scholarly journals Gamma Precorrection and Phase Error Compensation Methods Based on Three-Frequency with Three-Phase Shift

2021 ◽  
Vol 2021 ◽  
pp. 1-15
Author(s):  
Wei Feng ◽  
Shaojing Tang ◽  
Shinan Xu ◽  
Tong Qu ◽  
Daxing Zhao
Keyword(s):  
Phase Shift ◽  
Error Compensation ◽  
Phase Error ◽  
Three Dimensional ◽  
Harmonic Component ◽  
Measurement Technology ◽  
Compensation Methods ◽  
Three Phase ◽  
Phase Calculation ◽  
Fringe Patterns

Digital fringe projection measurement technology has been widely used in computer vision and optical three-dimensional (3D) measurement. Considering the phase error caused by the gamma distortion and nonlinear error, the active gamma precorrection and phase error compensation methods based on the three-frequency with three-phase shifts are designed to reversely solve the initial phase and accurately compensate phase error. On the one hand, the gamma coefficient of the measurement system depends on precoding two groups of fringe sequences with different gamma coefficients to calculate the corresponded proportional coefficient of harmonic component. On the other hand, the phase error compensation method is designed to compensate the phase error and improve the accuracy and speed of phase calculation after gamma correction. Experiments show that the proposed precalibration gamma coefficient method can effectively reduce the sinusoidal error in nearly 80 percent which only needs fewer fringe patterns. Compared with the traditional three-frequency with four-phase shift method, the proposed method not only has higher phase accuracy and better noise resistance but also has good robustness and flexibility, which is not limited to the gamma distortion model.

scholarly journals Perfilometría 3D por proyección desenfocada de patrones binarios

2020 ◽  
Vol 1 (1) ◽  
pp. 18-24
Author(s):  
A. Silva ◽  
J. L. Flores ◽  
A. Muñoz ◽  
G. García-Torales
Keyword(s):  
Phase Shift ◽  
Linear Response ◽  
Moving Objects ◽  
Structured Light ◽  
Phase Error ◽  
Three Dimensional ◽  
Three Dimensional Reconstruction ◽  
El Sistema ◽  
Dimensional Reconstruction ◽  
Fringe Patterns

Las técnicas basadas en proyección de luz estructurada son ampliamente estudiadas y utilizadas en el área de perfilometría tridimensional, esto debido a la capacidad para obtener información completa de la superficie de objetos. Algunas de estas técnicas se basan en la proyección de patrones de intensidad sinusoidal y el uso de algoritmos de corrimiento de fase. En el caso de la reconstrucción tridimensional de objetos dinámicos en movimiento, uno de los desafíos es reducir el número de pasos o imágenes a ser proyectadas. Sin embargo, la precisión de estos sistemas se reduce conforme decrece el número de patrones (a un mínimo de tres). El sistema de proyección presenta una respuesta no lineal, lo cual introduce armónicos en los patrones adquiridos y en la recuperación de fase. En los últimos años, la proyección desenfocada de patrones binarios para generar patrones de franjas cuasi sinusoidales ha emergido como una alternativa para evitar el problema de no linealidad del proyector y, por ende, reducir el error en la fase. En este trabajo se presenta una revisión de distintos métodos propuestos en la literatura para generar patrones binarios, los cuales sintetizan patrones cuasi sinusoidales cuando son proyectados fuera de foco. Adicionalmente, analizamos el error de fase en función a la cantidad de desenfoque y el tamaño del periodo fundamental de las franjas. The techniques of structured light projection are widely studied in the area of three-dimensional profilometry, due to its ability to obtain information from the surface of an object. In particular, those based on the projection of a sequence of sinusoidal intensity patterns and the use of phase shift algorithms. In the case of three-dimensional reconstruction of dynamic or moving objects, one of the trends is to reduce the number of steps or patterns to be projected. However, the accuracy of these systems is reduced as the number of steps decreases (to a minimum of 3 steps). This is because the projection systems present a non-linear response, which translates into the introduction of harmonics in the acquired sinusoidal patterns, and therefore, error in the recovered phase. In the last years, the defocused projection of binary patterns has emerged as an alternative to avoid the projector’s non-linearity and generates quasi-sinusoidal fringe patterns to reduce the phase error. In this work, we review different techniques that have been proposed in the literature to generate binary patterns, which synthesize quasi-sinusoidal patterns when projected out of focus. In addition, we analyze the error in the phase as a function of the defocusing amount and the fringe pitch.

Phase error compensation methods for high-accuracy profile measurement

2016 ◽  
Vol 27 (4) ◽  
pp. 045201 ◽  
Author(s):  
Zewei Cai ◽  
Xiaoli Liu ◽  
Xiang Peng ◽  
Zonghua Zhang ◽  
Hao Jiang ◽  
...  
Keyword(s):  
Error Compensation ◽  
Phase Error ◽  
High Accuracy ◽  
Profile Measurement ◽  
Accuracy Profile ◽  
Compensation Methods

scholarly journals Phase error compensation for three-dimensional shape measurement with projector defocusing

2011 ◽  
Vol 50 (17) ◽  
pp. 2572 ◽  
Author(s):  
Ying Xu ◽  
Laura Ekstrand ◽  
Junfei Dai ◽  
Song Zhang
Keyword(s):  
Error Compensation ◽  
Phase Error ◽  
Three Dimensional ◽  
Shape Measurement ◽  
Dimensional Shape ◽  
Three Dimensional Shape

Saturation Model and Phase Recovering for Phase Measuring Profilometry

2014 ◽  
Vol 513-517 ◽  
pp. 3996-3999 ◽  
Author(s):  
Ji Rong Sun ◽  
Wei Zou
Keyword(s):  
Phase Error ◽  
Three Dimensional ◽  
Light Illumination ◽  
Phase Measuring Profilometry ◽  
Structured Light Illumination ◽  
Simulation And Experiment ◽  
Intensity Saturation ◽  
Fringe Patterns ◽  
Saturated Intensity ◽  
Saturation Phase

Phase measuring profilometry is a method of structured light illumination whose three-dimensional reconstructions are susceptible to error from intensity saturation. Phase error caused by intensity saturation of fringe patterns is studied in this work. A mathematical model is derived for recovering saturated intensity by means of other patterns without saturation, and thus we can decrease the phase error introduced by the saturation. Both simulation and experiment results show that the phase error arisen from intensity saturation can be efficiently suppressed with the proposed algorithm.

Initial Alignment Error and Navigation Error Compensation Methods for SINS/CNS Integration

2013 ◽  
Vol 390 ◽  
pp. 490-494 ◽  
Author(s):  
Jia Sheng Yang ◽  
Yue Gang Wang
Keyword(s):  
Error Compensation ◽  
Phase Error ◽  
Alignment Error ◽  
Initial Alignment ◽  
Theory Analysis ◽  
Integration System ◽  
Velocity Error ◽  
Compensation Methods ◽  
Navigation Error ◽  
Simulation Results

To remove the navigation error accumulated in the boost phase of the missile’s SINS/CNS integration system, an error compensation algorithm is presented, which uses the saved IMU data and reverse attitude updating algorithm to remove the error caused by initial misalignments, and uses the off-line navigation computation to correct the boost phase error. The theory analysis show that the proposed algorithm’s performance is mainly dependent on the CNS precision , while the errors caused by gyro and accelerometer drift are tiny., the simulation results show that the proposed algorithm can reduce the velocity error to 0.012m/s and the position error to 1.12 meter, which leads to the navigation error compensated greatly.

scholarly journals Phase Error Analysis and Correction for Crossed-Grating Phase-Shifting Profilometry

Sensors ◽  
2021 ◽  
Vol 21 (19) ◽  
pp. 6475
Author(s):  
Fuqian Li ◽  
Wenjing Chen
Keyword(s):  
Mathematical Model ◽  
Phase Error ◽  
Three Dimensional ◽  
Correction Method ◽  
Phase Shifting ◽  
Gamma Correction ◽  
Projection System ◽  
Comparison Results ◽  
Linearity Error ◽  
Fringe Patterns

Crossed-grating phase-shifting profilometry (CGPSP) has great utility in three-dimensional shape measurement due to its ability to acquire horizontal and vertical phase maps in a single measurement. However, CGPSP is extremely sensitive to the non-linearity effect of a digital fringe projection system, which is not studied in depth yet. In this paper, a mathematical model is established to analyze the phase error caused by the non-linearity effect. Subsequently, two methods used to eliminate the non-linearity error are discussed in detail. To be specific, a double five-step algorithm based on the mathematical model is proposed to passively suppress the second non-linearity. Furthermore, a precoding gamma correction method based on probability distribution function is introduced to actively attenuate the non-linearity of the captured crossed fringe. The comparison results show that the active gamma correction method requires less fringe patterns and can more effectively reduce the non-linearity error compared with the passive method. Finally, employing CGPSP with gamma correction, a faster and reliable inverse pattern projection is realized with less fringe patterns.

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