Evgeny Zlokazov

MINACE filter: variants of realization in 4-f correlator

Minimum Noise And Correlation Energy (MINACE) filters application provides good ability to recognize in case of grayscale input images of an object with background noises. For fast correlation matching MINACE filters can be used in 4-f correlators as a computer generated hologram (holographic filters). In this paper different variants of holographic filters realization were discussed. The results of correlation recognition with holographic MINACE filters are presented.

Variants of minimum correlation energy filters: comparative study

Application of distortion invariant filters (DIF) provides the possibility of invariant image recognition with increased speed of correlation matching. DIF with the minimization of correlation energy enable to control the properties of output correlation signal due to the parameterization during its synthesis. There are several types of such a filters presented nowadays. The relevance degree of each type of filter application is determined by the specific conditions of the recognition task. Thus it requires a comparative analysis of the filters performance. The simulations were provided for the DIF of the following types: MACE (Minimum Average Correlation Energy Filter), GMACE (Gaussian-minimum average correlation energy filters), MINACE (Minimum noise and correlation energy filter) and WMACE (the version of GMACE where the smoothing function is the wavelet). The synthesis of filters was carried out under identical conditions of gray-scale image recognition problem (out of plane rotated objects). The comparison results of discrimination characteristics and the requirements of DIFs synthesis are described and discussed.

Invariant correlation filter with linear phase coefficient holographic realization in 4-F correlator

Realization of distortion invariant correlation filters in optical image correlators open possibilities for object identification with remarkably high computational capabilities. Application of the linear phase coefficient composite filter (LPCCF) is attractive for recognition of binary edged images. We use methods of digital holographic synthesis to realize LPCCF in a coherent 4-F correlator as a computer-generated amplitude holographic filter. A high resolution spatial light modulator (SLM) has to be implemented for such a filter representation. Transparency limitations of high frame rate and high resolution SLMs and its effect on recognition performance of holographic filter in the 4-F correlator are discussed in the given paper.

Correlation method for quality control of master matrix used for embossing security holograms

Security holograms (SH) are widely used for authenticity protection of document and product due to difficulties of such a protection mark falsification. Mass production of SH uses widespread technology of hot foil or lavsan paper stamping. The quality of holograms significantly depends on perfection of nickel master-matrix that is used in stamping equipment. We represent the method for automated quality inspection of nickel mastermatrix based on digital processing of its surface relief images. Proposed processing algorithm is based on combination of image spatial frequency analysis and image matching using distortion invariant correlation filters. The results of our method application for real master-matrix inspection are shown in this paper.

Distortion invariant correlation filters application for quality inspection of master-matrix for security holograms

Security holograms (SH) are perspective for document and product authenticity protection due to difficulties of such a protection mark falsification. Mass production of SH uses widespread technology of hot foil or lavsan paper stamping. The quality of holograms significantly depends on perfection of nickel master-matrix that is used in stamping equipment. We represent the method of automatic quality inspection of nickel master-matrix based on digital processing of its surface relief microphotographs. Proposed processing algorithm is based on combination of image spatial frequency analysis and image matching using distortion invariant correlation filters. The results of our method application for real SH master-matrices inspection are shown in this paper.

MINACE filter realization as computer generated hologram for 4-f correlator

Optical correlators are well known to be perspective for real time image recognition. Application of distortion invariant filters (DIF) provides image recognition with increased speed of correlation image matching. Minimum noise and correlation energy filters (MINACE filters) provide good recognition in the case of gray-scale input images. These filters possess a good mathematical basis and can be efficiently implemented in digital processing systems or in hybrid opto-digital correlators at a high rate. This paper is subjected to synthesis and realization of MINACE filters for 4-f correlator as computer generated holograms (holographic filters).

The device for automated quality inspection and authentication of security holograms

Security holograms are widely used for anti-counterfeiting of banknotes, documents and consumer products. The development of automated devices for operative authentication and quality inspection of security holograms is still an actual task. There are several approaches to solving this problem. One of them is based on an image comparison of inspected and reference holograms. Also for quality inspection of security holograms, the methods based on direct and indirect measurements of microrelief parameters are used. In this article we present a complex solution for automated quality inspection and authentication of security holograms.

Computer Generated Fourier Holograms Application for Projection Type Holographic Memory System

The specificities of synthesis, record and reconstruction of computer generated Fourier-microholograms for application in projection type holographic memory optical system are discussed. Also we represent the computer generated 1D-Fourier holograms suitable for multiplexed record.

Holographic memory based on computer generated Fourier-holograms

Classic holographic memory systems use two-beam approach based on fixation of interference pattern between object and reference coherent beams on holographic recording medium. The size of single pattern is about several micrometers. High precision optical set up is required to form such a microhologram, that is the reason of excessive price for holographic recording devices. Methods of computer holographic synthesis allow to calculate holographic patterns numerically as 2D images. These images can be realized with the use of spatial light modulator, then reduced in optical projection system and exposed on holographic medium. In this paper we represent the research of holographic memory system based on computer generated Fourier holograms projection.

Holographic filter based on Linear Phase Coefficient Composite Filter for image recognition using 4-F correlator

Distortion invariant correlation filters application allows correlation image recognition robust to distortions of target objects such as rotation and scaling etc. One of the most perspective is Linear Phase Coefficient Composite Filter (LPCCF) which can be realized in coherent 4-F correlator as computer generated holographic filter. Given paper introduces different aspects of LPCCF realization in 4-F correlator.