  
Shape Measurement ◽  
Dimensional Shape ◽  
Three Dimensional Shape

Three Dimensional Shape Measurement of Micro Droplet Utilizing Micro LIF Technique

2008 ◽  
Author(s):  
Yasuhiko Sugii
Keyword(s):  
Measurement Accuracy ◽  
Three Dimensional ◽  
Ccd Camera ◽  
Optical Filters ◽  
Calibration Method ◽  
Two Phase ◽  
Depth Direction ◽  
High Measurement ◽  
Dimensional Shape ◽  
Three Dimensional Shape

This paper describes a novel measurement technique for three dimensional shape of micro droplet utilizing micro LIF (Laser Induced Fluorescence) technique. A measurement system consisted of microscope equipped with 10x lens, high sensitive CCD camera, CW Nd:YAG laser, optical filters and so on. Calibration curve between thickness of micro droplet and emission of fluorescence dye solution was obtained by the use of the PDMS (polydimethylsiloxane) microchip, whose depth varied from 8 to 120 μm fabricated using photo lithography technique. The microchip based calibration method provides high measurement accuracy and eliminate photobreaching effect. Measurement accuracy of the present method in depth direction was about 2 μm assessed using laser displace meter and the spatial resolution in the x-y plane became 6.7 μm. The technique is useful to investigate a two phase flow in micro scale.

scholarly journals Measurement of the Three-Dimensional Shape of Discontinuous Specular Objects Using Infrared Phase-Measuring Deflectometry

Sensors ◽  
2019 ◽  
Vol 19 (21) ◽  
pp. 4621 ◽  
Author(s):  
Caixia Chang ◽  
Zonghua Zhang ◽  
Nan Gao ◽  
Zhaozong Meng
Keyword(s):  
Automobile Industry ◽  
Three Dimensional ◽  
Calibration Method ◽  
Ir Camera ◽  
Geometric Calibration ◽  
3D Shape ◽  
Phase Data ◽  
Specular Objects ◽  
Fringe Patterns ◽  
Specular Surfaces

Phase-measuring deflectometry (PMD)-based methods have been widely used in the measurement of the three-dimensional (3D) shape of specular objects, and the existing PMD methods utilize visible light. However, specular surfaces are sensitive to ambient light. As a result, the reconstructed 3D shape is affected by the external environment in actual measurements. To overcome this problem, an infrared PMD (IR-PMD) method is proposed to measure specular objects by directly establishing the relationship between absolute phase and depth data for the first time. Moreover, the proposed method can measure discontinuous surfaces. In addition, a new geometric calibration method is proposed by combining fringe projection and fringe reflection. The proposed IR-PMD method uses a projector to project IR sinusoidal fringe patterns onto a ground glass, which can be regarded as an IR digital screen. The IR fringe patterns are reflected by the measured specular surfaces, and the deformed fringe patterns are captured by an IR camera. A multiple-step phase-shifting algorithm and the optimum three-fringe number selection method are applied to the deformed fringe patterns to obtain wrapped and unwrapped phase data, respectively. Then, 3D shape data can be directly calculated by the unwrapped phase data on the screen located in two positions. The results here presented validate the effectiveness and accuracy of the proposed method. It can be used to measure specular components in the application fields of advanced manufacturing, automobile industry, and aerospace industry.

scholarly journals Three-Dimensional Shape Measurements of Specular Objects Using Phase-Measuring Deflectometry

Sensors ◽  
2017 ◽  
Vol 17 (12) ◽  
pp. 2835 ◽  
Author(s):  
Zonghua Zhang ◽  
Yuemin Wang ◽  
Shujun Huang ◽  
Yue Liu ◽  
Caixia Chang ◽  
...  
Keyword(s):  
Three Dimensional ◽  
Dimensional Shape ◽  
Specular Objects ◽  
Three Dimensional Shape

Profilometry by projecting sinusoidal stripe patterns with motion blurring

2008 ◽  
Vol 222 (8) ◽  
pp. 1551-1555 ◽  
Author(s):  
M Chang
Keyword(s):  
Fringe Pattern ◽  
Three Dimensional ◽  
Image Plane ◽  
Stripe Pattern ◽  
Projection System ◽  
Optical Projection ◽  
Different Types ◽  
Dimensional Shape ◽  
Fringe Patterns ◽  
Three Dimensional Shape

This paper proposes a method of projecting sinusoidal fringe patterns for measuring a three-dimensional shape. In the proposed method, fringe patterns are plated on a piece of glass with chromium, and each stripe of the fringe pattern is composed of small sinusoidal segments. The glass is placed on the image plane of an optical projection system. By linearly moving the glass along the direction of the stripe pattern, the projection system generates the motion-blurring phenomenon, and as a result, produces a blurred-stripe pattern whose intensity profile is sinusoidal along the direction perpendicular to the stripe pattern. Experimental results are provided for three different types of fringe patterns: rectangle, diamond, and sinusoid. Sinusoidal phase-shifted patterns generated by the proposed method produce smaller phase angle errors.

Sign in / Sign up

Export Citation Format

Share Document