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Krzysztof Patorski - One of the best experts on this subject based on the ideXlab platform.
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Automatic Fringe Pattern enhancement using truly adaptive period-guided bidimensional empirical mode decomposition.
Optics Express, 2020Co-Authors: Paweł Gocłowski, Maciej Trusiak, Azeem Ahmad, Adam Styk, Vicente Micó, Balpreet Singh Ahluwalia, Krzysztof PatorskiAbstract:Fringe Patterns encode the information about the result of a measurement performed via widely used optical full-field testing methods, e.g., interferometry, digital holographic microscopy, moire techniques, structured illumination etc. Affected by the optical setup, changing environment and the sample itself Fringe Patterns are often corrupted with substantial noise, strong and uneven background illumination and exhibit low contrast. Fringe Pattern enhancement, i.e., noise minimization and background term removal, at the pre-processing stage prior to the phase map calculation (for the measurement result decoding) is therefore essential to minimize the jeopardizing effect the mentioned error sources have on the optical measurement outcome. In this contribution we propose an automatic, robust and highly effective Fringe Pattern enhancement method based on the novel period-guided bidimensional empirical mode decomposition algorithm (PG-BEMD). The spatial distribution of the Fringe period is estimated using the novel windowed approach and then serves as an indicator for the truly adaptive decomposition with the filter size locally adjusted to the Fringe Pattern density. In this way the Fringe term is successfully extracted in a single (first) decomposition component alleviating the cumbersome mode mixing phenomenon and greatly simplifying the automatic signal reconstruction. Hence, the Fringe term is dissected without the need for modes selection nor summation. The noise removal robustness is ensured employing the block matching 3D filtering of the Fringe Pattern prior to its decomposition. Performance validation against previously reported modified empirical mode decomposition techniques is provided using numerical simulations and experimental data verifying the versatility and effectiveness of the proposed approach.
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automatized Fringe Pattern preprocessing using unsupervised variational image decomposition
Optics Express, 2019Co-Authors: Maria Cywinska, Maciej Trusiak, Krzysztof PatorskiAbstract:Successful single-frame Fringe Pattern preprocessing comprising high-frequency noise minimization and low-frequency background removal represents often the crucial step of the Fringe Pattern based full-field optical metrology (i.e., interferometry, moire, structured light). It directly determines the measurement accuracy. Data-driven decomposition by means of the 2D empirical mode decomposition (EMD) serves the filtering purpose in adaptive and detail-preserving manner. The mode-mixing phenomenon resulting in troublesome automatic grouping of modes into three main Fringe Pattern components (background, information part and noise) is significantly limiting this process, however. In this paper we are introducing the unsupervised variational image decomposition (uVID) model especially tailored to overcome this preprocessing problem and assure successful sparse three-component Fringe Pattern decomposition. Comprehensive analysis and detailed studies of accomplished significant advancements ensuring automation, versatility and robustness of the proposed approach are provided. Main advancements include: (1) tailoring the VID calculation scheme to Fringe Pattern preprocessing purpose by focusing onto accurate Fringe extraction with tolerance parameter and custom-made decomposition parameter values; (2) Fringe Pattern tailored BM3D denoising algorithm with fixed parameter values. Numerical and experimental investigations corroborate that the demonstrated uVID method compares favorably with the reference 2D EMD algorithm and classical VID model. Remarkable range of acceptable local variations of the Fringe Pattern orientation, period, noise, contrast and background terms is to be highlighted.
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single shot Fringe Pattern phase demodulation using hilbert huang transform aided by the principal component analysis
Optics Express, 2016Co-Authors: Maciej Trusiak, łukasz Sluzewski, Krzysztof PatorskiAbstract:Hybrid single shot algorithm for accurate phase demodulation of complex Fringe Patterns is proposed. It employs empirical mode decomposition based adaptive Fringe Pattern enhancement (i.e., denoising, background removal and amplitude normalization) and subsequent boosted phase demodulation using 2D Hilbert spiral transform aided by the Principal Component Analysis method for novel, correct and accurate local Fringe direction map calculation. Robustness to Fringe Pattern significant noise, uneven background and amplitude modulation as well as local Fringe period and shape variations is corroborated by numerical simulations and experiments. Proposed automatic, adaptive, fast and comprehensive Fringe analysis solution compares favorably with other previously reported techniques.
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adaptive enhancement of optical Fringe Patterns by selective reconstruction using fabemd algorithm and hilbert spiral transform
Optics Express, 2012Co-Authors: Maciej Trusiak, Krzysztof Patorski, Maciej WielgusAbstract:Presented method for Fringe Pattern enhancement has been designed for processing and analyzing low quality Fringe Patterns. It uses a modified fast and adaptive bidimensional empirical mode decomposition (FABEMD) for the extraction of bidimensional intrinsic mode functions (BIMFs) from an interferogram. Fringe Pattern is then selectively reconstructed (SR) taking the regions of selected BIMFs with high modulation values only. Amplitude demodulation and normalization of the reconstructed image is conducted using the spiral phase Hilbert transform (HS). It has been tested using computer generated interferograms and real data. The performance of the presented SR-FABEMD-HS method is compared with other normalization techniques. Its superiority, potential and robustness to high Fringe density variations and the presence of noise, modulation and background illumination defects in analyzed Fringe Patterns has been corroborated.
Maciej Trusiak - One of the best experts on this subject based on the ideXlab platform.
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Automatic Fringe Pattern enhancement using truly adaptive period-guided bidimensional empirical mode decomposition.
Optics Express, 2020Co-Authors: Paweł Gocłowski, Maciej Trusiak, Azeem Ahmad, Adam Styk, Vicente Micó, Balpreet Singh Ahluwalia, Krzysztof PatorskiAbstract:Fringe Patterns encode the information about the result of a measurement performed via widely used optical full-field testing methods, e.g., interferometry, digital holographic microscopy, moire techniques, structured illumination etc. Affected by the optical setup, changing environment and the sample itself Fringe Patterns are often corrupted with substantial noise, strong and uneven background illumination and exhibit low contrast. Fringe Pattern enhancement, i.e., noise minimization and background term removal, at the pre-processing stage prior to the phase map calculation (for the measurement result decoding) is therefore essential to minimize the jeopardizing effect the mentioned error sources have on the optical measurement outcome. In this contribution we propose an automatic, robust and highly effective Fringe Pattern enhancement method based on the novel period-guided bidimensional empirical mode decomposition algorithm (PG-BEMD). The spatial distribution of the Fringe period is estimated using the novel windowed approach and then serves as an indicator for the truly adaptive decomposition with the filter size locally adjusted to the Fringe Pattern density. In this way the Fringe term is successfully extracted in a single (first) decomposition component alleviating the cumbersome mode mixing phenomenon and greatly simplifying the automatic signal reconstruction. Hence, the Fringe term is dissected without the need for modes selection nor summation. The noise removal robustness is ensured employing the block matching 3D filtering of the Fringe Pattern prior to its decomposition. Performance validation against previously reported modified empirical mode decomposition techniques is provided using numerical simulations and experimental data verifying the versatility and effectiveness of the proposed approach.
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automatized Fringe Pattern preprocessing using unsupervised variational image decomposition
Optics Express, 2019Co-Authors: Maria Cywinska, Maciej Trusiak, Krzysztof PatorskiAbstract:Successful single-frame Fringe Pattern preprocessing comprising high-frequency noise minimization and low-frequency background removal represents often the crucial step of the Fringe Pattern based full-field optical metrology (i.e., interferometry, moire, structured light). It directly determines the measurement accuracy. Data-driven decomposition by means of the 2D empirical mode decomposition (EMD) serves the filtering purpose in adaptive and detail-preserving manner. The mode-mixing phenomenon resulting in troublesome automatic grouping of modes into three main Fringe Pattern components (background, information part and noise) is significantly limiting this process, however. In this paper we are introducing the unsupervised variational image decomposition (uVID) model especially tailored to overcome this preprocessing problem and assure successful sparse three-component Fringe Pattern decomposition. Comprehensive analysis and detailed studies of accomplished significant advancements ensuring automation, versatility and robustness of the proposed approach are provided. Main advancements include: (1) tailoring the VID calculation scheme to Fringe Pattern preprocessing purpose by focusing onto accurate Fringe extraction with tolerance parameter and custom-made decomposition parameter values; (2) Fringe Pattern tailored BM3D denoising algorithm with fixed parameter values. Numerical and experimental investigations corroborate that the demonstrated uVID method compares favorably with the reference 2D EMD algorithm and classical VID model. Remarkable range of acceptable local variations of the Fringe Pattern orientation, period, noise, contrast and background terms is to be highlighted.
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single shot Fringe Pattern phase demodulation using hilbert huang transform aided by the principal component analysis
Optics Express, 2016Co-Authors: Maciej Trusiak, łukasz Sluzewski, Krzysztof PatorskiAbstract:Hybrid single shot algorithm for accurate phase demodulation of complex Fringe Patterns is proposed. It employs empirical mode decomposition based adaptive Fringe Pattern enhancement (i.e., denoising, background removal and amplitude normalization) and subsequent boosted phase demodulation using 2D Hilbert spiral transform aided by the Principal Component Analysis method for novel, correct and accurate local Fringe direction map calculation. Robustness to Fringe Pattern significant noise, uneven background and amplitude modulation as well as local Fringe period and shape variations is corroborated by numerical simulations and experiments. Proposed automatic, adaptive, fast and comprehensive Fringe analysis solution compares favorably with other previously reported techniques.
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adaptive enhancement of optical Fringe Patterns by selective reconstruction using fabemd algorithm and hilbert spiral transform
Optics Express, 2012Co-Authors: Maciej Trusiak, Krzysztof Patorski, Maciej WielgusAbstract:Presented method for Fringe Pattern enhancement has been designed for processing and analyzing low quality Fringe Patterns. It uses a modified fast and adaptive bidimensional empirical mode decomposition (FABEMD) for the extraction of bidimensional intrinsic mode functions (BIMFs) from an interferogram. Fringe Pattern is then selectively reconstructed (SR) taking the regions of selected BIMFs with high modulation values only. Amplitude demodulation and normalization of the reconstructed image is conducted using the spiral phase Hilbert transform (HS). It has been tested using computer generated interferograms and real data. The performance of the presented SR-FABEMD-HS method is compared with other normalization techniques. Its superiority, potential and robustness to high Fringe density variations and the presence of noise, modulation and background illumination defects in analyzed Fringe Patterns has been corroborated.
Qian Kemao - One of the best experts on this subject based on the ideXlab platform.
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comparison of fourier transform windowed fourier transform and wavelet transform methods for phase extraction from a single Fringe Pattern in Fringe projection profilometry
Optics and Lasers in Engineering, 2010Co-Authors: Lei Huang, Qian Kemao, Anand AsundiAbstract:Fringe projection profilometry is widely used for three-dimensional (3-D) surface shape measurement using phase-shifting (PS) methods with multiple images or transform methods with single projected Fringe Pattern. In this paper, phase extraction methods from a single Fringe Pattern using different transform methods are compared using both simulations and experiments. The principles of Fourier transform (FT), windowed Fourier transform (WFT) and wavelet transform (WT) methods for Fringe Pattern processing are introduced. Implementation of 1-D and 2-D algorithms and phase compensation are discussed. Noisy and non-sinusoidal waveforms are involved into this comparison. The merits and limitations of each of these processing methods are indicated.
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real time 2d parallel windowed fourier transform for Fringe Pattern analysis using graphics processing unit
Optics Express, 2009Co-Authors: Nguyen Thi Thanh Huyen, Qian KemaoAbstract:In optical interferometers, Fringe projection systems, and synthetic aperture radars, Fringe Patterns are common outcomes and usually degraded by unavoidable noises. The presence of noises makes the phase extraction and phase unwrapping challenging. Windowed Fourier transform (WFT) based algorithms have been proven to be effective for Fringe Pattern analysis to various applications. However, the WFT-based algorithms are computationally expensive, prohibiting them from real-time applications. In this paper, we propose a fast parallel WFT-based library using graphics processing units and computer unified device architecture. Real-time WFT-based algorithms are achieved with 4 frames per second in processing 256×256 Fringe Patterns. Up to 132× speedup is obtained for WFT-based algorithms using NVIDIA GTX295 graphics card than sequential C in quad-core 2.5GHz Intel(R)Xeon(R) CPU E5420.
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windowed fourier transform for Fringe Pattern analysis theoretical analyses
Applied Optics, 2008Co-Authors: Qian Kemao, Haixia WangAbstract:A windowed Fourier ridges (WFR) algorithm and a windowed Fourier filtering (WFF) algorithm have been proposed for Fringe Pattern analysis and have been demonstrated to be versatile and effective. Theoretical analyses of their performances are of interest. Local frequency and phase extraction errors by the WFR and WFF algorithms are analyzed in this paper. Effectiveness of the WFR and WFF algorithms will thus be theoretically proven. Consider four phase-shifted Fringe Patterns with local quadric phase [c20=c02=0.005 rad/(pixel)2], and assume that the noise in these Fringe Patterns have mean values of zero and standard deviations the same as the Fringe amplitude. If the phase is directly obtained using the four-step phase-shifting algorithm, the phase error has a mean of zero and a standard deviation of 0.7 rad. However, when using the WFR algorithm with a window size of σx=σy=10 pixels, the local frequency extraction error has a mean of zero and a standard deviation of less than 0.01 rad/pixel and the phase extraction error in the WFR algorithm has a mean of zero and a standard deviation of about 0.02 rad. When using the WFF algorithm with the same window size, the phase extraction error has a mean of zero and a standard deviation of less than 0.04 rad and the local frequency extraction error also has a mean of zero and a standard deviation of less than 0.01 rad/pixel. Thus, an unbiased estimation with very low standard deviation is achievable for local frequencies and phase distributions through windowed Fourier transforms. Algorithms applied to different Fringe Patterns, different noise models, and different dimensions are discussed. The theoretical analyses are verified by numerical simulations.
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sequential demodulation of a single Fringe Pattern guided by local frequencies
Optics Letters, 2007Co-Authors: Qian Kemao, Seah Hock SoonAbstract:A simple but effective approach for the demodulation of a single Fringe Pattern is proposed. The phase with an undetermined sign is directly obtained by taking the arccosine value of a preprocessed Fringe Pattern. The local frequencies, also with an undetermined sign, are then estimated by local matching. The sign ambiguity is then removed simply by forcing the continuity of the local frequencies. The priority of sign determination is guided by the value of total local frequency (Fringe density) so that the critical points are processed last. The proposed approach is verified by successful demodulation of a simulated Fringe Pattern and two experimental Fringe Patterns.
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windowed fourier transform for Fringe Pattern analysis
Applied Optics, 2004Co-Authors: Qian KemaoAbstract:Fringe Patterns in optical metrology systems need to be demodulated to yield the desired parameters. Time-frequency analysis is a useful concept for Fringe demodulation, and a windowed Fourier transform is chosen for the determination of phase and phase derivative. Two approaches are developed: the first is based on the concept of filtering the Fringe Patterns, and the second is based on the best match between the Fringe Pattern and computer-generated windowed exponential elements. I focus on the extraction of phase and phase derivatives from either phase-shifted Fringe Patterns or a single carrier Fringe Pattern. Principles as well as examples are given to show the effectiveness of the proposed methods.
Anand Asundi - One of the best experts on this subject based on the ideXlab platform.
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fast full field out of plane deformation measurement using Fringe reflectometry
Optics and Lasers in Engineering, 2012Co-Authors: Lei Huang, Chi Seng Ng, Anand AsundiAbstract:Full-field out-of-plane deformation measurement of specular surfaces can be implemented quickly and conveniently using Fringe reflectometry. The system configuration is simple and processing is fast. With the assistance of an advanced Fringe Pattern processing technique, the windowed Fourier ridges method, only a single two-directional Fringe Pattern is necessary for determination of the deformed surface profile. Thus, the whole measurement only requires a single image with the potential for high speed or even real time measurement.
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comparison of fourier transform windowed fourier transform and wavelet transform methods for phase extraction from a single Fringe Pattern in Fringe projection profilometry
Optics and Lasers in Engineering, 2010Co-Authors: Lei Huang, Qian Kemao, Anand AsundiAbstract:Fringe projection profilometry is widely used for three-dimensional (3-D) surface shape measurement using phase-shifting (PS) methods with multiple images or transform methods with single projected Fringe Pattern. In this paper, phase extraction methods from a single Fringe Pattern using different transform methods are compared using both simulations and experiments. The principles of Fourier transform (FT), windowed Fourier transform (WFT) and wavelet transform (WT) methods for Fringe Pattern processing are introduced. Implementation of 1-D and 2-D algorithms and phase compensation are discussed. Noisy and non-sinusoidal waveforms are involved into this comparison. The merits and limitations of each of these processing methods are indicated.
Naoyuki Morishige - One of the best experts on this subject based on the ideXlab platform.
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multicenter study of intense pulsed light therapy for patients with refractory meibomian gland dysfunction
Cornea, 2018Co-Authors: Reiko Arita, Takanori Mizoguchi, Shima Fukuoka, Naoyuki MorishigeAbstract:PURPOSE: To evaluate the efficacy of intense pulsed light (IPL) therapy combined with meibomian gland expression (MGX) for refractory meibomian gland dysfunction (MGD) in a prospective study conducted at 3 sites in Japan. METHODS: Patients with refractory obstructive MGD were enrolled and underwent 4 to 8 IPL-MGX treatment sessions at 3-week intervals. Clinical assessment included the Standard Patient Evaluation of Eye Dryness questionnaire; noninvasive breakup time of the tear film and interferometric Fringe Pattern as determined by tear interferometry; lid margin abnormalities, fluorescein breakup time of the tear film, corneal and conjunctival fluorescein staining (CFS), and meibum grade as evaluated with a slit-lamp microscope; meibomian gland morphology (meiboscore); and tear production as measured by the Schirmer test without anesthesia. RESULTS: Sixty-two eyes of 31 patients (17 women, 14 men; mean age ± SD, 47.6 ± 16.8 years) were enrolled. The Standard Patient Evaluation of Eye Dryness score (P < 0.001), noninvasive breakup time (P < 0.001), and interferometric Fringe Pattern (P < 0.001) were significantly improved after therapy, with 74% of eyes showing a change in the interferometric Fringe Pattern from 1 characteristic of lipid deficiency to the normal condition. Meibum grade, lid margin abnormality scores, fluorescein breakup time, and CFS were also significantly improved (P < 0.001, P < 0.001, P < 0.001, and P = 0.002, respectively) after treatment, whereas the meiboscore and Schirmer test value remained unchanged. CONCLUSIONS: IPL-MGX ameliorated symptoms and improved the condition of the tear film in patients with refractory MGD and is therefore a promising treatment option for this disorder.
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multicenter study of intense pulsed light therapy for patients with refractory meibomian gland dysfunction
Cornea, 2018Co-Authors: Reiko Arita, Takanori Mizoguchi, Shima Fukuoka, Naoyuki MorishigeAbstract:PURPOSE To evaluate the efficacy of intense pulsed light (IPL) therapy combined with meibomian gland expression (MGX) for refractory meibomian gland dysfunction (MGD) in a prospective study conducted at 3 sites in Japan. METHODS Patients with refractory obstructive MGD were enrolled and underwent 4 to 8 IPL-MGX treatment sessions at 3-week intervals. Clinical assessment included the Standard Patient Evaluation of Eye Dryness questionnaire; noninvasive breakup time of the tear film and interferometric Fringe Pattern as determined by tear interferometry; lid margin abnormalities, fluorescein breakup time of the tear film, corneal and conjunctival fluorescein staining (CFS), and meibum grade as evaluated with a slit-lamp microscope; meibomian gland morphology (meiboscore); and tear production as measured by the Schirmer test without anesthesia. RESULTS Sixty-two eyes of 31 patients (17 women, 14 men; mean age ± SD, 47.6 ± 16.8 years) were enrolled. The Standard Patient Evaluation of Eye Dryness score (P < 0.001), noninvasive breakup time (P < 0.001), and interferometric Fringe Pattern (P < 0.001) were significantly improved after therapy, with 74% of eyes showing a change in the interferometric Fringe Pattern from 1 characteristic of lipid deficiency to the normal condition. Meibum grade, lid margin abnormality scores, fluorescein breakup time, and CFS were also significantly improved (P < 0.001, P < 0.001, P < 0.001, and P = 0.002, respectively) after treatment, whereas the meiboscore and Schirmer test value remained unchanged. CONCLUSIONS IPL-MGX ameliorated symptoms and improved the condition of the tear film in patients with refractory MGD and is therefore a promising treatment option for this disorder.
