A brief review of the technological advancements of phase measuring deflectometry

Xu, Yongjia; Gao, Feng; Jiang, Xiangqian

doi:10.1186/s43074-020-00015-9

Cited by 55 publications

(37 citation statements)

References 70 publications

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“…However, it takes a large amount of time while searching for space points. Similar to our classifications of PMD, Xu et al 52 classified those PMD methods into single screen and sensor-based PMD, multiscreen-based PMD, and multisensor-based PMD.…”

Section: Establishments Of Pmdmentioning

confidence: 76%

Phase measuring deflectometry for obtaining 3D shape of specular surface: a review of the state-of-the-art

et al. 2021

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Phase measuring deflectometry (PMD) is a superior technique to obtain three-dimensional (3D) shape information of specular surfaces because of its advantages of large dynamic range, noncontact operation, full-field measurement, fast acquisition, high precision, and automatic data processing. We review the recent advances on PMD. The basic principle of PMD is introduced following several PMD methods based on fringe reflection. First, a direct PMD (DPMD) method is reviewed for measuring 3D shape of specular objects having discontinuous surfaces. The DPMD method builds the direct relationship between phase and depth data, without gradient integration procedure. Second, an infrared PMD (IR-PMD) method is reviewed to measure specular objects. Because IR light is used as a light source, the IR-PMD method is insensitive to the effect of ambient light on the measured results and has high measurement accuracy. Third, a proposed method is reviewed to measure the 3D shape of partial reflective objects having discontinuous surfaces by combining fringe projection profilometry and DPMD. Then, the effects of error sources that mainly include phase error and geometric calibration error on the measurement results are analyzed, and the performance of the 3D shape measurement system is also evaluated. Finally, the future research directions of PMD are discussed.

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Section: Establishments Of Pmdmentioning

confidence: 76%

Phase measuring deflectometry for obtaining 3D shape of specular surface: a review of the state-of-the-art

et al. 2021

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“…Willomitzer et al introduced stitched panoramic measurements of stained-glass windows with a mobile device [16]. PMD for more traditional technical surfaces is well-described in recent literature reviews [17,18].…”

Section: Regular Deflectometry Measurementmentioning

confidence: 99%

“…One tooling ball just barely touches the rear side of the reflective mylar UUT (b). The full optomechanical mounting scheme for the 1 m mirror is described in detail [18].…”

Section: Experimental Setupsmentioning

confidence: 99%

Surface Measurement of a Large Inflatable Reflector in Cryogenic Vacuum

et al. 2021

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The metrology of membrane structures, especially inflatable, curved, optical surfaces, remains challenging. Internal pressure, mechanical membrane properties, and circumferential boundary conditions imbue highly dynamic slopes to the final optic surface. Here, we present our method and experimental results for measuring a 1 m inflatable reflector’s shape response to dynamic perturbations in a thermal vacuum chamber. Our method uses phase-measuring deflectometry to track shape change in response to pressure change, thermal gradient, and controlled puncture. We use an initial measurement as a virtual null reference, allowing us to compare 500 mm of measurable aperture of the concave f/2, 1-meter diameter inflatable optic. We built a custom deflectometer that attaches to the TVAC window to make full use of its clear aperture, with kinematic references behind the test article for calibration. Our method produces 500 × 500 pixel resolution 3D surface maps with a repeatability of 150 nm RMS within a cryogenic vacuum environment (T = 140 K, P = 0.11 Pa).

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“…Usually, a one-dimensional linear search method is used in stereo deflectometry to overcome the "height slope ambiguity" problem [21], [11]. By assuming the position of the measured point on the incident light direction of the main camera, the normal vector is calculated using Eq.…”

Section: Principlementioning

confidence: 99%

“…An infinite number of surfaces can be reconstructed using the same corresponding information. Thus, an extra screen [8] or preknowledge of the surface topography and position [9], [10] are used to address this problem [11], as depicted in Figs. 1(b) and 1(c).…”

Section: Introductionmentioning

confidence: 99%

On-Machine Calibration Method for In Situ Stereo Deflectometry System

Liu

Ren

Gao

et al. 2021

IEEE Trans. Instrum. Meas.

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Deflectometry is a promising method for the in-situ measurement of specular surfaces. However, the accuracy of this method largely depends on the geometrical calibration, which suffers from a low convergence rate and local minima during the optimization. Off-machine calibration results in a change in geometry parameters owing to the repeated disassembly of the measurement system and change of ambient temperature, which largely affects the measurement accuracy. This paper presents a flexible on-machine calibration method with fewer intermediate parameters to accelerate the optimization for the in-situ stereo deflectometry system. An inclined mirror with a fixed angle was mounted on the spindle of an ultraprecision machine tool and used as a reference plane reflecting the fringe displayed on the display screen. The reflected fringe captured by the cameras was encoded by an inclined mirror moving along the C-axis and Z-axis of the machine tool. The preknowledge of the movement distance of the ultraprecision machine tool along the Z-axis and rotation angle of the spindle with a nanoscale accuracy was used to largely reduce the number of intermediate variables involved in the optimization, thus improving the convergence speed of the global optimization method and calibration reliability. The experiment results show that this calibration method has higher calibration accuracy, measurement accuracy and reliability compared to the conventional off-machine calibration method.

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A brief review of the technological advancements of phase measuring deflectometry

Cited by 55 publications

References 70 publications

Phase measuring deflectometry for obtaining 3D shape of specular surface: a review of the state-of-the-art

Phase measuring deflectometry for obtaining 3D shape of specular surface: a review of the state-of-the-art

Surface Measurement of a Large Inflatable Reflector in Cryogenic Vacuum

On-Machine Calibration Method for In Situ Stereo Deflectometry System

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