Mostafa Agour | Aswan University (original) (raw)
Papers by Mostafa Agour
Applied Physics B, 2016
We present an extension of the adaptive spatial carrier frequency method which is proposed for fa... more We present an extension of the adaptive spatial carrier frequency method which is proposed for fast measuring optical properties of fibrous materials. The method can be considered as a two complementary steps. In the first step, the support of the adaptive filter shall be defined. In the second step, the angle between the sample under test and the interference fringe system generated by the utilized interferometer has to be determined. Thus, the support of the optical filter associated with the implementation of the adaptive spatial carrier frequency method is accordingly rotated. This method is experimentally verified by measuring optical properties of polypropylene (PP) fibre with the help of a Mach–Zehnder interferometer. The results show that errors resulting from rotating the fibre with respect to the interference fringes of the interferometer are reduced compared with the traditional band pass filter method. This conclusion was driven by comparing results of the mean refractive index of drown PP fibre at parallel polarization direction obtained from the new and adaptive spatial carrier frequency method.
Optics Express
We present a fast shape measurement of micro-parts based on depth discrimination in imaging with ... more We present a fast shape measurement of micro-parts based on depth discrimination in imaging with LED illumination. It is based on a 4f-setup with an electrically adjusted tunable lens at the common Fourier plane. Using such a configuration, the opportunity to implement a fast depth scan by means of a tunable lens without the requirement of mechanically moving parts and depth discrimination using the limited spatial coherence of LED illumination is investigated. The technique allows the use of limited spatially partially coherent illumination which can be easily adapted to the test object by selecting the geometrical parameters of the system accordingly. Using this approach, we demonstrate the approach by measuring the 3D form of a tilted optically rough surface and a cold-formed micro-cup. The approach is robust, fast since required images are captured in less than a second, and eye-safe and offers an extended depth of focus in the range of few millimetres. Using a step height stand...
Optics Letters
Terahertz (THz) radiation has shown enormous potential for non-destructive inspection in many con... more Terahertz (THz) radiation has shown enormous potential for non-destructive inspection in many contexts. Here, we present a method for imaging defects in chocolate bars that can be extended to many other materials. Our method requires only a continuous wave (CW) monochromatic source and detector at relatively low frequencies (280 GHz) corresponding to a relatively long wavelength of 1.1 mm. These components are used to construct a common-path configuration enabling the capturing of several images of THz radiation diffracted by the test object at different axial depths. The captured diffraction-rich images are used to constrain the associated phase retrieval problem enabling full access to the wave field, i.e., real amplitude and phase distributions. This allows full-field diffraction-limited phase-contrast imaging. Thus, we experimentally demonstrate the possibility of identifying contaminant particles with dimensions comparable to the wavelength.
Optics and Photonics for Advanced Dimensional Metrology II, 2022
This video illustrates how the reconstruction process works.
The media visualizes the intensity captured at the imaging plane of a 4f-system during the object... more The media visualizes the intensity captured at the imaging plane of a 4f-system during the object depth scan process implemented using a digital micro-mirror device (DMD). This shows the area with limited depth of focus areasing from the spatially partially illumination. In addition, the media shows the movement of the limited depth of focus area till it coveres the whole test object.
Translational Biophotonics: Diagnostics and Therapeutics, 2021
The present study aims at utilizing holographic projection to reconstruct 3D information of brain... more The present study aims at utilizing holographic projection to reconstruct 3D information of brain tumor progression. The holograms were calculated using an adaptive iterative Fourier transform algorithm and projected using a spatial light modulator.
2021 3rd Novel Intelligent and Leading Emerging Sciences Conference (NILES), 2021
This study attempts to visualize the whole retina and its anatomical structures using only a sing... more This study attempts to visualize the whole retina and its anatomical structures using only a single hologram giving the ophthalmologist an opportunity to examine it. Since all fundus cameras capture images for only a portion of the retina, retinal image registration was first applied to the captured images of the same eye to obtain a mosaic containing the complete map of the retina, allowing proper diagnosis. Then, accurate morphological detection of the main anatomical structures of the retina including blood vessels, macula and optic disc which are extremely important signs for estimating retinal disorders were extracted and/or highlighted on the mosaic. Subsequently, computer-generated holograms (GHs) of the mosaic, blood vessels, macula and optic disc were calculated using an adapted iterative approach based on the well-known Gerchberg-Saxton (GS) algorithm. The resulting CGHs were then holographically projected using a reflective phase-only spatial light modulator (SLM). In conclusion, the integration of CGH with fundus photography can be a valuable and crucial diagnostic tool for retinal disorders and can make significant contributions in the field of ophthalmology.
Lecture Notes in Production Engineering, 2019
Optics and Photonics Journal, 2014
Generally, wave field reconstructions obtained by phase-retrieval algorithms are noisy, blurred a... more Generally, wave field reconstructions obtained by phase-retrieval algorithms are noisy, blurred and corrupted by var-ious artifacts such as irregular waves, spots, etc. These dis-turbances, arising due to many factors such as non-idealities of optical system (misalignment, focusing errors), dust on optical elements, reflections, vibration, are hard to be local-ized and specified. It is assumed that there is a generalized pupil function at the object plane which describes aberra-tions in the coherent imaging system manifested at the sensor plane. Here we propose a novel two steps phase-retrieval al-gorithm to compensate these distortions. We first estimate the cumulative disturbance, called “background”, using special calibration experiments. Then, we use this background for reconstruction of the object amplitude and phase. The second part of the algorithm is based on the maximum likelihood approach and, in this way, targeted on the optimal amplitude and phase reconstruction from noi...
Digital Holography and Three-Dimensional Imaging 2019, 2019
arXiv: Optics, 2012
A new method for the compensation of misalignment in the spatial light modulator based optical li... more A new method for the compensation of misalignment in the spatial light modulator based optical linear filtering techniques is presented. It is based on the correlation of the wave fields generated across the input and the output planes of filtering setups. Experimental results are given to demonstrate the effectiveness of the method.
Optics letters, 2020
We present a new technique for fast form measurement based on imaging with partially coherent ill... more We present a new technique for fast form measurement based on imaging with partially coherent illumination. It consists of a 4f-imaging system with a digital micro-mirror device (DMD) located in the Fourier plane of its two lenses. The setup benefits from spatially partially coherent illumination that allows for depth discrimination and a DMD that enables a fast depth scan. Evaluating the intensity contrast, the 3D form of an object is reconstructed. We show that the technique additionally offers extended depth of focus imaging in microscopy and short measurement times of less than a second.
This study reports on a holographic projection system for brain tissue and its white and gray mat... more This study reports on a holographic projection system for brain tissue and its white and gray matter extracted from magnetic resonance data where computer-generated holograms are calculated and projected using a phase-only spatial light modulator.
We present an experimental configuration for phase retrieval utilizing fast object’s depth scanni... more We present an experimental configuration for phase retrieval utilizing fast object’s depth scanning. The configuration is composesed of a digital micro-mirror device enabling fast manipulation of light-fields with binarized holograms of the transfer-function of propagation.
PLOS ONE
We propose a new optical method based on comparative holographic projection for visual comparison... more We propose a new optical method based on comparative holographic projection for visual comparison between two abnormal follow-up magnetic resonance (MR) exams of glioblastoma patients to effectively visualize and assess tumor progression. First, the brain tissue and tumor areas are segmented from the MR exams using the fast marching method (FMM). The FMM approach is implemented on a computed pixel weight matrix based on an automated selection of a set of initialized target points. Thereafter, the associated phase holograms are calculated for the segmented structures based on an adaptive iterative Fourier transform algorithm (AIFTA). Within this approach, a spatial multiplexing is applied to reduce the speckle noise. Furthermore, hologram modulation is performed to represent two different reconstruction schemes. In both schemes, all calculated holograms are superimposed into a single two-dimensional (2D) hologram which is then displayed on a reflective phase-only spatial light modulator (SLM) for optical reconstruction. The optical reconstruction of the first scheme displays a 3D map of the tumor allowing to visualize the volume of the tumor after treatment and at the progression. Whereas, the second scheme displays the follow-up exams in a side-by-side mode highlighting tumor areas, so the assessment of each case can be fast achieved. The proposed system can be used as a valuable tool for interpretation and assessment of the tumor progression with respect to the treatment method providing an improvement in diagnosis and treatment planning.
Applied Physics B, 2016
We present an extension of the adaptive spatial carrier frequency method which is proposed for fa... more We present an extension of the adaptive spatial carrier frequency method which is proposed for fast measuring optical properties of fibrous materials. The method can be considered as a two complementary steps. In the first step, the support of the adaptive filter shall be defined. In the second step, the angle between the sample under test and the interference fringe system generated by the utilized interferometer has to be determined. Thus, the support of the optical filter associated with the implementation of the adaptive spatial carrier frequency method is accordingly rotated. This method is experimentally verified by measuring optical properties of polypropylene (PP) fibre with the help of a Mach–Zehnder interferometer. The results show that errors resulting from rotating the fibre with respect to the interference fringes of the interferometer are reduced compared with the traditional band pass filter method. This conclusion was driven by comparing results of the mean refractive index of drown PP fibre at parallel polarization direction obtained from the new and adaptive spatial carrier frequency method.
Optics Express
We present a fast shape measurement of micro-parts based on depth discrimination in imaging with ... more We present a fast shape measurement of micro-parts based on depth discrimination in imaging with LED illumination. It is based on a 4f-setup with an electrically adjusted tunable lens at the common Fourier plane. Using such a configuration, the opportunity to implement a fast depth scan by means of a tunable lens without the requirement of mechanically moving parts and depth discrimination using the limited spatial coherence of LED illumination is investigated. The technique allows the use of limited spatially partially coherent illumination which can be easily adapted to the test object by selecting the geometrical parameters of the system accordingly. Using this approach, we demonstrate the approach by measuring the 3D form of a tilted optically rough surface and a cold-formed micro-cup. The approach is robust, fast since required images are captured in less than a second, and eye-safe and offers an extended depth of focus in the range of few millimetres. Using a step height stand...
Optics Letters
Terahertz (THz) radiation has shown enormous potential for non-destructive inspection in many con... more Terahertz (THz) radiation has shown enormous potential for non-destructive inspection in many contexts. Here, we present a method for imaging defects in chocolate bars that can be extended to many other materials. Our method requires only a continuous wave (CW) monochromatic source and detector at relatively low frequencies (280 GHz) corresponding to a relatively long wavelength of 1.1 mm. These components are used to construct a common-path configuration enabling the capturing of several images of THz radiation diffracted by the test object at different axial depths. The captured diffraction-rich images are used to constrain the associated phase retrieval problem enabling full access to the wave field, i.e., real amplitude and phase distributions. This allows full-field diffraction-limited phase-contrast imaging. Thus, we experimentally demonstrate the possibility of identifying contaminant particles with dimensions comparable to the wavelength.
Optics and Photonics for Advanced Dimensional Metrology II, 2022
This video illustrates how the reconstruction process works.
The media visualizes the intensity captured at the imaging plane of a 4f-system during the object... more The media visualizes the intensity captured at the imaging plane of a 4f-system during the object depth scan process implemented using a digital micro-mirror device (DMD). This shows the area with limited depth of focus areasing from the spatially partially illumination. In addition, the media shows the movement of the limited depth of focus area till it coveres the whole test object.
Translational Biophotonics: Diagnostics and Therapeutics, 2021
The present study aims at utilizing holographic projection to reconstruct 3D information of brain... more The present study aims at utilizing holographic projection to reconstruct 3D information of brain tumor progression. The holograms were calculated using an adaptive iterative Fourier transform algorithm and projected using a spatial light modulator.
2021 3rd Novel Intelligent and Leading Emerging Sciences Conference (NILES), 2021
This study attempts to visualize the whole retina and its anatomical structures using only a sing... more This study attempts to visualize the whole retina and its anatomical structures using only a single hologram giving the ophthalmologist an opportunity to examine it. Since all fundus cameras capture images for only a portion of the retina, retinal image registration was first applied to the captured images of the same eye to obtain a mosaic containing the complete map of the retina, allowing proper diagnosis. Then, accurate morphological detection of the main anatomical structures of the retina including blood vessels, macula and optic disc which are extremely important signs for estimating retinal disorders were extracted and/or highlighted on the mosaic. Subsequently, computer-generated holograms (GHs) of the mosaic, blood vessels, macula and optic disc were calculated using an adapted iterative approach based on the well-known Gerchberg-Saxton (GS) algorithm. The resulting CGHs were then holographically projected using a reflective phase-only spatial light modulator (SLM). In conclusion, the integration of CGH with fundus photography can be a valuable and crucial diagnostic tool for retinal disorders and can make significant contributions in the field of ophthalmology.
Lecture Notes in Production Engineering, 2019
Optics and Photonics Journal, 2014
Generally, wave field reconstructions obtained by phase-retrieval algorithms are noisy, blurred a... more Generally, wave field reconstructions obtained by phase-retrieval algorithms are noisy, blurred and corrupted by var-ious artifacts such as irregular waves, spots, etc. These dis-turbances, arising due to many factors such as non-idealities of optical system (misalignment, focusing errors), dust on optical elements, reflections, vibration, are hard to be local-ized and specified. It is assumed that there is a generalized pupil function at the object plane which describes aberra-tions in the coherent imaging system manifested at the sensor plane. Here we propose a novel two steps phase-retrieval al-gorithm to compensate these distortions. We first estimate the cumulative disturbance, called “background”, using special calibration experiments. Then, we use this background for reconstruction of the object amplitude and phase. The second part of the algorithm is based on the maximum likelihood approach and, in this way, targeted on the optimal amplitude and phase reconstruction from noi...
Digital Holography and Three-Dimensional Imaging 2019, 2019
arXiv: Optics, 2012
A new method for the compensation of misalignment in the spatial light modulator based optical li... more A new method for the compensation of misalignment in the spatial light modulator based optical linear filtering techniques is presented. It is based on the correlation of the wave fields generated across the input and the output planes of filtering setups. Experimental results are given to demonstrate the effectiveness of the method.
Optics letters, 2020
We present a new technique for fast form measurement based on imaging with partially coherent ill... more We present a new technique for fast form measurement based on imaging with partially coherent illumination. It consists of a 4f-imaging system with a digital micro-mirror device (DMD) located in the Fourier plane of its two lenses. The setup benefits from spatially partially coherent illumination that allows for depth discrimination and a DMD that enables a fast depth scan. Evaluating the intensity contrast, the 3D form of an object is reconstructed. We show that the technique additionally offers extended depth of focus imaging in microscopy and short measurement times of less than a second.
This study reports on a holographic projection system for brain tissue and its white and gray mat... more This study reports on a holographic projection system for brain tissue and its white and gray matter extracted from magnetic resonance data where computer-generated holograms are calculated and projected using a phase-only spatial light modulator.
We present an experimental configuration for phase retrieval utilizing fast object’s depth scanni... more We present an experimental configuration for phase retrieval utilizing fast object’s depth scanning. The configuration is composesed of a digital micro-mirror device enabling fast manipulation of light-fields with binarized holograms of the transfer-function of propagation.
PLOS ONE
We propose a new optical method based on comparative holographic projection for visual comparison... more We propose a new optical method based on comparative holographic projection for visual comparison between two abnormal follow-up magnetic resonance (MR) exams of glioblastoma patients to effectively visualize and assess tumor progression. First, the brain tissue and tumor areas are segmented from the MR exams using the fast marching method (FMM). The FMM approach is implemented on a computed pixel weight matrix based on an automated selection of a set of initialized target points. Thereafter, the associated phase holograms are calculated for the segmented structures based on an adaptive iterative Fourier transform algorithm (AIFTA). Within this approach, a spatial multiplexing is applied to reduce the speckle noise. Furthermore, hologram modulation is performed to represent two different reconstruction schemes. In both schemes, all calculated holograms are superimposed into a single two-dimensional (2D) hologram which is then displayed on a reflective phase-only spatial light modulator (SLM) for optical reconstruction. The optical reconstruction of the first scheme displays a 3D map of the tumor allowing to visualize the volume of the tumor after treatment and at the progression. Whereas, the second scheme displays the follow-up exams in a side-by-side mode highlighting tumor areas, so the assessment of each case can be fast achieved. The proposed system can be used as a valuable tool for interpretation and assessment of the tumor progression with respect to the treatment method providing an improvement in diagnosis and treatment planning.