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Papers by / Abdallah Hamed
The European Physical Journal Plus
We suggest triangular aperture modeling for the computation of speckle size using the point sprea... more We suggest triangular aperture modeling for the computation of speckle size using the point spread function (PSF) concept. The fast Fourier transform (FFT) algorithm indicates three models of triangular apertures in the point spread function (PSF) computation. We calculated for the first time the average speckle size from the full width at half maximum (FWHM) for the triangular apertures in the PSF. The results are compared with the speckle sizes results obtained from the autocorrelation of speckle images corresponding to the considered models showed an agreement. In the analysis, I consider the 1st model with four equilateral triangular apertures, each of equal sides (b), along the Cartesian coordinates at equal distances from the center (xd). In the 2nd model, I assume 16 triangular apertures in a circular contour. In contrast, in the 3rd model, a sequence of six equilateral triangular black and white (B/W) zones is shown where the central triangle is black. I consider central obs...
In this paper, five modulated apertures are considered. The first has linear distribution, the se... more In this paper, five modulated apertures are considered. The first has linear distribution, the second has conic shape, the third has quadratic distribution, the fourth has Gaussian distribution, and the fifth has B/W concentric annuli. These apertures are recognized from the fringe shift occurred in the interferometric images using the CFPI. The recognized modulated apertures are compared with the fringe shift corresponding to the uniform circular aperture. The improved multiple beam Interferometer or the CFPI working in transmission is considered for the aperture recognition. The sharp interferometric images obtained from the CFPI provided with the apertures are constructed using MatLab code.
We investigate the Gastroesophageal reflux disease (GERD)using the speckle imaging. The speckle i... more We investigate the Gastroesophageal reflux disease (GERD)using the speckle imaging. The speckle images are computed from the convolution product of Fourier transform of the diffuser and Fourier spectrum of the original image. In addition, contour and digital images are given. This study is made since this disease is still affect a great cluster of peoples in the developed countries. The MatLab code is used for the computation of speckle and other images.
Optik, 2017
Highlights This study is made looking forward to get further improvement in resolution of conve... more Highlights This study is made looking forward to get further improvement in resolution of conventional and confocal microscopes. The described models of apertures are selected in order to get better PSF and consequently better resolution. A combination from modulated linear and quadratic distributions inside the aperture allows getting better resolution than the ordinary circular aperture. The resolution of a hyper-resolving aperture in the form of three different concentric layers is investigated. This new aperture has a successive quadratic, linear, and constant layers from the center. The central quadratic distributed segment from the aperture is selected to attenuate the low spatial frequencies. Another model of hyper-resolving aperture in the form of four concentric layers is investigated. In this aperture, from the center, a dark central disk followed by a higher order, 6 , distribution, the next is linear, and the last has constant layer. In this case, the spatial frequency attenuation is realized by the central dark disk followed by the 6 distribution. The point spread function (PSF) of the described two apertures is computed and compared with the corresponding annular and circular apertures. In addition, the coherent transfer function of the confocal microscope computed using the hyper-resolving apertures.
Pramana, 2008
A quadratic model is suggested to describe the fringe shift occurred due to the phase variations ... more A quadratic model is suggested to describe the fringe shift occurred due to the phase variations of uncladded glass fiber introduced between the two plates of the liquid wedge interferometer. The fringe shift of the phase object is represented in the harmonic term which appears in the denominator of the Airy distribution formula of Fabry-Perot's interferometer. A computer program is written to plot the computed fringe shifts of the described model. An experiment is conducted using liquid wedge interferometer where the fiber of a nearly quadratic thickness variation is introduced between the two plates of the interferometer. The obtained fringe shift shows a good agreement with the proposed quadratic model. Also, it is compared with the previous theoretical shift based on ray optics of semi-circular shape.
Beni-Suef University Journal of Basic and Applied Sciences
Background A hyper-resolving aperture composed of a polynomial distribution is suggested. The poi... more Background A hyper-resolving aperture composed of a polynomial distribution is suggested. The point spread function (PSF) is computed and compared with that corresponding to linear, quadratic, and circular apertures. In addition, the influence of the number of zones on the PSF is discussed. An application on confocal scanning laser microscope using Siemen’s star pattern as an object considering the polynomial apertures is given. Results We have made polynomial apertures using MATLAB code, and we tested the resolution from the computation of the cut-off spatial frequency obtained from the computation of the point spread function. Conclusions We get compromised resolution and contrast for the polynomial apertures as compared with uniform circular apertures.
Beni-Suef University Journal of Basic and Applied Sciences
Background An aperture in the form of four squares arranged symmetrically along the cartesian coo... more Background An aperture in the form of four squares arranged symmetrically along the cartesian coordinates with equal distances from the center investigated. Three models are suggested in the computation of the Point Spread Function PSF using the FFT technique. In the 1st model, circular annulus is placed in the center, while in the 2nd model a square annulus is shown, and in the 3rd model, two symmetric squares in the models 1, 2 are replaced by two symmetric rectangles while the center remains of square annulus. In all the models, central obstruction is made seeking to improve the PSF. Results An analytical formula for the PSF for the aperture described in the 1st model is obtained. In addition, the autocorrelation corresponding to these apertures are computed and compared with the known autocorrelation corresponding to the whole square aperture. An application on speckle imaging is given using these apertures combined with the diffuser. All images for the design of the apertures a...
The famous work on the PSF is made by Sheppard et. al. [1-12] using annular and Gaussian aperture... more The famous work on the PSF is made by Sheppard et. al. [1-12] using annular and Gaussian apertures. Improvement of axial resolution in confocal microscopy using annular pupil is investigated in [9].Practical limits of resolution in confocal and nonlinear microscopy is presented in [11]. The effect of numerical aperture on interference fringe spacing is shown in [13]. Linear, quadratic, B/W concentric annuli, and graded index apertures is suggested by Hamed et. al. [14-20]. They computed the PSF considering the above modulated apertures giving lateral resolution improvement. Image analysis of modified Hamming aperture and an application on confocal microscopy and holography is given in [20]. Modulatedalignment dual-axis (MAD) confocal microscopy for deep optical sectioning in tissues is presented in [21]. While an image scanning microscopy with a quadrant detector is recently investigated [22].
Pramana, 2020
In this paper, a new concentric Hamming linear aperture is suggested. The point spread function (... more In this paper, a new concentric Hamming linear aperture is suggested. The point spread function (PSF) is computed for concentric Hamming linear aperture and it is compared with the corresponding circular, conventional Hamming and obstructed Hamming apertures. In addition, the autocorrelation corresponding to the aperture under consideration is computed and plotted. Application of the Hamming linear aperture in the formation of modulated speckle images of Ramses II statues using definite random diffuser is given. A diffuser limited by a circular uniform aperture is the basic element in the formation of ordinary speckle images located in the Fourier plane. Meanwhile, the Fourier spectrum of images of Ramses II multiplied by the ordinary speckle give modulated speckle images. Discrimination between the modulated speckle images is justified by comparing the profiles corresponding to each speckle image. Finally, the speckle contours and correlation of the modulated speckle images compared to the ordinary speckle images are investigated. It is noted that all computation and formation of images and plots are based on fast Fourier transform (FFT) techniques using Matlab codes.
Optics & Laser Technology, 1984
ABSTRACT
SPIE Proceedings, 1989
The Coherent Scanning Microscope (CSM) is mainly composed of two objectives arranged in tandem co... more The Coherent Scanning Microscope (CSM) is mainly composed of two objectives arranged in tandem combined with the scanned object. The synchronized scanning of both of the object and the electron beam emitted from the cathod ray monitor will assure the construction of the temporal image. Since it is easy to aligne the first objective of the CSM, while it is not the case for the second objective, hence we assume that the later objective is subjected to tilting and to a lateral shift with respect to the first aligned objective. Another case assumes that the second objective is influenced by coma of third order in addition to the exoentration errors. In both cases, the resulting impulse response hr= h1h2, is calculated. The above mentioned problems of excentration errors combined with wavefront aberration, which are both harmfull for the microscope resolution, are discussed.
Optik
On presente un microscope coherent opto―electronique pour etudier theoriquement les deplacements ... more On presente un microscope coherent opto―electronique pour etudier theoriquement les deplacements lateraux et longitudinaux introduits dus aux mauvais alignements du systeme optique. Calcul de la degradation de l'intensite de l'image
Optik - International Journal for Light and Electron Optics
Firstly, the resultant point spread function (RPSF) is calculated for five different apertures ha... more Firstly, the resultant point spread function (RPSF) is calculated for five different apertures having p n distribution in a confocal imaging system. A computer program is constructed and the computed values of the RPSF are plotted and compared with the curve obtained in case of uniform circular aperture. Secondly, an approximate expression describing the resolution criterion is derived in case of modulated apertures and it is compared with the ordinary criterion of the resolution obtained in case of uniform circular aperture.
Optik - International Journal for Light and Electron Optics
We propose a Coherent Non-Scanned Microscope (CNSM) as an image processor based on confocal imagi... more We propose a Coherent Non-Scanned Microscope (CNSM) as an image processor based on confocal imaging. In this CNSM, a fixed object is positioned in the object plane of the confocal arrangement instead of using the mechanically scanning of the object in the Coherent Scanning Microscope (CSM). The whole image is constructed using a coherent detector composed of an array matrix of photodectors placed in the imaging plane. A polychromatic image processor is studied in case of CSM.
We study the malignant and benign mammographic x – ray images using speckle techniques. Discrimin... more We study the malignant and benign mammographic x – ray images using speckle techniques. Discrimination between the mammographic images is outlined using circular aperture segmentation. The algorithm is based on the selection of the interested segment from the mammographic image. We multiply the segment by a uniform circular aperture of diameter nearly equal the dimensions of the segment. Then, we multiply the modulated segment by a diffuse function. Finally, we operate the Fourier transform upon the three matrices to get a modulated speckle images. These modulated images are dependent upon the information on the selected image segment. The modulated speckle images and profiles of the mammographic images are investigated using mat-lab code.
In this paper, apertures in the form of graded index distribution and truncated apertures are inv... more In this paper, apertures in the form of graded index distribution and truncated apertures are investigated. The 1 st type of graded index aperture has central black zone followed by steps with increased intensity directed outwards. The second aperture has successive black and transparent annuls with central opaque zone. The third has four different truncated apertures. Digital diffuser is fabricated to get modulated speckle images for all described apertures. The profile of the speckle images and the corresponding autocorrelation profiles are plotted and the speckle sizes are computed for the different cited apertures. A Mat-lab code is written to compute and plot all of the above images.
Journal of Modern Optics, 2015
ABSTRACT Digital truncated and obstructed Hamming apertures are used in confocal laser scanning m... more ABSTRACT Digital truncated and obstructed Hamming apertures are used in confocal laser scanning microscope (CLSM) to improve the resolution. The resultant point spread function (RPSF) and the coherent transfer function of the defined microscope, using the modified Hamming apertures, are computed. The mammographic images are used in the CLSM to test resolution of the investigated apertures. The image is computed from the modulus square of the convolution product of the RPSF and the complex amplitude of the object. A comparison with the images obtained in case of circular uniform apertures is investigated. Another application on holography allows the recognition of the modulated Hamming apertures.
Optics and Photonics Journal, 2013
In this paper, we present an elongated speckle images produced from diffusers using sharp ellipti... more In this paper, we present an elongated speckle images produced from diffusers using sharp elliptical apertures. The orientation of the elliptic aperture is recognized from the direction of the elongation in the speckle images. The aperture tilting out of the plane is investigated. Three models of elliptical apertures are considered and the corresponding speckle images are obtained. The 1st model is composed of two orthogonal ellipses or plus symbol pupil; the 2nd has four symmetric ellipses with an angle of 45˚ between each of them or in the form of a snow flake pupil and the 3rd model looks like an airplane. Also, the autocorrelation profiles of the speckle images corresponding to the diffused airplane are obtained from which the average speckle size is computed. Finally, the reconstructed images of the described elliptical models and its autocorrelation images, making use of Mat lab code, are obtained.
The European Physical Journal Plus
We suggest triangular aperture modeling for the computation of speckle size using the point sprea... more We suggest triangular aperture modeling for the computation of speckle size using the point spread function (PSF) concept. The fast Fourier transform (FFT) algorithm indicates three models of triangular apertures in the point spread function (PSF) computation. We calculated for the first time the average speckle size from the full width at half maximum (FWHM) for the triangular apertures in the PSF. The results are compared with the speckle sizes results obtained from the autocorrelation of speckle images corresponding to the considered models showed an agreement. In the analysis, I consider the 1st model with four equilateral triangular apertures, each of equal sides (b), along the Cartesian coordinates at equal distances from the center (xd). In the 2nd model, I assume 16 triangular apertures in a circular contour. In contrast, in the 3rd model, a sequence of six equilateral triangular black and white (B/W) zones is shown where the central triangle is black. I consider central obs...
In this paper, five modulated apertures are considered. The first has linear distribution, the se... more In this paper, five modulated apertures are considered. The first has linear distribution, the second has conic shape, the third has quadratic distribution, the fourth has Gaussian distribution, and the fifth has B/W concentric annuli. These apertures are recognized from the fringe shift occurred in the interferometric images using the CFPI. The recognized modulated apertures are compared with the fringe shift corresponding to the uniform circular aperture. The improved multiple beam Interferometer or the CFPI working in transmission is considered for the aperture recognition. The sharp interferometric images obtained from the CFPI provided with the apertures are constructed using MatLab code.
We investigate the Gastroesophageal reflux disease (GERD)using the speckle imaging. The speckle i... more We investigate the Gastroesophageal reflux disease (GERD)using the speckle imaging. The speckle images are computed from the convolution product of Fourier transform of the diffuser and Fourier spectrum of the original image. In addition, contour and digital images are given. This study is made since this disease is still affect a great cluster of peoples in the developed countries. The MatLab code is used for the computation of speckle and other images.
Optik, 2017
Highlights This study is made looking forward to get further improvement in resolution of conve... more Highlights This study is made looking forward to get further improvement in resolution of conventional and confocal microscopes. The described models of apertures are selected in order to get better PSF and consequently better resolution. A combination from modulated linear and quadratic distributions inside the aperture allows getting better resolution than the ordinary circular aperture. The resolution of a hyper-resolving aperture in the form of three different concentric layers is investigated. This new aperture has a successive quadratic, linear, and constant layers from the center. The central quadratic distributed segment from the aperture is selected to attenuate the low spatial frequencies. Another model of hyper-resolving aperture in the form of four concentric layers is investigated. In this aperture, from the center, a dark central disk followed by a higher order, 6 , distribution, the next is linear, and the last has constant layer. In this case, the spatial frequency attenuation is realized by the central dark disk followed by the 6 distribution. The point spread function (PSF) of the described two apertures is computed and compared with the corresponding annular and circular apertures. In addition, the coherent transfer function of the confocal microscope computed using the hyper-resolving apertures.
Pramana, 2008
A quadratic model is suggested to describe the fringe shift occurred due to the phase variations ... more A quadratic model is suggested to describe the fringe shift occurred due to the phase variations of uncladded glass fiber introduced between the two plates of the liquid wedge interferometer. The fringe shift of the phase object is represented in the harmonic term which appears in the denominator of the Airy distribution formula of Fabry-Perot's interferometer. A computer program is written to plot the computed fringe shifts of the described model. An experiment is conducted using liquid wedge interferometer where the fiber of a nearly quadratic thickness variation is introduced between the two plates of the interferometer. The obtained fringe shift shows a good agreement with the proposed quadratic model. Also, it is compared with the previous theoretical shift based on ray optics of semi-circular shape.
Beni-Suef University Journal of Basic and Applied Sciences
Background A hyper-resolving aperture composed of a polynomial distribution is suggested. The poi... more Background A hyper-resolving aperture composed of a polynomial distribution is suggested. The point spread function (PSF) is computed and compared with that corresponding to linear, quadratic, and circular apertures. In addition, the influence of the number of zones on the PSF is discussed. An application on confocal scanning laser microscope using Siemen’s star pattern as an object considering the polynomial apertures is given. Results We have made polynomial apertures using MATLAB code, and we tested the resolution from the computation of the cut-off spatial frequency obtained from the computation of the point spread function. Conclusions We get compromised resolution and contrast for the polynomial apertures as compared with uniform circular apertures.
Beni-Suef University Journal of Basic and Applied Sciences
Background An aperture in the form of four squares arranged symmetrically along the cartesian coo... more Background An aperture in the form of four squares arranged symmetrically along the cartesian coordinates with equal distances from the center investigated. Three models are suggested in the computation of the Point Spread Function PSF using the FFT technique. In the 1st model, circular annulus is placed in the center, while in the 2nd model a square annulus is shown, and in the 3rd model, two symmetric squares in the models 1, 2 are replaced by two symmetric rectangles while the center remains of square annulus. In all the models, central obstruction is made seeking to improve the PSF. Results An analytical formula for the PSF for the aperture described in the 1st model is obtained. In addition, the autocorrelation corresponding to these apertures are computed and compared with the known autocorrelation corresponding to the whole square aperture. An application on speckle imaging is given using these apertures combined with the diffuser. All images for the design of the apertures a...
The famous work on the PSF is made by Sheppard et. al. [1-12] using annular and Gaussian aperture... more The famous work on the PSF is made by Sheppard et. al. [1-12] using annular and Gaussian apertures. Improvement of axial resolution in confocal microscopy using annular pupil is investigated in [9].Practical limits of resolution in confocal and nonlinear microscopy is presented in [11]. The effect of numerical aperture on interference fringe spacing is shown in [13]. Linear, quadratic, B/W concentric annuli, and graded index apertures is suggested by Hamed et. al. [14-20]. They computed the PSF considering the above modulated apertures giving lateral resolution improvement. Image analysis of modified Hamming aperture and an application on confocal microscopy and holography is given in [20]. Modulatedalignment dual-axis (MAD) confocal microscopy for deep optical sectioning in tissues is presented in [21]. While an image scanning microscopy with a quadrant detector is recently investigated [22].
Pramana, 2020
In this paper, a new concentric Hamming linear aperture is suggested. The point spread function (... more In this paper, a new concentric Hamming linear aperture is suggested. The point spread function (PSF) is computed for concentric Hamming linear aperture and it is compared with the corresponding circular, conventional Hamming and obstructed Hamming apertures. In addition, the autocorrelation corresponding to the aperture under consideration is computed and plotted. Application of the Hamming linear aperture in the formation of modulated speckle images of Ramses II statues using definite random diffuser is given. A diffuser limited by a circular uniform aperture is the basic element in the formation of ordinary speckle images located in the Fourier plane. Meanwhile, the Fourier spectrum of images of Ramses II multiplied by the ordinary speckle give modulated speckle images. Discrimination between the modulated speckle images is justified by comparing the profiles corresponding to each speckle image. Finally, the speckle contours and correlation of the modulated speckle images compared to the ordinary speckle images are investigated. It is noted that all computation and formation of images and plots are based on fast Fourier transform (FFT) techniques using Matlab codes.
Optics & Laser Technology, 1984
ABSTRACT
SPIE Proceedings, 1989
The Coherent Scanning Microscope (CSM) is mainly composed of two objectives arranged in tandem co... more The Coherent Scanning Microscope (CSM) is mainly composed of two objectives arranged in tandem combined with the scanned object. The synchronized scanning of both of the object and the electron beam emitted from the cathod ray monitor will assure the construction of the temporal image. Since it is easy to aligne the first objective of the CSM, while it is not the case for the second objective, hence we assume that the later objective is subjected to tilting and to a lateral shift with respect to the first aligned objective. Another case assumes that the second objective is influenced by coma of third order in addition to the exoentration errors. In both cases, the resulting impulse response hr= h1h2, is calculated. The above mentioned problems of excentration errors combined with wavefront aberration, which are both harmfull for the microscope resolution, are discussed.
Optik
On presente un microscope coherent opto―electronique pour etudier theoriquement les deplacements ... more On presente un microscope coherent opto―electronique pour etudier theoriquement les deplacements lateraux et longitudinaux introduits dus aux mauvais alignements du systeme optique. Calcul de la degradation de l'intensite de l'image
Optik - International Journal for Light and Electron Optics
Firstly, the resultant point spread function (RPSF) is calculated for five different apertures ha... more Firstly, the resultant point spread function (RPSF) is calculated for five different apertures having p n distribution in a confocal imaging system. A computer program is constructed and the computed values of the RPSF are plotted and compared with the curve obtained in case of uniform circular aperture. Secondly, an approximate expression describing the resolution criterion is derived in case of modulated apertures and it is compared with the ordinary criterion of the resolution obtained in case of uniform circular aperture.
Optik - International Journal for Light and Electron Optics
We propose a Coherent Non-Scanned Microscope (CNSM) as an image processor based on confocal imagi... more We propose a Coherent Non-Scanned Microscope (CNSM) as an image processor based on confocal imaging. In this CNSM, a fixed object is positioned in the object plane of the confocal arrangement instead of using the mechanically scanning of the object in the Coherent Scanning Microscope (CSM). The whole image is constructed using a coherent detector composed of an array matrix of photodectors placed in the imaging plane. A polychromatic image processor is studied in case of CSM.
We study the malignant and benign mammographic x – ray images using speckle techniques. Discrimin... more We study the malignant and benign mammographic x – ray images using speckle techniques. Discrimination between the mammographic images is outlined using circular aperture segmentation. The algorithm is based on the selection of the interested segment from the mammographic image. We multiply the segment by a uniform circular aperture of diameter nearly equal the dimensions of the segment. Then, we multiply the modulated segment by a diffuse function. Finally, we operate the Fourier transform upon the three matrices to get a modulated speckle images. These modulated images are dependent upon the information on the selected image segment. The modulated speckle images and profiles of the mammographic images are investigated using mat-lab code.
In this paper, apertures in the form of graded index distribution and truncated apertures are inv... more In this paper, apertures in the form of graded index distribution and truncated apertures are investigated. The 1 st type of graded index aperture has central black zone followed by steps with increased intensity directed outwards. The second aperture has successive black and transparent annuls with central opaque zone. The third has four different truncated apertures. Digital diffuser is fabricated to get modulated speckle images for all described apertures. The profile of the speckle images and the corresponding autocorrelation profiles are plotted and the speckle sizes are computed for the different cited apertures. A Mat-lab code is written to compute and plot all of the above images.
Journal of Modern Optics, 2015
ABSTRACT Digital truncated and obstructed Hamming apertures are used in confocal laser scanning m... more ABSTRACT Digital truncated and obstructed Hamming apertures are used in confocal laser scanning microscope (CLSM) to improve the resolution. The resultant point spread function (RPSF) and the coherent transfer function of the defined microscope, using the modified Hamming apertures, are computed. The mammographic images are used in the CLSM to test resolution of the investigated apertures. The image is computed from the modulus square of the convolution product of the RPSF and the complex amplitude of the object. A comparison with the images obtained in case of circular uniform apertures is investigated. Another application on holography allows the recognition of the modulated Hamming apertures.
Optics and Photonics Journal, 2013
In this paper, we present an elongated speckle images produced from diffusers using sharp ellipti... more In this paper, we present an elongated speckle images produced from diffusers using sharp elliptical apertures. The orientation of the elliptic aperture is recognized from the direction of the elongation in the speckle images. The aperture tilting out of the plane is investigated. Three models of elliptical apertures are considered and the corresponding speckle images are obtained. The 1st model is composed of two orthogonal ellipses or plus symbol pupil; the 2nd has four symmetric ellipses with an angle of 45˚ between each of them or in the form of a snow flake pupil and the 3rd model looks like an airplane. Also, the autocorrelation profiles of the speckle images corresponding to the diffused airplane are obtained from which the average speckle size is computed. Finally, the reconstructed images of the described elliptical models and its autocorrelation images, making use of Mat lab code, are obtained.