Optoelectronics, Instrumentation and Data Processing (v.47, #3)
Detection of local artificial changes in images by N. I. Glumov; A. V. Kuznetsov (207-214).
A solution for the problem of detecting local artificial changes (forgery) in images is proposed. Basic properties of images (availability of duplicates, re-sampling, and application of JPEG compression) that can be analyzed to detect changes made in the image are considered. Currently existing methods of detecting the above-mentioned properties satisfy all requirements to photograph authenticity estimation neither in terms of reliability nor in terms of computational complexity. The problem of further development of these methods and improvement of their characteristics for the purpose of possible application for detecting local artificial changes in large-scale images is solved.
Keywords: re-sampling; JPEG; duplicates; Fourier-Mellin transform
Application of stochastic approximation in the Hilbert space to solving the problem of detecting the instant of arrival of an object in a sequence of noisy images by V. P. Pyatkin; G. I. Salov (215-219).
Application of stochastic approximation in an infinite-dimensional Hilbert space to the problem of object detection on one observed image distorted by noise and to the problem of fast detection of object arrival in a sequence of noisy images is considered. No a priori information is assumed to be available. The observer is supposed to have two stochastically independent sequences of independent “exact” noisy images, one containing and one not containing the object that has to be (repeatedly) detected by the observer in the nearest time.
Keywords: noisy image; sequence of images; detection of objects; learning detection
Fast algorithm of detection of boundary points in images by V. S. Kirichuk; V. A. Kulikov (220-225).
A method of detecting boundary points in brightness images, based on subpixel calculation of the brightness difference, is proposed. In a fragment 4×4 pixels in size, this method allows calculating 12 directions of the jump in brightness; the algorithm complexity is ∼34N atomic operations. The method considered is compared with available methods of detection of boundary points in the image. The algorithm proposed is demonstrated to be more stable to the “salt and pepper” noise, ensures more stable determination of the brightness jump direction, and provides a more intense response to the signal. An application of the method is noted.
Keywords: search for boundary points; mask operators; detection of contours
Detection and color correction of artifacts in digital images by S. A. Bibikov; R. K. Zakharov; A. V. Nikonorov; V. A. Fursov; P. Yu. Yakimov (226-232).
A problem of automated retouching of point artifacts in the pre-press process is considered. A new algorithm of detection and localization of multiple point flares is proposed. The algorithm is based on using the so-called conjugate indicator. A scheme for constructing learning rules for tuning the system for different types of artifacts is developed. An example illustrating the proposed algorithm performance on a real image is given.
Keywords: digital processing of images; point flare; color correction; recognition; identification
Recognition of natural objects on air photographs using neural networks by M. N. Favorskaya; N. Yu. Petukhov (233-238).
This paper presents a method for recognizing natural objects on air photographs based on a two-level segmentation procedure and a complex calculation of statistical and fractal parameters using artificial neural networks to determine the category of a natural object and then the type of the object in the category determined. This method is effective for recognizing tree species on air photographs. The basic formulas for calculating the characteristics of natural textures are given, and the topology of the artificial neural networks used is substantiated.
Keywords: recognition of landscape images; fractal parameters; artificial neural networks
Solution of three-dimensional and four-dimensional problems of computerized tomography using interflation of functions by O. N. Litvin; Yu. I. Pershina (239-244).
We propose a new method for reconstructing the internal structure of a three-dimensional body using four tomograms constructed on the basis of interflation of functions of three variables, and a new method for describing changes that occur in the object using the tomograms obtained at different times on a system of planes crossing the object.
Keywords: interflation of functions; computerized tomography; three-dimensional and four-dimensional mathematical models; mixed approximation; interpolation
Ensemble of clustering algorithms for large datasets by I. A. Pestunov; V. B. Berikov; E. A. Kulikova; S. A. Rylov (245-252).
The ensemble clustering algorithm ECCA (Ensemble of Combined Clustering Algorithms) for processing large datasets is proposed and theoretically substantiated. Results of an experimental study of the algorithm on simulated and real data proving its effectiveness are presented
Keywords: ensemble clustering algorithm; grid-based approach; large datasets
Equalization of rotationally variant signals by Pei Xiao; Honggang Zhang; Colin Cowan (253-263).
Several equalization algorithms utilizing the rotationally variant nature of the received signals are presented in this paper to combat the detrimental effect of intersymbol interference (ISI) introduced by frequency selective channels. Their adaptive implementations and application to a time-reversal space-time block coded (TR-STBC) system are also considered. In addition, a turbo equalization algorithm is derived for systems employing the error correction code. The proposed equalizers and turbo equalizer are evaluated over broadband fixed wireless access channels, and are shown to yield superior performance compared to the conventional equalization schemes.
Keywords: equalization; intersymbol interference; rotationally variant nature of the received signals; frequency selective channels
Automated supervisory control systems for major hazard facilities by S. A. Belokon; V. V. Vasil’ev; Yu. N. Zolotukhin; A. S. Maltsev; M. A. Sobolev; M. N. Filippov; A. P. Yan (264-273).
A method of constructing supervisory control systems for major hazard facilities is proposed. The hardware architecture and software based on these principles are described. An automated system for controlling the motion of trains of the Novosibirsk subway is presented.
Keywords: automated supervisor traffic control system; major hazard facilities; SCADA system; controlling the motion of subway trains
Use of a relay controller for automatic extremum seeking in nonlinear systems by G. A. Frantsuzova (274-280).
This paper presents a new approach to solving the problem of automatic extremum seeking for a nonlinear one-channel object with inaccurately known parameters. Its distinguishing feature is the implementation of a two-loop system with a sliding-mode inner loop which includes the dynamic part of the object. Using a special dynamic subsystem in this loop as a device for estimating state variables leads to self-oscillations in it. The latter are proposed to be used as search oscillations to estimate the gradient of the static quality function, as is done in the synchronous detection method. Automatic motion to an extremum is provided by the integral control of the outer loop of the system. Features of the proposed approach are illustrated by simulation.
Keywords: control; extremum seeking; nonlinear system; sliding mode; self-oscillations
Control systems with additive adjustment based on the velocity vector method by O. Ya. Shpilevaya (281-286).
This paper considers the stabilization of a dynamic system with variable uncontrolled perturbations using a controller containing additive adjustment. The variable parameters are perturbations in the form of piecewise continuous functions. The parameters change at arbitrary and unknown times. The adaptive controller and adapter are synthesized using the reference equation method and the velocity vector method, respectively. The closed-loop system has feedback on derivatives of state variables, which leads to different time-scale motions. The stability of the control system is investigated using a common Lyapunov function and the method of separation of motions. The properties of the control system are illustrated by a numerical example
Keywords: adaptive control; perturbation variables; stability; common Lyapunov function
Calculation of guaranteed boundaries of reachable sets of controlled systems by A. N. Rogalev (287-296).
It is noted that, in many cases, object control is performed under conditions of a prior uncertainty in external actions and uncertainty in the current state of the object. Guaranteed methods are described which provide quantitative estimates of the boundaries of all possible phase states of a system taking into account all actions. Examples of calculations of inclusions of reachable sets are given.
Keywords: guaranteed boundary; symbolic formula; reachable set
Determining direct measures of performance based on the location of zeros and pole of the transfer function by S. V. Efimov; M. I. Pushkarev (297-302).
An analysis is made of the effect of zeros and poles of a closed-loop automatic control system on its direct measures of performance: overcontrol and control time. The necessity of determining the dominant poles in the root-locus plane is shown. A criterion for the ɛ-dominance of the components of the transient function of automatic control system is presented. A method for calculating direct measures of performance based on the location of zeros and poles of the system is developed. Numerical examples are considered.
Keywords: automatic control system; direct measures of performance; overcontrol; control time; dominant pole; root-locus plane
Control system of a linear induction accelerator of an X-ray complex: Structure, hardware, and test performance by P. A. Bak; A. M. Batrakov; R. A. Kadyrov; P. V. Logachev; A. V. Pavlenko; A. N. Panov; V. Ya. Sazanskii; G. A. Fatkin (303-312).
The structure, operation logic, and hardware tools of the control system of a linear induction accelerator for an X-ray complex are considered. The hardware developed in the CompactPCI standard for the control system is described. The possibility of embedding of smart microelectronic equipment into high-voltage elements of the facility is analyzed.
Keywords: control system; induction accelerator; CompactPCI; automation; PMC module
Generalized structure of an intelligent control system for technological objects and experience of its use by V. B. Trofimov; S. M. Kulakov (313-320).
The functional structure of typical representatives of intelligent systems is considered in relation to technological control objects. A generalized structure of intelligent control systems is developed. The proposed approach was instantiated for specific processes.
Keywords: intelligent control; expert systems; neural networks