Absolute phase retrieval methods for digital fringe projection profilometry: A review

Micro Fourier Transform Profilometry ($μ$FTP): 3D shape measurement at 10,000 frames per second

Status, challenges, and future perspectives of fringe projection profilometry

High-speed three-dimensional shape measurement using GOBO projection

A stereo-phase-based absolute three-dimensional (3D) shape measurement method is provided that requires neither phase unwrapping nor projector calibration. This proposed method can be divided into two steps: (1) obtain a coarse disparity map from the quality map; and (2) refine the disparity map using local phase information. Experiments demonstrated that the proposed method could achieve high-quality 3D measurement even with extremely low-quality fringe patterns. The method is particular well-suited for a number of different applications including in mobile devices such as phones.

https://lib.dr.iastate.edu/cgi/viewcontent.cgi?article=1076&context=me_pubs

Absolute three-dimensional shape measurement using coded fringe patterns without phase unwrapping or projector calibration

Many three-dimensional (3D) shape measurement techniques in stereophotogrammetry with temporal coded structured illumination are limited to static scenes because the time for measurement is too long in comparison to the object speed. The measurement of moving objects result in erroneous reconstructions. This is apparent to reduce measurement time to overcome this limitation, which is often done by increasing the projection rate for illumination while shrinking the amount of images taken for reconstruction. The projection rate limits most applications in its speed because digital light processing (DLP) projectors, which are widely used, bring a limited projection rate along. Our approach, in contrast, does not take a DLP. Instead we use laser speckles as projected patterns which are switched using an acousto-optical deflector. The projection rate is 10× higher than what the fastest stripe projection systems to our knowledge achieve. Hence, we present this uncommon but potential approach for highspeed (≈250 3Dfps= [3D measurements per second]), dense, and accurate 3D measurements of spatially separated objects and show the media that emphasizes the ability of accurate measurements while the objects under testing move.

High-speed three-dimensional shape measurements of objects with laser speckles and acousto-optical deflection

The field of image-based shape measurements using structured illumination has been an active research area for several decades now. A lot of different methods are widely used e.g. for industrial inspection, surveillance as well as multimedia purposes. Usually, short measurement times and high correspondence accuracy are mutually exclusive properties, due to the limitations of the used projection technology. Using a standard stereo-photogrammetry approach, as well as a simple, yet powerful structured light projection concept based on a slide-projector, we demonstrate an acquisition rate of more than 700 dense and accurate 3D measurements per second.

/pdf/fast-data-acquisition-for-three-dimensional-shape-2bdiil8ege.pdf

Fast data acquisition for three-dimensional shape measurement using fixed-pattern projection and temporal coding

Common correlation-based photogrammetric 3D shape measurement techniques evaluate either temporal or spatial features. Temporal approaches achieve high accuracies but are limited to the measurement of static objects. Spatial techniques can deal with moving objects but provide relatively inaccurate results. Our goal is to combine these methods in order to measure dynamic scenes that contain static and moving objects. Therefore, we present a spatiotemporal correlation that adapts its temporal and spatial support locally to the motion of the measured objects. In addition, our technique compensates motion by warping the correlated image regions temporally. Our approach is based on structured illumination of random patterns, which are well suited for dynamic scenes due to high possible frame rates. The proposed technique is tested with simulated data and real measurements.

3D shape measurement of static and moving objects with adaptive spatiotemporal correlation

Two-beam interference is a fundamental and well-understood approach to create Fizeau's interference fringes. With a Mach-Zehnder interferometer, we utilize these two-beam interference Fizeau fringes for three-dimensional (3D) shape measurements. By introducing an acousto-optical deflector the phase of the interference fringes can be shifted with a rate of up to 200,000 Hz. When used in conjunction with highspeed cameras, this stereo-photogrammetric approach performs well for highspeed applications in comparison with the commonly used digital light processing projectors for stripe projection. Maximum speed and the achievable accuracy are discussed. Experiments and media substantiate the suitability, accuracy, and speed of this technique for very fast 3D shape measurements.

Coherent two-beam interference fringe projection for highspeed three-dimensional shape measurements

The method involves projecting multiple different spectral narrow band optical patterns to be changed and having higher image rate on the three-dimensional object surface to be measured. The projected different patterns with their changes are detected by a detector as location-differing corresponding image pattern of the object surface to be measured and are evaluated for gaining three-dimensional information of the object (1). Light waves of the spectral narrow band optical pattern are changed during the exposure time of the detector by a phase variation. The spectral narrow band optical patterns with their light wave changes are projected on the object and are detected by the detector as location-differing corresponding image pattern of the object surface to be measured. An independent claim is included for a device for three-dimensional measurement of objects.

Method for three-dimensional optical surface measurement of objects by measurement device, involves projecting spectral narrow band optical patterns on object, and detecting patterns as location-differing image pattern of object surface

Bastian Harendt

Papers

High-speed three-dimensional shape measurements of objects with laser speckles and acousto-optical deflection

Fast data acquisition for three-dimensional shape measurement using fixed-pattern projection and temporal coding

3D shape measurement of static and moving objects with adaptive spatiotemporal correlation

Coherent two-beam interference fringe projection for highspeed three-dimensional shape measurements

Method for three-dimensional optical surface measurement of objects by measurement device, involves projecting spectral narrow band optical patterns on object, and detecting patterns as location-differing image pattern of object surface