A method of generating amplitude masks with a constant power spectra and using them to measure the two-dimensional modulation-transfer functions of optical systems

Evtikhiev, Nikolay N.; Krasnov, Vitaly V.; Starikov, Sergey N.

doi:10.1364/jot.80.000294

Cited by 14 publications

(6 citation statements)

References 7 publications

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“…The third stage is aimed at reducing the synthesis error based on the results of the first stage. For this, the DSRT technique is used [ 25 , 26 ]. Every hologram pixel is consequently changed in order set by the random trajectory.…”

Section: The Methodsmentioning

confidence: 99%

“…To change this, an iterative method of synthesis of amplitude binary inline Fresnel holograms in divergent beams was recently proposed [ 23 ]. It consists of three components: the modified Gerchberg–Saxton algorithm, Otsu binarization [ 24 ] and direct search with random trajectory technique (DSRT) [ 25 , 26 ] at the end of the method. The application of DSRT allows to substantially increase reconstruction quality and DE.…”

Section: Introductionmentioning

confidence: 99%

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What Binarization Method Is the Best for Amplitude Inline Fresnel Holograms Synthesized for Divergent Beams Using the Direct Search with Random Trajectory Technique?

et al. 2023

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Fast reconstruction of holographic and diffractive optical elements (DOE) can be implemented by binary digital micromirror devices (DMD). Since micromirrors of the DMD have two positions, the synthesized DOEs must be binary. This work studies the possibility of improving the method of synthesis of amplitude binary inline Fresnel holograms in divergent beams. The method consists of the modified Gerchberg–Saxton algorithm, Otsu binarization and direct search with random trajectory technique. To achieve a better quality of reconstruction, various binarization methods were compared. We performed numerical and optical experiments using the DMD. Holograms of halftone image with size up to 1024 × 1024 pixels were synthesized. It was determined that local and several global threshold methods provide the best quality. Compared to the Otsu binarization used in the original method of the synthesis, the reconstruction quality (MSE and SSIM values) is improved by 46% and the diffraction efficiency is increased by 27%.

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Section: The Methodsmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

What Binarization Method Is the Best for Amplitude Inline Fresnel Holograms Synthesized for Divergent Beams Using the Direct Search with Random Trajectory Technique?

et al. 2023

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“…Direct search with random trajectory (DSRT) method [10,21] was used for encryption key generation as described in [10] .…”

Section: Optical Encryption In Spatially-incoherent Monochromatic Ligmentioning

confidence: 99%

Optical encryption in spatially-incoherent light using two LC SLMs for both information input and encryption element imaging

et al. 2014

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At present time methods of optical encryption are actively developed. The majority of existing methods of optical encryption use not only light intensity distribution, easily registered with photosensors, but also its phase distribution which require application of complex holographic schemes in conjunction with spatially coherent monochromatic illumination. This leads to complex optical schemes and low decryption quality. To eliminate these disadvantages it is possible to implement optical encryption using spatially incoherent monochromatic illumination which requires registration of light intensity distribution only.Encryption is accomplished by means of optical convolution of image of scene to be encrypted and encryption diffractive optical element (DOE) point spread function (PSF) which serves as encryption key. Encryption process is described as follows. Scene is illuminated with spatially-incoherent monochromatic light. In the absence of encryption DOE lens forms image of scene in photosensor plane. DOE serves as encryption element, its PSF -encryption key. Light passing through DOE forms convolution of object image and DOE PSF. Registered by photosensor convolution is encrypted image. Decryption was conducted numerically on computer by means of inverse filtration with regularization. Kinoforms were used as encryption DOE because they have single diffraction order. Two liquid crystal (LC) spatial light modulators (SLM) were used to implement dynamic digital information input and dynamic encryption key change. As input scene amplitude LC SLM HoloEye LC2002 with 800×600 pixels 32×32 μm 2 and 256 gray levels was used. To image synthesized encryption kinoforms phase LC SLM HoloEye PLUTO VIS with 1920×1080 pixels 8×8 μm 2 and 256 phase levels was used. Set of test images was successfully optically encrypted and then numerically decrypted. Encrypted images contents are hidden. Decrypted images despite quite high noise levels are positively recognizable. Results of optical encryption and numerical decryption are presented.

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“…[9][10][11][12][13][15][16][17][18] However, the random image can also be used as a 2-D target since its image brightness changes in two orthogonal directions and is available for measuring 2-D MTF. In 2013, Evtikhiev et al 19 proposed a new random target to reduce the noise impact for the 2-D MTF measurement.…”

Section: Introductionmentioning

confidence: 99%

Measurement and comparison of one- and two-dimensional modulation transfer function of optical imaging systems based on the random target method

2014

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Abstract. One-dimensional modulation transfer function (1-D MTF) has been generally calculated to evaluate the image quality of optical imaging systems, such as the horizontal MTF and vertical MTF. These MTFs can be measured by the use of some mature ways. However, the information of 1-D MTF for performance evaluation may not enough for the systems handling two-dimensional (2-D) targets of high resolution, thus discussing 2-D MTF will be necessary. We investigate the measurement method for the 1-D and 2-D MTF of optical imaging systems based on the random target method, and the characteristics of 2-D MTF and 1-D MTF in terms of MTF values and cutoff frequency are also noted. © The Authors. Published by SPIE under a Creative Commons Attribution 3.0 Unported License. Distribution or reproduction of this work in whole or in part requires full attribution of the original publication, including its DOI.

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A method of generating amplitude masks with a constant power spectra and using them to measure the two-dimensional modulation-transfer functions of optical systems

Cited by 14 publications

References 7 publications

What Binarization Method Is the Best for Amplitude Inline Fresnel Holograms Synthesized for Divergent Beams Using the Direct Search with Random Trajectory Technique?

What Binarization Method Is the Best for Amplitude Inline Fresnel Holograms Synthesized for Divergent Beams Using the Direct Search with Random Trajectory Technique?

Optical encryption in spatially-incoherent light using two LC SLMs for both information input and encryption element imaging

Measurement and comparison of one- and two-dimensional modulation transfer function of optical imaging systems based on the random target method

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