A single scan longitudinal calibration technique for fringe projection profilometry

Mahmoud, Dalia; Khalil, Abdallah; Younes, M. A.

doi:10.1016/j.ijleo.2018.04.038

Cited by 3 publications

(4 citation statements)

References 20 publications

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“…Phase shift (rad) As a practical example to study the effect of changing phase error with ambient illumination level, a cylindrical object is measured using three sinusoidal fringe images with fringe period equals to 35 pixels and intensity amplitude (50-200) shifted by 2π/3. Figure (16) shows captured images of cylindrical object at different illumination level. Dark (a), median (b), and full illumination level (c).…”

Section: Phase Error (Rms) Radmentioning

confidence: 99%

“…Image of the deformed patterns is captured by CCD camera [10,11] then analyzed by one of fringe analysis techniques such as Fourier transform [12] , wavelet transform [13] , and phase shifting technique [14] to obtain phase map, then unwrapped to get continuous phase map. Finally, a calibration step is done to transform from continuous phase map to X, Y, Z coordinates [15,16] . Performance of DFPP system is characterized by many factors such as resolution, speed and the most important factor is accuracy.…”

Section: -Introductionmentioning

confidence: 99%

“…D is the distance between the optical axis of the camera and projector. F is the frequency of fringe patterns ∆φ is the phase shift value caused by the object height [16] , these parameters are shown schematically in figure (2) Since L and D, and f are fixed values for the system, the accuracy of height measurements depends on the accuracy of calculating the phase shift caused by the object height.…”

Section: -Introductionmentioning

confidence: 99%

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Effect of System Parameters on Phase Error of Focus-Free Digital Fringe Projection Profilometry System

Ali

Amer

Omaraa

2021

Egyptian Journal of Solids

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Digital Fringe projection profilometry (DFPP) is a noncontact, fast, accurate and flexible technique for 3D measurements. Phase calculation is an important step that affects the accuracy of measurements. in phase calculation, the critical source of error is phase error due to nonlinear gamma effect of the system. This paper introduces an experimental investigation of the nonlinear gamma effect of DFPP system as well as the effect of system parameters, such as fringe intensity, fringe period, surface distance from the camera and projector and finally the ambient illumination, on phase error and consequently system measurements. Fringe patterns are generated using Matlab 2018a and projected by digital laser projector. The deformed patterns are captured using colored CCD camera. Phase shifting technique is used to calculate phase map. The system shows a linear response in the intensity range (50-220) and has small phase error without any compensation for nonlinear gamma effect. The phase error of the system slightly increases with increasing fringe period and the surface distance from the camera and projector, while it is nearly constant with ambient illumination changes from dark to median level and shows a bigger change if the ambient is completely illuminated. In the worst conditions the phase error does not accedes 0.0387 rad without any compensation for nonlinear gamma effect, make the system a useful tool for 3D measurements in different working fields.

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Section: Phase Error (Rms) Radmentioning

confidence: 99%

Section: -Introductionmentioning

confidence: 99%

Section: -Introductionmentioning

confidence: 99%

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Effect of System Parameters on Phase Error of Focus-Free Digital Fringe Projection Profilometry System

Ali

Amer

Omaraa

2021

Egyptian Journal of Solids

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“…In the last few years, 3D optical scanners [ 5 ] are replacing laser trackers as the most used measuring equipment for the dimensional quality control assessment of machined and casting parts. Modeling and calibration issues are mentioned in [ 13 , 14 , 15 , 16 ], whereas some examples of application are studied in [ 17 , 18 ] and even accuracy performance is determined for lighting conditions in [ 19 ]. Although their accuracy is still a bit lower (±30 µm/m) than laser-tracker technologies (±15 + 6 µm/m) for high accuracy applications, casting part verification methodologies have been adapted to these technologies as they offer a volumetric view of the part compared to its nominal CAD definition.…”

Section: Introductionmentioning

confidence: 99%

Accuracy Evaluation of Dense Matching Techniques for Casting Part Dimensional Verification

Kortaberria

Mutilba

Gomez-Acedo

et al. 2018

Sensors

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Product optimization for casting and post-casting manufacturing processes is becoming compulsory to compete in the current global manufacturing scenario. Casting design, simulation and verification tools are becoming crucial for eliminating oversized dimensions without affecting the casting component functionality. Thus, material and production costs decrease to maintain the foundry process profitable on the large-scale component supplier market. New measurement methods, such as dense matching techniques, rely on surface texture of casting parts to enable the 3D dense reconstruction of surface points without the need of an active light source as usually applied with 3D scanning optical sensors. This paper presents the accuracy evaluation of dense matching based approaches for casting part verification. It compares the accuracy obtained by dense matching technique with already certified and validated optical measuring methods. This uncertainty evaluation exercise considers both artificial targets and key natural points to quantify the possibilities and scope of each approximation. Obtained results, for both lab and workshop conditions, show that this image data processing procedure is fit for purpose to fulfill the required measurement tolerances for casting part manufacturing processes.

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Phase-to-depth calibration in fringe projection profilometry based on blockwise surface fitting

Huang

et al. 2020

Optics & Laser Technology

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A single scan longitudinal calibration technique for fringe projection profilometry

Cited by 3 publications

References 20 publications

Effect of System Parameters on Phase Error of Focus-Free Digital Fringe Projection Profilometry System

Effect of System Parameters on Phase Error of Focus-Free Digital Fringe Projection Profilometry System

Accuracy Evaluation of Dense Matching Techniques for Casting Part Dimensional Verification

Phase-to-depth calibration in fringe projection profilometry based on blockwise surface fitting

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